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1.  Fecal Occult Blood Test for Colorectal Cancer Screening 
Executive Summary
The colorectal cancer (CRC) screening project was undertaken by the Medical Advisory Secretariat (MAS) in collaboration with the Cancer Care Ontario (CCO).
In November 2007, the Ontario Health Technology Advisory Committee (OHTAC) MAS to conduct an evidence-based analysis of the available data with respect to colorectal cancer diagnosis and prevention. The general purpose of the project was to investigate the effectiveness, cost effectiveness, and safety of the various methods and techniques used for colorectal cancer screening in average risk people, 50 years of age and older.
The options currently offered for colorectal cancer screening were reviewed and five technologies were selected for review:
Computed tomographic (CT) colonography
Magnetic resonance (MR) colonography
Wireless capsule endoscopy (PillCam Colon)
Fecal occult blood test (FOBT)
Flexible sigmoidoscopy
In this review, colonoscopy was considered as the “gold standard” technique by which the effectiveness of all other modalities could be evaluated. An economic analysis was also conducted to determine cost-effectiveness of different screening modalities.
Evidence-based analyses have been prepared for each of these technologies, as well as summary document that includes an economic analysis, all of which are presented at the MAS Web site: http://www.health.gov.on.ca/english/providers/program/mas/tech/techmn.html
Objective
The objective of this evidence review is to examine the effectiveness and cost-effectiveness of fecal occult blood testing (FOBT), including guaiac FOBT (gFOBT) and immunochemical FOBT (iFOBT), for use in colorectal cancer (CRC) screening in asymptomatic, average-risk adults.
Specifically:
Is the use of gFOBT or iFOBT associated with a reduction in CRC and overall mortality?
What are the sensitivity and specificity of gFOBT and iFOBT for the detection of 1) CRC and 2) large polyps (≥ 1 cm)?
Clinical Need
CRC is the most common cause of non-tobacco related cancer death in Canada. It has been estimated that in 2007, 7,800 people were diagnosed with CRC in Ontario and 3,250 died from the disease, making the province’s incidence and mortality rate of CRC amongst the highest in the world.
Description of Technology/Therapy
There are two general types of FOBT that are categorized according to the analyte detected: guaiac FOBT (gFOBT) and immunochemical FOBT (iFOBT). Blood in the stool is a nonspecific finding but may originate from CRC or larger (>1 cm) polyps (small adenomatous polyps do not tend to bleed). Bleeding from cancers and larger polyps may be intermittent and not always detectable in a single sample. The FOBT thus requires regular testing that consists of collecting specimens from consecutive bowel movements. A positive gFOBT or iFOBT involves a diagnostic workup with colonoscopy to examine the entire colon in order to rule out the presence of cancer or advanced neoplasia.
Methods of Evidence-Based Analysis
A literature search was conducted from January 2003 to June 2008 that included OVID MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, EMBASE, the Cumulative Index to Nursing & Allied Health Literature (CINAHL), The Cochrane Library, and the International Agency for Health Technology Assessment/Centre for Review and Dissemination.
Inclusion Criteria
Patients at average risk for CRC
All patients must be at least 50 years of age
Biennial FOBT as a screening modality and use of colonoscopy as the reference standard
Systematic reviews and randomized controlled trials (RCTs)
Outcomes: CRC mortality, overall mortality, sensitivity, specificity, adverse effects
Exclusion Criteria
Studies involving fewer than 100 patients
Studies that do not report sufficient data for analysis
Comparisons of Interest
Evidence exists for these comparisons of interest:
gFOBT compared with the reference “gold standard” colonoscopy (or double-contrast barium enema where colonoscopy is incomplete or contraindicated)
iFOBT compared with the reference gold standard colonoscopy (or DCBE where colonoscopy is incomplete or contraindicated)
gFOBT compared with iFOBT
The quality of the diagnostic studies was examined according to the ‘GRADE Working Group criteria’ for grading quality of evidence and strength of recommendations for diagnostic tests and strategies.
Summary of Findings
Single-Test Studies
There is limited direct/indirect evidence that iFOBT has sensitivity/specificity superior to that of unrehydrated gFOBT for CRC detection:
sensitivity for gFOBT:
pooled iFOBT sensitivity:
There is evidence that iFOBT and gFOBT have lower sensitivities for adenoma detection than for CRC detection:
sensitivity for rehydrated gFOBT
pooled iFOBT sensitivity
Repeated-Test Studies
No trials have examined CRC mortality outcomes after repeated testing of iFOBT.
Two RCTs from the United Kingdom and Denmark showed significant reduction in CRC mortality using unrehydrated gFOBT biennially
Relative risk reductions of 13% (UK trial) and 16% (Danish trial); absolute difference of 0.1% (UK trial) and 0.2% (Danish trial).
No significant reduction in overall mortality
Interval cancers (CRC that develop in the intervals between routine screening)
United Kingdom trial: 236 CRCs detected by positive test, 236 interval CRCs after negative test
Danish trial: 120 CRCs detected by positive test, 146 interval CRCs after negative test
Unrehydrated gFOBT has low sensitivity for CRC detection (45% in the UK trial and 54% in the Danish trial).
true positive rate
false positive rate
true negative rate
false negative rate
Guaiac FOBT – GRADE Quality of Evidence for Interventions
CRC indicates colorectal cancer; FOBT, fecal occult blood test; GRADE, Grading of Recommendations Assessment, Development and Evaluation; RCT, randomized controlled trial.
Unlikely to be an important uncertainty.
GRADE Quality of Evidence for Diagnostic Tests: Implications of Testing Focusing on Accuracy
Benefit from diagnosis and treatment after confirmatory colonoscopy
Small risk of bowel perforation during colonoscopy
Benefit of reassurance
Anxiety/worry leading up to confirmatory colonoscopy
Small risk of bowel perforation during confirmatory colonoscopy
Detriment from delayed diagnosis
Some uncertainty (until after confirmatory colonoscopy)
No Uncertainty
Uncertainty
Uncertainty
FOBT indicates fecal occult blood test; GRADE, Grading of Recommendations Assessment, Development and Evaluation.
Immunochemical FOBT – GRADE Quality of Evidence for Diagnostic Studies
FN indicates false negative; FOBT, fecal occult blood test; FP, false positive; Development and Evaluation; TN, true negative; TP, true positive.
Uncertainty until after confirmatory colonoscopy
Stress/worry for patient until confirmatory colonoscopy
Detrimental effects due to delayed diagnosis.
For these 3 reasons, downgrade quality from High to Moderate.
For these 3 reasons, downgrade quality from Moderate to Low.
Considerations for the Ontario Health System
Executive Summary Table 4 shows the potential system pressures and benefit/risk analysis for the use of FOBT and colonoscopy to screen for CRC in average-risk adults, ages 50 and over in Ontario.
Summary of Potential System Pressures for FOBT Screening
Prevent and detect
Detect
Every 10 years
Must repeat at regular intervals
Every 2 years
Must repeat at regular intervals
Observational studies
RCTs
Used as gold standard in studies
Intervention GRADE quality: High (gFOBT)
Diagnostic GRADE quality: Low (iFOBT)
No RCTs examining the effectiveness of repeated iFOBT on CRC mortality reduction were identified
Limited direct/indirect evidence that iFOBT has superior sensitivity/specificity to unrehydrated gFOBT for detection of CRC
0.1% risk of serious bleeding and perforation requiring surgery
0.3% risk of serious complications (stroke/bleeding requiring hospitalization/ myocardial infarction)
High interval cancer rate
The small benefit in CRC mortality reduction (absolute difference 0.1% to 0.2%) also coincides with a 0.3% risk of serious complications.
No food 1 day prior to exam
Office/hospital visit
Complete bowel preparation
Sedation
Eliminate citrus fruit and juices and vitamin C from diet for 3 days prior to/during stool collection.
Person applies 2 samples per bowel movement (each occurring on 3 different days) onto test areas of FOBT cards.
Increased demand for colonoscopies and colonoscopists or nurses who perform colonoscopies.
Patient receives kit from family physician, pharmacist
Patients mail completed FOBT kit to participating laboratory
Results sent back to patient
Increased demand for colonoscopies for positive patients
Removal of polyp during colonoscopy or surgery
Referral to colonoscopy
Cost-effective
Cost-effective
2nd of 5 choices in a patient survey study
5th of 5 choices in a patient survey study
FOBT indicates fecal occult blood test;; gFOBT, guaiac FOBT; GRADE, Grading of Recommendations Assessment, Development and Evaluation; iFOBT, immunochemical FOBT; RCT, randomized controlled trial.
