Correlation Between Screening Mammography Interpretive Performance on a Test Set and Performance in Clinical Practice.

RATIONALE AND OBJECTIVES: Evidence is inconsistent about whether radiologists' interpretive performance on a screening mammography test set reflects their performance in clinical practice. This study aimed to estimate the correlation between test set and clinical performance and determine if the correlation is influenced by cancer prevalence or lesion difficulty in the test set. MATERIALS AND METHODS: This institutional review board-approved study randomized 83 radiologists from six Breast Cancer Surveillance Consortium registries to assess one of four test sets of 109 screening mammograms each; 48 radiologists completed a fifth test set of 110 mammograms 2 years later. Test sets differed in number of cancer cases and difficulty of lesion detection. Test set sensitivity and specificity were estimated using woman-level and breast-level recall with cancer status and expert opinion as gold standards. Clinical performance was estimated using women-level recall with cancer status as the gold standard. Spearman rank correlations between test set and clinical performance with 95% confidence intervals (CI) were estimated. RESULTS: For test sets with fewer cancers (N = 15) that were more difficult to detect, correlations were weak to moderate for sensitivity (woman level = 0.46, 95% CI = 0.16, 0.69; breast level = 0.35, 95% CI = 0.03, 0.61) and weak for specificity (0.24, 95% CI = 0.01, 0.45) relative to expert recall. Correlations for test sets with more cancers (N = 30) were close to 0 and not statistically significant. CONCLUSIONS: Correlations between screening performance on a test set and performance in clinical practice are not strong. Test set performance more accurately reflects performance in clinical practice if cancer prevalence is low and lesions are challenging to detect.

Characterizing the Mammography Technologist Workforce in North Carolina.

PURPOSE: Mammography technologists' level of training, years of experience, and feedback on technique may play an important role in the breast-cancer screening process. However, information on the mammography technologist workforce is scant. METHODS: In 2013, we conducted a survey mailed to 912 mammography technologists working in 224 facilities certified by the Mammography Quality Standards Act in North Carolina. Using standard survey methodology, we developed and implemented a questionnaire on the education and training, work experiences, and workplace interactions of mammography technologists. We aggregated responses using survey weights to account for nonresponse. We describe and compare lead (administrative responsibilities) and nonlead (supervised by another technologist) mammography technologist characteristics, testing for differences, using t-tests and χ(2) analysis. RESULTS: A total of 433 mammography technologists responded (survey response rate = 47.5%; 95% confidence interval [CI]: 44.2%-50.7%), including 128 lead and 305 nonlead technologists. Most mammography technologists were non-Hispanic, white women; their average age was 48 years. Approximately 93% of lead and nonlead technologists had mammography-specific training, but <4% had sonography certification, and 3% had MRI certification. Lead technologists reported more years of experience performing screening mammography (P = .02) and film mammography (P = .03), more administrative hours (P < .0001), and more workplace autonomy (P = .002) than nonlead technologists. Nonlead technologists were more likely to report performing diagnostic mammograms (P = .0004) or other breast imaging (P = .001), discuss image quality with a peer (P = .013), and have frequent face-to-face interaction with radiologists (P = .03). CONCLUSIONS: Our findings offer insights into mammography technologists' training and work experiences, highlighting variability in characteristics of lead versus nonlead technologists.

Do mammographic technologists affect radiologists' diagnostic mammography interpretative performance?

OBJECTIVE: The purpose of this study was to determine whether the technologist has an effect on the radiologists' interpretative performance of diagnostic mammography. MATERIALS AND METHODS: Using data from a community-based mammography registry from 1994 to 2009, we identified 162,755 diagnostic mammograms interpreted by 286 radiologists and performed by 303 mammographic technologists. We calculated sensitivity, false-positive rate, and positive predictive value (PPV) of the recommendation for biopsy from mammography for examinations performed (i.e., images acquired) by each mammographic technologist, separately for conventional (film-screen) and digital modalities. We assessed the variability of these performance measures among mammographic technologists, using mixed effects logistic regression and taking into account the clustering of examinations within women, radiologists, and radiology practices. RESULTS: Among the 291 technologists performing conventional examinations, mean sensitivity of the examinations performed was 83.0% (95% CI, 80.8-85.2%), mean false-positive rate was 8.5% (95% CI, 8.0-9.0%), and mean PPV of the recommendation for biopsy from mammography was 27.1% (95% CI, 24.8-29.4%). For the 45 technologists performing digital examinations, mean sensitivity of the examinations they performed was 79.6% (95% CI, 73.1-86.2%), mean false-positive rate was 8.8% (95% CI, 7.5-10.0%), and mean PPV of the recommendation for biopsy from mammography was 23.6% (95% CI, 18.8-28.4%). We found significant variation by technologist in the sensitivity, false-positive rate, and PPV of the recommendation for biopsy from mammography for conventional but not digital mammography (p < 0.0001 for all three interpretive performance measures). CONCLUSION: Our results suggest that the technologist has an influence on radiologists' interpretive performance for diagnostic conventional but not digital mammography. Future studies should examine why this difference between modalities exists and determine if similar patterns are observed for screening mammography.

