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1.  Added value of cost-utility analysis in simple diagnostic studies of accuracy: 18F-fluoromethylcholine PET/CT in prostate cancer staging 
Diagnostic studies of accuracy targeting sensitivity and specificity are commonly done in a paired design in which all modalities are applied in each patient, whereas cost-effectiveness and cost-utility analyses are usually assessed either directly alongside to or indirectly by means of stochastic modeling based on larger randomized controlled trials (RCTs). However the conduct of RCTs is hampered in an environment such as ours, in which technology is rapidly evolving. As such, there is a relatively limited number of RCTs. Therefore, we investigated as to which extent paired diagnostic studies of accuracy can be also used to shed light on economic implications when considering a new diagnostic test. We propose a simple decision tree model-based cost-utility analysis of a diagnostic test when compared to the current standard procedure and exemplify this approach with published data from lymph node staging of prostate cancer. Average procedure costs were taken from the Danish Diagnosis Related Groups Tariff in 2013 and life expectancy was estimated for an ideal 60 year old patient based on prostate cancer stage and prostatectomy or radiation and chemotherapy. Quality-adjusted life-years (QALYs) were deduced from the literature, and an incremental cost-effectiveness ratio (ICER) was used to compare lymph node dissection with respective histopathological examination (reference standard) and 18F-fluoromethylcholine positron emission tomography/computed tomography (FCH-PET/CT). Lower bounds of sensitivity and specificity of FCH-PET/CT were established at which the replacement of the reference standard by FCH-PET/CT comes with a trade-off between worse effectiveness and lower costs. Compared to the reference standard in a diagnostic accuracy study, any imperfections in accuracy of a diagnostic test imply that replacing the reference standard generates a loss in effectiveness and utility. We conclude that diagnostic studies of accuracy can be put to a more extensive use, over and above a mere indication of sensitivity and specificity of an imaging test, and that health economic considerations should be undertaken when planning a prospective diagnostic accuracy study. These endeavors will prove especially fruitful when comparing several imaging techniques with one another, or the same imaging technique using different tracers, with an independent reference standard for the evaluation of results.
PMCID: PMC4396007  PMID: 25973339
Diagnostic study; accuracy study; sensitivity; specificity; cost-effectiveness; molecular imaging; positron-emission tomography/computed tomography; 18F-fluoromethylcholine; prostate cancer; staging
2.  Single Photon Emission Computed Tomography for the Diagnosis of Coronary Artery Disease 
Executive Summary
In July 2009, the Medical Advisory Secretariat (MAS) began work on Non-Invasive Cardiac Imaging Technologies for the Diagnosis of Coronary Artery Disease (CAD), an evidence-based review of the literature surrounding different cardiac imaging modalities to ensure that appropriate technologies are accessed by patients suspected of having CAD. This project came about when the Health Services Branch at the Ministry of Health and Long-Term Care asked MAS to provide an evidentiary platform on effectiveness and cost-effectiveness of non-invasive cardiac imaging modalities.
After an initial review of the strategy and consultation with experts, MAS identified five key non-invasive cardiac imaging technologies for the diagnosis of CAD. Evidence-based analyses have been prepared for each of these five imaging modalities: cardiac magnetic resonance imaging, single photon emission computed tomography, 64-slice computed tomographic angiography, stress echocardiography, and stress echocardiography with contrast. For each technology, an economic analysis was also completed (where appropriate). A summary decision analytic model was then developed to encapsulate the data from each of these reports (available on the OHTAC and MAS website).
The Non-Invasive Cardiac Imaging Technologies for the Diagnosis of Coronary Artery Disease series is made up of the following reports, which can be publicly accessed at the MAS website at: or at
Single Photon Emission Computed Tomography for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis
Stress Echocardiography for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis
Stress Echocardiography with Contrast for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis
64-Slice Computed Tomographic Angiography for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis
Cardiac Magnetic Resonance Imaging for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis
Pease note that two related evidence-based analyses of non-invasive cardiac imaging technologies for the assessment of myocardial viability are also available on the MAS website:
Positron Emission Tomography for the Assessment of Myocardial Viability: An Evidence-Based Analysis
Magnetic Resonance Imaging for the Assessment of Myocardial Viability: an Evidence-Based Analysis
The Toronto Health Economics and Technology Assessment Collaborative has also produced an associated economic report entitled:
The Relative Cost-effectiveness of Five Non-invasive Cardiac Imaging Technologies for Diagnosing Coronary Artery Disease in Ontario [Internet]. Available from:
The objective of the analysis is to determine the diagnostic accuracy of single photon emission tomography (SPECT) in the diagnosis of coronary artery disease (CAD) compared to the reference standard of coronary angiography (CA). The analysis is primarily meant to allow for indirect comparisons between non-invasive strategies for the diagnosis of CAD, using CA as a reference standard.
Cardiac SPECT, or myocardial perfusion scintigraphy (MPS), is a widely used nuclear, non-invasive image acquisition technique for investigating ischemic heart disease. SPECT is currently appropriate for all aspects of detecting and managing ischemic heart disease including diagnosis, risk assessment/stratification, assessment of myocardial viability, and the evaluation of left ventricular function. Myocardial perfusion scintigraphy was originally developed as a two-dimensional planar imaging technique, but SPECT acquisition has since become the clinical standard in current practice. Cardiac SPECT for the diagnosis of CAD uses an intravenously administered radiopharmaceutical tracer to evaluate regional coronary blood flow usually at rest and after stress. The radioactive tracers thallium (201Tl) or technetium-99m (99mTc), or both, may be used to visualize the SPECT acquisition. Exercise or a pharmacologic agent is used to achieve stress. After the administration of the tracer, its distribution within the myocardium (which is dependent on myocardial blood flow) is imaged using a gamma camera. In SPECT imaging, the gamma camera rotates around the patients for 10 to 20 minutes so that multiple two-dimensional projections are acquired from various angles. The raw data are then processed using computational algorithms to obtain three-dimensional tomographic images.
Since its inception, SPECT has evolved and its techniques/applications have become increasingly more complex and numerous. Accordingly, new techniques such as attenuation correction and ECG gating have been developed to correct for attenuation due to motion or soft-tissue artifact and to improve overall image clarity.
Research Questions
What is the diagnostic accuracy of SPECT for the diagnosis of CAD compared to the reference standard of CA?
Is SPECT cost-effective compared to other non-invasive cardiac imaging modalities for the diagnosis of CAD?
What are the major safety concerns with SPECT when used for the diagnosis of CAD?
A preliminary literature search was performed across OVID MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, EMBASE, the Cochrane Library, and the International Agency for Health Technology Assessment (INAHTA) for all systematic reviews/meta-analysis published between January 1, 2004 and August 22, 2009. A comprehensive systematic review was identified from this search and used as a basis for an updated search.
A second comprehensive literature search was then performed on October 30, 2009 across the same databases for studies published between January 1, 2002 and October 30, 2009. Abstracts were reviewed by a single reviewer and, for those studies meeting the eligibility criteria, full-text articles were obtained. Reference lists were also hand-searched for any additional studies.
Systematic reviews, meta-analyses, controlled clinical trials, and observational studies
Minimum sample size of 20 patients who completed coronary angiography
Use of CA as a reference standard for the diagnosis of CAD
Data available to calculate true positives (TP), false positives (FP), false negatives (FN) and true negatives (TN)
Accuracy data reported by patient not by segment
English language
Non-systematic reviews, case reports
Grey literature and abstracts
Trials using planar imaging only
Trials conducted in patients with non-ischemic heart disease
Studies done exclusively in special populations (e.g., patients with left branch bundle block, diabetics, minority populations) unless insufficient data available
Summary of Findings
Eighty-four observational studies, one non-randomized, single arm controlled clinical trial, and one poorly reported trial that appeared to be a randomized controlled trial (RCT) met the inclusion criteria for this review. All studies assessed the diagnostic accuracy of myocardial perfusion SPECT for the diagnosis of CAD using CA as a reference standard. Based on the results of these studies the following conclusions were made:
According to very low quality evidence, the addition of attenuation correction to traditional or ECG-gated SPECT greatly improves the specificity of SPECT for the diagnosis of CAD although this improvement is not statistically significant. A trend towards improvement of specificity was also observed with the addition of ECG gating to traditional SPECT.
According to very low quality evidence, neither the choice of stress agent (exercise or pharmacologic) nor the choice of radioactive tracer (technetium vs. thallium) significantly affect the diagnostic accuracy of SPECT for the diagnosis of CAD although a trend towards accuracy improvement was observed with the use of pharmacologic stress over exercise stress and technetium over thallium.
Considerably heterogeneity was observed both within and between trials. This heterogeneity may explain why some of the differences observed between accuracy estimates for various subgroups were not statistically significant.
More complex analytic techniques such as meta-regression may help to better understand which study characteristics significantly influence the diagnostic accuracy of SPECT.
PMCID: PMC3377554  PMID: 23074411
3.  The role of the Data and Safety Monitoring Board in a clinical trial: The CRISIS Study 
Randomized clinical trials are commonly overseen by a data and safety monitoring board (DSMB) comprised of experts in medicine, ethics, and biostatistics. DSMB responsibilities include protocol approval, interim review of study enrollment, protocol compliance, safety, and efficacy data. DSMB decisions can affect study design and conduct, as well as reported findings. Researchers must incorporate DSMB oversight into the design, monitoring, and reporting of randomized trials.
Case study, narrative review.
The DSMB’s role during the comparative pediatric Critical Illness Stress-Induced Immune Suppression (CRISIS) Prevention Trial is described.