PMCID: PMC3377532  PMID: 23074514
2.  Aberrant methylation of NPY, PENK, and WIF1 as a promising marker for blood-based diagnosis of colorectal cancer 
BMC Cancer  2013;13:566.
Background
DNA methylation is a well-known epigenetic mechanism involved in epigenetic gene regulation. Several genes were reported hypermethylated in CRC, althought no gene marker was proven to be individually of sufficient sensitivity or specificity in routine clinical practice. Here, we identified novel epigenetic markers and assessed their combined use for diagnostic accuracy.
Methods
We used methylation arrays on samples from several effluents to characterize methylation profiles in CRC samples and controls, as established by colonoscopy and pathology findings, and selected two differentially methylated candidate epigenetic genes (NPY, PENK). To this gene panel we added WIF, on the basis of being reported in literature as silenced by promoter hypermethylation in several cancers, including CRC. We measured their methylation degrees by quantitative multiplex-methylation specific PCR (QM-MSP) on 15 paired carcinomas and adjacent non-cancerous colorectal tissues and we subsequently performed a clinical validation on two different series of 266 serums, subdivided in 32 CRC, 26 polyps, 47 other cancers and 161 with normal colonoscopy. We assessed the results by receiver operating characteristic curve (ROC), using cumulative methylation index (CMI) as variable threshold.
Results
We obtained CRC detection on tissues with both sensitivity and specificity of 100%. On serum CRC samples, we obtained sensitivity/specificity values of, e.g., 87%/80%, 78%/90% and 59%/95%, and negative predictive value/positive predictive value figures of 97%/47%, 95%/61% and 92%/70%. On serum samples from other cancers we obtained sensitivity/specificity of, e.g, 89%/25%, 43%/80% and 28%/91%.
Conclusions
We showed the potential of NPY, PENK, and WIF1 as combined epigenetic markers for CRC diagnosis, both in tissue and serum and tested their use as serum biomarkers in other cancers. We optimized a QM-MSP for simultaneously quantifying their methylation levels. Our assay can be an effective blood test for patients where CRC risk is present but difficult to assess (e.g. mild symptoms with no CRC family history) and who would therefore not necessarily choose to go for further examination. This panel of markers, if validated, can also be a cost effective screening tool for the detection of asymptomatic cancer patients for colonoscopy.
doi:10.1186/1471-2407-13-566
PMCID: PMC4219483  PMID: 24289328
Colorectal cancer; Circulating DNA methylation; QM-MSP; Epigenetic markers
3.  Effect of Flexible Sigmoidoscopy-Based Screening on Incidence and Mortality of Colorectal Cancer: A Systematic Review and Meta-Analysis of Randomized Controlled Trials 
PLoS Medicine  2012;9(12):e1001352.
A systematic review and meta-analysis of randomized trials conducted by B. Joseph Elmunzer and colleagues reports that that flexible sigmoidoscopy-based screening reduces the incidence of colorectal cancer in average-risk patients, as compared to usual care or no screening.
Background
Randomized controlled trials (RCTs) have yielded varying estimates of the benefit of flexible sigmoidoscopy (FS) screening for colorectal cancer (CRC). Our objective was to more precisely estimate the effect of FS-based screening on the incidence and mortality of CRC by performing a meta-analysis of published RCTs.
Methods and Findings
Medline and Embase databases were searched for eligible articles published between 1966 and 28 May 2012. After screening 3,319 citations and 29 potentially relevant articles, two reviewers identified five RCTs evaluating the effect of FS screening on the incidence and mortality of CRC. The reviewers independently extracted relevant data; discrepancies were resolved by consensus. The quality of included studies was assessed using criteria set out by the Evidence-Based Gastroenterology Steering Group. Random effects meta-analysis was performed.
The five RCTs meeting eligibility criteria were determined to be of high methodologic quality and enrolled 416,159 total subjects. Four European studies compared FS to no screening and one study from the United States compared FS to usual care. By intention to treat analysis, FS-based screening was associated with an 18% relative risk reduction in the incidence of CRC (0.82, 95% CI 0.73–0.91, p<0.001, number needed to screen [NNS] to prevent one case of CRC = 361), a 33% reduction in the incidence of left-sided CRC (RR 0.67, 95% CI 0.59–0.76, p<0.001, NNS = 332), and a 28% reduction in the mortality of CRC (relative risk [RR] 0.72, 95% CI 0.65–0.80, p<0.001, NNS = 850). The efficacy estimate, the amount of benefit for those who actually adhered to the recommended treatment, suggested that FS screening reduced CRC incidence by 32% (p<0.001), and CRC-related mortality by 50% (p<0.001).
Limitations of this meta-analysis include heterogeneity in the design of the included trials, absence of studies from Africa, Asia, or South America, and lack of studies comparing FS with colonoscopy or stool-based testing.
Conclusions
This meta-analysis of randomized controlled trials demonstrates that FS-based screening significantly reduces the incidence and mortality of colorectal cancer in average-risk patients.
Please see later in the article for the Editors' Summary
Editor's Summary
Background
Colorectal cancer (CRC) is the second leading cause of cancer-related death in the United States. Regular CRC screening has been shown to reduce the risk of dying from CRC by 16%, and CRC screening can identify early stage cancers in otherwise healthy people, which allows for early treatment and management of the disease. Screening for colorectal cancer is frequently performed using a flexible sigmoidoscopy (FS), which is a thin, flexible tube with a tiny camera and light on the end, allowing a doctor to look at the inside wall of the bowel and remove any small growths or polyps. Although screening may detect early cancers, the life-saving and health benefits of screening are uncertain because the polyp may not necessarily progress. This could lead to anxiety and unnecessary interventions and treatments amongst those screened. Randomized controlled trials (RCTs) are needed to determine all of the risks involved in cancer screenings, however the guidelines that recommend FS-based screening do not rely upon RCT data. Recently, the results of four large-scale RCTs evaluating FS screening for CRC have been published. The conflicting results with respect to the incidence and mortality of CRC in these studies have called into question the effectiveness of endoscopic screening.
Why Was This Study Done?
The results of RCTs measuring the risks and outcomes of CRC screening have shown varying estimates of the benefits of using FS screening. If better estimates of the risks and benefits of FS screening are developed, then the current CRC screening guidelines may be updated to reflect this new information. In this study, the authors show the results of a meta-analysis of published RCTs, which more precisely estimates the effects of FS-based screening on the incidence and mortality of colorectal cancer.
What Did the Researchers Do and Find?
The researchers used the Medline and Embase databases to find relevant studies from 1966 to May 28, 2012. After screening 3,319 citations and 29 potentially relevant articles, five RCTs of high methodologic quality and 416,159 total subjects evaluating the effect of FS screening on the incidence and mortality of CRC were identified. The data were extracted and random effects meta-analysis was performed. The meta-analysis revealed that FS-based screening was associated with an 18% relative risk reduction in the incidence of CRC (0.82, 95% CI 0.73–0.91, p<0.001, number needed to screen (NNS) to prevent one case of CRC = 361), a 33% reduction in the incidence of left-sided CRC (RR 0.67, 95% CI 0.59–0.76, p<0.001, NNS = 332), and a 28% reduction in the mortality of CRC (RR 0.72, 95% CI 0.65–0.80, p<0.001, NNS = 850). The amount of benefit for those who adhered to the recommended treatment suggested that FS screening reduced CRC incidence by 32% (p<0.001), and CRC-related mortality by 50% (p<0.001).
What Do These Findings Mean?
This meta-analysis of RCTs evaluating the effect of FS on CRC incidence and mortality demonstrates that a FS-based strategy for screening is very effective in reducing the incidence and mortality of CRC in patients. The current recommendations for endoscopic screening are based on observational studies, which may not accurately reflect the effect of FS-based screening on the incidence and mortality of CRC. Here, the authors performed a systematic review and meta-analysis of five recent RCTs to better estimate the true effect of FS-based screening on the incidence and mortality of CRC. Thus, the results of this meta-analysis may affect health policy, and directly impact patients and clinicians.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001352.
