The mammogram that cried Wolfe.
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Biomedical subjects
Publications and source records attributed to Karla Kerlikowske.
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BACKGROUND: A major health priority is to increase colorectal cancer screening, and colonoscopy has become an increasingly important method of screening. The Medicare program began coverage for colonoscopy for average risk individuals in 2001. OBJECTIVES: We sought to examine whether overall colorectal cancer screening increased over time and whether these increases were a result of increased utilization of all methods or a result of greater use of colonoscopy but reduced use of other methods, whether the enactment of Medicare coverage was associated with an increase in colonoscopy among Medicare enrollees, and whether these trends equally affected subpopulations. METHODS: We used nationally representative data from the 2000 and 2003 National Health Interview Surveys and analyzed data using used chi, difference-in-differences tests, and logistic regression analyses to examine whether screening rates differed between 2000 and 2003. RESULTS: The percentage of individuals being screened for colorectal cancer using any method increased modestly from 2000 to 2003 (3%), with increases a result of increased use of colonoscopy and a reduction in the use of other methods. Increases in colonoscopy use were significant among all populations except the insured, non-Medicare population with low incomes. Among Medicare enrollees with high/middle incomes, colonoscopy use increased 14% from 2000 to 2003 compared with an increase of only 7% among low-income groups, which was a significant difference (P < 0.01). Similarly, among insured, non-Medicare enrollees with high/middle incomes, colonoscopy use increased 11% from 2000 to 2003 compared with an increase of only 4% among low-income groups, which also was a significant difference (P < 0.01). CONCLUSIONS: Colorectal cancer screening utilization increased modestly from 2000 to 2003, with the increases that primarily were the result of increased colonoscopy use. Increases in colonoscopy use, however, were primarily among high/middle income groups. Although Medicare coverage may have indirectly facilitated the increase in colonoscopy, we could not determine that coverage directly increased screening rates. Screening rates remain modest and lower income individuals continue to be screened less. Topics for future research include approaches to facilitating screening among low-income individuals and evaluating the impact of policy coverage decisions.
BACKGROUND: Risk prediction models for breast cancer can be improved by the addition of recently identified risk factors, including breast density and use of hormone therapy. We used prospective risk information to predict a diagnosis of breast cancer in a cohort of 1 million women undergoing screening mammography. METHODS: There were 2,392,998 eligible screening mammograms from women without previously diagnosed breast cancer who had had a prior mammogram in the preceding 5 years. Within 1 year of the screening mammogram, 11,638 women were diagnosed with breast cancer. Separate logistic regression risk models were constructed for premenopausal and postmenopausal examinations by use of a stringent (P<.0001) criterion for the inclusion of risk factors. Risk models were constructed with 75% of the data and validated with the remaining 25%. Concordance of the predicted with the observed outcomes was assessed by a concordance (c) statistic after logistic regression model fit. All statistical tests were two-sided. RESULTS: Statistically significant risk factors for breast cancer diagnosis among premenopausal women included age, breast density, family history of breast cancer, and a prior breast procedure. For postmenopausal women, the statistically significant factors included age, breast density, race, ethnicity, family history of breast cancer, a prior breast procedure, body mass index, natural menopause, hormone therapy, and a prior false-positive mammogram. The model may identify high-risk women better than the Gail model, although predictive accuracy was only moderate. The c statistics were 0.631 (95% confidence interval [CI] = 0.618 to 0.644) for premenopausal women and 0.624 (95% CI = 0.619 to 0.630) for postmenopausal women. CONCLUSION: Breast density is a strong additional risk factor for breast cancer, although it is unknown whether reduction in breast density would reduce risk. Our risk model may be able to identify women at high risk for breast cancer for preventive interventions or more intensive surveillance.
