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1.  Distinguishing Screening from Diagnostic Mammograms using Medicare Claims Data 
Medical care  2012;10.1097/MLR.0b013e318269e0f5.
Background
Medicare claims data may be a fruitful data source for research or quality measurement in mammography. However, it is uncertain whether claims data can accurately distinguish screening from diagnostic mammograms, particularly when claims are not linked with cancer registry data.
Objectives
To validate claims-based algorithms that can identify screening mammograms with high positive predictive value (PPV) in claims data with and without cancer registry linkage.
Research Design
Development of claims-derived algorithms using classification and regression tree analyses within a random half-sample of bilateral mammogram claims with validation in the remaining half-sample.
Subjects
Female fee-for-service Medicare enrollees age 66 years and older who underwent bilateral mammography from 1999 to 2005 within Breast Cancer Surveillance Consortium (BCSC) registries in four states (CA, NC, NH, and VT), enabling linkage of claims and BCSC mammography data (N=383,730 mammograms obtained by 146,346 women).
Measures
Sensitivity, specificity, and PPV of algorithmic designation of a “screening” purpose of the mammogram using a BCSC-derived reference standard.
Results
In claims data without cancer registry linkage, a three-step claims derived algorithm identified screening mammograms with 97.1% sensitivity, 69.4% specificity, and a PPV of 94.9%. In claims that are linked to cancer registry data, a similar three-step algorithm had higher sensitivity (99.7%), similar specificity (62.7%), and higher PPV (97.4%).
Conclusions
Simple algorithms can identify Medicare claims for screening mammography with high predictive values in Medicare claims alone and in claims linked with cancer registry data.
doi:10.1097/MLR.0b013e318269e0f5
PMCID: PMC3534834  PMID: 22922433
Breast Cancer Screening; Mammography; Validation Studies; Medicare; Quality Assessment
2.  Short-Term Outcomes of Screening Mammography Using Computer-Aided Detection 
Annals of internal medicine  2013;158(8):580-587.
Background
Computer-aided detection (CAD) has rapidly diffused into screening mammography practice despite limited and conflicting data on its clinical effect.
Objective
To determine associations between CAD use during screening mammography and the incidence of ductal carcinoma in situ (DCIS) and invasive breast cancer, invasive cancer stage, and diagnostic testing.
Design
Retrospective cohort study.
Setting
Medicare program.
Participants
Women aged 67 to 89 years having screening mammography between 2001 and 2006 in U.S. SEER (Surveillance, Epidemiology and End Results) regions (409 459 mammograms from 163 099 women).
Measurements
Incident DCIS and invasive breast cancer within 1 year after mammography, invasive cancer stage, and diagnostic testing within 90 days after screening among women without breast cancer.
Results
From 2001 to 2006, CAD prevalence increased from 3.6% to 60.5%. Use of CAD was associated with greater DCIS incidence (adjusted odds ratio [OR], 1.17 [95% CI, 1.11 to 1.23]) but no difference in invasive breast cancer incidence (adjusted OR, 1.00 [CI, 0.97 to 1.03]). Among women with invasive cancer, CAD was associated with greater likelihood of stage I to II versus III to IV cancer (adjusted OR, 1.27 [CI, 1.14 to 1.41]). In women without breast cancer, CAD was associated with increased odds of diagnostic mammography (adjusted OR, 1.28 [CI, 1.27 to 1.29]), breast ultrasonography (adjusted OR, 1.07 [CI, 1.06 to 1.09]), and breast biopsy (adjusted OR, 1.10 [CI, 1.08 to 1.12]).
Limitation
Short follow-up for cancer stage, potential unmeasured confounding, and uncertain generalizability to younger women.
Conclusion
Use of CAD during screening mammography among Medicare enrollees is associated with increased DCIS incidence, the diagnosis of invasive breast cancer at earlier stages, and increased diagnostic testing among women without breast cancer.
Primary Funding Source
Center for Healthcare Policy and Research, University of California, Davis.
doi:10.7326/0003-4819-158-8-201304160-00002
PMCID: PMC3772716  PMID: 23588746
3.  External Validation of Medicare Claims Codes for Digital Mammography and Computer-Aided Detection 
Background
While Medicare claims are a potential resource for clinical mammography research or quality monitoring, the validity of key data elements remains uncertain. Claims codes for digital mammography and computer-aided detection (CAD), for example, have not been validated against a credible external reference standard.