The NIH-appointed CRISIS DSMB was charged with monitoring sample size adequacy and feasibility, safety with respect to adverse events and 28-day mortality, and efficacy with respect to the primary nosocomial infection/sepsis outcome. The Federal Drug Administration also requested DSMB interim review before opening CRISIS to children below one year of age. The first interim analysis found higher 28-day mortality in one treatment arm. The DSMB maintained trial closure to younger children, and requested a second interim data review six months later. At this second meeting, mortality was no longer of concern, while a weak efficacy trend of lower infection/sepsis rates in one study arm emerged. As over 40% of total patients had been enrolled, the DSMB elected to examine conditional power, and unmask treatment arm identities. Upon finding somewhat greater efficacy in the placebo arm, the DSMB recommended stopping CRISIS due to futility.
The design and operating procedures of a multicenter randomized trial must consider a pivotal DSMB role. Maximum study design flexibility must be allowed, and investigators must be prepared for protocol modifications due to interim findings. The DSMB must have sufficient clinical and statistical expertise to assess potential importance of interim treatment differences in the setting of multiple looks at accumulating data with numerous outcomes and subgroups.
PMCID: PMC3648617  PMID: 23392377
clinical trials; randomized; interim analysis; safety; nosocomial infection; sepsis
4.  18F-fluoride positron emission tomography/computed tomography and bone scintigraphy for diagnosis of bone metastases in newly diagnosed, high-risk prostate cancer patients: study protocol for a multicentre, diagnostic test accuracy study 
BMC Cancer  2016;16:10.
For decades, planar bone scintigraphy has been the standard practice for detection of bone metastases in prostate cancer and has been endorsed by recent oncology/urology guidelines. It is a sensitive method with modest specificity. 18F-fluoride positron emission tomography/computed tomography has shown improved sensitivity and specificity over bone scintigraphy, but because of methodological issues such as retrospective design and verification bias, the existing level of evidence with 18F-fluoride positron emission tomography/computed tomography is limited. The primary objective is to compare the diagnostic properties of 18F-fluoride positron emission tomography/computed tomography versus bone scintigraphy on an individual patient basis.
One hundred forty consecutive, high-risk prostate cancer patients will be recruited from several hospitals in Denmark. Sample size was calculated using Hayen’s method for diagnostic comparative studies. This study will be conducted in accordance with recommendations of standards for reporting diagnostic accuracy studies. Eligibility criteria comprise the following: 1) biopsy-proven prostate cancer, 2) PSA ≥50 ng/ml (equals a prevalence of bone metastasis of ≈ 50 % in the study population on bone scintigraphy), 3) patients must be eligible for androgen deprivation therapy, 4) no current or prior cancer (within the past 5 years), 5) ability to comply with imaging procedures, and 6) patients must not receive any investigational drugs. Planar bone scintigraphy and 18F-fluoride positron emission tomography/computed tomography will be performed within a window of 14 days at baseline. All scans will be repeated after 26 weeks of androgen deprivation therapy, and response of individual lesions will be used for diagnostic classification of the lesions on baseline imaging among responding patients. A response is defined as PSA normalisation or ≥80 % reduction compared with baseline levels, testosterone below castration levels, no skeletal related events, and no clinical signs of progression. Images are read by blinded nuclear medicine physicians. The protocol is currently recruiting.
To the best of our knowledge, this is one of the largest prospective studies comparing 18F-fluoride positron emission tomography/computed tomography and bone scintigraphy. It is conducted in full accordance with recommendations for diagnostic accuracy trials. It is intended to provide valid documentation for the use of 18F-fluoride positron emission tomography/computed tomography for examination of bone metastasis in the staging of prostate cancer.
PMCID: PMC4709935  PMID: 26753880
Positron emission tomography/computed tomography; 18F-fluoride; Planar bone scintigraphy; Bone metastases; Prostate cancer
5.  Evaluating Clinical Trial Designs for Investigational Treatments of Ebola Virus Disease 
PLoS Medicine  2015;12(4):e1001815.
Experimental treatments for Ebola virus disease (EVD) might reduce EVD mortality. There is uncertainty about the ability of different clinical trial designs to identify effective treatments, and about the feasibility of implementing individually randomised controlled trials during an Ebola epidemic.
Methods and Findings
A treatment evaluation programme for use in EVD was devised using a multi-stage approach (MSA) with two or three stages, including both non-randomised and randomised elements. The probabilities of rightly or wrongly recommending the experimental treatment, the required sample size, and the consequences for epidemic outcomes over 100 d under two epidemic scenarios were compared for the MSA, a sequential randomised controlled trial (SRCT) with up to 20 interim analyses, and, as a reference case, a conventional randomised controlled trial (RCT) without interim analyses.
Assuming 50% 14-d survival in the population treated with the current standard of supportive care, all designs had similar probabilities of identifying effective treatments correctly, while the MSA was less likely to recommend treatments that were ineffective. The MSA led to a smaller number of cases receiving ineffective treatments and faster roll-out of highly effective treatments. For less effective treatments, the MSA had a high probability of including an RCT component, leading to a somewhat longer time to roll-out or rejection. Assuming 100 new EVD cases per day, the MSA led to between 6% and 15% greater reductions in epidemic mortality over the first 100 d for highly effective treatments compared to the SRCT. Both the MSA and SRCT led to substantially fewer deaths than a conventional RCT if the tested interventions were either highly effective or harmful. In the proposed MSA, the major threat to the validity of the results of the non-randomised components is that referral patterns, standard of care, or the virus itself may change during the study period in ways that affect mortality. Adverse events are also harder to quantify without a concurrent control group.
The MSA discards ineffective treatments quickly, while reliably providing evidence concerning effective treatments. The MSA is appropriate for the clinical evaluation of EVD treatments.
Ben Cooper and colleagues model different trial designs, including a multi-stage approach that contains non-randomized and randomized elements.
Editors' Summary
The current outbreak of Ebola virus disease (EVD)—a frequently fatal disease that first appeared in human populations in 1976 in remote villages in central Africa—has infected more than 24,000 people and killed more than 10,000 people in Guinea, Sierra Leone, and Liberia since early 2014. Ebola virus is transmitted to people from wild animals and spreads in human populations through direct contact with the bodily fluids (including blood, saliva, and urine) or with the organs of infected people or through contact with bedding and other materials contaminated with bodily fluids. The symptoms of EVD which start 2–21 days after infection, include fever, headache, vomiting, diarrhea, and internal and external bleeding. Infected individuals are not infectious until they develop symptoms but remain infectious as long as their bodily fluids contain virus. There is no proven treatment or vaccine for EVD, but supportive care—given under strict isolation conditions to prevent the spread of the disease to other patients or to healthcare workers—improves survival.
Why Was This Study Done?
Potential treatments for EVD include several antiviral drugs and injections of antibodies against Ebola virus from patients who have survived EVD. Before such therapies can be used clinically, their safety and effectiveness need to be evaluated, but experts disagree about how to undertake this evaluation. Drugs for clinical use are usually evaluated by undertaking a series of clinical trials. A phase I trial establishes the safety of the treatment and how the human body copes with it by giving several healthy volunteers the drug. Next, a phase II trial provides early indications of the drug’s efficacy by giving a few patients the drug. Finally, a large-scale multi-arm phase III randomized controlled trial (RCT) confirms the drug’s efficacy by comparing outcomes in patients randomly chosen to receive the investigational drug or standard care. This evaluation process is very lengthy. Moreover, it is hard to ethically justify undertaking an RCT in which only some patients receive a potentially life-saving drug during an Ebola epidemic. Here, the researchers evaluate a multi-stage approach (MSA) to EVD drug evaluation that comprises a single-arm phase II study followed by one or two phase III trials, one of which may be a sequential RCT (SRCT), a type of RCT that allows for multiple interim analyses, each of which may lead to study termination.
What Did the Researchers Do and Find?
The researchers used analytic methods and computer simulations to compare EVD drug evaluation using the MSA, an SRCT, and a conventional RCT without interim analyses. Specifically, they estimated the probabilities of rightly or wrongly recommending the experimental treatment and the consequences for epidemic outcomes over 100 days for the three approaches. Assuming 50% survival at 14 days after symptom development in patients treated with supportive care only, all three trial designs were equally likely to identify effective treatments, but the MSA was less likely than the other designs to incorrectly recommend an ineffective treatment. Notably, the MSA led to fewer patients receiving ineffective treatments and faster roll-out of highly effective treatments. In an epidemic where 100 new cases occurred per day, for highly effective treatments, the MSA led to between 6% and 15% larger reductions in epidemic mortality over the first 100 days of the epidemic than the SRCT did. Finally, both the MSA and the SRCT led to fewer deaths than the conventional RCT if the tested interventions were either highly effective or harmful.
What Do These Findings Mean?
These findings suggest that for experimental treatments that offer either no clinically significant benefit or large reductions in mortality the MSA can provide useful information about drug effectiveness faster than the other approaches tested. Thus, the MSA has the potential to reduce patient harm and the time to roll-out of an effective treatment for EVD. Although alternative evaluation designs are possible, the researchers suggest that including a non-randomized design in phase II is the quickest way to triage potential treatments and to decide how to test them further. For treatments that show strong evidence of benefit, it might even be possible to recommend the treatment without undertaking an RCT, they suggest. Moreover, for treatments that show only modest benefit in phase II, it should be easier (and more ethical) to set up RCTs to test the treatment further.
Additional Information
Please access these websites via the online version of this summary at
The World Health Organization (WHO) provides information about EVD, information about potential EVD therapies, and regular updates on the current EVD epidemic; a summary of the discussion of a WHO Ethics Working Group Meeting on the ethical issues related to study design for EVD drug trials is available; the WHO website also provides information about efforts to control Ebola in the field and personal stories from people who have survived EVD
The UK National Health Service Choices website provides detailed information on EVD
The US Centers for Disease Control and Prevention also provides information about EVD
Wikipedia provides information about adaptive clinical trial design; a Lancet Global Health blog argues why adaptive trial designs should be used to evaluate drugs for the treatment of EVD
PMCID: PMC4397078  PMID: 25874579
6.  Sequential interim analyses of survival data in DNA microarray experiments 
BMC Bioinformatics  2011;12:127.
