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.

International comparison of performance measures for screening mammography: can it be done?

Objective: Published screening mammography performance measures vary across countries. An international study was undertaken to assess the comparability of two performance measures: the recall rate and positive predictive value (PPV). These measures were selected because they do not require identification of all cancers in the screening population, which is not always possible.

Setting: The screening mammography programs or data registries in 25 member countries of the International Breast Cancer Screening Network (IBSN).

Methods: In 1999 an assessment form was distributed to IBSN country representatives in order to obtain information on how screening mammography was performed and what specific data related to recall rates and PPV were collected. Participating countries were then asked to provide data to allow calculation of recall rates, PPV and cancer detection rates for screening mammography by age group for women screened in the period 1997–1999.

Results: Twenty-two countries completed the assessment form and 14 countries provided performance data. Differences in screening mammography delivery and data collection were evident. For most countries, recall rates were higher for initial than for subsequent mammograms. There was no consistent relationship of initial to subsequent PPV, although PPV generally decreased as the recall rate increased. Recall rates decreased with increasing age, while PPV increased as age increased.

Conclusion: Similar patterns for mammography performance measures were evident across countries. However, the development of a more standardized approach to defining and collecting data would allow more valid international comparisons, with the potential to optimize mammography performance. At present, international comparisons of performance should be made with caution due to differences in defining and collecting mammography data.

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.

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.

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 case–control 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.

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.

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.

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.

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.

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.

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.

Effect of observing change from comparison mammograms on performance of screening mammography in a large community-based population

PURPOSE

To evaluate the effect of comparison mammograms on accuracy, sensitivity, specificity, positive predictive value (PPV(1)), and cancer detection rate (CDR) of screening mammography to determine the role played by identification of change on comparison mammograms.

MATERIALS AND METHODS

This HIPAA-compliant and institutional review board-approved prospective study was performed with waiver of patient informed consent. A total of 1,157,980 screening mammograms obtained between 1994 and 2008 in 435,183 women aged at least 40 years were included. Radiologists recorded presence of comparison mammograms and change, if seen. Women were followed for 1 year to monitor cancer occurrence. Performance measurements were calculated for screening with comparison mammograms versus screening without comparison mammograms and for screening with comparison mammograms that showed a change versus screening with comparison mammograms that did not show a change while controlling for age, breast density, and data clustering.

RESULTS

Comparison mammograms were available in 93% of examinations. For screening with comparison mammograms versus screening without comparison mammograms, CDR per 1000 women was 3.7 versus 7.1; recall rate, 6.9% versus 14.9%; sensitivity, 78.9% versus 87.4%; specificity, 93.5% versus 85.7%; and PPV(1), 5.4% versus 4.8%. For screening with comparison mammograms that showed a change versus screening with comparison mammograms that did not show a change, CDR per 1000 women was 25.4 versus 0.8; recall rate, 41.4% versus 2.0%; sensitivity, 96.6% versus 43.5%; specificity, 60.4% versus 98.1%; and PPV(1), 6.0% versus 3.9%. Detected cancers with change were 21.1% ductal carcinoma in situ and 78.9% invasive carcinoma. Detected cancers with no change were 19.3% ductal carcinoma in situ and 80.7% invasive carcinoma.

CONCLUSION

Performance is affected when change from comparison mammograms is noted. Without change, sensitivity is low and specificity is high. With change, sensitivity is high, with a high false-positive rate (low specificity). Further work is needed to appreciate changes that might indicate cancer and to identify changes that are likely not indicative of cancer.

Cumulative probability of false-positive recall or biopsy recommendation after 10 years of screening mammography: a cohort study

BACKGROUND

False-positive mammography results are common. Biennial screening may decrease the cumulative probability of false-positive results across many years of repeated screening but could also delay cancer diagnosis.

OBJECTIVE

To compare the cumulative probability of false-positive results and the stage distribution of incident breast cancer after 10 years of annual or biennial screening mammography.

DESIGN

Prospective cohort study.

SETTING

7 mammography registries in the National Cancer Institute-funded Breast Cancer Surveillance Consortium.

PARTICIPANTS

169,456 women who underwent first screening mammography at age 40 to 59 years between 1994 and 2006 and 4492 women with incident invasive breast cancer diagnosed between 1996 and 2006.

MEASUREMENTS

False-positive recalls and biopsy recommendations stage distribution of incident breast cancer.

RESULTS

False-positive recall probability was 16.3% at first and 9.6% at subsequent mammography. Probability of false-positive biopsy recommendation was 2.5% at first and 1.0% at subsequent examinations. Availability of comparison mammograms halved the odds of a false-positive recall (adjusted odds ratio, 0.50 [95% CI, 0.45 to 0.56]). When screening began at age 40 years, the cumulative probability of a woman receiving at least 1 false-positive recall after 10 years was 61.3% (CI, 59.4% to 63.1%) with annual and 41.6% (CI, 40.6% to 42.5%) with biennial screening. Cumulative probability of false-positive biopsy recommendation was 7.0% (CI, 6.1% to 7.8%) with annual and 4.8% (CI, 4.4% to 5.2%) with biennial screening. Estimates were similar when screening began at age 50 years. A non-statistically significant increase in the proportion of late-stage cancers was observed with biennial compared with annual screening (absolute increases, 3.3 percentage points [CI, -1.1 to 7.8 percentage points] for women age 40 to 49 years and 2.3 percentage points [CI, -1.0 to 5.7 percentage points] for women age 50 to 59 years) among women with incident breast cancer.

LIMITATIONS

Few women underwent screening over the entire 10-year period. Radiologist characteristics influence recall rates and were unavailable. Most mammograms were film rather than digital. Incident cancer was analyzed in a small sample of women who developed cancer.