Methods
We matched Medicare mammography claims for women who received bilateral mammograms from 2003 to 2006 to corresponding mammography data from the Breast Cancer Surveillance Consortium (BCSC) registries in four U.S. states (N=253,727 mammograms received by 120,709 women). We assessed the accuracy of the claims-based classifications of bilateral mammograms as either digital vs. film and CAD vs. non-CAD relative to a reference standard derived from BCSC data.
Results
Claims data correctly classified the large majority of film and digital mammograms (97.2% and 97.3%, respectively), yielding excellent agreement beyond chance (kappa=0.90). Claims data correctly classified the large majority of CAD mammograms (96.6%) but a lower percentage of non-CAD mammograms (86.7%). Agreement beyond chance remained high for CAD classification (kappa = 0.83). From 2003 to 2006, the predictive values of claims-based digital and CAD classifications increased as the sample prevalences of each technology increased.
Conclusion
Medicare claims data can accurately distinguish film and digital bilateral mammograms and mammograms performed with and without CAD.
Impact
The validity of Medicare claims data regarding film vs. digital mammography and computer-aided detection suggests that these data elements can be useful in research and quality improvement.
doi:10.1158/1055-9965.EPI-12-0406
PMCID: PMC3422017  PMID: 22695737
4.  Delivery of Cancer Screening 
Archives of internal medicine  2007;167(6):580-585.
Background
Patients and physicians strongly endorse the importance of preventive or periodic health examinations (PHEs). However, the extent to which PHEs contribute to the delivery of cancer screening is uncertain.
Methods
In a retrospective cohort study, we determined the association between receipt of a PHE and cancer testing in a population-based sample of enrollees in a Washington State health plan who were aged 52 to 78 years and eligible for colorectal, breast, or prostate cancer screening in 2002–2003 (N = 64 288). Outcomes included completion of any colorectal cancer testing (fecal occult blood testing, sigmoidoscopy, colonoscopy, or barium enema), screening mammography, and prostate-specific antigen testing.
Results
More than half (52.4%) of the enrollees received a PHE during the study period. After adjusting for demographics, comorbidity, number of outpatient visits, and historical preventive service use before January 1, 2002, receipt of a PHE was significantly associated with completion of colorectal cancer testing (incidence difference, 40.4% [95% confidence interval (CI), 39.4%–41.3%]; relative incidence, 3.47 [95% CI, 3.34–3.59]), screening mammography [incidence difference, 14.2% [95% CI, 12.7%–15.7%]; relative incidence, 1.23 [95% CI, 1.20–1.25]), and prostate-specific antigen testing (incidence difference, 39.4% [95% CI, 38.3%–40.5%]; relative incidence, 3.06 [95% CI, 2.95–3.18]).
Conclusions
Among managed care enrollees eligible for cancer screening, PHE receipt is associated with completion of colorectal, breast, and prostate cancer testing. In similar populations, the PHE may serve as a clinically important forum for the promotion of evidence-based colorectal cancer and breast cancer screening and of screening with relatively less empirical support, such as prostate cancer screening.
doi:10.1001/archinte.167.6.580
PMCID: PMC3443471  PMID: 17389289
5.  Effectiveness of Computer-Aided Detection in Community Mammography Practice 
Background
Computer-aided detection (CAD) is applied during screening mammography for millions of US women annually, although it is uncertain whether CAD improves breast cancer detection when used by community radiologists.
Methods
We investigated the association between CAD use during film-screen screening mammography and specificity, sensitivity, positive predictive value, cancer detection rates, and prognostic characteristics of breast cancers (stage, size, and node involvement). Records from 684 956 women who received more than 1.6 million film-screen mammograms at Breast Cancer Surveillance Consortium facilities in seven states in the United States from 1998 to 2006 were analyzed. We used random-effects logistic regression to estimate associations between CAD and specificity (true-negative examinations among women without breast cancer), sensitivity (true-positive examinations among women with breast cancer diagnosed within 1 year of mammography), and positive predictive value (breast cancer diagnosed after positive mammograms) while adjusting for mammography registry, patient age, time since previous mammography, breast density, use of hormone replacement therapy, and year of examination (1998–2002 vs 2003–2006). All statistical tests were two-sided.