Discovery of biomarkers that are correlated with therapy response and thus with survival is an important goal of medical research on severe diseases, e.g. cancer. Frequently, microarray studies are performed to identify genes of which the expression levels in pretherapeutic tissue samples are correlated to survival times of patients. Typically, such a study can take several years until the full planned sample size is available.
Therefore, interim analyses are desirable, offering the possibility of stopping the study earlier, or of performing additional laboratory experiments to validate the role of the detected genes. While many methods correcting the multiple testing bias introduced by interim analyses have been proposed for studies of one single feature, there are still open questions about interim analyses of multiple features, particularly of high-dimensional microarray data, where the number of features clearly exceeds the number of samples. Therefore, we examine false discovery rates and power rates in microarray experiments performed during interim analyses of survival studies. In addition, the early stopping based on interim results of such studies is evaluated. As stop criterion we employ the achieved average power rate, i.e. the proportion of detected true positives, for which a new estimator is derived and compared to existing estimators.
In a simulation study, pre-specified levels of the false discovery rate are maintained in each interim analysis, where reduced levels as used in classical group sequential designs of one single feature are not necessary. Average power rates increase with each interim analysis, and many studies can be stopped prior to their planned end when a certain pre-specified power rate is achieved. The new estimator for the power rate slightly deviates from the true power rate but is comparable to other estimators.
Interim analyses of microarray experiments can provide evidence for early stopping of long-term survival studies. The developed simulation framework, which we also offer as a new R package 'SurvGenesInterim' available at, can be used for sample size planning of the evaluated study design.
PMCID: PMC3098786  PMID: 21527044
7.  When to perform positron emission tomography/computed tomography or radionuclide bone scan in patients with recently diagnosed prostate cancer 
Skeletal metastases are very common in prostate cancer and represent the main metastatic site in about 80% of prostate cancer patients, with a significant impact in patients’ prognosis. Early detection of bone metastases is critical in the management of patients with recently diagnosed high-risk prostate cancer: radical treatment is recommended in case of localized disease; systemic therapy should be preferred in patients with distant secondary disease. Bone scintigraphy using radiolabeled bisphosphonates is of great importance in the management of these patients; however, its main drawback is its low overall accuracy, due to the nonspecific uptake in sites of increased bone turnover. Positron-emitting radiopharmaceuticals, such as fluorine-18-fluorodeoxyglucose, choline-derived drugs (fluorine-18-fluorocholine and carbon-11-choline) and sodium fluorine-18-fluoride, are increasingly used in clinical practice to detect metastatic spread, and particularly bone involvement, in patients with prostate cancer, to reinforce or substitute information provided by bone scan. Each radiopharmaceutical has a specific mechanism of uptake; therefore, diagnostic performances may differ from one radiopharmaceutical to another on the same lesions, as demonstrated in the literature, with variable sensitivity, specificity, and overall accuracy values in the same patients. Whether bone scintigraphy can be substituted by these new methods is a matter of debate. However, greater radiobiological burden, higher costs, and the necessity of an in-site cyclotron limit the use of these positron emission tomography methods as first-line investigations in patients with prostate cancer: bone scintigraphy remains the mainstay for the detection of bone metastases in current clinical practice.
PMCID: PMC3704306  PMID: 23861598
bone metastases; prostate cancer; bisphosphonates; positron emission tomography
8.  Comparison of 99mTc-3PRGD2 Integrin Receptor Imaging with 99mTc-MDP Bone Scan in Diagnosis of Bone Metastasis in Patients with Lung Cancer: A Multicenter Study 
PLoS ONE  2014;9(10):e111221.
99mTc-3PRGD2, a promising tracer targeting integrin receptor, may serve as a novel tumor-specific agent for single photon emission computed tomography (SPECT). A multi-center study was prospectively designed to evaluate the diagnostic accuracy of 99mTc-3PRGD2 imaging for bone metastasis in patients with lung cancer in comparison with the conventional 99mTc-MDP bone scan.
The patients underwent whole-body scan and chest tomography successively at both 1 h and 4 h after intravenous injection of 11.1 MBq/Kg 99mTc-3PRGD2. 99mTc-MDP whole-body bone scan was routinely performed within 1 week for comparison. Three experienced nuclear medicine physicians blindly read the 99mTc-3PRGD2 and 99mTc-MDP images. The final diagnosis was established based on the comprehensive assessment of all available data.
A total of 44 patients (29 male, 59±10 years old) with suspected lung cancer were recruited from 4 centers. Eighty-nine bone lesions in 18 patients were diagnosed as metastases and 23 bone lesions in 9 patients were benign. In a lesion-based analysis, 99mTc-3PRGD2 imaging demonstrated a sensitivity, specificity, and accuracy of 92.1%, 91.3%, and 92.0%, respectively. The corresponding diagnostic values for 99mTc-MDP bone scan were 87.6%, 60.9%, and 82.1%, respectively in the same patients. 99mTc-MDP bone scan had better contrast in most lesions, whereas the 99mTc-3PRGD2 imaging seemed to be more effective to exclude pseudo-positive lesions and detect bone metastases without osteogenesis.
99mTc-3PRGD2 is a novel tumor-specific agent based on SPECT technology with a promising value in diagnosis of bone metastasis in patients with lung cancer.
Trial Registration NCT01737112
PMCID: PMC4206469  PMID: 25338281
9.  Use of Expert Panels to Define the Reference Standard in Diagnostic Research: A Systematic Review of Published Methods and Reporting 
PLoS Medicine  2013;10(10):e1001531.
Loes C. M. Bertens and colleagues survey the published diagnostic research literature for use of expert panels to define the reference standard, characterize components and missing information, and recommend elements that should be reported in diagnostic studies.
Please see later in the article for the Editors' Summary
In diagnostic studies, a single and error-free test that can be used as the reference (gold) standard often does not exist. One solution is the use of panel diagnosis, i.e., a group of experts who assess the results from multiple tests to reach a final diagnosis in each patient. Although panel diagnosis, also known as consensus or expert diagnosis, is frequently used as the reference standard, guidance on preferred methodology is lacking. The aim of this study is to provide an overview of methods used in panel diagnoses and to provide initial guidance on the use and reporting of panel diagnosis as reference standard.
Methods and Findings
PubMed was systematically searched for diagnostic studies applying a panel diagnosis as reference standard published up to May 31, 2012. We included diagnostic studies in which the final diagnosis was made by two or more persons based on results from multiple tests. General study characteristics and details of panel methodology were extracted. Eighty-one studies were included, of which most reported on psychiatry (37%) and cardiovascular (21%) diseases. Data extraction was hampered by incomplete reporting; one or more pieces of critical information about panel reference standard methodology was missing in 83% of studies. In most studies (75%), the panel consisted of three or fewer members. Panel members were blinded to the results of the index test results in 31% of studies. Reproducibility of the decision process was assessed in 17 (21%) studies. Reported details on panel constitution, information for diagnosis and methods of decision making varied considerably between studies.
Methods of panel diagnosis varied substantially across studies and many aspects of the procedure were either unclear or not reported. On the basis of our review, we identified areas for improvement and developed a checklist and flow chart for initial guidance for researchers conducting and reporting of studies involving panel diagnosis.
Please see later in the article for the Editors' Summary
Editors' Summary
Before any disease or condition can be treated, a correct diagnosis of the condition has to be made. Faced with a patient with medical problems and no diagnosis, a doctor will ask the patient about their symptoms and medical history and generally will examine the patient. On the basis of this questioning and examination, the clinician will form an initial impression of the possible conditions the patient may have, usually with a most likely diagnosis in mind. To support or reject the most likely diagnosis and to exclude the other possible diagnoses, the clinician will then order a series of tests and diagnostic procedures. These may include laboratory tests (such as the measurement of blood sugar levels), imaging procedures (such as an MRI scan), or functional tests (such as spirometry, which tests lung function). Finally, the clinician will use all the data s/he has collected to reach a firm diagnosis and will recommend a program of treatment or observation for the patient.
Why Was This Study Done?
Researchers are continually looking for new, improved diagnostic tests and multivariable diagnostic models—combinations of tests and characteristics that point to a diagnosis. Diagnostic research, which assesses the accuracy of new tests and models, requires that each patient involved in a diagnostic study has a final correct diagnosis. Unfortunately, for most conditions, there is no single, error-free test that can be used as the reference (gold) standard for diagnosis. If an imperfect reference standard is used, errors in the final disease classification may bias the results of the diagnostic study and may lead to a new test being adopted that is actually less accurate than existing tests. One widely used solution to the lack of a reference standard is “panel diagnosis” in which two or more experts assess the results from multiple tests to reach a final diagnosis for each patient in a diagnostic study. However, there is currently no formal guidance available on the conduct and reporting of panel diagnosis. Here, the researchers undertake a systematic review (a study that uses predefined criteria to identify research on a given topic) to provide an overview of the methodology and reporting of panel diagnosis.
What Did the Researchers Do and Find?
The researchers identified 81 published diagnostic studies that used panel diagnosis as a reference standard. 37% of these studies reported on psychiatric diseases, 21% reported on cardiovascular diseases, and 12% reported on respiratory diseases. Most of the studies (64%) were designed to assess the accuracy of one or more diagnostic test. Notably, one or more critical piece of information on methodology was missing in 83% of the studies. Specifically, information on the constitution of the panel was missing in a quarter of the studies and information on the decision-making process (whether, for example, a diagnosis was reached by discussion among panel members or by combining individual panel member's assessments) was incomplete in more than two-thirds of the studies. In three-quarters of the studies for which information was available, the panel consisted of only two or three members; different fields of expertise were represented in the panels in nearly two-thirds of the studies. In a third of the studies for which information was available, panel members made their diagnoses without access to the results of the test being assessed. Finally, the reproducibility of the decision-making process was assessed in a fifth of the studies.