BACKGROUND: Reasons for persistent differences in breast cancer mortality rates among various racial and ethnic groups have been difficult to ascertain. OBJECTIVE: To determine reasons for disparities in breast cancer outcomes across racial and ethnic groups. DESIGN: Prospective cohort. SETTING: The authors pooled data from 7 mammography registries that participate in the National Cancer Institute-funded Breast Cancer Surveillance Consortium. Cancer diagnoses were ascertained through linkage with pathology databases; Surveillance, Epidemiology, and End Results programs; and state tumor registries. PARTICIPANTS: 1,010,515 women 40 years of age and older who had at least 1 mammogram between 1996 and 2002; 17,558 of these women had diagnosed breast cancer. MEASUREMENTS: Patterns of mammography and the probability of inadequate mammography screening were examined. The authors evaluated whether overall and advanced cancer rates were similar across racial and ethnic groups and whether these rates were affected by the use of mammography. RESULTS: African-American, Hispanic, Asian, and Native American women were more likely than white women to have received inadequate mammographic screening (relative risk, 1.2 [95% CI, 1.2 to 1.2], 1.3 [CI, 1.2 to 1.3], 1.4 [CI, 1.3 to 1.4], and 1.2 [CI, 1.1 to 1.2] respectively). African-American women were more likely than white, Asian, and Native American women to have large, advanced-stage, high-grade, and lymph node-positive tumors of the breast. The observed differences in advanced cancer rates between African American and white women were attenuated or eliminated after the cohort was stratified by screening history. Among women who were previously screened at intervals of 4 to 41 months, African-American women were no more likely to have large, advanced-stage tumors or lymph node involvement than white women with the same screening history. African-American women had higher rates of high-grade tumors than white women regardless of screening history. The lower rates of advanced cancer among Asian and Native American women persisted when the cohort was stratified by mammography history. LIMITATIONS: Results are based on a cohort of women who had received mammographic evaluations. CONCLUSIONS: African-American women are less likely to receive adequate mammographic screening than white women, which may explain the higher prevalence of advanced breast tumors among African-American women. Tumor characteristics may also contribute to differences in cancer outcomes because African-American women have higher-grade tumors than white women regardless of screening. These results suggest that adherence to recommended mammography screening intervals may reduce breast cancer mortality rates.
BACKGROUND: Results of 2 trials of postmenopausal hormone therapy (HT) challenged established practice patterns; 1 was not associated with changes in HT use, whereas the other was associated with substantial decline. Differential coverage by lay newspapers may have contributed to the differential impact. OBJECTIVE: To examine newspaper coverage of HT before and after the publication of the Heart and Estrogen Replacement Study (HERS) in August 1998, and the main findings of the estrogen plus progestin therapy arm of the Women's Health Initiative (EPT-WHI) in July 2002. DESIGN: Longitudinal review of newspaper articles, 1998 to 2003 (n=663). SETTING: Twenty local and 6 regional/national newspapers. MEASUREMENTS: Number and content of articles about HT. RESULTS: The average number of articles about HT published during the month of the publication of the EPT-WHI was at least 8-fold greater than the number of articles published on the topic during any prior period. While the majority of articles in all periods presented information about the potential benefits of HT, information about harms became more common than information about benefits during the 2 months before the publication of the EPT-WHI, when the trial participants were notified of the early termination of the study. The presentation of specific health harms was more common after the publication of the EPT-WHI than after the publication of HERS. Few articles in any period used visual aids. CONCLUSIONS: The publication of the EPT-WHI was associated with a change in both the volume and content of newspaper coverage about HT.