CONCLUSION

After 10 years of annual screening, more than half of women will receive at least 1 false-positive recall, and 7% to 9% will receive a false-positive biopsy recommendation. Biennial screening appears to reduce the cumulative probability of false-positive results after 10 years but may be associated with a small absolute increase in the probability of late-stage cancer diagnosis.

PRIMARY FUNDING SOURCE

National Cancer Institute.

Comparative effectiveness of digital versus film-screen mammography in community practice in the United States: a cohort study

BACKGROUND

Few studies have examined the comparative effectiveness of digital versus film-screen mammography in U.S. community practice.

OBJECTIVE

To determine whether the interpretive performance of digital and film-screen mammography differs.

DESIGN

Prospective cohort study.

SETTING

Mammography facilities in the Breast Cancer Surveillance Consortium.

PARTICIPANTS

329,261 women aged 40 to 79 years underwent 869 286 mammograms (231 034 digital; 638 252 film-screen).

MEASUREMENTS

Invasive cancer or ductal carcinoma in situ diagnosed within 12 months of a digital or film-screen examination and calculation of mammography sensitivity, specificity, cancer detection rates, and tumor outcomes.

RESULTS

Overall, cancer detection rates and tumor characteristics were similar for digital and film-screen mammography, but the sensitivity and specificity of each modality varied by age, tumor characteristics, breast density, and menopausal status. Compared with film-screen mammography, the sensitivity of digital mammography was significantly higher for women aged 60 to 69 years (89.9% vs. 83.0%; P = 0.014) and those with estrogen receptor-negative cancer (78.5% vs. 65.8%; P = 0.016); borderline significantly higher for women aged 40 to 49 years (82.4% vs. 75.6%; P = 0.071), those with extremely dense breasts (83.6% vs. 68.1%; P = 0.051), and pre- or perimenopausal women (87.1% vs. 81.7%; P = 0.057); and borderline significantly lower for women aged 50 to 59 years (80.5% vs. 85.1%; P = 0.097). The specificity of digital and film-screen mammography was similar by decade of age, except for women aged 40 to 49 years (88.0% vs. 89.7%; P < 0.001).

LIMITATION

Statistical power for subgroup analyses was limited.

CONCLUSION

Overall, cancer detection with digital or film-screen mammography is similar in U.S. women aged 50 to 79 years undergoing screening mammography. Women aged 40 to 49 years are more likely to have extremely dense breasts and estrogen receptor-negative tumors; if they are offered mammography screening, they may choose to undergo digital mammography to optimize cancer detection.

PRIMARY FUNDING SOURCE

National Cancer Institute.

Cumulative probability of false-positive recall or biopsy recommendation after 10 years of screening mammography: a cohort study

BACKGROUND

False-positive mammography results are common. Biennial screening may decrease the cumulative probability of false-positive results across many years of repeated screening but could also delay cancer diagnosis.

OBJECTIVE

To compare the cumulative probability of false-positive results and the stage distribution of incident breast cancer after 10 years of annual or biennial screening mammography.

DESIGN

Prospective cohort study.

SETTING

7 mammography registries in the National Cancer Institute-funded Breast Cancer Surveillance Consortium.

PARTICIPANTS

169,456 women who underwent first screening mammography at age 40 to 59 years between 1994 and 2006 and 4492 women with incident invasive breast cancer diagnosed between 1996 and 2006.

MEASUREMENTS

False-positive recalls and biopsy recommendations stage distribution of incident breast cancer.

RESULTS

False-positive recall probability was 16.3% at first and 9.6% at subsequent mammography. Probability of false-positive biopsy recommendation was 2.5% at first and 1.0% at subsequent examinations. Availability of comparison mammograms halved the odds of a false-positive recall (adjusted odds ratio, 0.50 [95% CI, 0.45 to 0.56]). When screening began at age 40 years, the cumulative probability of a woman receiving at least 1 false-positive recall after 10 years was 61.3% (CI, 59.4% to 63.1%) with annual and 41.6% (CI, 40.6% to 42.5%) with biennial screening. Cumulative probability of false-positive biopsy recommendation was 7.0% (CI, 6.1% to 7.8%) with annual and 4.8% (CI, 4.4% to 5.2%) with biennial screening. Estimates were similar when screening began at age 50 years. A non-statistically significant increase in the proportion of late-stage cancers was observed with biennial compared with annual screening (absolute increases, 3.3 percentage points [CI, -1.1 to 7.8 percentage points] for women age 40 to 49 years and 2.3 percentage points [CI, -1.0 to 5.7 percentage points] for women age 50 to 59 years) among women with incident breast cancer.

LIMITATIONS

Few women underwent screening over the entire 10-year period. Radiologist characteristics influence recall rates and were unavailable. Most mammograms were film rather than digital. Incident cancer was analyzed in a small sample of women who developed cancer.

CONCLUSION

After 10 years of annual screening, more than half of women will receive at least 1 false-positive recall, and 7% to 9% will receive a false-positive biopsy recommendation. Biennial screening appears to reduce the cumulative probability of false-positive results after 10 years but may be associated with a small absolute increase in the probability of late-stage cancer diagnosis.

PRIMARY FUNDING SOURCE

National Cancer Institute.

Using a tailored web-based intervention to set goals to reduce unnecessary recall

RATIONALE AND OBJECTIVES

To examine whether an intervention strategy consisting of a tailored web-based intervention, which provides individualized audit data with peer comparisons and other data that can affect recall, can assist radiologists in setting goals for reducing unnecessary recall.