The influence of mammographic technologists on radiologists' ability to interpret screening mammograms in community practice.

RATIONALE AND OBJECTIVES: To determine whether the mammographic technologist has an effect on the radiologists' interpretative performance of screening mammography in community practice. MATERIALS AND METHODS: In this institutional review board-approved retrospective cohort study, we included Carolina Mammography Registry data from 372 radiologists and 356 mammographic technologists from 1994 to 2009 who performed 1,003,276 screening mammograms. Measures of interpretative performance (recall rate, sensitivity, specificity, positive predictive value [PPV1], and cancer detection rate [CDR]) were ascertained prospectively with cancer outcomes collected from the state cancer registry and pathology reports. To determine if the mammographic technologist influenced the radiologists' performance, we used mixed effects logistic regression models, including a radiologist-specific random effect and taking into account the clustering of examinations across women, separately for screen-film mammography (SFM) and full-field digital mammography (FFDM). RESULTS: Of the 356 mammographic technologists included, 343 performed 889,347 SFM examinations, 51 performed 113,929 FFDM examinations, and 38 performed both SFM and FFDM examinations. A total of 4328 cancers were reported for SFM and 564 cancers for FFDM. The technologists had a statistically significant effect on the radiologists' recall rate, sensitivity, specificity, and CDR for both SFM and FFDM (P values <.01). For PPV1, variability by technologist was observed for SFM (P value <.0001) but not for FFDM (P value = .088). CONCLUSIONS: The interpretative performance of radiologists in screening mammography varies substantially by the technologist performing the examination. Additional studies should aim to identify technologist characteristics that may explain this variation.

Breast MRI BI-RADS assessments and abnormal interpretation rates by clinical indication in US community practices.

RATIONALE AND OBJECTIVES: As breast magnetic resonance imaging (MRI) use grows, benchmark performance parameters are needed for auditing and quality assurance purposes. We describe the variation in breast MRI abnormal interpretation rates (AIRs) by clinical indication among a large sample of US community practices. MATERIALS AND METHODS: We analyzed data from 41 facilities across five Breast Cancer Surveillance Consortium imaging registries. Each registry obtained institutional review board approval for this Health Insurance Portability and Accountability Act compliant analysis. We included 11,654 breast MRI examinations conducted in 2005-2010 among women aged 18-79 years. We categorized clinical indications as 1) screening, 2) extent of disease, 3) diagnostic (eg, breast symptoms), and 4) other (eg, short-interval follow-up). We characterized assessments as positive (ie, Breast Imaging Reporting and Data System [BI-RADS] 0, 4, and 5) or negative (ie, BI-RADS 1, 2, and 6) and provide results with BI-RADS 3 categorized as positive and negative. We tested for differences in AIRs across clinical indications both unadjusted and adjusted for patient characteristics and registry and assessed for changes in AIRs by year within each clinical indication. RESULTS: When categorizing BI-RADS 3 as positive, AIRs were 21.0% (95% confidence interval [CI], 19.8-22.3) for screening, 31.7% (95% CI, 29.6-33.8) for extent of disease, 29.7% (95% CI, 28.3-31.1) for diagnostic, and 27.4% (95% CI, 25.0-29.8) for other indications (P < .0001). When categorizing BI-RADS 3 as negative, AIRs were 10.5% (95% CI, 9.5-11.4) for screening, 21.8% (95% CI, 19.9-23.6) for extent of disease, 17.7% (95% CI, 16.5-18.8) for diagnostic, and 13.3% (95% CI, 11.6-15.2) for other indications (P < .0001). The significant differences in AIRs by indication persisted even after adjusting for patient characteristics and registry (P < .0001). In addition, for most indications, there were no significant changes in AIRs over time. CONCLUSIONS: Breast MRI AIRs differ significantly by clinical indication. Practices should stratify breast MRI examinations by indication for quality assurance and auditing purposes.