BACKGROUND: To the authors' knowledge, a comprehensive analysis of pathology outcomes after screening mammography, as it is practiced clinically in the U.S. general population, has not been performed. METHODS: Breast Cancer Surveillance Consortium data from 1996-2001 were used to identify pathology specimens that were obtained within 1 year of screening mammograms performed on 786,846 women ages 40-89 years. The pathology results were classified as invasive carcinoma, ductal carcinoma in situ (DCIS), or benign. The associations between overall pathology outcomes and invasive tumor size and lymph node status were analyzed by age and mammography assessment category. RESULTS: The rates of both recommending and performing a biopsy varied little with age. The 1,664,032 screening mammograms were followed by 26,748 known biopsies (1.6%) and 8815 diagnoses of breast carcinoma (0.53%). Overall, 81% of carcinomas were invasive, and 78% of those were pathologically lymph node-negative tumors, in contrast to the 66% prevalence observed in the Surveillance, Epidemiology, and End Results (SEER) data during the same period. Most invasive tumors measured between 0 mm and 10 mm (35%) or between 11 mm and 20 mm (36%) in greatest dimension, and 92% and 78% were lymph node-negative tumors, respectively: Biopsy results that were classified as malignant increased with age (P < 0.0001) and were most likely to follow Breast Imaging, Reporting, and Diagnosis System Category 5 and 4 assessments, respectively. Ductal hyperplasia (19.6%), fibroadenoma (18.5%), and other benign findings (56.1%) were the most common benign diagnoses. CONCLUSIONS: Pathologically negative lymph nodes were more prevalent in this mammographically screened population than in the overall SEER population. The prevalence of invasive carcinoma, DCIS, and benign findings presented herein establish a range of expected biopsy outcomes for women after screening mammography in the general U.S. population.
OBJECTIVE: Annual cervical cancer screening in women with many prior normal Pap tests is common despite limited evidence on the cost-effectiveness of this strategy. We estimated the cost-effectiveness of screening women with 3 or more prior normal tests compared with screening those with no prior tests. METHODS: We used a validated cost-effectiveness model in conjunction with data on the prevalence of biopsy-proven cervical neoplasia in women enrolled in the Centers for Disease Control and Prevention National Breast and Cervical Cancer Early Detection Program. Women were grouped according to age at the final Program Pap test (aged < 30, 30-44, 45-59, and 60-65 years) and by screening history (0, 1, 2, and 3+ consecutive prior normal Program tests) to estimate cost per life-year and quality-adjusted life-year associated with annual, biennial, and triennial screening. RESULTS: For women aged 30-44 years with no prior tests, incremental cost-effectiveness ratios ranged from 20,533 US dollars for screening triennially (compared with no further screening) to 331,837 US dollars for screening annually (compared with biennially) per life-year saved. Among same-aged women with 3 or more prior normal Program tests, incremental cost-effectiveness ratios for the same measures ranged from 60,029 US dollars to 709,067 US dollars per life-year saved. Inclusion of the most conservative utility estimates resulted in incremental cost-effectiveness ratios in excess of 100,000 US dollars per quality-adjusted life-year saved associated with annual screening of same-aged women with 3 or more prior normal tests compared with biennial screening. CONCLUSION: As the number of prior normal Pap tests increases, the costs per life-year saved increase substantially. Resources should be prioritized for screening those never or rarely screened women. LEVEL OF EVIDENCE: II-2.