MATERIALS AND METHODS

In a multisite randomized controlled study, we used a tailored web-based intervention to assess radiologists' ability to set goals to improve interpretive performance. The intervention provided peer comparison audit data, profiled breast cancer risk in each radiologist's respective patient populations, and evaluated the possible impact of medical malpractice concerns. We calculated the percentage of radiologists who would consider changing their recall rates, and examined the specific goals they set to reduce recall rates. We describe characteristics of radiologists who developed realistic goals to reduce their recall rates, and their reactions to the importance of patient risk factors and medical malpractice concerns.

RESULTS

Forty-one of 46 radiologists (89.1%) who started the intervention completed it. Thirty-one (72.1%) indicated they would like to change their recall rates and 30 (69.8%) entered a text response about changing their rates. Sixteen of the 30 (53.3%) radiologists who included a text response set realistic goals that would likely result in reducing unnecessary recall. The actual recall rates of those who set realistic goals were not statistically different from those who did not (13.8% vs. 15.1%, respectively). The majority of selected goals involved re-reviewing cases initially interpreted as Breast Imaging Reporting and Data System category 0. More than half of radiologists who commented on the influence of patient risk (56.3%) indicated that radiologists planned to pay more attention to risk factors, and 100% of participants commented on concerns radiologists have about malpractice with the primary concern (37.5%) being fear of lawsuits.

CONCLUSIONS

Interventions designed to reduce unnecessary recall can succeed in assisting radiologists to develop goals that may ultimately reduce unnecessary recall.

Breast MRI in community practice: equipment and imaging techniques at facilities in the Breast Cancer Surveillance Consortium

PURPOSE

MRI is increasingly used for the detection of breast carcinoma. Little is known about breast MRI techniques among community practice facilities. The aim of this study was to evaluate equipment and acquisition techniques used by community facilities across the United States, including compliance with minimum standards by the ACRIN® 6667 Trial and the European Society of Breast Imaging.

METHODS

Breast Cancer Surveillance Consortium facilities performing breast MRI were identified and queried by survey regarding breast MRI equipment and technical parameters. Variables included scanner field strength, coil type, acquisition coverage, slice thickness, and the timing of the initial postcontrast sequence. Results were tallied and percentages of facilities meeting ACRIN® and European Society of Breast Imaging standards were calculated.

RESULTS

From 23 facilities performing breast MRI, results were obtained from 14 (61%) facilities with 16 MRI scanners reporting 18 imaging parameters. Compliance with equipment recommendations of ≥1.5-T field strength was 94% and of a dedicated breast coil was 100%. Eighty-three percent of acquisitions used bilateral postcontrast techniques, and 78% used slice thickness≤3 mm. The timing of initial postcontrast sequences ranged from 58 seconds to 8 minutes 30 seconds, with 63% meeting recommendations for completion within 4 minutes.

CONCLUSIONS

Nearly all surveyed facilities met ACRIN and European Society of Breast Imaging standards for breast MRI equipment. The majority met standards for acquisition parameters, although techniques varied, in particular for the timing of initial postcontrast imaging. Further guidelines by the ACR Breast MRI Accreditation Program will be of importance in facilitating standardized and high-quality breast MRI.

Feasibility and satisfaction with a tailored web-based audit intervention for recalibrating radiologists' thresholds for conducting additional work-up

RATIONALE AND OBJECTIVES

To examine the feasibility of and satisfaction with a tailored web-based intervention designed to decrease radiologists' recommendation of inappropriate additional work-up after a screening mammogram.

MATERIALS AND METHODS

We developed a web-based educational intervention designed to reduce inappropriate recall. Radiologists were randomly assigned to participate in an early intervention group or a late (control) intervention group, the latter of which served as a control for a 9-month follow-up period, after which they were invited to participate in the intervention. Intervention content was derived from our prior research and included three modules: 1) an introduction to audit statistics for mammography performance; 2) a review of data showing radiologists' inflated perceptions of medical malpractice risks related to breast imaging, and 3) a review of data on breast cancer risk among women seen in their practices. Embedded within the intervention were individualized audit data for each participating radiologists obtained from the national Breast Cancer Surveillance Consortium.

RESULTS

Seventy-four radiologists (37.8%; 74/196) consented to the intervention, which was completed by 67.5% (27/40) of those randomized to the early intervention group and 41.2% (14/34) of those randomized to the late (control) group. Thus, a total of 41 (55%) completed the intervention. On average, three log-ins were used to complete the program (range 1-14), which took approximately 1 hour. Ninety-five percent found the program moderately to very helpful in understanding how to calculate basic performance measures. Ninety-three percent found viewing their own performance measures moderately to very helpful, and 83% reported it being moderately to very important to learn that the breast cancer risk in their screening population program was lower than perceived. The percentage of radiologists who reported that the risk of medical malpractice influences their recall rates dropped from 36.3% preintervention to 17.8% after intervention with a similar drop in perceived influence of malpractice risk on their recommendations for breast biopsy (36.4 to 17.3%). More than 75% of radiologists answered the postintervention knowledge questions correctly, and the percent of time spent in breast imaging did not appear to influence responses. The majority (>92%) of participants correctly responded that the target recall rate in the United States is 9%. The mean self-reported recall rates were 13.0 for radiologists spending <40% time in breast imaging and 14.9% for those spending >40% time spent in breast imaging, which was highly correlated with their actual recall rates (0.991; P < .001).

CONCLUSIONS

Radiologists who begin an internet-based tailored intervention designed to help reduce unnecessary recall will likely complete it, although only 55% who consented to the study actually undertook the intervention. Participants found the program useful in helping them understand why their recall rates may be elevated.

Influence of annual interpretive volume on screening mammography performance in the United States

PURPOSE

To examine whether U.S. radiologists' interpretive volume affects their screening mammography performance.