Effect of radiologists' diagnostic work-up volume on interpretive performance.

PURPOSE: To examine radiologists' screening performance in relation to the number of diagnostic work-ups performed after abnormal findings are discovered at screening mammography by the same radiologist or by different radiologists. MATERIALS AND METHODS: In an institutional review board-approved HIPAA-compliant study, the authors linked 651 671 screening mammograms interpreted from 2002 to 2006 by 96 radiologists in the Breast Cancer Surveillance Consortium to cancer registries (standard of reference) to evaluate the performance of screening mammography (sensitivity, false-positive rate [ FPR false-positive rate ], and cancer detection rate [ CDR cancer detection rate ]). Logistic regression was used to assess the association between the volume of recalled screening mammograms ("own" mammograms, where the radiologist who interpreted the diagnostic image was the same radiologist who had interpreted the screening image, and "any" mammograms, where the radiologist who interpreted the diagnostic image may or may not have been the radiologist who interpreted the screening image) and screening performance and whether the association between total annual volume and performance differed according to the volume of diagnostic work-up. RESULTS: Annually, 38% of radiologists performed the diagnostic work-up for 25 or fewer of their own recalled screening mammograms, 24% performed the work-up for 0-50, and 39% performed the work-up for more than 50. For the work-up of recalled screening mammograms from any radiologist, 24% of radiologists performed the work-up for 0-50 mammograms, 32% performed the work-up for 51-125, and 44% performed the work-up for more than 125. With increasing numbers of radiologist work-ups for their own recalled mammograms, the sensitivity (P = .039), FPR false-positive rate (P = .004), and CDR cancer detection rate (P < .001) of screening mammography increased, yielding a stepped increase in women recalled per cancer detected from 17.4 for 25 or fewer mammograms to 24.6 for more than 50 mammograms. Increases in work-ups for any radiologist yielded significant increases in FPR false-positive rate (P = .011) and CDR cancer detection rate (P = .001) and a nonsignificant increase in sensitivity (P = .15). Radiologists with a lower annual volume of any work-ups had consistently lower FPR false-positive rate , sensitivity, and CDR cancer detection rate at all annual interpretive volumes. CONCLUSION: These findings support the hypothesis that radiologists may improve their screening performance by performing the diagnostic work-up for their own recalled screening mammograms and directly receiving feedback afforded by means of the outcomes associated with their initial decision to recall. Arranging for radiologists to work up a minimum number of their own recalled cases could improve screening performance but would need systems to facilitate this workflow.

Educational interventions to improve screening mammography interpretation: a randomized controlled trial.

OBJECTIVE: The objective of our study was to conduct a randomized controlled trial of educational interventions that were created to improve performance of screening mammography interpretation. MATERIALS AND METHODS: We randomly assigned physicians who interpret mammography to one of three groups: self-paced DVD, live expert-led educational seminar, or control. The DVD and seminar interventions used mammography cases of varying difficulty and provided associated teaching points. Interpretive performance was compared using a pretest-posttest design. Sensitivity, specificity, and positive predictive value (PPV) were calculated relative to two outcomes: cancer status and consensus of three experts about recall. The performance measures for each group were compared using logistic regression adjusting for pretest performance. RESULTS: One hundred two radiologists completed all aspects of the trial. After adjustment for preintervention performance, the odds of improved sensitivity for correctly identifying a lesion relative to expert recall were 1.34 times higher for DVD participants than for control subjects (95% CI, 1.00-1.81; p = 0.050). The odds of an improved PPV for correctly identifying a lesion relative to both expert recall (odds ratio [OR] = 1.94; 95% CI, 1.24-3.05; p = 0.004) and cancer status (OR = 1.81; 95% CI, 1.01-3.23; p = 0.045) were significantly improved for DVD participants compared with control subjects, with no significant change in specificity. For the seminar group, specificity was significantly lower than the control group (OR relative to expert recall = 0.80; 95% CI, 0.64-1.00; p = 0.048; OR relative to cancer status = 0.79; 95% CI, 0.65-0.95; p = 0.015). CONCLUSION: In this randomized controlled trial, the DVD educational intervention resulted in a significant improvement in screening mammography interpretive performance on a test set, which could translate into improved interpretative performance in clinical practice.