BACKGROUND: Medicare data may be a useful source for determining the utilization of mammography among elderly women, but the accuracy of these data has not been established. OBJECTIVE: We determined whether Medicare physician billing claims are an accurate reflection of mammography utilization among women ages 65 and older and whether they can be used to assess the use of screening as compared with diagnostic mammography. DATA SOURCES: Mammography use was assessed using Medicare billing claims and radiology reports from 2 mammography registries; the San Francisco Mammography Registry and the New Mexico Mammography Registry. METHODS: Completeness of the Medicare data was assessed by comparing mammography use based on Medicare, with radiology reports from the mammography registries, which served as the referent standard. Capture rates for Medicare claims for individual mammograms were examined, and women were characterized as having undergone at least 1 mammogram within each 2-year period based on the Medicare data, and these rates were compared with the referent standard. To determine whether Medicare data can distinguish between screening and diagnostic mammography, we performed a classification analysis using the mammography registries screening/diagnostic designation as the referent standard (dependent variable) and Medicare claim information as the independent/predictor variable. On the basis of the mammogram level classification analysis, women were categorized as having been frequently screened (at least 2 screening mammograms spaced by 12 to 36 months), screened (at least 1 screening mammogram), or not screened. SUBJECTS: Women ages 65 and older, diagnosed with breast cancer between 1992-1999, who had at least 1 mammogram between 1992-1999 were examined. RESULTS: A total of 3340 mammograms were obtained in 1371 women between 1992 and 1999. Overall, 83% of mammograms obtained by these women had a corresponding billing claim in Medicare. This increased from 65% in 1992 to 90% in 1999. Of women who underwent at least 1 mammogram during each 2-year period per the referent standard, 94% of women were accurately classified by Medicare claims as also having undergone mammography during the same 2-year period. In multivariable analysis, a mammogram was more likely to be associated with a billing claim over time, for women 80 years or older, and for white and Asian as compared with Hispanic women. Neither socioeconomic status nor screening/diagnostic designation affected the likelihood that a mammogram would be associated with a billing claim. The Medicare data accurately categorized a given mammogram as screening or diagnostic for 87.5% of mammograms. Lastly, there was moderate to substantial agreement in the categorization of women as frequently screened, screened or not screened between the 2 data sets (weighted kappa 0.74, 95% confidence interval 0.70-0.78). CONCLUSION: Medicare administrative claims are reliable for assessment of mammography utilization and have become more accurate over time. Medicare claims data also provide a mechanism for designating mammography as screening or diagnostic, which subsequently may allow accurate description of a woman's screening history.
We compare mammography breast density (BD(MD)) to the measure of breast composition using a clinical dual energy absorptiometry (DXA) system (BD(DXA)) calibrated to measure breast density. A DXA scanning protocol was developed to scan breasts isolated in the DXA scan field in either a prone pendulous or decubitus mediolateral position. A total of 17 participants were recruited among women undergoing clinical mammography examinations. Each participant had duplicate DXA scans and duplicate craniocaudal-view mammograms of their right breast with repositioning between each scan and one DXA and one craniocaudal-view mammogram of their left breast. The in vivo repeatability (RMS SD) of BD(DXA) and BD(MD) on duplicate scans was found to be 1.2% for BD(DXA) and 1.4% for BD(MD) when repeat BD(MD) measures were made on the same day. When repeat BD(MD) measures of the same breast were made more than 50 days apart, the repeatability decreased to 5.5%. Left and right breast measurements were highly correlated with both techniques at r2 = 0.98 for BD(DXA) and r2 = 0.86 for BD(MD). Moderate correlation (r2 = 0.52) was found between BD(DXA) and BD(MD) measurements. However, after recalibrating the DXA system to mammography reference materials, negative percent fibroglandular values were measured for the most fatty breasts. Thus, our results are reproducible and accurate to common mammography tissue standards, but did not accurately reflect true percent fibroglandular levels and further development of phantom standards are necessary. We conclude that breast composition can be precisely evaluated and assessed with clinical DXA densitometers at a lower dose than with mammographic breast density methods.
PURPOSE: To retrospectively compare the concordance of initial and final assessment categories for mammograms with management recommendations made before and after the final rules of the Mammography Quality Standards Act (MQSA) were in effect for screening and diagnostic mammography. MATERIALS AND METHODS: The study included mammograms from 1996 to 2001 from the seven mammography registries of the Breast Cancer Surveillance Consortium (BCSC). The authors defined the pre-MQSA period as January 1, 1996-April 27, 1999, and the post-MQSA period as April 28, 1999-December 31, 2001 (2470151 screening and 194199 diagnostic mammograms). Assessment was cross-classified according to management recommendation. Changes in concordance between assessment and recommendation were evaluated by year and by period (before and after MQSA) for computer-linked data and for all data by using Pearson chi(2) test to evaluate differences. Mantel-Haenszel chi(2) test was used to measure change in concordance over time. Each registry and the BCSC Statistical Coordinating Center had a Federal Certificate of Confidentiality and approval from each institution's review board for protection of human subjects to collect and send data to coordinating center and conduct research with these data. Active consent was required at only one site in this HIPAA-compliant study. RESULTS: Concordance increased significantly in the post-MQSA period for Breast Imaging Reporting and Data System categories 3-5 assessments at both screening and diagnostic mammography. The most substantial improvements were in the use of the management recommendation for "additional imaging," which decreased from 41% in 1996 to 15% in 2001 for screening mammograms with an initial assessment of category 4 (P < .001). Recommendation for short-interval follow-up in women with screening mammograms with a category 3 final assessment increased from 51% in 1996 to 76% in 2001 (P < .001). Concordance for diagnostic mammograms assigned category 0 improved from 65% in the pre-MQSA period to 81% in the post-MQSA period (P < .001). CONCLUSION: This analysis demonstrates that over a relatively short period of time, major improvement in radiology reporting has occurred.