Cancer research UK provides comprehensive information about screening for colorectal cancers as does the UK National Screening Committee
PubMed Health has general information about colon cancer
The National Cancer Institute also has comprehensive resources on colorectal cancer and treatment
The Mayo Clinic provides an overview of all aspects of colon cancer
doi:10.1371/journal.pmed.1001352
PMCID: PMC3514315  PMID: 23226108
4.  Detection of Colorectal Cancer by Serum and Tissue Protein Profiling: A Prospective Study in a Population at Risk 
Biomarker Insights  2008;3:375-385.
Colorectal cancer (CRC) is the second most common cause of cancer-related death in Europe and its prognosis is largely dependent on stage at diagnosis. Currently, there are no suitable tumour markers for early detection of CRC. In a retrospective study we previously found discriminative CRC serum protein profiles with surface enhanced laser desorption ionisation—time of flight mass spectrometry (SELDI-TOF MS). We now aimed at prospective validation of these profiles. Additionally, we assessed their applicability for follow-up after surgery and investigated tissue protein profiles of patients with CRC and adenomatous polyps (AP). Serum and tissue samples were collected from patients without known malignancy with an indication for colonoscopy and patients with AP and CRC during colonoscopy. Serum samples of controls (CON; n = 359), patients with AP (n = 177) and CRC (n = 73), as well as tissue samples from AP (n = 52) and CRC (n = 47) were analysed as described previously. Peak intensities were compared by non-parametric testing. Discriminative power of differentially expressed proteins was assessed with support vector machines (SVM). We confirmed the decreased serum levels of apolipoprotein C-1 in CRC in the current population. No differences were observed between CON and AP. Apolipoprotein C-I levels did not change significantly within 1 month post-surgery, although a gradual return to normal levels was observed. Several proteins differed between AP and CRC tissue, among which a peak with similar mass as apolipoprotein C-1. This peak was increased in CRC compared to AP. Although we prospectively validated the serum decrease of apolipoprotein C-1 in CRC, serum protein profiles did not yield SVM classifiers with suitable sensitivity and specificity for classification of our patient groups.
PMCID: PMC2688344  PMID: 19578519
biomarkers; colorectal cancer; SELDI-TOF MS; validation
5.  Prospective evaluation of methylated SEPT9 in plasma for detection of asymptomatic colorectal cancer 
Gut  2013;63(2):317-325.
Background
As screening methods for colorectal cancer (CRC) are limited by uptake and adherence, further options are sought. A blood test might increase both, but none has yet been tested in a screening setting.
Objective
We prospectively assessed the accuracy of circulating methylated SEPT9 DNA (mSEPT9) for detecting CRC in a screening population.
Design
Asymptomatic individuals ≥50 years old scheduled for screening colonoscopy at 32 US and German clinics voluntarily gave blood plasma samples before colon preparation. Using a commercially available assay, three independent blinded laboratories assayed plasma DNA of all CRC cases and a stratified random sample of other subjects in duplicate real time PCRs. The primary outcomes measures were standardised for overall sensitivity and specificity estimates.
Results
7941 men (45%) and women (55%), mean age 60 years, enrolled. Results from 53 CRC cases and from 1457 subjects without CRC yielded a standardised sensitivity of 48.2% (95% CI 32.4% to 63.6%; crude rate 50.9%); for CRC stages I–IV, values were 35.0%, 63.0%, 46.0% and 77.4%, respectively. Specificity was 91.5% (95% CI 89.7% to 93.1%; crude rate 91.4%). Sensitivity for advanced adenomas was low (11.2%).
Conclusions
Our study using the blood based mSEPT9 test showed that CRC signal in blood can be detected in asymptomatic average risk individuals undergoing screening. However, the utility of the test for population screening for CRC will require improved sensitivity for detection of early cancers and advanced adenomas.
Clinical Trial Registration Number:
NCT00855348
doi:10.1136/gutjnl-2012-304149
PMCID: PMC3913123  PMID: 23408352
Colorectal Cancer Screening; Methylation; Colonoscopy; Colorectal Adenomas; Colorectal Neoplasm
6.  Colorectal Cancer Screening for Average-Risk North Americans: An Economic Evaluation 
PLoS Medicine  2010;7(11):e1000370.
An economic analysis of different screening methods for detection of colorectal cancers suggests that in US or Canadian settings, screening with fecal immunochemical testing results in lower health-care costs as compared with other screening approaches.
Background
Colorectal cancer (CRC) fulfills the World Health Organization criteria for mass screening, but screening uptake is low in most countries. CRC screening is resource intensive, and it is unclear if an optimal strategy exists. The objective of this study was to perform an economic evaluation of CRC screening in average risk North American individuals considering all relevant screening modalities and current CRC treatment costs.
Methods and Findings
An incremental cost-utility analysis using a Markov model was performed comparing guaiac-based fecal occult blood test (FOBT) or fecal immunochemical test (FIT) annually, fecal DNA every 3 years, flexible sigmoidoscopy or computed tomographic colonography every 5 years, and colonoscopy every 10 years. All strategies were also compared to a no screening natural history arm. Given that different FIT assays and collection methods have been previously tested, three distinct FIT testing strategies were considered, on the basis of studies that have reported “low,” “mid,” and “high” test performance characteristics for detecting adenomas and CRC. Adenoma and CRC prevalence rates were based on a recent systematic review whereas screening adherence, test performance, and CRC treatment costs were based on publicly available data. The outcome measures included lifetime costs, number of cancers, cancer-related deaths, quality-adjusted life-years gained, and incremental cost-utility ratios. Sensitivity and scenario analyses were performed. Annual FIT, assuming mid-range testing characteristics, was more effective and less costly compared to all strategies (including no screening) except FIT-high. Among the lifetimes of 100,000 average-risk patients, the number of cancers could be reduced from 4,857 to 1,782 and the number of CRC deaths from 1,393 to 457, while saving CAN$68 per person. Although screening patients with FIT became more expensive than a strategy of no screening when the test performance of FIT was reduced, or the cost of managing CRC was lowered (e.g., for jurisdictions that do not fund expensive biologic chemotherapeutic regimens), CRC screening with FIT remained economically attractive.
Conclusions
CRC screening with FIT reduces the risk of CRC and CRC-related deaths, and lowers health care costs in comparison to no screening and to other existing screening strategies. Health policy decision makers should consider prioritizing funding for CRC screening using FIT.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Colorectal (bowel) cancer is the second leading cause of cancer deaths for both men and women in North America. Colorectal cancer screening is an important means for reducing morbidity and mortality and fulfils the World Health Organization criteria for mass screening. However, a variety of CRC screening approaches are available. Colonoscopy is viewed as the gold standard of colorectal cancer screening as it has a high sensitivity for identifying adenomas and cancer and polyps can be removed during the screening examination. However, colonoscopy is associated with a number of complications and there are also barriers to access. Another type of test, the guaiac fecal occult blood test, has been shown to reduce mortality from colorectal cancer but this test has low sensitivity for identifying colorectal neoplasia, particularly adenomas. Fecal immunochemical tests, which also detect blood in the stool, have improved test performance characteristics (high sensitivity and specificity) and the potential to improve participation rates compared to guaiac fecal occult blood test and flexible sigmoidoscopy. Fecal DNA (a stool test, based on the detection of DNA shed by cancerous tissue) is another screening option, as is computed tomographic colonography (“virtual” colonoscopy), that might rival colonoscopy in detecting advanced adenomas and colorectal cancer but is expensive and requires a full colonic preparation.
Why Was This Study Done?
In the absence of firm comparative evidence to guide the selection of any one screening modality and given the varied test performance characteristics and the significant differences in costs and resources associated with each, a robust cost-effectiveness analysis might help health policy makers in deciding whether or not to offer screening and if so, in selecting the most appropriate and cost effective screening modality. In this study the researchers conducted a full economic evaluation of all relevant colorectal cancer screening modalities in North America.
What Did the Researchers Do and Find?