What Do These Findings Mean?
These findings indicate that the methodology of panel diagnosis varies substantially among diagnostic studies and that reporting of this methodology is often unclear or absent. Both the methodology and reporting of panel diagnosis could, therefore, be improved substantially. Based on their findings, the researchers provide a checklist and flow chart to help guide the conduct and reporting of studies involving panel diagnosis. For example, they suggest that, when designing a study that uses panel diagnosis as the reference standard, the number and background of panel members should be considered, and they provide a list of options that should be considered when planning the decision-making process. Although more research into each of the options identified by the researchers is needed, their recommendations provide a starting point for the development of formal guidelines on the methodology and reporting of panel diagnosis for use as a reference standard in diagnostic research.
Additional Information
Please access these Web sites via the online version of this summary at
Wikipedia has a page on medical diagnosis (note: Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
The Equator Network is an international initiative that seeks to improve the reliability and value of medical research literature by promoting transparent and accurate reporting of research studies; its website includes information on a wide range of reporting guidelines, including the STAndards for the Reporting of Diagnostic accuracy studies (STARD), an initiative that aims to improve the accuracy and completeness of reporting of studies of diagnostic accuracy
PMCID: PMC3797139  PMID: 24143138
10.  A comparative study of 18F-fluorodeoxyglucose positron emission tomography/computed tomography and 99mTc-MDP whole-body bone scanning for imaging osteolytic bone metastases 
BMC Medical Imaging  2015;15:7.
The objective of this study was to evaluate the feasibility and diagnostic value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) and 99mTc-methylenediphosphonate (MDP) whole-body bone scanning (BS) for the detection of osteolytic bone metastases.
Thirty-four patients with pathologically confirmed malignancies and suspected osteolytic bone metastases underwent 18F-FDG PET/CT and 99mTc-MDP whole-body BS within 30 days. The sensitivity, specificity, and accuracy with respect to the diagnosis of osteolytic bone metastases and bone lesions were compared between the two imaging methods.
The sensitivity, specificity, and accuracy of 18F-FDG PET/CT for the diagnosis of osteolytic bone metastases were 94.3% (95% confidence interval [CI], 91.6–96.2%), 83.3% (95% CI, 43.6–96.9%), and 94.2% (95% CI, 91.5–96.1%), respectively. It was found that 99mTc-MDP whole-body BS could discriminate between patients with 50.2% (95% CI, 45.4–55.1%) sensitivity, 50.0% (95% CI, 18.8–81.2%) specificity, and 50.2% (95% CI, 45.5–55.1%) accuracy. 18F-FDG PET/CT achieved higher sensitivity, specificity, and accuracy in detecting osteolytic bone metastases than 99mTc-MDP whole-body BS (p<0.001).
F-FDG PET/CT has a higher diagnostic value than 99mTc-MDP whole-body BS in the detection of osteolytic bone metastases, especially in the vertebra.
PMCID: PMC4358702  PMID: 25885599
Positron emission tomography; Radionuclide imaging; Skeleton; Metastatic tumor; Osteolytic
11.  Multi-Detector Computed Tomography Angiography for Coronary Artery Disease 
Executive Summary
Computed tomography (CT) scanning continues to be an important modality for the diagnosis of injury and disease, most notably for indications of the head and abdomen. (1) According to a recent report published by the Canadian Institutes of Health Information, (1) there were about 10.3 scanners per million people in Canada as of January 2004. Ontario had the fewest number of CT scanners per million compared to the other provinces (8 CT scanners per million). The wait time for CT in Ontario of 5 weeks approaches the Canadian median of 6 weeks.
This health technology and policy appraisal systematically reviews the published literature on multidetector CT (MDCT) angiography as a diagnostic tool for the newest indication for CT, coronary artery disease (CAD), and will apply the results of the review to current health care practices in Ontario. This review does not evaluate MDCT to detect coronary calcification without contrast medium for CAD screening purposes.
The Technology
Compared with conventional CT scanning, MDCT can provide smaller pieces of information and can cover a larger area faster. (2) Advancing MDCT technology (8, 16, 32, 64 slice systems) is capable of producing more images in less time. For general CT scanning, this faster capability can reduce the time that patients must stay still during the procedure, thereby reducing potential movement artefact. However, the additional clinical utility of images obtained from faster scanners compared to the images obtained from conventional CT scanners for current CT indications (i.e., non-moving body parts) is not known.
There are suggestions that the new fast scanners can reduce wait times for general CT. MDCT angiography that utilizes a contrast medium, has been proposed as a minimally invasive replacement to coronary angiography to detect coronary artery disease. MDCT may take between 15 to 45 minutes; coronary angiography may take up to 1 hour.
Although 16-slice and 32-slice CT scanners have been available for a few years, 64-slice CT scanners were released only at the end of 2004.
Review Strategy
There are many proven, evidence-based indications for conventional CT. It is not clear how MDCT will add to the clinical utility and management of patients for established CT indications. Therefore, because cardiac imaging, specifically MDCT angiography, is a new indication for CT, this literature review focused on the safety, effectiveness, and cost-effectiveness of MDCT angiography compared with coronary angiography in the diagnosis and management of people with CAD.
This review asked the following questions:
Is the most recent MDCT angiography effective in the imaging of the coronary arteries compared with conventional angiography to correctly diagnose of significant (> 50% lumen reduction) CAD?
What is the utility of MDCT angiography in the management and treatment of patients with CAD?
How does MDCT angiography in the management and treatment of patients with CAD affect longterm outcomes?
The published literature from January 2003 to January 31, 2005 was searched for articles that focused on the detection of coronary artery disease using 16-slice CT or faster, compared with coronary angiography. The search yielded 138 articles; however, 125 were excluded because they did not meet the inclusion criteria (comparison with coronary angiography, diagnostic accuracy measures calculated, and a sample size of 20 or more). As screening for CAD is not advised, studies that utilized MDCT for this purpose or studies that utilized MDCT without contrast media were also excluded. Overall, 13 studies were included in this review.
Summary of Findings
The published literature focused on 16-slice CT angiography for the detection of CAD. Two abstracts that were presented at the 2005 European Congress of Radiology meeting in Vienna compared 64-slice CT angiography with coronary angiography.
The 13 studies focussing on 16-slice CT angiography were stratified into 2 groups: Group 1 included 9 studies that focused on the detection of CAD in symptomatic patients, and Group 2 included 4 studies that examined the use of 16-slice CT angiography to detect disease progression after cardiac interventions. The 2 abstracts on 64-slice CT angiography were presented separately, but were not critically appraised due to the lack of information provided in the abstracts.
16-Slice Computed Tomography Angiography
The STARD initiative to evaluate the reporting quality of studies that focus on diagnostic tests was used. Overall the studies were relatively small (fewer than 100 people), and only about one-half recruited consecutive patients. Most studies reported inclusion criteria, but 5 did not report exclusion criteria. In these 5, the patients were highly selected; therefore, how representative they are of the general population of people with suspicion if CAD or those with disease progression after cardiac intervention is questionable. In most studies, patients were either already taking, or were given, β-blockers to reduce their heart rates to improve image quality sufficiently. Only 6 of the 13 studies reported interobserver reliability quantitatively. The studies typically assessed the quality of the images obtained from 16-slice CT angiography, excluded those of poor quality, and compared the rest with the gold standard, coronary angiography. This practice necessarily inflated the diagnostic accuracy measures. Only 3 studies reported confidence intervals around their measures.
Evaluation of the studies in Group 1 reported variable sensitivity, from just over 60% to 96%, but a more stable specificity, at more than 95%. The false positive rate ranged from 5% to 8%, but the false negative rate was at best under 10% and at worst about 30%. This means that up to one-third of patients who have disease may be missed. These patients may therefore progress to a more severe level of disease and require more invasive procedures. The calculated positive and negative likelihood ratios across the studies suggested that 16-slice CT angiography may be useful to detect disease, but it is not useful to rule out disease. The prevalence of disease, measured by conventional coronoary angiography, was from 50% to 80% across the studies in this review. Overall, 16-slice CT angiography may be useful, but there is no conclusive evidence to suggest that it is equivalent to or better than coronary angiography to detect CAD in symptomatic patients.
In the 4 studies in Group 2, sensitivity and specificity were both reported at more than 95% (except for 1 that reported sensitivity of about 80%). The positive and negative likelihood ratios suggested that the test might be useful to detect disease progression in patients who had cardiac interventions. However, 2 of the 4 studies recruited patients who had been asymptomatic since their intervention. As many of the patients studied were not symptomatic, the relevance of performing MDCT angiography in the patient population may be in question.
64-Slice Computed Tomography Angiography
An analysis from the interim results based on 2 abstracts revealed that 64-slice CT angiography was insufficient compared to coronary angiography and may not be better than 16-slice CT angiography to detect CAD.
Cardiac imaging is a relatively new indication for CT. A systematic review of the literature was performed from 2003 to January 2005 to determine the effectiveness of MDCT angiography (16-slice and 64-slice) compared to coronary angiography to detect CAD. At the time of this report, there was no published literature on 64-slice CT for any indications.
Based on this review, the Medical Advisory Secretariat concluded that there is insufficient evidence to suggest that 16-slice or 64-slice CT angiography is equal to or better than coronary angiography to diagnose CAD in people with symptoms or to detect disease progression in patients who had previous cardiac interventions. An analysis of the evidence suggested that in investigating suspicion of CAD, a substantial number of patients would be missed. This means that these people would not be appropriately treated. These patients might progress to more severe disease and possibly more adverse events. Overall, the clinical utility of MDCT in patient management and long-term outcomes is unknown.
Based on the current evidence, it is unlikely that CT angiography will replace coronary angiography completely, but will probably be used adjunctively with other cardiac diagnostic tests until more definitive evidence is published.