PURPOSE: To retrospectively evaluate the range of performance outcomes of the radiologist in an audit of screening mammography by using a representative sample of U.S. radiologists to allow development of performance benchmarks for screening mammography. MATERIALS AND METHODS: Institutional review board approval was obtained, and study was HIPAA compliant. Informed consent was or was not obtained according to institutional review board guidelines. Data from 188 mammographic facilities and 807 radiologists obtained between 1996 and 2002 were analyzed from six registries from the Breast Cancer Surveillance Consortium (BCSC). Contributed data included demographic information, clinical findings, mammographic interpretation, and biopsy results. Measurements calculated were positive predictive values (PPVs) from screening mammography (PPV(1)), biopsy recommendation (PPV(2)), biopsy performed (PPV(3)), recall rate, cancer detection rate, mean cancer size, and cancer stage. Radiologist performance data are presented as 50th (median), 10th, 25th, 75th, and 90th percentiles and as graphic presentations by using smoothed curves. RESULTS: There were 2 580 151 screening mammographic studies from 1 117 390 women (age range, <30 to >/=80 years). The respective means and ranges of performance outcomes for the middle 50% of radiologists were as follows: recall rate, 9.8% and 6.4%-13.3%; PPV(1), 4.8% and 3.4%-6.2%; and PPV(2), 24.6% and 18.8%-32.0%. Mean cancer detection rate was 4.7 per 1000, and the median [corrected] mean size of invasive cancers was 13 mm. The range of performance outcomes for the middle 80% of radiologists also was presented. CONCLUSION: Community screening mammographic performance measurements of cancer outcomes for the majority of radiologists in the BCSC surpass performance recommendations. Recall rate for almost half of radiologists, however, is higher than the recommended rate.
BACKGROUND: With recent advances in breast cancer risk reduction practices, it is increasingly important to assess both the breadth of and disparities in use across different racial/ethnic groups. METHODS: We conducted telephone interviews with 1,700 women ages 40 to 74, from four racial/ethnic groups, without prior history of breast cancer, who received mammograms at one of five mammography facilities in San Francisco. Main outcomes measured included recognition of tamoxifen, raloxifene, genetic testing, and prophylactic surgery. Global indicators (recognition of any therapy, discussion of breast cancer risk) were developed from original outcome measures and analyzed using logistic regression. RESULTS: Multivariate analyses indicate that race/ethnicity and interview language affected recognition of therapies and discussion of risk. White women were more likely than all other women to recognize any therapy and more likely than Asian-Americans to discuss risk. Women at high risk, who had a prior abnormal mammogram, who perceived themselves to be at high risk, or who were exposed to breast health information were more likely to discuss risk. CONCLUSIONS: Women are aware of preventive therapies, although discussion and use is limited. Interventions to increase use of therapies should focus on those at high risk.