The researchers used an incremental cost-utility analysis, a sophisticated modeling technique, and two hypothetical patient cohorts (individuals with an “average risk,” i.e., no family history of colorectal cancer, aged 50–64 and 65–75) to compare guaiac-based fecal occult blood test or fecal immunochemical test annually (the researchers considered three distinct fecal immunochemical testing strategies on the basis of assays and collection methods taken from studies that have reported “low,” “mid,” and “high” test performance characteristics), fecal DNA every three years, flexible sigmoidoscopy or computed tomographic colonography every 5 years, and colonoscopy every 10 years. The researchers also included a no screening natural history arm as a comparison to each screening approach. For the baseline data of their model, the researchers used adenoma and colorectal prevalence rates from a recent systematic review and based screening adherence, test performance, and colorectal treatment costs on available data. The researchers found that annual fecal immunochemical testing with mid-range testing characteristics, was more effective and less costly compared to all strategies (including no screening). Using this screening modality, among the lifetimes of 100,000 average-risk patients, the number of cancers could be reduced from 4,857 to 1,393 and the number of deaths from colorectal cancer from 1,782 to 457, while saving CAN$68 per person. Although in the sensitivity and scenario analysis, screening patients using fecal immunochemical testing became more expensive than a strategy of no screening when the test performance of fecal immunochemical testing was reduced, or the cost of managing colorectal cancers was lowered, the researchers found that screening for colorectal cancer with fecal immunochemical testing remained the most economically attractive screening option.
What Do These Findings Mean?
This model-based economic analysis found that fecal immunochemical testing is more effective and less costly than all other colorectal screening strategies, including the most commonly-used stool-based screening test, guaiac-based fecal occult blood testing, and no screening. Furthermore, this study suggests that annual screening with fecal immunochemical testing (assuming mid-range test performance characteristics) reduces the risk of colorectal cancer and colorectal cancer–related deaths, and lowers health care costs in comparison to all other screening strategies and to no screening. Therefore, health policy makers should consider prioritizing funding for fecal immunochemical testing as the screening modality for colorectal cancer.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000370.
Cancer.org has information for patients on colorectal cancer
The US Centers for Disease Control (CDC) list colorectal screening guidelines
The CDC also provides patient information on colorectal cancer Screening
doi:10.1371/journal.pmed.1000370
PMCID: PMC2990704  PMID: 21124887
7.  Serum M2-pyruvate kinase: A promising non-invasive biomarker for colorectal cancer mass screening 
AIM: To explore the value of serum M2-pyruvate kinase (M2-PK) in colorectal cancer (CRC) mass screening.
METHODS: We conducted a molecular epidemiology study in Hangzhou, China, from year 2006 to year 2008. Serum samples were collected from 93 CRC, 41 advanced adenomas, 137 adenomas, 47 non-adenomatous polyps, and 158 normal participants in a community setting. Serum M2-PK and carcinoembryonic antigen (CEA) were measured using Enzyme-linked immunosorbent assay. SPSS 16.0 software was used to perform data analysis. Area under the receiver operating characteristic curve (AUC), sensitivity, and specificities were estimated for serum M2-PK in diagnosis of colorectal lesions and compared with CEA.
RESULTS: Average serum M2-PK value among 158 normal people was 2.96 U/mL and not affected by gender (P = 0.47) or age (P = 0.59). Average serum M2-PK (U/mL) was 14.75 among stage III and 13.10 among stage I and II CRC patients, about 4 times higher than that among normal people. Average serum M2-PK was 8.58, 6.70, 5.13 and 2.51 U/mL among advanced adenoma, adenomas, non-adenomatous polyps, and inflammatory bowel disease patients, respectively. AUC for serum M2-PK was greater than that for CEA among all colorectal lesions. AUC for serum M2-PK was 0.89 (0.84, 0.94) (95% confidence interval), higher than that for CEA [0.70 (0.62-0.79)] in CRC stage I and II, 0.89 (0.84-0.94) vs 0.73 (0.63-0.83) in CRC stage III, 0.81 (0.74-0.86) vs 0.63 (0.53 - 0.73) in advanced adenomas, 0.69 (0.64-0.76) vs 0.54 (0.47-0.60) in adenomas, and 0.69 (0.62-0.78) vs 0.58 (0.48-0.68) in non-adenomatous polyps. The diagnostic sensitivity for all colorectal lesions increased with decrease in the cut-off value of serum M2-PK. The diagnostic sensitivity (%) of serum M2-PK was 100.00 for CRC, 95.12 advanced adenoma, 82.48 adenoma, and 82.98 non-adenomatous polyp. There were no CRC cases missed and 40.51% of unnecessary colonoscopies were avoided when the cut-off value was 2.00 U/mL.
CONCLUSION: Serum M2-PK can be used as a primary screening test in CRC mass screening. It may be a promising non-invasive biomarker for CRC early detection.
doi:10.4251/wjgo.v4.i6.145
PMCID: PMC3382661  PMID: 22737276
Serum M2-pyruvate kinase; Colorectal cancer screening; Serum biomarker; Carcinoembryonic antigen
8.  Fecal immunochemical test accuracy in average-risk colorectal cancer screening 
AIM: To assess the fecal immunochemical test (FIT) accuracy for colorectal cancer (CRC) and advanced neoplasia (AN) detection in CRC screening.
METHODS: We performed a multicentric, prospective, double blind study of diagnostic tests on asymptomatic average-risk individuals submitted to screening colonoscopy. Two stool samples were collected and the fecal hemoglobin concentration was determined in the first sample (FIT1) and the highest level of both samples (FITmax) using the OC-sensor™. Areas under the curve (AUC) for CRC and AN were calculated. The best FIT1 and FITmax cut-off values for CRC were determined. At this threshold, number needed to scope (NNS) to detect a CRC and an AN and the cost per lesion detected were calculated.
RESULTS: About 779 individuals were included. An AN was found in 97 (12.5%) individuals: a CRC in 5 (0.6%) and an advanced adenoma (≥ 10 mm, villous histology or high grade dysplasia) in 92 (11.9%) subjects. For CRC diagnosis, FIT1 AUC was 0.96 (95%CI: 0.95-0.98) and FITmax AUC was 0.95 (95%CI: 0.93-0.97). For AN, FIT1 and FITmax AUC were similar (0.72, 95%CI: 0.66-0.78 vs 0.73, 95%CI: 0.68-0.79, respectively, P = 0.34). Depending on the number of determinations and the positivity threshold cut-off used sensitivity for AN detection ranged between 28% and 42% and specificity between 91% and 97%. At the best cut-off point for CRC detection (115 ng/mL), the NNS to detect a CRC were 10.2 and 15.8; and the cost per CRC was 1814€ and 2985€ on FIT1 and FITmax strategies respectively. At this threshold the sensitivity, NNS and cost per AN detected were 30%, 1.76, and 306€, in FIT1 strategy, and 36%, 2.26€ and 426€, in FITmax strategy, respectively.
CONCLUSION: Performing two tests does not improve diagnostic accuracy, but increases cost and NNS to detect a lesion.
doi:10.3748/wjg.v20.i4.1038
PMCID: PMC3921527  PMID: 24574776
Colorectal neoplasms; Early detection of cancer; Sensitivity and specificity; Adenoma; Occult blood; Cost-benefit analysis
9.  Gender differences in attitudes impeding colorectal cancer screening 
BMC Public Health  2013;13:500.
Background
Colorectal cancer screening (CRCS) is the only type of cancer screening where both genders reduce risks by similar proportions with identical procedures. It is an important context for examining gender differences in disease-prevention, as CRCS significantly reduces mortality via early detection and prevention. In efforts to increase screening adherence, there is increasing acknowledgment that obstructive attitudes prevent CRCS uptake. Precise identification of the gender differences in obstructive attitudes is necessary to improve uptake promotion. This study randomly sampled unscreened, screening - eligible individuals in Ontario, employing semi-structured interviews to elicit key differences in attitudinal obstructions towards colorectal cancer screening with the aim of deriving informative differences useful in planning promotions of screening uptake.
Methods
N = 81 participants (49 females, 32 males), 50 years and above, with no prior CRCS, were contacted via random-digit telephone dialing, and consented via phone-mail contact. Altogether, N = 4,459 calls were made to yield N = 85 participants (1.9% response rate) of which N = 4 participants did not complete interviews. All subjects were eligible for free-of-charge CRCS in Ontario, and each was classified, via standard interview by CRCS screening decision-stage. Telephone-based, semi-structured interviews (SSIs) were employed to investigate gender differences in CRCS attitudes, using questions focused on 5 attitudinal domains: 1) Screening experience at the time of interview; 2) Barriers to adherence; 3) Predictors of Adherence; 4) Pain-anxiety experiences related to CRCS; 5) Gender-specific experiences re: CRCS, addressing all three modalities accessible through Ontario’s program: a) fecal occult blood testing; b) flexible sigmoidoscopy; c) colonoscopy.