MATERIALS AND METHODS

Annual interpretive volume measures (total, screening, diagnostic, and screening focus [ratio of screening to diagnostic mammograms]) were collected for 120 radiologists in the Breast Cancer Surveillance Consortium (BCSC) who interpreted 783 965 screening mammograms from 2002 to 2006. Volume measures in 1 year were examined by using multivariate logistic regression relative to screening sensitivity, false-positive rates, and cancer detection rate the next year. BCSC registries and the Statistical Coordinating Center received institutional review board approval for active or passive consenting processes and a Federal Certificate of Confidentiality and other protections for participating women, physicians, and facilities. All procedures were compliant with the terms of the Health Insurance Portability and Accountability Act.

RESULTS

Mean sensitivity was 85.2% (95% confidence interval [CI]: 83.7%, 86.6%) and was significantly lower for radiologists with a greater screening focus (P = .023) but did not significantly differ by total (P = .47), screening (P = .33), or diagnostic (P = .23) volume. The mean false-positive rate was 9.1% (95% CI: 8.1%, 10.1%), with rates significantly higher for radiologists who had the lowest total (P = .008) and screening (P = .015) volumes. Radiologists with low diagnostic volume (P = .004 and P = .008) and a greater screening focus (P = .003 and P = .002) had significantly lower false-positive and cancer detection rates, respectively. Median invasive tumor size and proportion of cancers detected at early stages did not vary by volume.

CONCLUSION

Increasing minimum interpretive volume requirements in the United States while adding a minimal requirement for diagnostic interpretation could reduce the number of false-positive work-ups without hindering cancer detection. These results provide detailed associations between mammography volumes and performance for policymakers to consider along with workforce, practice organization, and access issues and radiologist experience when reevaluating requirements.

A prospective assessment of racial/ethnic differences in future mammography behavior among women who had early mammography

BACKGROUND

Twenty-nine percent of women, aged 30 to 39, report having had a mammogram, though sensitivity and specificity are low. We investigate racial/ethnic differences in future mammography behavior among women who had a baseline screening mammogram prior to age 40.

METHODS

Using 1994-2008 data from the Breast Cancer Surveillance Consortium (BCSC), we identified 29,390 women aged 35 to 39 with a baseline screening mammogram. We followed this cohort for 2 outcomes: (i) future BCSC mammography between ages 40 and 45; and (2) among those, delay in screening mammography until ages 43 to 45 compared with ages 40 to 42. Using adjusted log-linear models, we estimated the relative risk (RR) of these outcomes by race/ethnicity, while also considering the impact of false-positive/true-negative (FP/TN) baseline mammography results on these outcomes.

RESULTS

Relative to non-Hispanic white women, Hispanic women had an increased risk of no future BCSC mammography (RR: 1.21, 95% CI: 1.13-1.30); Asian women had a decreased risk (RR: 0.67, 95% CI: 0.61-0.74). Women with a FP result, compared with a TN result, had a decreased risk of no future BCSC mammography (RR: 0.89, 95% CI: 0.85-0.95). Among those with future BCSC screening mammography, African American women were more likely to delay the timing (RR: 1.26, 95% CI: 1.09-1.45). The interaction between race/ethnicity and FP/TN baseline results was not significant.

CONCLUSIONS

Race/ethnicity is differentially associated with future BCSC mammography and the timing of screening mammography after age 40.

IMPACT

These findings introduce the need for research that examines disparities in lifetime mammography use patterns from the initiation of mammography screening.

Radiologists' perceptions of computer aided detection versus double reading for mammography interpretation

RATIONALE AND OBJECTIVES

The aim of this study was to examine radiologists' use and perceptions of computer-aided detection (CAD) and double reading for screening mammography interpretation.

MATERIALS AND METHODS

A mailed survey of 257 community radiologists participating in the national Breast Cancer Surveillance Consortium was used to assess perceptions and practices related to CAD and double reading. Latent class analysis was used to classify radiologists' overall perceptions of CAD and double reading on the basis of their agreement or disagreement with specific statements about CAD and double reading.

RESULTS

Most radiologists (64%) reported using CAD for more than half the screening mammograms they interpreted, but only <5% reported double reading that much. More radiologists perceived that double reading improved cancer detection rates compared to CAD (74% vs 55% reported), whereas fewer radiologists thought that double reading decreased recall rates compared to CAD (50% vs 65% reported). Radiologists with the most favorable perceptions of CAD were more likely to think that CAD improved cancer detection rates without taking too much time compared to radiologists with the most unfavorable overall perceptions. In latent class analysis, an overall favorable perception of CAD was significantly associated with the use of CAD (81%), a higher percentage of workload in screening mammography (80%), academic affiliation (71%), and fellowship training (58%). Perceptions of double reading that were most favorable were associated with academic affiliation (98%).

CONCLUSIONS

Radiologists' perceptions were more favorable toward double reading by a second clinician than by a computer, although fewer used double reading in their own practice. The majority of radiologists perceived both CAD and double reading at least somewhat favorably, although for largely different reasons.

Effect of previous benign breast biopsy on the interpretive performance of subsequent screening mammography

BACKGROUND

Most breast biopsies will be negative for cancer. Benign breast biopsy can cause changes in the breast tissue, but whether such changes affect the interpretive performance of future screening mammography is not known.

METHODS

We prospectively evaluated whether self-reported benign breast biopsy was associated with reduced subsequent screening mammography performance using examination data from the mammography registries of the Breast Cancer Surveillance Consortium from January 2, 1996, through December 31, 2005. A positive interpretation was defined as a recommendation for any additional evaluation. Cancer was defined as any invasive breast cancer or ductal carcinoma in situ diagnosed within 1 year of mammography screening. Measures of mammography performance (sensitivity, specificity, and positive predictive value 1 [PPV1]) were compared both at woman level and breast level in the presence and absence of self-reported benign biopsy history. Referral to biopsy was considered a positive interpretation to calculate positive predictive value 2 (PPV2). Multivariable analysis of a correct interpretation on each performance measure was conducted after adjusting for registry, year of examination, patient characteristics, months since last mammogram, and availability of comparison film. Accuracy of the mammogram interpretation was measured using area under the receiver operating characteristic curve (AUC). All statistical tests were two-sided.