If multi-slice CT scanners are used for coronary angiography in Ontario, access to the current compliment of CT scanners will necessarily increase wait times for general CT scanning. It is unlikely that these newer-generation scanners will improve patient throughput, despite the claim that they are faster.
Screening for CAD in asymptomatic patients and who have no history of ischemic heart disease using any modality is not advised, based on the World Health Organization criteria for screening. Therefore, this review did not examine the use of multi-slice CT for this purpose.
PMCID: PMC3382628  PMID: 23074474
12.  Effect of Selenium and Vitamin E on Risk of Prostate Cancer and Other Cancers: The Selenium and Vitamin E Cancer Prevention Trial (SELECT) 
Secondary analyses of two randomized controlled trials (RCTs) and supportive epidemiologic and preclinical indicated the potential of selenium and vitamin E for preventing prostate cancer.
To determine whether selenium or vitamin E or both could prevent prostate cancer with little or no toxicity in relatively healthy men.
Design, Setting, and Participants
Randomization of a planned 32,400 men to selenium, vitamin E, selenium plus vitamin E, and placebo in a double-blinded fashion. Participants were recruited and followed in community practices, local hospitals and HMOs, and tertiary cancer centers in the United States, Canada and Puerto Rico. Baseline eligibility included 50 years or older (African American) or 55 years or older (all others), a serum prostate-specific antigen (PSA) ≤ 4 ng/mL, and a digital rectal examination (DRE) not suspicious for prostate cancer. Between 2001 and 2004, 35,533 men (10% more than planned because of a faster-than-expected accrual rate) were randomly assigned to the four study arms, which were well balanced with respect to all potentially important risk factors.
Oral selenium (200 µg/day from L-selenomethionine) and matched vitamin E placebo, vitamin E (400 IU/day of all rac-α-tocopheryl acetate) and matched selenium placebo, or the two combined or placebo plus placebo for a planned minimum of 7 and maximum of 12 years.
Main Outcome Measures
Prostate cancer (as determined by routine community diagnostic standards) and prespecified secondary outcomes including lung, colorectal and overall cancer.
Study supplements were discontinued at the recommendation of the Data and Safety Monitoring Committee at a planned 7-year interim analysis because the evidence convincingly demonstrated no benefit from either study agent (p < 0.0001) and no possibility of a benefit to the planned degree with additional follow-up. As of October 23, 2008, median overall follow-up was 5.46 years (range, 4.17 and 7.33). Hazard ratios (number of prostate cancers, 99% confidence intervals [CIs]) for prostate cancer were 1.13 for vitamin E (n=473; CI, 0.91–1.41), 1.04 for selenium (n=432; CI, 0.83–1.30), and 1.05 for the combination (n=437; CI, 0.83–1.31) compared with placebo (n=416). There were no significant differences (all p-values > 0.15) in any prespecified cancer endpoints. There were nonsignificant increased risks of prostate cancer in the vitamin E arm (p=0.06; relative risk [RR]=1.13; 99% CI, 0l95–1.35) and of Type 2 diabetes mellitus in the selenium arm (p=0.16; RR=1.07; 99% CI, 0.94–1.22), but they were not observed in the combination arm.
Selenium or vitamin E, alone or in combination, did not prevent prostate cancer in this population at the doses and formulations used.
PMCID: PMC3682779  PMID: 19066370
13.  Back Pain in Children and Diagnostic Value of 99mTc MDP Bone Scintigraphy 
Acta Informatica Medica  2014;22(5):297-301.
The aim of our study is to assess the diagnostic value of Technituim-99m-Methyle diphosphonate (99mTc-MDP) Bone scintigraphy in the assessment of children with back pain.
Included in this retrospective study were 68 child referred to us complaining of back pain (mean age of 13+ 2). There were 45 boys and 23 girls. All children have been investigated with conventional x-ray which revealed normal or inconclusive result. All underwent bone scintigraphy after the injection of 99mTc-MDP with calculated doses according to there body weights.
Bone scintigraphy revealed 17 (25%) abnormal scans in 11 boys and 6 girls. Scans findings were suggestive of spondylolysis (n=4); malignancy including primary tumors and metastases (n=3); infection including osteomyelitis and discitis (n=3); sacroiliitis (n=2); benign tumors (n=2); pseudo fractures in ribs (n=1); necrosis in femoral head epiphysis(n=1) and nonskeletal-renal retention due to hydronephrosis (n=1). Sensitivity, specificity and accuracy of bone scan in detecting gross skeletal abnormality as a cause for back pain were 94% and 100% and 99% respectively.
Bone isotope scan is a sensitive imaging modality in the assessment of pediatric patients with back pain. It is a reliable modality to detect and role out most benign and aggressive serious etiologies.
PMCID: PMC4272846  PMID: 25568576
Bone scan; back pain; pediatric; 99mTc-MDP
14.  Diagnosis of bone infection by complementary role of technetium-99m MDP and technetium-99m hexamethylpropylene-amineoxime-leukocytes 
Valuate complementary role of 99mTc-MDP bone scan and 99mTechnetium hexamethylpropylene-amineoxime (99mTc-HMPAO) labeled leukocyte scintigraphy in diagnosis of bone infection.
Patients and Methods:
Ninety one sites suspected to have bone infection were divided in to two groups: Group I 49 sites with current endo-prothesis; and group II 42 sites with no prosthesis. All patients were subjected to serial images of 99mTc-HMPAO labeled leukocyte (99mTc-white blood cells (WBCs)), triple phase bone scan (99mTc-MDP) and plain X-ray, in addition to clinical and bacteriological assessment, together with follow-up.
The overall sensitivity (Sn) was found to be 34.9%, 95.4%, and 86% for plain X-ray, 99mTc-MDP, and 99mTc-WBCs respectively. Concerning specificity (Sp) was found to be 47.9%, 45.8%, and 91.7% respectively for the three imaging modalities. 99mTc-WBCs showed better Sn, Sp, and accuracy in group I (95%, 93.1% and 93.9%, respectively) compared to 40%, 41.4%, and 40.8% for plain X-ray and 90%, 62%, and 73.5% respectively for 99mTc-MDP. On the other hand, 99mTc-MDP proved to have best Sn 100% versus 78.3% and 30.4% for 99mTc-WBCs and plain X-ray respectively. Yet, Sp and accuracy was found to best for 99mTc-WBCs (89.5% and 83.3% respectively) compared to 57.9% and 42.9% for plain X-ray and 21.1% and 64.3% for 99mTc-MDP.
Combined imaging with 99mTc-WBCs and 99mTc-MDP proved to be effective in early detection of bone infection in the presence or absence of prosthesis.
PMCID: PMC3728737  PMID: 23919069
Bone infection; prosthesis; triple phase bone scan; 99mTechnetium hexamethylpropylene-amineoxime-leukocyte
15.  Odanacatib for the treatment of postmenopausal osteoporosis: development history and design and participant characteristics of LOFT, the Long-Term Odanacatib Fracture Trial 
Osteoporosis International  2014;26(2):699-712.
Odanacatib is a cathepsin K inhibitor investigated for the treatment of postmenopausal osteoporosis. Phase 2 data indicate that 50 mg once weekly inhibits bone resorption and increases bone mineral density, with only a transient decrease in bone formation. We describe the background, design and participant characteristics for the phase 3 registration trial.
Odanacatib (ODN) is a selective cathepsin K inhibitor being evaluated for the treatment of osteoporosis. In a phase 2 trial, ODN 50 mg once weekly reduced bone resorption while preserving bone formation and progressively increased BMD over 5 years. We describe the phase III Long-Term ODN Fracture Trial (LOFT), an event-driven, randomized, blinded placebo-controlled trial, with preplanned interim analyses to permit early termination if significant fracture risk reduction was demonstrated. An extension was planned, with participants remaining on their randomized treatment for up to 5 years, then transitioning to open-label ODN.
The three primary outcomes were radiologically determined vertebral, hip, and clinical non-vertebral fractures. Secondary end points included clinical vertebral fractures, BMD, bone turnover markers, and safety and tolerability, including bone histology. Participants were women, 65 years or older, with a BMD T-score ≤−2.5 at the total hip (TH) or femoral neck (FN) or with a prior radiographic vertebral fracture and a T-score ≤−1.5 at the TH or FN. They were randomized to ODN or placebo tablets. All received weekly vitamin D3 (5600 international units (IU)) and daily calcium supplements as needed to ensure a daily intake of approximately 1200 mg.
Altogether, 16,713 participants were randomized at 387 centers. After a planned interim analysis, an independent data monitoring committee recommended that the study be stopped early due to robust efficacy and a favorable benefit/risk profile. Following the base study closeout, 8256 participants entered the study extension.
This report details the background and study design of this fracture end point trial and describes the baseline characteristics of its participants.
Electronic supplementary material
The online version of this article (doi:10.1007/s00198-014-2944-6) contains supplementary material, which is available to authorized users.
PMCID: PMC4312384  PMID: 25432773
Cathepsin K; Fracture; Odanacatib; Osteoporosis; Postmenopausal
16.  Repetitive Transcranial Magnetic Stimulation for the Treatment of Major Depressive Disorder 
Executive Summary
This review was conducted to assess the effectiveness of repetitive transcranial magnetic stimulation (rTMS) in the treatment of major depressive disorder (MDD).
The Technology
rTMS is a noninvasive way to stimulate nerve cells in areas of the brain. During rTMS, an electrical current passes through a wire coil placed over the scalp. The current induces a magnetic field that produces an electrical field in the brain that then causes nerve cells to depolarize, resulting in the stimulation or disruption of brain activity.
Researchers have investigated rTMS as an option to treat MDD, as an add-on to drug therapy, and, in particular, as an alternative to electroconvulsive therapy (ECT) for patients with treatment-resistant depression.