Results
Interview transcript analyses indicated divergent themes related to CRCS for each gender: 1) bodily intrusion, 2) perforation anxiety, and 3) embarrassment for females and; 1) avoidant procrastination with underlying fatalism, 2) unnecessary health care and 3) uncomfortable vulnerability for males. Respondents adopted similar attitudes towards fecal occult blood testing, flexible sigmoidoscopy and colonoscopy, and were comparable in decision stage across tests. Gender differences were neither closely tied to screening stage nor modality. Women had more consistent physician relationships, were more screening-knowledgeable and better able to articulate views on screening. Men reported less consistent physician relationships, were less knowledgeable and kept decision-making processes vague and emotionally distanced (i.e. at ‘arm’s length’).
Conclusions
Marked differences were observed in obstructive CRCS attitudes per gender. Females articulated reservations about CRCS-associated distress and males suppressed negative views while ambiguously procrastinating about the task of completing screening. Future interventions could seek to reduce CRCS-related stress (females) and address the need to overcome procrastination (males).
doi:10.1186/1471-2458-13-500
PMCID: PMC3672022  PMID: 23706029
10.  Reduction of novel circulating long-chain fatty acids in colorectal cancer patients is independent of tumor burden and correlates with age 
BMC Gastroenterology  2010;10:140.
Background
Serum levels of novel hydroxy polyunsaturated ultra long-chain fatty acids (hPULCFAs) have been previously shown to be reduced in pre-treatment CRC patients compared to disease-free subjects, independent of disease stage. However, whether reduced levels of hPULCFAs result from the presence of cancer is currently unknown, as is the distribution of hPULCFAs in the general population. The following studies were carried out to assess whether conventional therapy would result in restoration of systemic hPULCFAs in CRC patients, and to investigate the relationship between hPULCFA levels and age.
Methods
Tandem mass spectrometry was used to determine serum levels of the 28 carbon-containing hPULCFA C28H46O4 (CRC-446) in the following cohorts: two independent Japanese CRC populations following surgical tumor removal (n = 86), a North American Caucasian CRC cohort (n = 150) following post-surgery combination chemo/radiation therapy, 990 randomly selected anonymized serum samples from subjects ranging between 11 and 99 years of age, as well as longitudinally collected serum samples from healthy normals (n = 8, up to 90 weeks) and stage IV CRC subjects on combination therapy (n = 12, up to 63 weeks).
Results
Serum CRC-446 levels in CRC subjects were significantly lower than controls (mean of 0.297 ± 0.07 ug/ml in controls versus 0.092 ± 0.03 in CRCs, p < 0.001), and were unaffected by surgical tumor removal or by chemo/radiation treatment (p > 0.05 between pre vs post surgery). CRC-446 levels showed a strong inverse association with age (p < E-11) across the randomly-selected cohort of 990 subjects, with no correlation observed in the CRC-positive subjects. Longitudinal intra-subject results, however, showed relatively stable CRC-446 levels over the short term of up to 90 weeks in both disease-free subjects and late-stage CRC patients.
Conclusions
Our findings show that CRC-446 levels are not affected by conventional CRC treatment and inversely correlate with age, which suggest that reduced serum CRC-446 levels likely exist prior to the development of CRC. Extrapolation of the results to a simple screening scenario showed that, compared to fecal blood testing, pre-colonoscopy screening using serum CRC-446 levels would require 80% fewer colonoscopies, would identify risk in subjects under the age of 50, and would result in increased numbers of early cases detected. The precise role these serum metabolites play in the aetiology of cancer development remains to be determined.
doi:10.1186/1471-230X-10-140
PMCID: PMC3009636  PMID: 21114854
11.  Detection of mismatch repair gene germline mutation carrier among Chinese population with colorectal cancer 
BMC Cancer  2008;8:44.
Background
Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant syndrome. The National Cancer Institute (NCI) has recommended the Revised Bethesda guidelines for screening HNPCC. There has been a great deal of research on the value of these tests in other countries. However, literature about the Chinese population is scarce. Our objective is to detect and study microsatellite instability (MSI) and mismatch repair (MMR) gene germline mutation carriers among a Chinese population with colorectal cancer.
Methods
In 146 prospectively recruited consecutive patients with clinically proven colorectal cancer, MSI carriers were identified by analysis of tumor tissue using multiplex fluorescence polymerase chain reaction (PCR) using the NCI recommended panel and classified into microsatellite instability-low (MSI-L), microsatellite instability-high (MSI-H) and microsatellite stable (MSS) groups. Immunohistochemical staining for MSH2, MSH6 and MLH1 on tissue microarrays (TMAs) was performed, and methylation of the MLH1 promoter was analyzed by quantitative methylation specific PCR (MSP). Germline mutation analysis of blood samples was performed for MSH2, MSH6 and MLH1 genes.
Results
Thirty-four out of the 146 colorectal cancers (CRCs, 23.2%) were MSI, including 19 MSI-H CRCs and 15 MSI-L CRCS. Negative staining for MSH2 was found in 8 CRCs, negative staining for MSH6 was found in 6 CRCs. One MSI-H CRC was negative for both MSH6 and MSH2. Seventeen CRCs stained negatively for MLH1. MLH1 promoter methylation was determined in 34 MSI CRCs. Hypermethylation of the MLH1 promoter occurred in 14 (73.7%) out of 19 MSI-H CRCs and 5 (33.3%) out of 15 MSI-L CRCs. Among the 34 MSI carriers and one MSS CRC with MLH1 negative staining, 8 had a MMR gene germline mutation, which accounted for 23.5% of all MSI colorectal cancers and 5.5% of all the colorectal cancers. Five patients harbored MSH2 germline mutations, and three patients harbored MSH6 germline mutations. None of the patients had an MLH1 mutation. Mutations were commonly located in exon 7 and 12 of MSH2 and exon 5 of MSH6. Right colonic lesions and mucinous carcinoma were not common in MSI carriers.
Conclusion
Our data may imply that the characteristics of HNPCC in the Chinese population are probably different from those of Western countries. Application of NCI recommended criteria may not be effective enough to identify Chinese HNPCC families. Further studies are necessary to echo or refute our results so as to make the NCI recommendation more universally applicable.
doi:10.1186/1471-2407-8-44
PMCID: PMC2275286  PMID: 18257912
12.  Colon Cancer-Specific Antigen-2 May Be Used as a Detecting and Prognostic Marker in Colorectal Cancer: A Preliminary Observation 
PLoS ONE  2014;9(4):e94252.
Background
A specific and sensitive serum marker for colorectal cancer (CRC) detection and surveillance is central to effective treatment. It was preliminarily reported that some nuclear matrix proteins may be served as a specific blood based marker for colon cancer. The objective of this study is to evaluate the value of serum CCSA-2 detection in diagnosis, prognostic estimation and surveillance for CRC.
Method
Serum CCSA-2 protein was measured in 181 various patient populations and 20 healthy donors before surgery. For 106 CRC patients, it was also measured on day 7 after surgery. Among them, 49 CRC patients' CCSA-2 protein were measured during the follow-up period according to NCCN Guideline.
Results
The serum CCSA-2 concentration in CRC patients was significantly higher than which in other patients and healthy individuals. Serum CCSA-2, at the cut-off point of 64.10 ng/mL, had a sensitivity of 98.10% and a specificity of 97.90% in separating CRC populations from all other individuals. The CCSA-2 assay was significantly more sensitive than CEA and CA19-9 assay in CRC detection. After surgery, the serum CCSA-2 level of CRC patients declined significantly, but it rebounded to a high level when recurrences occurred. The pre-operative serum CCSA-2 level in patients who had a relapse within the follow-up period was significantly higher than which in patients without relapse.