RESULTS

A total of 2,007,381 screening mammograms were identified among 799,613 women, of which 14.6% mammograms were associated with self-reported previous breast biopsy. Multivariable adjusted models for mammography performance showed reduced specificity (odds ratio [OR] = 0.74, 95% confidence interval [CI] = 0.73 to 0.75, P < .001), PPV2 (OR = 0.85, 95% CI = 0.79 to 0.92, P < .001), and AUC (AUC 0.892 vs 0.925, P < .001) among women with self-reported benign biopsy. There was no difference in sensitivity or PPV1 in the same adjusted models, although unadjusted differences in both were found. Specificity was lowest among women with documented fine needle aspiration-the least invasive biopsy technique (OR = 0.58, 95% CI = 0.55 to 0.61, P < .001). Repeating the analysis among women with documented biopsy history, unilateral biopsy history, or restricted to invasive cancers did not change the results.

CONCLUSIONS

Self-reported benign breast biopsy history was associated with statistically significantly reduced mammography performance. The difference in performance was likely because of tissue characteristics rather than the biopsy itself.

Radiologists' attitudes and use of mammography audit reports

RATIONALE AND OBJECTIVES

The US Mammography Quality Standards Act mandates medical audits to track breast cancer outcomes data associated with interpretive performance. The objectives of our study were to assess the content and style of audits and examine use of, attitudes toward, and perceptions of the value that radiologists' have regarding mandated medical audits.

MATERIALS AND METHODS

Radiologists (n = 364) at mammography registries in seven US states contributing data to the Breast Cancer Surveillance Consortium (BCSC) were invited to participate. We examined radiologists' demographic characteristics, clinical experience, use, attitudes, and perceived value of audit reports from results of a self-administered survey. Information on the content and style of BCSC audits provided to radiologists and facilities was obtained from site investigators. Radiologists' characteristics were analyzed according to whether or not they self-reported receiving regular mammography audit reports. Latent class analysis was used to classify radiologists' individual perceptions of audit reports into overall probabilities of having "favorable," "less favorable," "neutral," or "unfavorable" attitudes toward audit reports.

RESULTS

Seventy-one percent (257 of 364) of radiologists completed the survey; two radiologists did not complete the audit survey question, leaving 255 for the final study cohort. Most survey respondents received regular audits (91%), paid close attention to their audit numbers (83%), found the reports valuable (87%), and felt that audit reports prompted them to improve interpretative performance (75%). Variability was noted in the style, target audience, and frequency of reports provided by the BCSC registries. One in four radiologists reported that if Congress mandates more intensive auditing requirements, but does not provide funding to support this regulation they may stop interpreting mammograms.

CONCLUSION

Radiologists working in breast imaging generally had favorable opinions of audit reports, which were mandated by Congress; however, almost 1 in 10 radiologists reported that they did not receive audits.

Performance of first mammography examination in women younger than 40 years

BACKGROUND

Few data have been published on mammography performance in women who are younger than 40 years.

METHODS

We pooled data from six mammography registries across the United States from the Breast Cancer Surveillance Consortium. We included 117 738 women who were aged 18-39 years when they had their first screening or diagnostic mammogram during 1995-2005 and followed them for 1 year to determine accuracy of mammography assessment. We measured the recall rate for screening examinations and the sensitivity, specificity, positive predictive value, and cancer detection rate for all mammograms.

RESULTS

For screening mammograms, no cancers were detected in 637 mammograms for women aged 18-24 years. For women aged 35-39 years who had the largest number of screening mammograms (n = 73 335) in this study, the recall rate was 12.7% (95% confidence interval [CI] = 12.4% to 12.9%), sensitivity was 76.1% (95% CI = 69.2% to 82.6%), specificity was 87.5% (95% CI = 87.2% to 87.7%), positive predictive value was 1.3% (95% CI = 1.1% to 1.5%), and cancer detection rate was 1.6 cancers per 1000 mammograms (95% CI = 1.3 to 1.9 cancers per 1000 mammograms). Most (67 468 [77.7%]) of the 86 871 women screened reported no family history of breast cancer. For diagnostic mammograms, the age-adjusted rates across all age groups were: sensitivity of 85.7% (95% CI = 82.7% to 88.7%), specificity of 88.8% (95% CI = 88.4% to 89.1%), positive predictive value of 14.6% (95% CI = 13.3% to 15.8%), and cancer detection rate of 14.3 cancers per 1000 mammograms (95% CI = 13.0 to 15.7 cancers per 1000 mammograms). Mammography performance, except for specificity, improved in the presence of a breast lump.

CONCLUSIONS

Younger women have very low breast cancer rates but after mammography experience high recall rates, high rates of additional imaging, and low cancer detection rates. We found no cancers in women younger than 25 years and poor performance for the large group of women aged 35-39 years. In a theoretical population of 10 000 women aged 35-39 years, 1266 women who are screened will receive further workup, with 16 cancers detected and 1250 women receiving a false-positive result.

Barriers to adherence to screening mammography among women with disabilities

OBJECTIVES

Given the lack of screening mammography studies specific to women with disabilities, we compared reasons offered by women with and without disabilities for not scheduling routine screening visits.

METHODS

We surveyed women in the Carolina Mammography Registry aged 40 to 79 years (n = 2970), who had been screened from 2001 through 2003 and did not return for at least 3 years, to determine reasons for noncompliance. In addition to women without disabilities, women with visual, hearing, physical, and multiple (any combination of visual, hearing, and physical) limitations were included in our analyses.