The advantages of rTMS over ECT for patients with severe refractory depression are that general anesthesia is not needed, it is an outpatient procedure, it requires less energy, the simulation is specific and targeted, and convulsion is not required. The advantages of rTMS as an add-on treatment to drug therapy may include hastening of the clinical response when used with antidepressant drugs.
Review Strategy
The Medical Advisory Secretariat used its standard search strategy to locate international health technology assessments and English-language journal articles published from January 1996 to March 2004.
Summary of Findings
Some early meta-analyses suggested rTMS might be effective for the treatment of MDD (for treatment-resistant MDD and as an add-on treatment to drug therapy for patients not specifically defined as treatment resistant). There were, however, several crucial methodological limitations in the included studies that were not critically assessed. These are discussed below.
Recent meta-analyses (including 2 international health technology assessments) have done evidence-based critical analyses of studies that have assessed rTMS for MDD. The 2 most recent health technology assessments (from the Oxford Cochrane Collaboration and the Norwegian Centre for Health Technology Assessment) concluded that there is no evidence that rTMS is effective for the treatment of MDD, either as compared with a placebo for patients with treatment-resistant or nontreatment-resistant MDD, or as an alternative to ECT for patients with treatment-resistant MDD. This mainly due to the poor quality of the studies.
The major methodological limitations were identified in older meta-analyses, recent health technology assessments, and the most recently published trials (Level 2–4 evidence) on the effectiveness of rTMS for MDD are discussed below.
Small sample size was a limitation acknowledged by many of the authors. There was also a lack of a priori sample size calculation or justification.
Biased randomization may have been a problem. Generally, the published reports lacked detailed information on the method of allocation concealment used. This is important because it is impossible to determine if there was a possible influence (direct or indirect) in the allocation of the patients to different treatment groups.
The trials were single blind, evaluated by external blinded assessors, rather than double blind. Double blinding is more robust, because neither the participants nor the investigators know which participants are receiving the active treatment and which are getting a placebo. Those administering rTMS, however, cannot be blinded to whether they are administering the active treatment or a placebo.
There was patient variability among the studies. In some studies, the authors said that patients were “medication resistant,” but the definitions of resistant, if provided, were inconsistent or unclear. For example, some described “medication resistant” as failing at least one trial of drugs during the current depressive episode. Furthermore, it was unclear if the term “medication resistant” referred to antidepressants only or to combinations of antidepressants and other drug augmentation strategies (such as neuroleptics, benzodiazepine, carbamazepine, and lithium). Also variable was the type of depression (i.e., unipolar and/or bipolar), if patients were inpatients or outpatients, if they had psychotic symptoms or no psychotic symptoms, and the chronicity of depression.
Dropouts or withdrawals were a concern. Some studies reported that patients dropped out, but provided no further details. Intent-to-treat analysis was not done in any of the trials. This is important, because ignoring patients who drop out of a trial can bias the results, usually in favour of the treatment. This is because patients who withdraw from trials are less likely to have had the treatment, more likely to have missed their interim checkups, and more likely to have experienced adverse effects when taking the treatment, compared with patients who do not withdraw. (1)
Measurement of treatment outcomes using scales or inventories makes interpreting results and drawing conclusions difficult. The most common scale, the Hamilton Depression Rating Scale (HDRS) is based on a semistructured interview. Some authors (2) reported that rating scales based on semistructured interviews are more susceptible to observation bias than are self-administered questionnaires such as the Beck Depression Inventory (BDI). Martin et al. (3) argued that the lack of consistency in effect as determined by the 2 scales (a positive result after 2 weeks of treatment as measured by the HDRS and a negative result for the BDI) makes definitive conclusions about the nature of the change in mood of patients impossible. It was suggested that because of difficulties interpreting results from psychometric scales, (4) and the subjective or unstable character of MDD, other, more objective, outcome measures such as readmission to hospital, time to hospital discharge, time to adjunctive treatment, and time off work should be used to assess rTMS for the treatment of depression.
A placebo effect could have influenced the results. Many studies reported response rates for patients who received placebo treatment. For example, Klein et al. (5) reported a control group response rate as high as 25%. Patients receiving placebo rTMS may receive a small dose of magnetic energy that may alter their depression.
Short-term studies were the most common. Patients received rTMS treatment for 1 to 2 weeks. Most studies followed-up patients for 2 to 4 weeks post-treatment. Dannon et al. (6) followed-up patients who responded to a course of ECT or rTMS for up to 6 months; however, the assessment procedure was not blinded, the medication regimen during follow-up was not controlled, and initial baseline data for the patient groups were not reported. The long-term effectiveness of rTMS for the treatment of depression is unknown, as is the long-term use, if any, of maintenance therapy. The cost-effectiveness of rTMS for the treatment of depression is also unknown. A lack of long-term studies makes cost-effectiveness analysis difficult.
The complexity of possible combinations for administering rTMS makes comparing like with like difficult. Wasserman and Lisanby (7) have said that the method for precisely targeting the stimulation in this area is unreliable. It is unknown if the left dorsolateral prefrontal cortex is the optimal location for treatment. Further, differences in rTMS administration include number of trains per session, duration of each train, and motor threshold.
Clinical versus statistical significance. Several meta-analyses and studies have found that the degree of therapeutic change associated with rTMS across studies is relatively modest; that is, results may be statistically, but not necessarily clinically, significant. (8-11). Conventionally, a 50% reduction in the HDRS scores is commonly accepted as a clinically important reduction in depression. Although some studies have observed a statistically significant reduction in the depression rating, many have not shows the clinically significant reduction of 50% on the HDRS. (11-13) Therefore, few patients in these studies would meet the standard criteria for response. (9)
Clinical/methodological diversity and statistical heterogeneity. In the Norwegian health technology assessment, Aarre et al. (14) said that a formal meta-analysis was not feasible because the designs of the studies varied too much, particularly in how rTMS was administered and in the characteristics of the patients. They noted that the quality of the study designs was poor. The 12 studies that comprised the assessment had small samples, and highly variable inclusion criteria and study designs. The patients’ previous histories, diagnoses, treatment histories, and treatment settings were often insufficiently characterized. Furthermore, many studies reported that patients had treatment-resistant MDD, yet did not listclear criteria for the designation. Without this information, Aarre and colleagues suggested that the interpretation of the results is difficult and the generalizability of results is questionable. They concluded that rTMS cannot be recommended as a standard treatment for depression: “More, larger and more carefully designed studies are needed to demonstrate convincingly a clinically relevant effect of rTMS.”
In the Cochrane Collaboration systematic review, Martin et al. (3;15) said that the complexity of possible combinations for administering rTMS makes comparison of like versus like difficult. A statistical test for heterogeneity (chi-square test) examines if the observed treatment effects are more different from each other than one would expect due to random error (or chance) alone. (16) However, this statistical test must be interpreted with caution because it has low power in the (common) situation of a meta-analysis when the trials have small sample sizes or are few. This means that while a statistically significant result may indicate a problem with heterogeneity, a nonsignificant result must not be taken as evidence of no heterogeneity.
Despite not finding statistically significant heterogeneity, Martin et al. reported that the overall mean baseline depression values for the severity of depression were higher in the treatment group than in the placebo group. (3;15) Although these differences were not significant at the level of each study, they may have introduced potential bias into the meta-analysis of pooled data by accentuating the tendency for regression to the mean of the more extreme values. Individual patient data from all the studies were not available; therefore, an appropriate adjustment according to baseline severity was not possible. Martin et al. concluded that the findings from the systematic review and meta-analysis provided insufficient evidence to suggest that rTMS is effective in the treatment of depression. Moreover, there were several confounding factors (e.g., definition of treatment resistance) in the studies, thus the authors concluded, “The rTMS technique needs more high quality trials to show its effectiveness for therapeutic use.”
Due to several serious methodological limitations in the studies that have examined the effectiveness of rTMS in patients with MDD, it is not possible to conclude that rTMS either is or is not effective as a treatment for MDD (in treatment-resistant depression or in nontreatment-resistant depression).
PMCID: PMC3387754  PMID: 23074457
17.  Approval Summary: Letrozole (Femara® Tablets) for Adjuvant and Extended Adjuvant Postmenopausal Breast Cancer Treatment: Conversion of Accelerated to Full Approval 
The Oncologist  2011;16(12):1762-1770.
Trials leading to the conversion of letrozole from accelerated to full approval for adjuvant and extended adjuvant (following 5 years of tamoxifen) treatment of postmenopausal women with hormone receptor–positive early breast cancer are summarized.
Learning Objectives
After completing this course, the reader will be able to: Compare the efficacy of letrozole and tamoxifen.Contrast the adverse effect profile of letrozole with those of tamoxifen and placebo.
This article is available for continuing medical education credit at
On April 30, 2010, the U.S. Food and Drug Administration converted letrozole (Femara®; Novartis Pharmaceuticals Corporation, East Hanover, NJ) from accelerated to full approval for adjuvant and extended adjuvant (following 5 years of tamoxifen) treatment of postmenopausal women with hormone receptor–positive early breast cancer.
The initial accelerated approvals of letrozole for adjuvant and extended adjuvant treatment on December 28, 2005 and October 29, 2004, respectively, were based on an analysis of the disease-free survival (DFS) outcome of patients followed for medians of 26 months and 28 months, respectively. Both trials were double-blind, multicenter studies. Both trials were unblinded early when an interim analysis showed a favorable letrozole effect on DFS.
In updated intention-to-treat analyses of both trials, the risk for a DFS event was lower with letrozole than with tamoxifen (hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.77–0.99; p = .03) in the adjuvant trial and was lower than with placebo (HR, 0.89; 95% CI, 0.76–1.03; p = .12) in the extended adjuvant trial. The latter analysis ignores the interim switch of 60% of placebo-treated patients to letrozole.
Bone fractures and osteoporosis were reported more frequently following treatment with letrozole whereas tamoxifen was associated with a higher risk for endometrial proliferation and endometrial cancer. Myocardial infarction was more frequently reported with letrozole than with tamoxifen, but the incidence of thromboembolic events was higher with tamoxifen than with letrozole. Lipid-lowering medications were required for 25% of patients on letrozole and 16% of patients on tamoxifen.