Conclusions
Serum CCSA-2 not only may be a potential biomarker using in screening and surveillance of CRC, but also may be an independent prognostic marker for CRC patients. Further clinical trials need to be performed in a larger population of patients to ulteriorly confirm these results.
doi:10.1371/journal.pone.0094252
PMCID: PMC3978011  PMID: 24710115
13.  Increased plasma levels of the APC-interacting protein MAPRE1, LRG1 and IGFBP2 preceding a diagnosis of colorectal cancer in women 
Longitudinal blood collections from cohort studies provide the means to search for proteins associated with disease prior to clinical diagnosis. We investigated plasma samples from the Women’s Health Initiative (WHI) cohort to determine quantitative differences in plasma proteins between subjects subsequently diagnosed with colorectal cancer (CRC) and matched controls that remained cancer free during the period of follow-up. Proteomic analysis of WHI samples collected prior to diagnosis of CRC resulted in the identification of six proteins with significantly (p <0.05) elevated concentrations in cases compared to controls. Proteomic analysis of two colorectal cancer cell lines showed 5 of the 6 proteins were produced by cancer cells. MAPRE1, IGFBP2, LRG1 and CEA were individually assayed by enzyme linked immunosorbent assay (ELISA) in 58 pairs of newly diagnosed CRC samples and controls and yielded significant elevations (p <0.05) among cases relative to controls. A combination of these four markers resulted in an ROC with an AUC=0.841 and 57% sensitivity at 95% specificity. This combination rule was tested in an independent set of WHI samples collected within 7 months prior to diagnosis from cases and matched controls resulting in 41% sensitivity at 95% specificity. A panel consisting of CEA, MAPRE1, IGFBP2 and LRG1 has predictive value in pre-diagnostic colorectal cancer plasmas.
doi:10.1158/1940-6207.CAPR-11-0412
PMCID: PMC3419141  PMID: 22277732
colorectal cancer; risk markers; Pre-Diagnostic samples
14.  Faecal immunochemical test accuracy in patients referred for surveillance colonoscopy: a multi-centre cohort study 
BMC Gastroenterology  2012;12:94.
Background
Given the increasing burden on colonoscopy capacity, it has been suggested that faecal immunochemical test (FIT) results could guide surveillance colonoscopy intervals. Against this background, we have evaluated the test accuracy of single and double FIT sampling to detect colorectal cancer (CRC) and/or advanced adenomas in an asymptomatic colonoscopy-controlled high-risk population.
Methods
Cohort study of asymptomatic high-risk patients (personal history of adenomas/CRC or family history of CRC), who provided one or two FITs before elective colonoscopy. Test accuracy of FIT for detection of CRC and advanced adenomas was determined (cut-off level 50 ng/ml).
Results
1,041 patients provided a FIT (516 personal history of adenomas, 172 personal history of CRC and 353 family history of CRC). Five CRCs (0.5%) and 101 advanced adenomas (9.7%) were detected by colonoscopy. Single FIT sampling resulted in a sensitivity, specificity, PPV and NPV for CRC of 80%, 89%, 3% and 99.9%, respectively, and for advanced adenoma of 28%, 91%, 24% and 92%, respectively. Double FIT sampling did not result in a significantly higher sensitivity for advanced neoplasia. Simulation of multiple screening rounds indicated that sensitivity of FIT for advanced adenoma could reach 81% after 5 screening rounds.
Conclusions
In once-only FIT sampling before surveillance colonoscopy, 70% of advanced neoplasia were missed. A simulation approach indicates that multiple screening rounds may be more promising in detecting advanced neoplasia and could potentially alleviate endoscopic burden.
doi:10.1186/1471-230X-12-94
PMCID: PMC3444435  PMID: 22828158
Colorectal cancer; Faecal immunochemical test (FIT); Surveillance; Advanced adenoma; Sensitivity
15.  MicroRNA-221 inhibits CDKN1C/p57 expression in human colorectal carcinoma 
Acta Pharmacologica Sinica  2011;32(3):375-384.
Aim:
To investigate the regulatory effect of microRNA-221 (miR-221) on CDKN1C/p57 expression in colorectal carcinoma (CRC).
Methods:
Thirty four CRC and adjacent non-tumorous tissue samples were collected individually. Total RNA and protein were isolatedand from these samples and four human CRC-derived cell lines (including HT-29, Lovo, SW-480 and Caco2). MiR-221 expression was examined using real-time RT-PCR. CRC cells were treated with or without anti-p57-siRNA prior to the addition of pre-miR-221 or anti-miR-221. The mRNA and protein levels of CDKN1C/p57 were examined using semi-quantitative RT-PCR and Western blot, respectively. CRC cell proliferation and apoptosis were assessed using MTT assay and flow cytometry, respectively. The CDKN1C/p57 3′-UTR fragment was amplified using PCR from the genomic DNA of human colon cells and inserted into a luciferase reporter construct. The reporter construct was then transfected into CRC cells together with pre-miR-221 or anti-miR-221, and the luciferase activity in the transfected cells was examined.
Results:
MiR-221 expression was significantly up-regulated in 90% of CRC samples compared to that in the adjacent non-tumorous tissue, and the expression level was positively correlated to an advanced TNM stage and local invasion. There was no significant difference in CDKN1C/p57 mRNA expression between CRC and corresponding non-tumorous tissues, whereas CDKN1C/p57 protein expression was markedly decreased in the CRC samples. A significant inverse correlation between miR-221 and CDKN1C/p57 expression was found in CRC cells. Moreover, a miR-221-specific inhibitor significantly increased CDKN1C/p57 protein expression in CRC cells. Anti-miR-221 markedly inhibited CRC cell proliferation and induced apoptosis. This inhibitory effect was abolished by pretreatment with anti-p57-siRNA, suggesting that the inhibition was mediated by CDKN1C/p57. A significant increase of the luciferase activity was observed in CRC cells co-transfected with the luciferase reporter construct and anti-miR-221.
Conclusion:
MiR-221 binds to the target site in the 3′-UTR of the CDKN1C/p57 mRNA to inhibit CDKN1C/p57 expression by post-transcriptional gene silencing to promote CRC occurrence and progress, therefore serving as a potential therapeutic target for the prevention and treatment of CRC.
doi:10.1038/aps.2010.206
PMCID: PMC4002764  PMID: 21278784
colorectal carcinoma; microRNA-221; CDKN1C/p57; proliferation; apoptosis
16.  Validation of Self-Reported Colorectal Cancer Screening Behaviors among Appalachian Residents 
Public health nursing (Boston, Mass.)  2013;30(4):10.1111/phn.12038.
Objectives
We determined the validity of self-reported colorectal cancer (CRC) screening data provided by Appalachian Ohio residents and identified correlates of providing accurate data.
Design
We conducted cross-sectional telephone interviews between September 2009 and April 2010.
Sample
Our study included Appalachian Ohio residents (n=721) ages 51–75.
Measurements
We compared self-reported CRC screening data to medical records to determine validity. Multivariable logistic regression was used to identify correlates of providing accurate self-reported screening data.
Results
About 68% of participants self-reported having any CRC screening test within recommended guidelines, while medical records indicated that only 49% were within guidelines (concordance=0.76). Concordance was higher for flexible sigmoidoscopy and FOBT compared to colonoscopy, though sensitivity and positive predictive value were much higher for colonoscopy. Participants overreported CRC screening behaviors for all tests. Participants who had a regular check-up in the last two years (OR=2.78, 95% CI: 1.15-6.73) or self-rated their health as good or better (OR=1.88, 95% CI: 1.12-3.16) were more likely to provide accurate screening data.
Conclusions
Many participants failed to provide accurate CRC screening data, and validity varied greatly across individual CRC screening tests. Future CRC screening studies among Appalachian residents should use medical records, if possible, to determine screening histories.
doi:10.1111/phn.12038
PMCID: PMC3809100  PMID: 23808856
Colorectal cancer; Cancer screening; Validity; Appalachia
17.  Colorectal cancer risk information presented by a nonphysician assistant does not increase screening rates 
Canadian Family Physician  2014;60(8):731-738.
Abstract
Objective
To determine the effectiveness of presenting individualized colorectal cancer (CRC) risk information for increasing CRC screening rates in primary care patients at above-average risk of CRC.
Design
Randomized controlled trial.
Setting
Georgia Regents University in Augusta—an academic family medicine clinic in the southeastern United States.
Participants
Outpatients (50 to 70 years of age) scheduled for routine visits in the family medicine clinic who were determined to be at above-average risk of CRC.
Interventions
Individualized CRC risk information calculated from the Your Disease Risk tool compared with a standard CRC screening handout.
Main outcome measures
Intention to complete CRC screening. Secondary measures included the proportions of subjects completing fecal occult blood tests, flexible sigmoidoscopy, and colonoscopy.