RESULTS

The most common reasons cited by women both with and without disabilities for not returning for screening were lack of a breast problem, pain and expense associated with a mammogram, and lack of a physician recommendation. Women with disabilities were less likely to receive a physician recommendation.

CONCLUSIONS

Women with disabilities are less likely than those without disabilities to receive a physician recommendation for screening mammography, and this is particularly the case among older women and those with multiple disabilities. There is a need for equitable preventive health care in this population.

Are there racial/ethnic disparities among women younger than 40 undergoing mammography?

While the probability of a woman developing invasive breast cancer at age <40 is low (<1%), mammography use reported among younger women (age <40) is substantial, and varies by race/ethnicity. Little detail is known about mammography use among women aged <40, particularly by race/ethnicity. We describe racial/ethnic differences in: (1) mammography indication after considering underlying risk factors (breast symptoms and family history); (2) follow-up recommendations, and (3) mammography outcomes for first mammograms in women aged <40. These 1996-2005 Breast Cancer Surveillance Consortium data are prospectively pooled from seven U.S. mammography registries. Our community-based sample included 99,615 women aged 18-39 who self-reported race/ethnicity and presented for a first mammogram (screening or diagnostic) with no history of breast cancer. Multivariable analyses controlled for registry site, age, family history of breast cancer, symptoms, and exam year. Overall, 73.6% of the women in our sample were seen for a screening mammogram. Following screening mammography, African American (AA) women were more likely than white women to be recommended for additional workup [relative risk (RR): 1.15 (95% CI: 1.07-1.23)]. Following diagnostic mammography, AA [RR: 1.30 (95% CI: 1.17-1.44)] and Asian [RR: 1.44 (95% CI: 1.26-1.64)] women were more likely to be recommended for biopsy, fine-needle aspiration, or surgical consultation. Depending on race/ethnicity, and considering the rate of true positive to total first screening mammograms of younger women, a women has a likelihood of a true positive of 1 in 363-1,122; she has a likelihood of a false positive of 1 in 7-10. This study of community-based practice found racial/ethnic variability in mammography indication, recommendations, and outcomes among women undergoing first mammography before 40. These findings highlight important areas for future research to understand the motivating factors for these practice patterns and the implications of early mammography use.

Do Early Screening Mammography Outcomes &lt;Age 40 Adversely Impact the Timing of Screening Mammography &gt;40 Differentially by Race?

Purpose: Previous studies suggest 29% of women ages 30-39 report having had a mammogram; this varies by race/ethnicity. Black women have a greater odds than White women of reporting multiple mammograms &lt;40; yet ≥40, Black and Asian women are less likely to receive adequate mammography screening. Could early mammography testing adversely impact future mammography use? Our objective is to determine whether racial/ethnic differences and the outcome of a first mammogram &lt;40 (false positive (FP) or true negative (TN)) may delay the age of the first mammogram ≥40.

Methods: Data were pooled from seven mammography registries of the National Cancer Institute's Breast Cancer Surveillance Consortium (BCSC), a network created to study performance and outcomes in community practice. Using 1996-2006 data, we identified 29,158 women with a screening mammogram between ages 40-45 who also underwent screening mammography for the first time ever at an age &lt;40 in the BCSC data. We used logistic regression to examine the association between race/ethnicity and first mammography outcomes on the odds of delayed mammography after 40 (ages 43-45 compared to 40-42).

Results: Overall, 96% of these women's first screens &lt;40 were at ages 35 or later, and 93% of their first screens &gt;40 were at ages 40-42. Regression models adjusted for age at first screen suggest: (1) Hispanic women have an increased odds of waiting to screen until 43-45 compared to White women, regardless of first screening outcome &lt;40; (2) White and Black women whose first screen &lt;40 was a FP have less odds of delaying future screening than those with a TN; and (3) among women with a TN, Black women have an increased odds of waiting to screen until 43-45 relative to White women, with no observed difference between Asian and White women.

Conclusions: Findings suggest a differential impact of early mammography outcomes on future mammography use by race/ethnicity, among the women in our sample with a known first screening mammogram before and after age 40. The concern for harmful effects of over-screening young women drives the need for additional work in this area.

Abstract A92: Racial and ethnic distribution of mammography outcomes before age 40

Purpose: The probability of a woman developing invasive breast cancer &lt; age 40 is low (&lt;1%). For in situ or invasive cancer, the incidence rate per 100,000 woman-years for African American (AA) and white women, respectively, is 16.8 and 15.1 (Brinton et al, 2008). Yet, 34% of non-Hispanic AA women, 30% of non-Hispanic white women, and 22% of Hispanic women ages 30–39 reported ever having a mammogram from a national population-based sample (Kapp et al, 2009). We describe first mammograms in younger women to investigate racial/ethnic differences (AA, Asian, Hispanic, white) in mammography outcomes.

Methods: Data are pooled from the National Cancer Institute's Breast Cancer Surveillance Consortium, a collaborative network of mammography registries created for the purpose of studying performance and outcomes in community practice. We included women ages 18–39, with no prior history of breast cancer, with a first mammogram (screening or diagnostic) between 1996 and 2005. We determined whether a cancer diagnosis (DCIS or invasive) was made within the 12 months following each mammogram and, using standard definitions, classified each mammogram as a true positive (TP), false positive (FP), true negative (TN) or false negative (FN).