Patterns of breast magnetic resonance imaging use in community practice.

IMPORTANCE: Breast magnetic resonance imaging (MRI) is increasingly used for breast cancer screening, diagnostic evaluation, and surveillance. However, we lack data on national patterns of breast MRI use in community practice. OBJECTIVE: To describe patterns of breast MRI use in US community practice during the period 2005 through 2009. DESIGN, SETTING, AND PARTICIPANTS: Observational cohort study using data collected from 2005 through 2009 on breast MRI and mammography from 5 national Breast Cancer Surveillance Consortium registries. Data included 8931 breast MRI examinations and 1,288,924 screening mammograms from women aged 18 to 79 years. MAIN OUTCOMES AND MEASURES: We calculated the rate of breast MRI examinations per 1000 women with breast imaging within the same year and described the clinical indications for the breast MRI examinations by year and age. We compared women screened with breast MRI to women screened with mammography alone for patient characteristics and lifetime breast cancer risk. RESULTS: The overall rate of breast MRI from 2005 through 2009 nearly tripled from 4.2 to 11.5 examinations per 1000 women, with the most rapid increase from 2005 to 2007 (P = .02). The most common clinical indication was diagnostic evaluation (40.3%), followed by screening (31.7%). Compared with women who received screening mammography alone, women who underwent screening breast MRI were more likely to be younger than 50 years, white non-Hispanic, and nulliparous and to have a personal history of breast cancer, a family history of breast cancer, and extremely dense breast tissue (all P < .001). The proportion of women screened using breast MRI at high lifetime risk for breast cancer (>20%) increased during the study period from 9% in 2005 to 29% in 2009. CONCLUSIONS AND RELEVANCE: Use of breast MRI for screening in high-risk women is increasing. However, our findings suggest that there is a need to improve appropriate use, including among women who may benefit from screening breast MRI.

Competing risks analysis in mortality estimation for breast cancer patients from independent risk groups.

This study quantifies breast cancer mortality in the presence of competing risks for complex patients. Breast cancer behaves differently in different patient populations, which can have significant implications for patient survival; hence these differences must be considered when making screening and treatment decisions. Mortality estimation for breast cancer patients has been a significant research question. Accurate estimation is critical for clinical decision making, including recommendations. In this study, a competing risks framework is built to analyze the effect of patient risk factors and cancer characteristics on breast cancer and other cause mortality. To estimate mortality probabilities from breast cancer and other causes as a function of not only the patient's age or race but also biomarkers for estrogen and progesterone receptor status, a nonparametric cumulative incidence function is formulated using data from the community-based Carolina Mammography Registry. Based on the log(-log) transformation, confidence intervals are constructed for mortality estimates over time. To compare mortality probabilities in two independent risk groups at a given time, a method with improved power is formulated using the log(-log) transformation.

Feasibility and acceptability of conducting a randomized clinical trial designed to improve interpretation of screening mammography.

PURPOSE: To describe recruitment, enrollment, and participation in a study of US radiologists invited to participate in a randomized controlled trial of two continuing medical education (CME) interventions designed to improve interpretation of screening mammography. METHODS: We collected recruitment, consent, and intervention-completion information as part of a large study involving radiologists in California, Oregon, Washington, New Mexico, New Hampshire, North Carolina, and Vermont. Consenting radiologists were randomized to receive either a 1-day live, expert-led educational session; to receive a self-paced DVD with similar content; or to a control group (delayed intervention). The impact of the interventions was assessed using a preintervention-postintervention test set design. All activities were institutional review board approved and HIPAA compliant. RESULTS: Of 403 eligible radiologists, 151 of 403 (37.5%) consented to participate in the trial and 119 of 151 (78.8%) completed the preintervention test set, leaving 119 available for randomization to one of the two intervention groups or to controls. Female radiologists were more likely than male radiologists to consent to and complete the study (P = .03). Consenting radiologists who completed all study activities were more likely to have been interpreting mammography for 10 years or less compared to radiologists who consented and did not complete all study activities or did not consent at all. The live intervention group was more likely to report their intent to change their clinical practice as a result of the intervention compared to those who received the DVD (50% versus 17.6%, P = .02). The majority of participants in both interventions groups felt the interventions were a useful way to receive CME mammography credits. CONCLUSIONS: Community radiologists found interactive interventions designed to improve interpretative mammography performance acceptable and useful for clinical practice. This suggests CME credits for radiologists should, in part, be for examining practice skills.