Results
Of 90 total facilities, 25 (27.8%) adopted CAD and used it for an average of 27.5 study months. In adjusted analyses, CAD use was associated with statistically significantly lower specificity (OR = 0.87, 95% confidence interval [CI] = 0.85 to 0.89, P < .001) and positive predictive value (OR = 0.89, 95% CI = 0.80 to 0.99, P = .03). A non-statistically significant increase in overall sensitivity with CAD (OR = 1.06, 95% CI = 0.84 to 1.33, P = .62) was attributed to increased sensitivity for ductal carcinoma in situ (OR = 1.55, 95% CI = 0.83 to 2.91; P = .17), although sensitivity for invasive cancer was similar with or without CAD (OR = 0.96, 95% CI = 0.75 to 1.24; P = .77). CAD was not associated with higher breast cancer detection rates or more favorable stage, size, or lymph node status of invasive breast cancer.
Conclusion
CAD use during film-screen screening mammography in the United States is associated with decreased specificity but not with improvement in the detection rate or prognostic characteristics of invasive breast cancer.
doi:10.1093/jnci/djr206
PMCID: PMC3149041  PMID: 21795668
6.  Influence of Computer-Aided Detection on Performance of Screening Mammography 
The New England journal of medicine  2007;356(14):1399-1409.
Background
Computer-aided detection identifies suspicious findings on mammograms to assist radiologists. Since the Food and Drug Administration approved the technology in 1998, it has been disseminated into practice, but its effect on the accuracy of interpretation is unclear.
Methods
We determined the association between the use of computer-aided detection at mammography facilities and the performance of screening mammography from 1998 through 2002 at 43 facilities in three states. We had complete data for 222,135 women (a total of 429,345 mammograms), including 2351 women who received a diagnosis of breast cancer within 1 year after screening. We calculated the specificity, sensitivity, and positive predictive value of screening mammography with and without computer-aided detection, as well as the rates of biopsy and breast-cancer detection and the overall accuracy, measured as the area under the receiver-operating-characteristic (ROC) curve.
Results
Seven facilities (16%) implemented computer-aided detection during the study period. Diagnostic specificity decreased from 90.2% before implementation to 87.2% after implementation (P<0.001), the positive predictive value decreased from 4.1% to 3.2% (P = 0.01), and the rate of biopsy increased by 19.7% (P<0.001). The increase in sensitivity from 80.4% before implementation of computer-aided detection to 84.0% after implementation was not significant (P = 0.32). The change in the cancer-detection rate (including invasive breast cancers and ductal carcinomas in situ) was not significant (4.15 cases per 1000 screening mammograms before implementation and 4.20 cases after implementation, P = 0.90). Analyses of data from all 43 facilities showed that the use of computer-aided detection was associated with significantly lower overall accuracy than was nonuse (area under the ROC curve, 0.871 vs. 0.919; P = 0.005).
Conclusions
The use of computer-aided detection is associated with reduced accuracy of interpretation of screening mammograms. The increased rate of biopsy with the use of computer-aided detection is not clearly associated with improved detection of invasive breast cancer.
doi:10.1056/NEJMoa066099
PMCID: PMC3182841  PMID: 17409321
7.  Reality Check: Perceived Versus Actual Performance of Community Mammographers 
OBJECTIVE
Federal regulations mandate that radiologists receive regular albeit limited feedback regarding their interpretive accuracy in mammography. We sought to determine whether radiologists who regularly receive more extensive feedback can report their actual performance in screening mammography accurately.
SUBJECTS AND METHODS
Radiologists (n = 105) who routinely interpret screening mammograms in three states (Washington, Colorado, and New Hampshire) completed a mailed survey in 2001. Radiologists were asked to estimate how frequently they recommended additional diagnostic testing after screening mammography and the positive predictive value of their recommendations for biopsy (PPV2). We then used outcomes from 336,128 screening mammography examinations interpreted by the radiologists from 1998 to 2001 to ascertain their true rates of recommendations for diagnostic testing and PPV2.