Results: Our sample included 73,353 screening mammograms and 26,262 diagnostic mammograms. Our FP results for screening mammograms reflected modest variability across race/ethnicity (10.4–14.1%). AA woman had a TP to total screening mammogram ratio of 1 in 363, compared to 1 in 623 for white women, while the ratio of a FP to total screening mammograms was similar across all racial/ethnic groups (1 in 7–10). Among diagnostic mammograms, the FP variability was greater, ranging from 8.7% for white women to 18.2% for Asian women with an absolute risk difference of a TP of &lt;1% among all racial/ethnic groups.

Conclusions: While the FP rates may vary moderately by race/ethnicity, their impact may vary substantially. Average risk AA women have greater odds than white women of reporting multiple mammograms &lt; age 40 (Kapp et al, 2009); yet ≥40 are less likely to receive adequate mammography screening (Smith-Bindman et al, 2006). Could early mammography testing adversely impact future mammography use? This deserves further study.

Citation Information: Cancer Prev Res 2010;3(1 Suppl):A92.

When radiologists perform best: the learning curve in screening mammogram interpretation

PURPOSE

To examine changes in screening mammogram interpretation as radiologists with and radiologists without fellowship training in breast imaging gain clinical experience.

MATERIALS AND METHODS

In an institutional review board-approved HIPAA-compliant study, the performance of 231 radiologists who interpreted screen-film screening mammograms from 1996 to 2005 at 280 facilities that contribute data to the Breast Cancer Surveillance Consortium was examined. Radiologists' demographic data and clinical experience levels were collected by means of a mailed survey. Mammograms were grouped on the basis of how many years the interpreting radiologist had been practicing mammography, and the influence of increasing experience on performance was examined separately for radiologists with and those without fellowship training in breast imaging, taking into account case-mix and radiologist-level differences.

RESULTS

A total of 1 599 610 mammograms were interpreted during the study period. Performance for radiologists without fellowship training improved most during their 1st 3 years of clinical practice, when the odds of a false-positive reading dropped 11%-15% per year (P < .015) with no associated decrease in sensitivity (P > .89). The number of women recalled per breast cancer detected decreased from 33 for radiologists in their 1st year of practice to 24 for radiologists with 3 years of experience to 19 for radiologists with 20 years of experience. Radiologists with fellowship training in breast imaging experienced no learning curve and reached desirable goals during their 1st year of practice.

CONCLUSION

Radiologists' interpretations of screening mammograms improve during their first few years of practice and continue to improve throughout much of their careers. Additional residency training and targeted continuing medical education may help reduce the number of work-ups of benign lesions while maintaining high cancer detection rates.

Variability in interpretive performance at screening mammography and radiologists' characteristics associated with accuracy

PURPOSE

To identify radiologists' characteristics associated with interpretive performance in screening mammography.

MATERIALS AND METHODS

The study was approved by institutional review boards of University of Washington (Seattle, Wash) and institutions at seven Breast Cancer Surveillance Consortium sites, informed consent was obtained, and procedures were HIPAA compliant. Radiologists who interpreted mammograms in seven U.S. regions completed a self-administered mailed survey; information on demographics, practice type, and experience in and perceptions of general radiology and breast imaging was collected. Survey data were linked to data on screening mammograms the radiologists interpreted between January 1, 1998, and December 31, 2005, and included patient risk factors, Breast Imaging Reporting and Data System assessment, and follow-up breast cancer data. The survey was returned by 71% (257 of 364) of radiologists; in 56% (205 of 364) of the eligible radiologists, complete data on screening mammograms during the study period were provided; these data were used in the final analysis. An evaluation of whether the radiologists' characteristics were associated with recall rate, false-positive rate, sensitivity, or positive predictive value of recall (PPV(1)) of the screening examinations was performed with logistic regression models that were adjusted for patients' characteristics and radiologist-specific random effects.

RESULTS

Study radiologists interpreted 1 036 155 screening mammograms; 4961 breast cancers were detected. Median percentages and interquartile ranges, respectively, were as follows: recall rate, 9.3% and 6.3%-13.2%; false-positive rate, 8.9% and 5.9%-12.8%; sensitivity, 83.8% and 74.5%-92.3%; and PPV(1), 4.0% and 2.6%-5.9%. Wide variability in sensitivity was noted, even among radiologists with similar false-positive rates. In adjusted regression models, female radiologists or fellowship-trained radiologists had significantly higher recall and false-positive rates (P < .05, all). Fellowship training in breast imaging was the only characteristic significantly associated with improved sensitivity (odds ratio, 2.32; 95% confidence interval: 1.42, 3.80; P < .001) and the overall accuracy parameter (odds ratio, 1.61; 95% confidence interval: 1.05, 2.45; P = .028).

CONCLUSION

Fellowship training in breast imaging may lead to improved cancer detection, but it is associated with higher false-positive rates.

Comparing Interval Breast Cancer Rates in Norway and North Carolina: Results and Challenges

Objective

To compare interval breast cancer rates (ICR) between a biennial organized screening programme in Norway and annual opportunistic screening in North Carolina (NC) for different conceptualizations of interval cancer.

Setting

Two regions with different screening practices and performance.

Methods

620,145 subsequent screens (1996–2002) performed in women aged 50–69 and 1280 interval cancers were analysed. Various definitions and quantification methods for interval cancers were compared.

Results

ICR for one year follow-up were lower in Norway compared with NC both when the rate was based on all screens (0.54 versus 1.29 per 1000 screens), negative final assessments (0.54 versus 1.29 per 1000 screens), and negative screening assessments (0.53 versus 1.28 per 1000 screens). The rate of ductal carcinoma in situ was significantly lower in Norway than in NC for cases diagnosed in both the first and second year after screening. The distributions of histopathological tumour size and lymph node involvement in invasive cases did not differ between the two regions for interval cancers diagnosed during the first year after screening. In contrast, in the second year after screening, tumour characteristics remained stable in Norway but became prognostically more favorable in NC.