BACKGROUND: The accuracy of screening mammography among Asian women in the United States has received little attention. We determined whether the accuracy of screening mammography for Chinese and Filipino women differs from that of white women. METHODS: We examined a cohort of white, Chinese, and Filipino women 40 years and older who underwent 200,402, 72,604, and 19,087 screening examinations, respectively, between January 1986 and December 2001 in San Francisco County, California, of whom 2177 were diagnosed with breast cancer within 12 months of a screening examination. By linking screening examinations to the regional Surveillance, Epidemiology and End Results program and the California Cancer Registry, we identified the occurrence of any invasive cancer or ductal carcinoma in situ and then calculated the rate of cancer per 1000 screenings and the sensitivity of mammography. RESULTS: The rate of invasive breast cancer per 1000 screenings was 45% lower for Chinese than for white women aged 50 to 69 years (3.8 vs 6.9; P<.001) and 29% lower for Filipino than for white women (4.9 vs 6.9; P = .03). Rates of ductal carcinoma in situ were similar across all ethnic groups (1.6-1.7 per 1000 screenings; P>or=.60). The sensitivity of mammography was similar for white, Chinese, and Filipino women (81.6%-84.3%; P>.30). CONCLUSIONS: Screening mammography has similar accuracy among white, Chinese, and Filipino women, although the absolute benefit of screening, in terms of breast cancer deaths averted, is likely to be less among Asian women because the rates of invasive cancer are lower compared with white women of similar age. Overdiagnosis of ductal carcinoma in situ with screening mammography among Asian women is likely to be comparable to that of white women because the rate of ductal carcinoma in situ was similar in all the examined ethnic groups.
BACKGROUND: Little is known about the participation of minorities in health behavior research. This manuscript assesses factors associated with participation among women in four racial/ethnic groups. METHODS: A total of 2800 Asian/Pacific Islander (API), Black, Latina, and non-Latina White women recruited through the San Francisco Mammography Registry was invited in 2002 and 2003 to participate in a telephone survey about breast cancer prevention. RESULTS: Minorities participated at lower rates (49% for APIs, 60% for Latinas, and 64% for Blacks) than Whites (77%). Increased participation was associated with younger age for Latinas (OR = 1.90, 95% CI 1.05-3.44) and Whites (OR = 1.77, CI 1.08-2.91), and with a family history of breast cancer for APIs (OR = 2.09, CI 1.24-3.52). Decreased participation was associated with having less than a high school education for APIs (OR = 0.47, CI 0.26-0.86), Blacks (OR = 0.29, CI 0.11-0.78), and Latinas (OR = 0.51, CI 0.28-0.94). CONCLUSIONS: Results suggest minorities' participation in health behavior research does not match Whites' and should be enhanced.
BACKGROUND: Mammographic breast density and bone mineral density (BMD) are markers of cumulative exposure to estrogen. Previous studies have suggested that women with high mammographic breast density or high BMD are at increased risk of breast cancer. We determined whether mammographic breast density and BMD of the hip and spine are correlated and independently associated with breast cancer risk. METHODS: We conducted a cross-sectional study (N = 15,254) and a nested case-control study (of 208 women with breast cancer and 436 control subjects) among women aged 28 years or older who had a screening mammography examination and hip BMD measurement within 2 years. Breast density for 3105 of the women was classified using the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) categories, and percentage mammographic breast density among the case patients and control subjects was quantified with a computer-based threshold method. Spearman rank partial correlation coefficient and Pearson's correlation coefficient were used to examine correlations between BI-RADS breast density and BMD and between percentage mammographic breast density and BMD, respectively, in women without breast cancer. Logistic regression was used to examine the association of breast cancer with percentage mammographic breast density and BMD. All statistical tests were two-sided. RESULTS: Neither BI-RADS breast density nor percentage breast density was correlated with hip or spine BMD (correlation coefficient = -.02 and -.01 for BI-RADS, respectively, and -.06 and .01 for percentage breast density, respectively). Neither hip BMD nor spine BMD had a statistically significant relationship with breast cancer risk. Women with breast density in the highest sextile had an approximately threefold increased risk of breast cancer compared with women in the lowest sextile (odds ratio = 2.7, 95% confidence interval = 1.4 to 5.4); adjusting for hip or spine BMD did not change the association between breast density and breast cancer risk. CONCLUSION: Breast density is strongly associated with increased risk of breast cancer, even after taking into account reproductive and hormonal risk factors, whereas BMD, although a possible marker of lifetime exposure to estrogen, is not. Thus, a component of breast density that is independent of estrogen-mediated effects may contribute to breast cancer risk.