Results
A total of 1147 consecutive records were reviewed to determine eligibility. Overall, 210 (37.7%) of 557 eligible participants were randomized to receive either individualized CRC risk information (prepared by a research assistant) or a standard CRC screening handout. The intervention group had a mean (SD) age of 55.7 (4.8) years and the control group had a mean (SD) age of 55.6 (4.6) years. Two-thirds of the participants in each group were female. The intervention group and the control group were matched by race (P = .40). There was no significant difference between groups for intention to complete CRC screening (P = .58). Overall, 26.7% of the intervention participants and 27.7% of the control participants completed 1 or more CRC screening tests (P = .66).
Conclusion
Presentation of individualized CRC risk information by a nonphysician assistant as a decision aid did not result in higher CRC screening rates in primary care patients compared with presentation of general CRC screening information. Future research is needed to determine if physician presentation of CRC risk information would result in increased screening rates compared with research assistant presentation.
PMCID: PMC4131964  PMID: 25122819
18.  Detection of Methylated SEPT9 in Plasma Is a Reliable Screening Method for Both Left- and Right-Sided Colon Cancers 
PLoS ONE  2012;7(9):e46000.
Background
Methylated Septin 9 (SEPT9) is a sensitive biomarker for colorectal cancer (CRC) from peripheral blood. However, its relationship to cancer localization, guaiac-based fecal occult blood test (gFOBT) and carcinoembryonic antigen (CEA) have not been described.
Methodology/Principal Findings
Plasma samples were collected for SEPT9 analysis from patients with no evidence of disease (NED) (n = 92) before colonoscopy and CRC (n = 92) before surgical treatment. DNA was isolated and bisulfite-converted using Epi proColon kit 2.0. Qualitative determination was performed using Epi proColon 2.0 RT-PCR assay. Samples for gFOBT and CEA analysis were collected from NED (n = 17 and 27, respectively) and CRC (n = 22 and 27, respectively). SEPT9 test was positive in 15.2% (14/92) of NED and 95.6% (88/92) of CRC, including 100% (67/67) from stage II to stage IV CRC and 84% (21/25) of stage I CRC when a sample was called positive if 1 out of 3 PCR replicates was positive. In a second analysis (2 out of 3 PCR replicates) specificity improved to 99% (91/92) of NEDs, at a sensitivity of 79.3% (73/92) of SEPT9 positives in CRC. gFOBT was positive in 29.4% (5/17) of NED and 68.2% (15/22) of CRC and elevated CEA levels were detected in 14.8% (4/27) of NED and 51.8% (14/27) of CRC. Both SEPT9 (84.8%) and CEA (85.2%) showed higher specificity than gFOBT (70.6%). SEPT9 was positive in 96.4% (54/56) of left-sided colon cancer (LSCC) cases and 94.4% (34/36) of right-sided colon cancer (RSCC) cases. gFOBT was positive in 83.3% (10/12) of cases with LSCC and 50% (5/10) of cases with RSCC, elevated CEA was detected 60% (9/15) of LSCC and 41.7% (5/12) of RSCC.
Conclusions/Significance
The high degree of sensitivity and specificity of SEPT9 in plasma makes it a better method to detect CRC than gFOBT and CEA, even for the more difficult to detect RSCC.
doi:10.1371/journal.pone.0046000
PMCID: PMC3457959  PMID: 23049919
19.  A systems biology approach to the global analysis of transcription factors in colorectal cancer 
BMC Cancer  2012;12:331.
Background
Biological entities do not perform in isolation, and often, it is the nature and degree of interactions among numerous biological entities which ultimately determines any final outcome. Hence, experimental data on any single biological entity can be of limited value when considered only in isolation. To address this, we propose that augmenting individual entity data with the literature will not only better define the entity’s own significance but also uncover relationships with novel biological entities.
To test this notion, we developed a comprehensive text mining and computational methodology that focused on discovering new targets of one class of molecular entities, transcription factors (TF), within one particular disease, colorectal cancer (CRC).
Methods
We used 39 molecular entities known to be associated with CRC along with six colorectal cancer terms as the bait list, or list of search terms, for mining the biomedical literature to identify CRC-specific genes and proteins. Using the literature-mined data, we constructed a global TF interaction network for CRC. We then developed a multi-level, multi-parametric methodology to identify TFs to CRC.
Results
The small bait list, when augmented with literature-mined data, identified a large number of biological entities associated with CRC. The relative importance of these TF and their associated modules was identified using functional and topological features. Additional validation of these highly-ranked TF using the literature strengthened our findings. Some of the novel TF that we identified were: SLUG, RUNX1, IRF1, HIF1A, ATF-2, ABL1, ELK-1 and GATA-1. Some of these TFs are associated with functional modules in known pathways of CRC, including the Beta-catenin/development, immune response, transcription, and DNA damage pathways.
Conclusions
Our methodology of using text mining data and a multi-level, multi-parameter scoring technique was able to identify both known and novel TF that have roles in CRC. Starting with just one TF (SMAD3) in the bait list, the literature mining process identified an additional 116 CRC-associated TFs. Our network-based analysis showed that these TFs all belonged to any of 13 major functional groups that are known to play important roles in CRC. Among these identified TFs, we obtained a novel six-node module consisting of ATF2-P53-JNK1-ELK1-EPHB2-HIF1A, from which the novel JNK1-ELK1 association could potentially be a significant marker for CRC.
doi:10.1186/1471-2407-12-331
PMCID: PMC3539921  PMID: 22852817
20.  Diagnostic Accuracy of Elevated Serum Carcinoembryonic Antigen for Recurrence in Postoperative Stage II Colorectal Cancer Patients: Comparison With Stage III 
Annals of Coloproctology  2013;29(4):155-159.
Purpose
Elevated levels of serum carcinoembryonic antigen (CEA) following a curative resection of colorectal cancer (CRC) indicate recurrence; however, the levels of CEA may be elevated above the normal limit without recurrence. The aim of this study is to analyze the diagnostic accuracy of elevated serum CEA for predicting recurrence in postoperative stage II and stage III CRC patients.
Methods
A total of 336 stage II and stage III CRC patients who underwent a curative resection between January 2005 and October 2009 were enrolled. Sensitivities, specificities, positive predictive values (PPVs), negative predictive values (NPVs), likelihood ratios and post-test probabilities of recurrence associated with elevated CEA were analyzed and compared.
Results
The median follow-up duration was 45 months (36 to 134 months). Twenty-seven of 189 stage II patients (14.3%) and 52 of 147 stage III patients (35.4%) developed recurrence during the follow-up period. Sensitivities, specificities, PPVs, and NPVs of elevated CEA were 37.0%, 91.4%, 41.7%, and 89.7%, respectively, in stage II patients and 46.2%, 90.5%, 72.7%, and 75.4% in stage III patients. Post-test probabilities of recurrence associated with elevated CEA were 41.8% in stage II patients and 71.9% in stage III patients.
Conclusion
The predictive performance of the probability of recurrence associated with elevated serum CEA after a curative resection in stage II CRC patients is lower than that in stage III CRC patients.
doi:10.3393/ac.2013.29.4.155
PMCID: PMC3767865  PMID: 24032116
Carcinoembryonic antigen; Tumor marker; Colorectal neoplasms; Recurrence; Accuracy
21.  The influence of health literacy on colorectal cancer screening knowledge, beliefs and behavior. 
OBJECTIVE: To determine if health literacy is associated with knowledge of colorectal cancer (CRC) and CRC screening tests, with perceived benefits and barriers to CRC screening, with perceived risk of CRC, with reported self-efficacy for completing CRC screening and with receipt of CRC tests. METHODS: A convenience sample of 99 subjects completed a health literacy assessment, the Rapid Estimate of Adult Literacy in Medicine (REALM) and a structured interview. RESULTS: Limited or inadequate health literacy was significantly associated with less knowledge about CRC and CRC screening and with more reported barriers to completing fecal occult blood testing (FOBT) and colonoscopy in multivariate analysis. Health literacy was not associated with perceived benefits or reported self-efficacy for completing FOBT or colonoscopy, with perceived risk of developing CRC or with completing CRC tests. However, our small sample size limited our power to detect differences. CONCLUSIONS: Patients with limited health literacy have less knowledge about CRC and CRC screening and report more barriers to completing FOBT and colonoscopy. Interventions to improve CRC screening should consider the health literacy of patients, especially when addressing barriers to screening. Future studies are needed to better define the role of health literacy in CRC screening.