PMCID: PMC3248775  PMID: 22089970
Letrozole; Femara®; Postmenopausal breast cancer; Adjuvant treatment
18.  Statistical aspects of the TNK-S2B trial of tenecteplase versus alteplase in acute ischemic stroke: an efficient, dose-adaptive, seamless phase II/III design 
Background TNK-S2B, an innovative, randomized, seamless phase II/III trial of tenecteplase versus rt-PA for acute ischemic stroke, terminated for slow enrollment before regulatory approval of use of phase II patients in phase III.
Purpose (1) To review the trial design and comprehensive type I error rate simulations and (2) to discuss issues raised during regulatory review, to facilitate future approval of similar designs.
Methods In phase II, an early (24-h) outcome and adaptive sequential procedure selected one of three tenecteplase doses for phase III comparison with rt-PA. Decision rules comparing this dose to rt-PA would cause stopping for futility at phase II end, or continuation to phase III. Phase III incorporated two co-primary hypotheses, allowing for a treatment effect at either end of the trichotomized Rankin scale. Assuming no early termination, four interim analyses and one final analysis of 1908 patients provided an experiment-wise type I error rate of <0.05.
Results Over 1,000 distribution scenarios, each involving 40,000 replications, the maximum type I error in phase III was 0.038. Inflation from the dose selection was more than offset by the one-half continuity correction in the test statistics. Inflation from repeated interim analyses was more than offset by the reduction from the clinical stopping rules for futility at the first interim analysis.
Limitations Design complexity and evolving regulatory requirements lengthened the review process.
Conclusions (1) The design was innovative and efficient. Per protocol, type I error was well controlled for the co-primary phase III hypothesis tests, and experiment-wise. (2a) Time must be allowed for communications with regulatory reviewers from first design stages. (2b) Adequate type I error control must be demonstrated. (2c) Greater clarity is needed on (i) whether this includes demonstration of type I error control if the protocol is violated and (ii) whether simulations of type I error control are acceptable. (2d) Regulatory agency concerns that protocols for futility stopping may not be followed may be allayed by submitting interim analysis results to them as these analyses occur.
PMCID: PMC3198122  PMID: 21737464
19.  Adaptive randomized phase II design for biomarker threshold selection and independent evaluation 
Chinese clinical oncology  2014;3(1):3489.
Frequently a biomarker capable of defining a patient population with enhanced response to an experimental agent is not fully validated with a known threshold at the start of a phase II trial. When such candidate predictive markers are evaluated and/or validated retrospectively, over-accrual of patients less likely to benefit from the regimen may result, leading to underpowered analyses or sub-optimal patient care.
We propose an adaptive randomized phase II study design incorporating prospective biomarker threshold identification (or non-identification), possible early futility stopping, potential mid-trial accrual restriction to marker-positive subjects, and final marker and treatment evaluation in the patient population identified as most likely to benefit.
An interim analysis is used to determine whether an initially unselected trial should stop early for futility, continue without a promising marker, or adapt accrual and resize (up to a pre-determined maximum) according to a promising biomarker. Final efficacy analyses are performed in the target population identified at the interim as most likely to benefit from the experimental regimen. Simulation studies demonstrate control of false-positive error rates, power, reduced average sample size, and other favorable aspects.
The design performs well at identifying a truly predictive biomarker at interim analysis, and subsequently restricting accrual to patients most likely to benefit from the experimental treatment. Type I and type II error rates are adequately controlled by restricting the range of marker prevalence via the candidate thresholds, and by careful consideration of the timing of interim analysis.
In situations where identification and validation of a naturally continuous biomarker are desired within a randomized phase II trial, the design presented herein offers a potential solution.
PMCID: PMC4255950  PMID: 25485277
Adaptive design; randomized clinical trial; threshold identification; predictive biomarker; phase II trial; interim futility analysis
20.  Sample size recalculation in sequential diagnostic trials 
Biostatistics (Oxford, England)  2009;11(1):151-163.
Before a comparative diagnostic trial is carried out, maximum sample sizes for the diseased group and the nondiseased group need to be obtained to achieve a nominal power to detect a meaningful difference in diagnostic accuracy. Sample size calculation depends on the variance of the statistic of interest, which is the difference between receiver operating characteristic summary measures of 2 medical diagnostic tests. To obtain an appropriate value for the variance, one often has to assume an arbitrary parametric model and the associated parameter values for the 2 groups of subjects under 2 tests to be compared. It becomes more tedious to do so when the same subject undergoes 2 different tests because the correlation is then involved in modeling the test outcomes. The calculated variance based on incorrectly specified parametric models may be smaller than the true one, which will subsequently result in smaller maximum sample sizes, leaving the study underpowered. In this paper, we develop a nonparametric adaptive method for comparative diagnostic trials to update the sample sizes using interim data, while allowing early stopping during interim analyses. We show that the proposed method maintains the nominal power and type I error rate through theoretical proofs and simulation studies.
PMCID: PMC2800369  PMID: 19822693
Diagnostic accuracy; Error spending function; ROC; Sensitivity; Specificity
21.  Efficacy of Pneumococcal Nontypable Haemophilus influenzae Protein D Conjugate Vaccine (PHiD-CV) in Young Latin American Children: A Double-Blind Randomized Controlled Trial 
PLoS Medicine  2014;11(6):e1001657.
In a double-blind randomized controlled trial, Xavier Saez-Llorens and colleagues examine the vaccine efficacy of PHiD-CV against community-acquired pneumonia in young children in Panama, Argentina, and Columbia.
Please see later in the article for the Editors' Summary
The relationship between pneumococcal conjugate vaccine–induced antibody responses and protection against community-acquired pneumonia (CAP) and acute otitis media (AOM) is unclear. This study assessed the impact of the ten-valent pneumococcal nontypable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) on these end points. The primary objective was to demonstrate vaccine efficacy (VE) in a per-protocol analysis against likely bacterial CAP (B-CAP: radiologically confirmed CAP with alveolar consolidation/pleural effusion on chest X-ray, or non-alveolar infiltrates and C-reactive protein ≥ 40 µg/ml); other protocol-specified outcomes were also assessed.
Methods and Findings
This phase III double-blind randomized controlled study was conducted between 28 June 2007 and 28 July 2011 in Argentine, Panamanian, and Colombian populations with good access to health care. Approximately 24,000 infants received PHiD-CV or hepatitis control vaccine (hepatitis B for primary vaccination, hepatitis A at booster) at 2, 4, 6, and 15–18 mo of age. Interim analysis of the primary end point was planned when 535 first B-CAP episodes, occurring ≥2 wk after dose 3, were identified in the per-protocol cohort. After a mean follow-up of 23 mo (PHiD-CV, n = 10,295; control, n = 10,201), per-protocol VE was 22.0% (95% CI: 7.7, 34.2; one-sided p = 0.002) against B-CAP (conclusive for primary objective) and 25.7% (95% CI: 8.4%, 39.6%) against World Health Organization–defined consolidated CAP. Intent-to-treat VE was 18.2% (95% CI: 5.5%, 29.1%) against B-CAP and 23.4% (95% CI: 8.8%, 35.7%) against consolidated CAP. End-of-study per-protocol analyses were performed after a mean follow-up of 28–30 mo for CAP and invasive pneumococcal disease (IPD) (PHiD-CV, n = 10,211; control, n = 10,140) and AOM (n = 3,010 and 2,979, respectively). Per-protocol VE was 16.1% (95% CI: −1.1%, 30.4%; one-sided p = 0.032) against clinically confirmed AOM, 67.1% (95% CI: 17.0%, 86.9%) against vaccine serotype clinically confirmed AOM, 100% (95% CI: 74.3%, 100%) against vaccine serotype IPD, and 65.0% (95% CI: 11.1%, 86.2%) against any IPD. Results were consistent between intent-to-treat and per-protocol analyses. Serious adverse events were reported for 21.5% (95% CI: 20.7%, 22.2%) and 22.6% (95% CI: 21.9%, 23.4%) of PHiD-CV and control recipients, respectively. There were 19 deaths (n = 11,798; 0.16%) in the PHiD-CV group and 26 deaths (n = 11,799; 0.22%) in the control group. A significant study limitation was the lower than expected number of captured AOM cases.
Efficacy was demonstrated against a broad range of pneumococcal diseases commonly encountered in young children in clinical practice.
Trial registration NCT00466947
Please see later in the article for the Editors' Summary
Editors' Summary
Pneumococcal diseases are illnesses caused by Streptococcus pneumoniae bacteria, pathogens (disease-causing organisms) that are transmitted through contact with infected respiratory secretions. S. pneumoniae causes mucosal diseases–infections of the lining of the body cavities that are connected to the outside world–such as community-acquired pneumonia (CAP; lung infection) and acute otitis media (AOM; middle-ear infection). It also causes invasive pneumococcal diseases (IPDs) such as septicemia and meningitis (infections of the bloodstream and the covering of the brain, respectively). Although pneumococcal diseases can sometimes be treated with antibiotics, CAP and IPDs are leading global causes of childhood deaths, particularly in developing countries. It is best therefore to avoid S. pneumoniae infections through vaccination. Vaccination primes the immune system to recognize and attack pathogens rapidly and effectively by exposing it to weakened or dead pathogens or to pathogen molecules that it recognizes as foreign (antigens). Because there are more than 90 S. pneumoniae variants (“serotypes”), each characterized by a different antigenic polysaccharide (complex sugar) coat, S. pneumoniae vaccines have to include antigens from multiple serotypes. For example, the PHiD-CV vaccine contains polysaccharides from ten S. pneumoniae serotypes.
Why Was This Study Done?