Association between mammographic density and basal-like and luminal A breast cancer subtypes.

INTRODUCTION: Mammographic density is a strong risk factor for breast cancer overall, but few studies have examined the association between mammographic density and specific subtypes of breast cancer, especially aggressive basal-like breast cancers. Because basal-like breast cancers are less frequently screen-detected, it is important to understand how mammographic density relates to risk of basal-like breast cancer. METHODS: We estimated associations between mammographic density and breast cancer risk according to breast cancer subtype. Cases and controls were participants in the Carolina Breast Cancer Study (CBCS) who also had mammograms recorded in the Carolina Mammography Registry (CMR). A total of 491 cases had mammograms within five years prior to and one year after diagnosis and 528 controls had screening or diagnostic mammograms close to the dates of selection into CBCS. Mammographic density was reported to the CMR using Breast Imaging Reporting and Data System categories. The expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 1 and 2 (HER1 and HER2), and cytokeratin 5/6 (CK5/6) were assessed by immunohistochemistry and dichotomized as positive or negative, with ER+ and/or PR+, and HER2- tumors classified as luminal A and ER-, PR-, HER2-, HER1+ and/or CK5/6+ tumors classified as basal-like breast cancer. Triple negative tumors were defined as negative for ER, PR and HER2. Of the 491 cases 175 were missing information on subtypes; the remaining cases included 181 luminal A, 17 luminal B, 48 basal-like, 29 ER-/PR-/HER2+, and 41 unclassified subtypes. Odds ratios comparing each subtype to all controls and case-case odds ratios comparing mammographic density distributions in basal-like to luminal A breast cancers were estimated using logistic regression. RESULTS: Mammographic density was associated with increased risk of both luminal A and basal-like breast cancers, although estimates were imprecise. The magnitude of the odds ratio associated with mammographic density was not substantially different between basal-like and luminal A cancers in case­control analyses and case-case analyses (case-case OR = 1.08 (95% confidence interval: 0.30, 3.84)). CONCLUSIONS: These results suggest that risk estimates associated with mammographic density are not distinct for separate breast cancer subtypes (basal-like/triple negative vs. luminal A breast cancers). Studies with a larger number of basal-like breast cancers are needed to confirm our findings.

Establishing a gold standard for test sets: variation in interpretive agreement of expert mammographers.

RATIONALE AND OBJECTIVES: Test sets for assessing and improving radiologic image interpretation have been used for decades and typically evaluate performance relative to gold standard interpretations by experts. To assess test sets for screening mammography, a gold standard for whether a woman should be recalled for additional workup is needed, given that interval cancers may be occult on mammography and some findings ultimately determined to be benign require additional imaging to determine if biopsy is warranted. Using experts to set a gold standard assumes little variation occurs in their interpretations, but this has not been explicitly studied in mammography. MATERIALS AND METHODS: Using digitized films from 314 screening mammography exams (n = 143 cancer cases) performed in the Breast Cancer Surveillance Consortium, we evaluated interpretive agreement among three expert radiologists who independently assessed whether each examination should be recalled, and the lesion location, finding type (mass, calcification, asymmetric density, or architectural distortion), and interpretive difficulty in the recalled images. RESULTS: Agreement among the three expert pairs for recall/no recall was higher for cancer cases (mean 74.3 ± 6.5) than for noncancers (mean 62.6 ± 7.1). Complete agreement on recall, lesion location, finding type and difficulty ranged from 36.4% to 42.0% for cancer cases and from 43.9% to 65.6% for noncancer cases. Two of three experts agreed on recall and lesion location for 95.1% of cancer cases and 91.8% of noncancer cases, but all three experts agreed on only 55.2% of cancer cases and 42.1% of noncancer cases. CONCLUSION: Variability in expert interpretive is notable. A minimum of three independent experts combined with a consensus should be used for establishing any gold standard interpretation for test sets, especially for noncancer cases.