PMCID: PMC2574401  PMID: 17987913
22.  Microsatellite instability among individuals of Hispanic origin with colorectal cancer 
Cancer  2010;116(21):4965-4972.
Background
Though the presence of microsatellite instability (MSI) in patients with colorectal cancer (CRC) may have implications for prognosis, therapy, and family counseling, MSI prevalence is not well described among individuals of Hispanic origin in the United States (US) with CRC.
Methods
We conducted a retrospective cohort study employing a hospital-based tumor registry to identify individuals of Hispanic origin diagnosed with CRC. Clinical data and tumor samples were retrieved. Molecular analyses included testing for MSI using a panel of 5 mononucleotide markers (BAT25, BAT26, NR21, NR24 and NR27) in a pentaplex polymerase chain reaction assay, as well as immunohistochemistry for the MMR proteins MLH1, MSH2, MSH6, and PMHS2 on representative tissue.
Results
111 individuals of Hispanic origin with CRC were identified. 41.1% were women, median age was 57 years (IQR:47.1–63.5). 11 (9.8%, 95%CI:4.2–15.6) had MSI CRC, while 14 (14.6%, 95%CI:7.3–21.8) had CRC with≥1 MMR protein abnormality. 10 of 11 individuals with MSI had clinical or molecular characteristics suspicious for Lynch syndrome such as abnormal expression of MSH2 and/or MSH6 (n=7) or age<50 at diagnosis (n=7).
Conclusions
The prevalence of MSI CRC among Hispanic individuals may be similar to other races and ethnicities, but clinical-pathological characteristics, including age at diagnosis and pattern of abnormal MMR protein expression, suggests that sporadic MSI CRC may be less common in individuals of Hispanic origin, and that much MSI observed in this situation may be attributable to Lynch syndrome. Further exploration of the causes of disparate presentations of CRC by ethnicity and race is warranted.
doi:10.1002/cncr.25486
PMCID: PMC2963686  PMID: 20665498
colorectal neoplasms; Hispanic Americans; genomic instability; microsatellite instability; DNA mismatch repair
23.  Detection of Methylated Septin 9 in Tissue and Plasma of Colorectal Patients with Neoplasia and the Relationship to the Amount of Circulating Cell-Free DNA 
PLoS ONE  2014;9(12):e115415.
Background
Determination of methylated Septin 9 (mSEPT9) in plasma has been shown to be a sensitive and specific biomarker for colorectal cancer (CRC). However, the relationship between methylated DNA in plasma and colon tissue of the same subjects has not been reported.
Methods
Plasma and matching biopsy samples were collected from 24 patients with no evidence of disease (NED), 26 patients with adenoma and 34 patients with CRC. Following bisulfite conversion of DNA a commercial RT-PCR assay was used to determine the total amount of DNA in each sample and the fraction of mSEPT9 DNA. The Septin-9 protein was assessed using immunohistochemistry.
Results
The percent of methylated reference (PMR) values for SEPT9 above a PMR threshold of 1% were detected in 4.2% (1/24) of NED, 100% (26/26) of adenoma and 97.1% (33/34) of CRC tissues. PMR differences between NED vs. adenoma and NED vs. CRC comparisons were significant (p<0.001). In matching plasma samples using a PMR cut-off level of 0.01%, SEPT9 methylation was 8.3% (2/24) of NED, 30.8% (8/26) of adenoma and 88.2% (30/34) of CRC. Significant PMR differences were observed between NED vs. CRC (p<0.01) and adenoma vs. CRC (p<0.01). Significant differences (p<0.01) were found in the amount of cfDNA (circulating cell-free DNA) between NED and CRC, and a modest correlation was observed between mSEPT9 concentration and cfDNA of cancer (R2 = 0.48). The level of Septin-9 protein in tissues was inversely correlated to mSEPT9 levels with abundant expression in normals, and diminished expression in adenomas and tumors.
Conclusions
Methylated SEPT9 was detected in all tissue samples. In plasma samples, elevated mSEPT9 values were detected in CRC, but not in adenomas. Tissue levels of mSEPT9 alone are not sufficient to predict mSEPT9 levels in plasma. Additional parameters including the amount of cfDNA in plasma appear to also play a role.
doi:10.1371/journal.pone.0115415
PMCID: PMC4272286  PMID: 25526039
24.  Serum miR-21 as a Diagnostic and Prognostic Biomarker in Colorectal Cancer 
Background
The oncogenic microRNAs (miRNAs) miR-21 and miR-31 negatively regulate tumor-suppressor genes. Their potential as serum biomarkers has not been determined in human colorectal cancer (CRC).
Methods
To determine whether miR-21 and miR-31 are secretory miRNAs, we screened expression in medium from 2 CRC cell lines, which was followed by serum analysis from 12 CRC patients and 12 control subjects. We validated expression of candidate miRNAs in serum samples from an independent cohort of 186 CRC patients, 60 postoperative patients, 43 advanced adenoma patients, and 53 control subjects. We analyzed miR-21 expression in 166 matched primary CRC tissues to determine whether serum miRNAs reflect expression in CRC. Patient survival analyses were performed by Kaplan–Meier analyses and Cox regression models. All statistical tests were two-sided.
Results
Although miR-21 was secreted from CRC cell lines and upregulated in serum of CRC patients, no statistically significant differences were observed in serum miR-31 expression between CRC patients and control subjects. In the validation cohort, miR-21 levels were statistically significantly elevated in preoperative serum from patients with adenomas (P < .001) and CRCs (P < .001). Importantly, miR-21 expression dropped in postoperative serum from patients who underwent curative surgery (P < .001). Serum miR-21 levels robustly distinguished adenoma (area under the curve [AUC] = 0.813; 95% confidence interval [CI] = 0.691 to 0.910) and CRC (AUC = 0.919; 95% CI = 0.867 to 0.958) patients from control subjects. High miR-21 expression in serum and tissue was statistically significantly associated with tumor size, distant metastasis, and poor survival. Moreover, serum miR-21 was an independent prognostic marker for CRC (hazard ratio = 4.12; 95% CI = 1.10 to 15.4; P = .03).
Conclusions
Serum miR-21 is a promising biomarker for the early detection and prognosis of CRC.
doi:10.1093/jnci/djt101
PMCID: PMC3687369  PMID: 23704278
25.  Effects of common haplotypes of the ileal sodium dependent bile acid transporter gene on the development of sporadic and familial colorectal cancer: A case control study 
BMC Medical Genetics  2008;9:70.
Background
The genetics of sporadic and non-syndromic familial colorectal cancer (CRC) is not well defined. However, genetic factors that promote the development of precursor lesions, i.e. adenomas, might also predispose to CRC. Recently, an association of colorectal adenoma with two variants (c.507C>T;p.L169L and c.511G>T;p.A171S) of the ileal sodium dependent bile acid transporter gene (SLC10A2) has been reported. Here, we reconstructed haplotypes of the SLC10A2 gene locus and tested for association with non-syndromic familial and sporadic CRC compared to 'hyper-normal' controls who displayed no colorectal polyps on screening colonoscopy.
Methods
We included 150 patients with sporadic CRC, 93 patients with familial CRC but exclusion of familial adenomatous polyposis and Lynch's syndrome, and 204 'hyper-normal' controls. Haplotype-tagging SLC10A2 gene variants were identified in the Hapmap database and genotyped using PCR-based 5' exonuclease assays with fluorescent dye-labelled probes. Haplotypes were reconstructed using the PHASE algorithm. Association testing was performed with both SNPs and reconstructed haplotypes.
Results
Minor allele frequencies of all SLC10A2 polymorphisms are within previously reported ranges, and no deviations from Hardy-Weinberg equilibrium are observed. However, we found no association with any of the SLC10A2 haplotypes with sporadic or familial CRC in our samples (all P values > 0.05).
Conclusion
Common variants of the SLC10A2 gene are not associated with sporadic or familial CRC. Hence, albeit this gene might be associated with early stages of colorectal neoplasia, it appears not to represent a major risk factor for progression to CRC.
doi:10.1186/1471-2350-9-70
PMCID: PMC2492852  PMID: 18644122

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