RESULTS
Radiologists’ self-reported rate of recommending immediate additional imaging (11.1%) exceeded their actual rate (9.1%) (mean difference, 1.9%; 95% confidence interval [CI], 0.9–3.0%). The mean self-reported rate of recommending short-interval follow-up was 6.2%; the true rate was 1.8% (mean difference, 4.3%; 95% CI, 3.6–5.1%). Similarly, the mean self-reported and true rates of recommending immediate biopsy or surgical evaluation were 3.2% and 0.6%, respectively (mean difference, 2.6%; 95% CI, 1.8–3.4%). Conversely, radiologists’ mean self-reported PPV2 (18.3%) was significantly less than their mean true PPV2 (27.6%) (mean difference, −9.3%; 95% CI, −12.4% to −6.2%).
CONCLUSION
Despite regular performance feedback, community radiologists may overestimate their true rates of recommending further evaluation after screening mammography and underestimate their true positive predictive value.
doi:10.2214/AJR.05.0455
PMCID: PMC3149896  PMID: 16794153
breast cancer; breast imaging; mammography
8.  Intraclass Correlation Estimates for Cancer Screening Outcomes: Estimates and Applications in the Design of Group-Randomized Cancer Screening Studies 
Background
Screening has become one of our best tools for early detection and prevention of cancer. The group-randomized trial is the most rigorous experimental design for evaluating multilevel interventions. However, identifying the proper sample size for a group-randomized trial requires reliable estimates of intraclass correlation (ICC) for screening outcomes, which are not available to researchers. We present crude and adjusted ICC estimates for cancer screening outcomes for various levels of aggregation (physician, clinic, and county) and provide an example of how these ICC estimates may be used in the design of a future trial.
Methods
Investigators working in the area of cancer screening were contacted and asked to provide crude and adjusted ICC estimates using the analysis of variance method estimator.
Results
Of the 29 investigators identified, estimates were obtained from 10 investigators who had relevant data. ICC estimates were calculated from 13 different studies, with more than half of the studies collecting information on colorectal screening. In the majority of cases, ICC estimates could be adjusted for age, education, and other demographic characteristics, leading to a reduction in the ICC. ICC estimates varied considerably by cancer site and level of aggregation of the groups.
Conclusions
Previously, only two articles had published ICCs for cancer screening outcomes. We have complied more than 130 crude and adjusted ICC estimates covering breast, cervical, colon, and prostate screening and have detailed them by level of aggregation, screening measure, and study characteristics. We have also demonstrated their use in planning a future trial and the need for the evaluation of the proposed interval estimator for binary outcomes under conditions typically seen in GRTs.
doi:10.1093/jncimonographs/lgq011
PMCID: PMC2924625  PMID: 20386058
9.  Intraclass Correlation Estimates for Cancer Screening Outcomes: Estimates and Applications in the Design of Group-Randomized Cancer Screening Studies 
Background
Screening has become one of our best tools for early detection and prevention of cancer. The group-randomized trial is the most rigorous experimental design for evaluating multilevel interventions. However, identifying the proper sample size for a group-randomized trial requires reliable estimates of intraclass correlation (ICC) for screening outcomes, which are not available to researchers. We present crude and adjusted ICC estimates for cancer screening outcomes for various levels of aggregation (physician, clinic, and county) and provide an example of how these ICC estimates may be used in the design of a future trial.
Methods
Investigators working in the area of cancer screening were contacted and asked to provide crude and adjusted ICC estimates using the analysis of variance method estimator.
Results
Of the 29 investigators identified, estimates were obtained from 10 investigators who had relevant data. ICC estimates were calculated from 13 different studies, with more than half of the studies collecting information on colorectal screening. In the majority of cases, ICC estimates could be adjusted for age, education, and other demographic characteristics, leading to a reduction in the ICC. ICC estimates varied considerably by cancer site and level of aggregation of the groups.