Reported mammographic density: film-screen versus digital acquisition.

PURPOSE: To test the hypothesis that American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) categories for breast density reported by radiologists are lower when digital mammography is used than those reported when film-screen (FS) mammography is used. MATERIALS AND METHODS: This study was institutional review board approved and HIPAA compliant. Demographic data, risk factors, and BI-RADS breast density categories were collected from five mammography registries that were part of the Breast Cancer Surveillance Consortium. Active, passive, or waiver of consent was obtained for all participants. Women aged 40 years and older who underwent at least two screening mammographic examinations less than 36 months apart between January 1, 2000, and December 31, 2009, were included. Women with prior breast cancer, augmentation, or use of agents known to affect density were excluded. The main sample included 89 639 women with both FS and digital mammograms. The comparison group included 259 046 women with two FS mammograms and 87 066 women with two digital mammograms. BI-RADS density was cross-tabulated according to the order in which the two types of mammogram were acquired and by the first versus second interpretation. RESULTS: Regardless of acquisition method, the percentage of women with a change in density from one reading to the next was similar. Breast density was lower in 19.8% of the women who underwent FS before digital mammography and 17.1% of those who underwent digital before FS mammography. Similarly, lower density classifications were reported on the basis of the second mammographic examination regardless of acquisition method (15.8%-19.8%). The percentage of agreement between density readings was similar regardless of mammographic types paired (67.3%-71.0%). CONCLUSION: The study results showed no difference in reported BI-RADS breast density categories according to acquisition method. Reported BI-RADS density categories may be useful in the development of breast cancer risk models in which FS, digital, or both acquisition methods are used.

The association of breast density with breast cancer mortality in African American and white women screened in community practice.

The effect of breast density on survival outcomes for American women who participate in screening remains unknown. We studied the role of breast density on both breast cancer and other cause of mortality in screened women. Data for women with breast cancer, identified from the community-based Carolina Mammography Registry, were linked with the North Carolina cancer registry and NC death tapes for this study. Cause-specific Cox proportional hazards models were developed to analyze the effect of several covariates on breast cancer mortality-namely, age, race (African American/White), cancer stage at diagnosis (in situ, local, regional, and distant), and breast density (BI-RADS( ® ) 1-4). Two stratified Cox models were considered controlling for (1) age and race, and (2) age and cancer stage, respectively, to further study the effect of density. The cumulative incidence function with confidence interval approximation was used to quantify mortality probabilities over time. For this study, 22,597 screened women were identified as having breast cancer. The non-stratified and stratified Cox models showed no significant statistical difference in mortality between dense tissue and fatty tissue, while controlling for other covariate effects (p value = 0.1242, 0.0717, and 0.0619 for the non-stratified, race-stratified, and cancer stage-stratified models, respectively). The cumulative mortality probability estimates showed that women with dense breast tissues did not have significantly different breast cancer mortality than women with fatty breast tissue, regardless of age (e.g., 10-year confidence interval of mortality probabilities for whites aged 60-69 white: 0.056-0.090 vs. 0.054-0.083). Aging, African American race, and advanced cancer stage were found to be significant risk factors for breast cancer mortality (hazard ratio >1.0). After controlling for cancer incidence, there was not a significant association between mammographic breast density and mortality, adjusting for the effects of age, race, and cancer stage.

Mammographic density and breast cancer risk in White and African American Women.

Mammographic density is a strong risk factor for breast cancer, but limited data are available in African American (AA) women. We examined the association between mammographic density and breast cancer risk in AA and white women. Cases (n = 491) and controls (n = 528) were from the Carolina Breast Cancer Study (CBCS) who also had mammograms recorded in the Carolina Mammography Registry (CMR). Mammographic density was reported to CMR using Breast Imaging Reporting and Data System (BI-RADS) categories. Increasing mammographic density was associated with increased breast cancer risk among all women. After adjusting for potential confounders, a monotonically increasing risk of breast cancer was observed between the highest versus the lowest BI-RADS density categories [OR = 2.45, (95 % confidence interval: 0.99, 6.09)]. The association was stronger in whites, with ~40 % higher risk among those with extremely dense breasts compared to those with scattered fibroglandular densities [1.39, (0.75, 2.55)]. In AA women, the same comparison suggested lower risk [0.75, (0.30, 1.91)]. Because age, obesity, and exogenous hormones have strong associations with breast cancer risk, mammographic density, and race in the CBCS, effect measure modification by these factors was considered. Consistent with previous literature, density-associated risk was greatest among those with BMI > 30 and current hormone users (P value = 0.02 and 0.01, respectively). In the CBCS, mammographic density is associated with increased breast cancer risk, with some suggestion of effect measure modification by race, although results were not statistically significant. However, exposures such as BMI and hormone therapy may be important modifiers of this association and merit further investigation.