Although in most countries PHiD-CV has been licensed for protection against IPD and pneumococcal AOM, at the time of study, it was not known how well it protected against CAP and overall AOM, which are important public health problems. In this double-blind randomized controlled trial (the Clinical Otitis Media and Pneumonia Study; COMPAS), the researchers investigate the efficacy of PHiD-CV against CAP and AOM and assess other clinical end points, such as IPD, in Latin American infants. Double-blind randomized controlled trials compare the effects of interventions by assigning study participants to different interventions randomly and measuring predefined outcomes without the study participants or researchers knowing who has received which intervention until the trial is completed. Vaccine efficacy is the reduction in the incidence of a disease (the number of new cases that occur in a population in a given time) among trial participants who receive the vaccine compared to the incidence among participants who do not receive the vaccine.
What Did the Researchers Do and Find?
The researchers enrolled around 24,000 infants living in urban areas of Argentina, Panama, and Colombia. Half the infants were given PHiD-CV at 2, 4, and 6 months of age and a booster dose at age 15–18 months. The remaining infants were given a hepatitis control vaccine at the same intervals. The trial's primary end point was likely bacterial CAP (B-CAP) –radiologically confirmed CAP, with the airspaces (alveoli) in the lungs filled with liquid instead of gas (alveolar consolidation) or with non-alveolar infiltrates and raised blood levels of C-reactive protein (a marker of inflammation). In a planned interim analysis, which was undertaken after an average follow-up of 23 months, the vaccine efficacy in the per-protocol cohort (the group of participants who actually received their assigned intervention) was 22% against B-CAP. Intent-to-treat vaccine efficacy in the interim analysis (which considered all the trial participants regardless of whether they received their assigned intervention) was 18.2%. At the end of the study (average follow up 30 months), the vaccine efficacy against B-CAP was 18.2% and 16.7% in the per-protocol and intent-to-treat cohorts, respectively. Per-protocol vaccine efficacies against clinically confirmed AOM and vaccine serotype AOM were 16.1% and 67.1%, respectively. Against any IPD and against vaccine serotype IPD, the respective vaccine efficacies were 65% and 100%. Finally, about one-fifth of children who received PHiD-CV and a similar proportion who received the control vaccine experienced a serious adverse event (for example, gastroenteritis); 19 children who received PHiD-CV died compared to 26 children who received the control vaccine.
What Do These Findings Mean?
These findings indicate that in Latin America, a region with an intermediate burden of pneumococcal disease, PHiD-CV is efficacious against a broad range of pneumococcal diseases that often affect young children. The accuracy of these findings may be limited by the withdrawal of 14% of participants from the trial because of adverse media coverage and by the low number of reported cases of AOM. Moreover, because most study participants lived in urban areas, these findings may not be generalizable to rural settings. Despite these and other study limitations, these findings provide new information about the magnitude of the effect of PHiD-CV vaccination against CAP and AOM, two mucosal pneumococcal diseases of global public health importance.
Additional Information
Please access these websites via the online version of this summary at
The US Centers for Disease Control and Prevention provides information for patients and health professionals on all aspects of pneumococcal disease and pneumococcal vaccination, including personal stories
Public Health England provides information on pneumococcal disease and on pneumococcal vaccines
The not-for-profit Immunization Action Coalition has information on pneumococcal disease, including personal stories
The GAVI Alliance provides information about pneumococcal disease and the importance of vaccination
MedlinePlus has links to further information about pneumococcal infections, including pneumonia and otitis media (in English and Spanish)
More information about COMPAS is available
The European Medicines Agency provides information about PHiD-CV (Synflorix)
PMCID: PMC4043495  PMID: 24892763
22.  Interim analysis for binary outcome trials with a long fixed follow-up time and repeated outcome assessments at pre-specified times 
SpringerPlus  2014;3:323.
In trials with binary outcomes, assessed repeatedly at pre-specified times and where the subject is considered to have experienced a failure at the first occurrence of the outcome, interim analyses are performed, generally, after half or more of the subjects have completed follow-up. Depending on the duration of accrual relative to the length of follow-up, this may be inefficient, since there is a possibility that the trial will have completed accrual prior to the interim analysis. An alternative is to plan the interim analysis after subjects have completed follow-up to a time that is less than the fixed full follow-up duration. Using simulations, we evaluated three methods to estimate the event proportion for the interim analysis in terms of type I and II errors and the probability of early stopping. We considered: 1) estimation of the event proportion based on subjects who have been followed for a pre-specified time (less than the full follow-up duration) or who experienced the outcome; 2) estimation of the event proportion based on data from all subjects that have been randomized by the time of the interim analysis; and 3) the Kaplan-Meier approach to estimate the event proportion at the time of the interim analysis. Our results show that all methods preserve and have comparable type I and II errors in certain scenarios. In these cases, we recommend using the Kaplan-Meier method because it incorporates all the available data and has greater probability of early stopping when the treatment effect exists.
PMCID: PMC4087327  PMID: 25019050
Interim analysis; Binary outcome; Power; Type I error
23.  False-Negative Bone Scan and Choline Pet/Ct Study in a Case of Prostate Cancer: The Pitfall of the Small Cell Prostate Carcinoma Variant 
We present a rare variant of prostate carcinoma. The patient is a 45-year-old male with elevated prostate-specific antigen levels at screening. Magnetic resonance imaging revealed hyperenhancing lesions throughout the axial skeleton. The fluorine-18 fluorocholine (FCH) positron emission tomography/computed tomography (PET/CT) scan showed no abnormal bone findings. Subsequently, a technetium-99 methydiphosphonate (Tc99m-MDP) bone scan was performed, with additional correlative single-photon emission computed tomography (SPECT)/CT imaging of the pelvis and the results were essentially normal. A percutaneous core biopsy of one of the bone lesions in L5 was performed and histology confirmed small cell (neuroendocrine) variant of prostate cancer. Our case illustrates a possible pitfall in molecular imaging of prostate carcinomas, whereby both bone scintigraphy and FCH PET/CT scans showed no definite bone lesions to correlate with marrow signal abnormalities seen on MR imaging. This highlights the need for caution in the diagnostic evaluation of prostate cancers with known small cell variants.
PMCID: PMC3555398  PMID: 23372441
Fluorocholine; positron emission tomography; prostate carcinoma; small cell cancer
24.  Is there any significance of lung cancer histology to compare the diagnostic accuracies of 18F-FDG-PET/CT and 99mTc-MDP BS for the detection of bone metastases in advanced NSCLC? 
Contemporary Oncology  2014;18(2):106-110.
Aim of the study
Bone scintigraphy (BS) and fluorine-18 deoxyglucose positron emission tomography computed tomography (18F-FDG-PET/CT) are widely used for the detection of bone involvement. The optimal imaging modality for the detection of bone metastases in histological subgroups of non-small cell lung cancer (NSCLC) remains ambiguous. The aim of this study was to compare the efficacy of 18F-FDG-PET/C and 99mTc-methylene diphosphonate (99mTc-MDP) BS in the detection of bone metastases of patients in NSCLC. Specifically, we compared the diagnostic accuracies of these imaging techniques evaluating bone metastasis in histological subgroups of NSCLC.
Material and methods
Fifty-three patients with advanced NSCLC, who had undergone both 18F-FDG-PET/CT and BS and were eventually diagnosed as having bone metastasis, were enrolled in this retrospective study.
The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 18F-FDG-PET/CT and BS were 90.4%, 99.4%, 98.1%, 96.6%, 97.0% and 84.6%, 93.1%, 82.5%, 93.2, 90.8%, respectively. The κ statistics were calculated for 18F-FDG-PET/CT and BS. The κ-value was 0.67 between 18F-FDG-PET/CT and BS in all patients. On the other hand, the κ-value was 0.65 in adenocarcinoma, and 0.61 in squamous cell carcinoma between 18F-FDG-PET/CT and BS. The κ-values suggested excellent agreement between all patients and histological subgroups of NSCLC.
18F-FDG-PET/CT was more favorable than BS in the screening of metastatic bone lesions, but the trend did not reach statistical significance in all patients and histological subgroups of NSCLC. Our results need to be validated in prospective and larger study clinical trials to further clarify this topic.
PMCID: PMC4068819  PMID: 24966793
18F-FDG-PET/CT; 99mTc- methylene diphosphonate bone scintigraphy; bone metastases; non-small cell lung cancer
25.  Approaches to interim analysis of cancer randomised clinical trials with time to event endpoints: A survey from the Italian National Monitoring Centre for Clinical Trials 
Trials  2008;9:46.
Although interim analysis approaches in clinical trials are widely known, information on current practice of planned monitoring is still scarce. Reports of studies rarely include details on the strategies for both data monitoring and interim analysis. The aim of this project is to investigate the forms of monitoring used in cancer clinical trials and in particular to gather information on the role of interim analyses in the data monitoring process of a clinical trial. This study focused on the prevalence of different types of interim analyses and data monitoring in cancer clinical trials.
Source of investigation were the protocols of cancer clinical trials included in the Italian registry of clinical trials from 2000 to 2005. Evaluation was restricted to protocols of randomised studies with a time to event endpoint, such as overall survival (OS) or progression free survival (PFS). A template data extraction form was developed and tested in a pilot phase. Selection of relevant protocols and data extraction were performed independently by two evaluators, with differences in the data assessment resolved by consensus with a third reviewer, referring back to the original protocol. Information was obtained on a) general characteristics of the protocol b) disease localization and patient setting; c) study design d) interim analyses; e) DSMC.
The analysis of the collected protocols reveals that 70.7% of the protocols incorporate statistical interim analysis plans, but only 56% have also a DSMC and be considered adequately planned. The most concerning cases are related to lack of any form of monitoring (20.0% of the protocols), and the planning of interim analysis, without DSMC (14.7%).
The results indicate that there is still insufficient attention paid to the implementation of interim analysis.
PMCID: PMC2533282  PMID: 18657271

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