Conclusions
Previously, only two articles had published ICCs for cancer screening outcomes. We have complied more than 130 crude and adjusted ICC estimates covering breast, cervical, colon, and prostate screening and have detailed them by level of aggregation, screening measure, and study characteristics. We have also demonstrated their use in planning a future trial and the need for the evaluation of the proposed interval estimator for binary outcomes under conditions typically seen in GRTs.
doi:10.1093/jncimonographs/lgq011
PMCID: PMC2924625  PMID: 20386058
10.  Influence of Primary Care Use on Population Delivery of Colorectal Cancer Screening 
Objective
Colorectal cancer (CRC) screening is commonly initiated during primary care visits. Thus, at the population level, limited primary care attendance may constitute a substantial barrier to CRC screening uptake. Within a defined population, we quantified the percent of CRC screening underuse that is potentially explained by low use of primary care visits.
Methods
Among 48,712 adults aged 50-78 years eligible for CRC screening within a Washington state health plan, we estimated the degree to which a lack of CRC screening in 2002-2003 (fecal occult blood testing, sigmoidoscopy, or colonoscopy) was attributable to low primary care use, expressed as the population attributable risk percent (PAR%) associated with 0 to 3 primary care visits during the two-year period.
Results
In analyses adjusted for age, comorbidity, non-primary care visit use, and prior preventive service use, low primary care use in 2002-2003 was strongly associated with a lack of CRC screening among both women and men. However, a majority of unscreened women and men had >=4 primary care visits. Thus, whether low primary care use was defined as 0, 0 to 1, 0 to 2, or 0 to 3 primary care visits, the PAR% associated with low primary care use was large in neither women (range: 3.0-6.8%) nor men (range: 5.6-11.5%).
Conclusions
Health plan outreach efforts to encourage primary care attendance would be unlikely to substantially increase population uptake of CRC screening. In similar settings, resources might be more fruitfully devoted to the optimization of screening delivery during primary care visits that patients already attend.
doi:10.1158/1055-9965.EPI-08-0765
PMCID: PMC2731702  PMID: 19190140
Primary Care; Colorectal Cancer Screening; Gender; Healthcare Disparities; Multivariable Analysis
11.  Mammography Facility Characteristics Associated With Interpretive Accuracy of Screening Mammography 
Background
Although interpretive performance varies substantially among radiologists, such variation has not been examined among mammography facilities. Understanding sources of facility variation could become a foundation for improving interpretive performance.
Methods
In this cross-sectional study conducted between 1996 and 2002, we surveyed 53 facilities to evaluate associations between facility structure, interpretive process characteristics, and interpretive performance of screening mammography (ie, sensitivity, specificity, positive predictive value [PPV1], and the likelihood of cancer among women who were referred for biopsy [PPV2]). Measures of interpretive performance were ascertained prospectively from mammography interpretations and cancer data collected by the Breast Cancer Surveillance Consortium. Logistic regression and receiver operating characteristic (ROC) curve analyses estimated the association between facility characteristics and mammography interpretive performance or accuracy (area under the ROC curve [AUC]). All P values were two-sided.
Results
Of the 53 eligible facilities, data on 44 could be analyzed. These 44 facilities accounted for 484 463 screening mammograms performed on 237 669 women, of whom 2686 were diagnosed with breast cancer during follow-up. Among the 44 facilities, mean sensitivity was 79.6% (95% confidence interval [CI] = 74.3% to 84.9%), mean specificity was 90.2% (95% CI = 88.3% to 92.0%), mean PPV1 was 4.1% (95% CI = 3.5% to 4.7%), and mean PPV2 was 38.8% (95% CI = 32.6% to 45.0%). The facilities varied statistically significantly in specificity (P < .001), PPV1 (P < .001), and PPV2 (P = .002) but not in sensitivity (P = .99). AUC was higher among facilities that offered screening mammograms alone vs those that offered screening and diagnostic mammograms (0.943 vs 0.911, P = .006), had a breast imaging specialist interpreting mammograms vs not (0.932 vs 0.905, P = .004), did not perform double reading vs independent double reading vs consensus double reading (0.925 vs 0.915 vs 0.887, P = .034), or conducted audit reviews two or more times per year vs annually vs at an unknown frequency (0.929 vs 0.904 vs 0.900, P = .018).