Factors facilitating acceptable mammography services for women with disabilities.

BACKGROUND: Prior research has described general barriers to breast cancer screening for women with disabilities (WWD). We explored specific accommodations described as necessary by WWD who have accessed screening services, and the presence of such accommodations in community-based screening programs. METHODS: We surveyed WWD in the Carolina Mammography Registry to determine what accommodations were needed when accessing breast screening services, and whether or not these needs were met. The sample of 1,348 WWD was identified through a survey of limitations, with a response rate of 45.5% (4,498/9,885). Of the 1,348 WWD eligible for the second survey, 739 responded for a response rate of 54.8%. RESULTS: The most frequently needed accommodations were an accessible changing area with a bench (60.0%), oral description of the procedure by the technologist (60.5%), and handicapped/accessible parking (27.6%). Handicapped parking was the need most likely to go unmet (3.1%). CONCLUSION: Most needs are being met by radiology facilities and staff, and the few needs going unmet are related to the physical/built environment. Overall, for WWD who are in screening, the mammography system seems to be more accessible than generally perceived.

Risk of advanced-stage breast cancer among older women with comorbidities.

BACKGROUND: Comorbidities have been suggested influencing mammography use and breast cancer stage at diagnosis. We compared mammography use, and overall and advanced-stage breast cancer rates, among female Medicare beneficiaries with different levels of comorbidity. METHODS: We used linked Breast Cancer Surveillance Consortium (BCSC) and Medicare claims data from 1998 through 2006 to ascertain comorbidities among 149,045 female Medicare beneficiaries ages 67 and older who had mammography. We defined comorbidities as either "unstable" (life-threatening or difficult to control) or "stable" (age-related with potential to affect daily activity) on the basis of claims within 2 years before each mammogram. RESULTS: Having undergone two mammograms within 30 months was more common in women with stable comorbidities (86%) than in those with unstable (80.3%) or no (80.9%) comorbidities. Overall rates of advanced-stage breast cancer were lower among women with no comorbidities [0.5 per 1,000 mammograms, 95% confidence interval (CI), 0.3-0.8] than among those with stable comorbidities (0.8; 95% CI, 0.7-0.9; P = 0.065 compared with no comorbidities) or unstable comorbidities (1.1; 95% CI, 0.9-1.3; P = 0.002 compared with no comorbidities). Among women having undergone two mammograms within 4 to 18 months, those with unstable and stable comorbidities had significantly higher advanced cancer rates than those with no comorbidities (P = 0.004 and P = 0.03, respectively). CONCLUSIONS: Comorbidities were associated with more frequent use of mammography but also higher risk of advanced-stage disease at diagnosis among the subset of women who had the most frequent use of mammography. IMPACT: Future studies need to examine whether specific comorbidities affect clinical progression of breast cancer.

Impact of an educational intervention designed to reduce unnecessary recall during screening mammography.