BACKGROUND: The association between physician experience and the accuracy of screening mammography in community practice is not well studied. We identified characteristics of U.S. physicians associated with the accuracy of screening mammography. METHODS: Data were obtained from the Breast Cancer Surveillance Consortium and the American Medical Association Master File. Unadjusted mammography sensitivity and specificity were calculated according to physician characteristics. We modeled mammography sensitivity and specificity by multivariable logistic regression as a function of patient and physician characteristics. All statistical tests were two-sided. RESULTS: We studied 209 physicians who interpreted 1,220,046 screening mammograms from January 1, 1995, through December 31, 2000, of which 7143 (5.9 per 1000 mammograms) were associated with breast cancer within 12 months of screening. Each physician interpreted a mean of 6011 screening mammograms (95% confidence interval [CI] = 4998 to 6677), including a mean of 34 (95% CI = 28 to 40) from women diagnosed with breast cancer. The mean sensitivity was 77% (range = 29%-97%), and the mean false-positive rate was 10% (range = 1%-29%). After adjustment for the patient characteristics of those whose mammograms they interpreted, physician characteristics were strongly associated with specificity. Higher specificity was associated with at least 25 years (versus less than 10 years) since receipt of a medical degree (for physicians practicing for 25-29 years, odds ratio [OR] = 1.54, 95% CI = 1.14 to 2.08; P = .006), interpretation of 2500-4000 (versus 481-750) screening mammograms annually (OR = 1.30, 95% CI = 1.06 to 1.59; P = .011) and a high focus on screening mammography compared with diagnostic mammography (OR = 1.59, 95% CI = 1.37 to 1.82; P<.001). Higher overall accuracy was associated with more experience and with a higher focus on screening mammography. Compared with physicians who interpret 481-750 mammograms annually and had a low screening focus, physicians who interpret 2500-4000 mammograms annually and had a high screening focus had approximately 50% fewer false-positive examinations and detected a few less cancers. CONCLUSION: Raising the annual volume requirements in the Mammography Quality Standards Act might improve the overall quality of screening mammography in the United States.
BACKGROUND: Estimating an individual woman's absolute risk for breast cancer is essential for decision making about screening and preventive recommendations. Although the current standard, the Gail model, is well calibrated in populations, it performs poorly for individuals. Mammographic breast density (BD) may improve the predictive accuracy of the Gail model. METHODS: Prospective observational cohort of 81,777 women in the San Francisco Mammography Registry presenting for mammography during 1993 through 2002 who had no prior diagnosis of breast cancer. Breast density was rated by clinical radiologists using the Breast Imaging Reporting and Data System classification (almost entirely fat; scattered fibroglandular densities; heterogeneously dense; extremely dense). Breast cancer cases were identified through linkage to Northern California Surveillance Epidemiology End Results (SEER) program. We compared the predictive accuracy of models with Gail risk, breast density, and the combination. All models were adjusted for age and ethnicity. RESULTS: During 5.1 years of follow-up, 955 women were diagnosed with invasive breast cancer. The Gail model had modest predictive accuracy (concordance index (c-index) 0.67; 95% CI 0.65-0.68). Adding breast density to the model increased the predictive accuracy to 0.68 (95% CI .66-.70, p < 0.01 compared with the Gail model alone). The model containing only breast density adjusted for age and ethnicity had predictive accuracy equivalent to the Gail model (c-index 0.67, 95% CI 0.65-0.68). CONCLUSION: The addition of breast density measured by BI-RADS categories minimally improved the predictive accuracy of the Gail model. A model based on breast density alone adjusted for age and ethnicity was as accurate as the Gail model.
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