Conclusion
Mammography interpretive performance varies statistically significantly by facility.
doi:10.1093/jnci/djn172
PMCID: PMC2430588  PMID: 18544742
12.  Specificity of Clinical Breast Examination in Community Practice 
Background
Millions of women receive clinical breast examination (CBE) each year, as either a breast cancer screening test or a diagnostic test for breast symptoms. While screening CBE had moderately high specificity (∼94%) in clinical trials, community clinicians may be comparatively inexperienced and may conduct relatively brief examinations, resulting in even higher specificity but lower sensitivity.
Objective
To estimate the specificity of screening and diagnostic CBE in clinical practice and identify patient factors associated with specificity.
Design
Retrospective cohort study.
Subjects
Breast-cancer-free female health plan enrollees in 5 states (WA, OR, CA, MA, and MN) who received CBE (N = 1,484).
Measurements
Medical charts were abstracted to ascertain breast cancer risk factors, examination purpose (screening vs diagnostic), and results (true-negative vs false-positive). Women were considered “average-risk” if they had neither a family history of breast cancer nor a prior breast biopsy and “increased-risk” otherwise.
Results
Among average- and increased-risk women, respectively, the specificity (true-negative proportion) of screening CBE was 99.4% [95% confidence interval (CI): 98.8–99.7%] and 97.1% (95% CI: 95.7–98.0%), and the specificity of diagnostic CBE was 68.7% (95% CI: 59.7–76.5%) and 57.1% (95% CI: 51.1–63.0%). The odds of a true-negative screening CBE (specificity) were significantly lower among women at increased risk of breast cancer (adjusted odds ratio 0.21; 95% CI: 0.10–0.46).
Conclusions
Screening CBE likely has higher specificity among community clinicians compared to examiners in clinical trials of breast cancer screening, even among women at increased breast cancer risk. Highly specific examinations, however, may have relatively low sensitivity for breast cancer. Diagnostic CBE, meanwhile, is relatively nonspecific.
doi:10.1007/s11606-006-0062-7
PMCID: PMC1824753  PMID: 17356964
breast cancer; sensitivity and specificity; screening; physical examination
13.  Specificity of Clinical Breast Examination in Community Practice 
Background
Millions of women receive clinical breast examination (CBE) each year, as either a breast cancer screening test or a diagnostic test for breast symptoms. While screening CBE had moderately high specificity (∼94%) in clinical trials, community clinicians may be comparatively inexperienced and may conduct relatively brief examinations, resulting in even higher specificity but lower sensitivity.
Objective
To estimate the specificity of screening and diagnostic CBE in clinical practice and identify patient factors associated with specificity.
Design
Retrospective cohort study.
Subjects
Breast-cancer-free female health plan enrollees in 5 states (WA, OR, CA, MA, and MN) who received CBE (N = 1,484).
Measurements
Medical charts were abstracted to ascertain breast cancer risk factors, examination purpose (screening vs diagnostic), and results (true-negative vs false-positive). Women were considered “average-risk” if they had neither a family history of breast cancer nor a prior breast biopsy and “increased-risk” otherwise.
Results
Among average- and increased-risk women, respectively, the specificity (true-negative proportion) of screening CBE was 99.4% [95% confidence interval (CI): 98.8–99.7%] and 97.1% (95% CI: 95.7–98.0%), and the specificity of diagnostic CBE was 68.7% (95% CI: 59.7–76.5%) and 57.1% (95% CI: 51.1–63.0%). The odds of a true-negative screening CBE (specificity) were significantly lower among women at increased risk of breast cancer (adjusted odds ratio 0.21; 95% CI: 0.10–0.46).
Conclusions
Screening CBE likely has higher specificity among community clinicians compared to examiners in clinical trials of breast cancer screening, even among women at increased breast cancer risk. Highly specific examinations, however, may have relatively low sensitivity for breast cancer. Diagnostic CBE, meanwhile, is relatively nonspecific.
doi:10.1007/s11606-006-0062-7
PMCID: PMC1824753  PMID: 17356964
breast cancer; sensitivity and specificity; screening; physical examination

Results 1-13 (13)