RATIONALE AND OBJECTIVES: The aim of this study was to describe the impact of a tailored Web-based educational program designed to reduce excessive screening mammography recall. MATERIALS AND METHODS: Radiologists enrolled in one of four mammography registries in the United States were invited to take part and were randomly assigned to receive the intervention or to serve as controls. The controls were offered the intervention at the end of the study, and data collection included an assessment of their clinical practice as well. The intervention provided each radiologist with individual audit data for his or her sensitivity, specificity, recall rate, positive predictive value, and cancer detection rate compared to national benchmarks and peer comparisons for the same measures; profiled breast cancer risk in each radiologist's respective patient populations to illustrate how low breast cancer risk is in population-based settings; and evaluated the possible impact of medical malpractice concerns on recall rates. Participants' recall rates from actual practice were evaluated for three time periods: the 9 months before the intervention was delivered to the intervention group (baseline period), the 9 months between the intervention and control groups (T1), and the 9 months after completion of the intervention by the controls (T2). Logistic regression models examining the probability that a mammogram was recalled included indication of intervention versus control and time period (baseline, T1, and T2). Interactions between the groups and time period were also included to determine if the association between time period and the probability of a positive result differed across groups. RESULTS: Thirty-one radiologists who completed the continuing medical education intervention were included in the adjusted model comparing radiologists in the intervention group (n = 22) to radiologists who completed the intervention in the control group (n = 9). At T1, the intervention group had 12% higher odds of positive mammographic results compared to the controls, after controlling for baseline (odds ratio, 1.12; 95% confidence interval, 1.00-1.27; P = .0569). At T2, a similar association was found, but it was not statistically significant (odds ratio, 1.10; 95% confidence interval, 0.96 to 1.25). No associations were found among radiologists in the control group when comparing those who completed the continuing medical education intervention (n = 9) to those who did not (n = 10). In addition, no associations were found between time period and recall rate among radiologists who set realistic goals. CONCLUSIONS: This study resulted in a null effect, which may indicate that a single 1-hour intervention is not adequate to change excessive recall among radiologists who undertook the intervention being tested.

Association between time spent interpreting, level of confidence, and accuracy of screening mammography.

OBJECTIVE: The objective of this study was to examine the effect of time spent viewing images and level of confidence on a screening mammography test set on interpretive performance. MATERIALS AND METHODS: Radiologists from six mammography registries participated in this study and were randomized to interpret one of four test sets and complete 12 survey questions. Each test set had 109 cases of digitized four-view screening screen-film mammograms with prior comparison screening views. Viewing time for each case was defined as the cumulative time spent viewing all mammographic images before recording which visible feature, if any, was the "most significant finding." Log-linear regression fit via the generalized estimating equation was used to test the effect of viewing time and level of confidence in the interpretation on test set sensitivity and false-positive rate. RESULTS: One hundred nineteen radiologists completed a test set and contributed data on 11,484 interpretations. The radiologists spent more time viewing cases that had significant findings or cases for which they had less confidence in their interpretation. Each additional minute of viewing time increased the probability of a true-positive interpretation among cancer cases by 1.12 (95% CI, 1.06-1.19; p < 0.001) regardless of confidence in the assessment. Among the radiologists who were very confident in their assessment, each additional minute of viewing time increased the adjusted risk of a false-positive interpretation among noncancer cases by 1.42 (95% CI, 1.21-1.68), and this viewing-time effect diminished with decreasing confidence. CONCLUSION: Longer interpretation times and higher levels of confidence in an interpretation are both associated with higher sensitivity and false-positive rates in mammography screening.

Mammographic interpretive volume and diagnostic mammogram interpretation performance in community practice.

PURPOSE: To investigate the association between radiologist interpretive volume and diagnostic mammography performance in community-based settings. MATERIALS AND METHODS: This study received institutional review board approval and was HIPAA compliant. A total of 117,136 diagnostic mammograms that were interpreted by 107 radiologists between 2002 and 2006 in the Breast Cancer Surveillance Consortium were included. Logistic regression analysis was used to estimate the adjusted effect on sensitivity and the rates of false-positive findings and cancer detection of four volume measures: annual diagnostic volume, screening volume, total volume, and diagnostic focus (percentage of total volume that is diagnostic). Analyses were stratified by the indication for imaging: additional imaging after screening mammography or evaluation of a breast concern or problem. RESULTS: Diagnostic volume was associated with sensitivity; the odds of a true-positive finding rose until a diagnostic volume of 1000 mammograms was reached; thereafter, they either leveled off (P < .001 for additional imaging) or decreased (P = .049 for breast concerns or problems) with further volume increases. Diagnostic focus was associated with false-positive rate; the odds of a false-positive finding increased until a diagnostic focus of 20% was reached and decreased thereafter (P < .024 for additional imaging and P < .001 for breast concerns or problems with no self-reported lump). Neither total volume nor screening volume was consistently associated with diagnostic performance. CONCLUSION: Interpretive volume and diagnostic performance have complex multifaceted relationships. Our results suggest that diagnostic interpretive volume is a key determinant in the development of thresholds for considering a diagnostic mammogram to be abnormal. Current volume regulations do not distinguish between screening and diagnostic mammography, and doing so would likely be challenging.