Conclusion

Even when applying a common set of definitions of interval cancer, the ICR was lower in Norway than in NC. Different definitions of interval cancer did not influence the ICR within Norway or NC. Organization of screening and screening performance might be major contributors to the differences in ICR between Norway and NC.

Disclosing harmful mammography errors to patients

PURPOSE

To assess radiologists' attitudes about disclosing errors to patients by using a survey with a vignette involving an error interpreting a patient's mammogram, leading to a delayed cancer diagnosis.

MATERIALS AND METHODS

We conducted an institutional review board-approved survey of 364 radiologists at seven geographically distinct Breast Cancer Surveillance Consortium sites that interpreted mammograms from 2005 to 2006. Radiologists received a vignette in which comparison screening mammograms were placed in the wrong order, leading a radiologist to conclude calcifications were decreasing in number when they were actually increasing, delaying a cancer diagnosis. Radiologists were asked (a) how likely they would be to disclose this error, (b) what information they would share, and (c) their malpractice attitudes and experiences.

RESULTS

Two hundred forty-three (67%) of 364 radiologists responded to the disclosure vignette questions. Radiologists' responses to whether they would disclose the error included "definitely not" (9%), "only if asked by the patient" (51%), "probably" (26%), and "definitely" (14%). Regarding information they would disclose, 24% would "not say anything further to the patient," 31% would tell the patient that "the calcifications are larger and are now suspicious for cancer," 30% would state "the calcifications may have increased on your last mammogram, but their appearance was not as worrisome as it is now," and 15% would tell the patient "an error occurred during the interpretation of your last mammogram, and the calcifications had actually increased in number, not decreased." Radiologists' malpractice experiences were not consistently associated with their disclosure responses.

CONCLUSION

Many radiologists report reluctance to disclose a hypothetical mammography error that delayed a cancer diagnosis. Strategies should be developed to increase radiologists' comfort communicating with patients.

Are mammography recommendations in women younger than 40 related to increased risk?

Our objective was to examine the association between self-reported breast cancer risk factors and reported physician recommendations for mammography among women younger than 40. This study uses the 2005 National Health Interview Survey (NHIS) and includes 2,703 women ages 30-39 who reported having seen a doctor in the past 12 months. The NHIS is a population-based, cross-sectional survey of adult respondents in the United States. Overall, 19.0% of these women reported a recent mammography recommendation. Among women reporting no prior mammogram, women ages 30-34 with risk factors for breast cancer were more likely to report a recent mammogram recommendation than women without risk factors. There was no such association for women ages 35-39. Among women who reported a prior mammogram, risk factors were not associated with a recommendation for mammography; there was an association with age and recent clinical breast examination. Despite a lack of evidence-based guidelines for women under 40 years of age, these data suggest some younger women are being recommended for early mammography without indication. The relative benefits and harms of recommending mammography in this age group need further examination.

Misclassification of American Indian race in state cancer data among non-federally recognized Indians in North Carolina

BACKGROUND

Equitable distribution of health care resources relies on accurate morbidity and mortality data, classified by race. Accurate classification is a problem, particularly for non-federally recognized American Indians (AI) receiving care outside of the Indian Health Service.

METHODS

We identified counties in North Carolina that had the majority of AIs belonging to the 7 state-recognized, non-federally recognized tribes. We collaborated with the tribe in each county and compared the incident cases of cancer in the North Carolina Central Cancer Registry (NCCCR) to the tribal rolls. Data were analyzed to calculate what percent of names on both lists were not correctly identified as AI in the NCCCR. We corrected the NCCCR classification and calculated the percentage misclassified, then recalculated the cancer incidence rates for 4 major cancers (prostate, female breast, lung, and colorectal). We compared the recalculated rate to the original rate.

RESULTS

There were 626 AIs on the tribal rolls; 112 (17.9%) were not identified as AI on the NCCCR list. Comparing 1996-2000 age-adjusted cancer incidence rates before and after reclassification, the increase in rates were prostate 41%, female breast 18%, lung 10%, and 11% for colorectal cancers. There was less than a 2% increase in cancer rates for the combined 4 sites for Blacks and Whites, before and after reclassification, and 19% for AIs.

CONCLUSIONS

The study estimated 18% misclassification of non-federally recognized AIs in cancer registration in North Carolina, and determined an underestimation of cancer rates in the population. The underestimation of cancer burden among AIs in North Carolina may affect resources allocated for prevention, screening, and treatment programs, as well as funding for research.

Evidence-based target recall rates for screening mammography

PURPOSE

To retrospectively identify target recall rates for screening mammography on the basis of how sensitivity shifts with recall rate.

MATERIALS AND METHODS

The study group included 1 872 687 subsequent and 171 104 first screening mammograms from 1996 to 2001 from 172 and 139 facilities, respectively, in six sites of the Breast Cancer Surveillance Consortium. Institutional review board (IRB) approval was obtained from each site. Informed consent requirements of the IRBs were followed. The study was HIPAA compliant. Recall rate was defined as the percentage of screening studies for which further work-up was recommended by the radiologist. Sensitivity was defined as the proportion of cancers that were detected at screening mammography. Piecewise linear regression was used to model sensitivity as a function of recall rate. This model allows detection of critical recall rates in which significant changes (shifts) occurred in the rates that sensitivity increased with increasing recall rate. Rates were interpreted as number of additional work-ups per additional cancer detected (AW/ACD) or, in other words, the estimated number of additional women needed to be recalled at a given rate to detect one additional cancer.

RESULTS

For first mammograms, a single shift in the estimated AW/ACD rate occurred at a recall rate of 10.0%, with the rate jumping dramatically from 35 to 172. For subsequent mammograms, four shifts were identified. At a recall rate of 6.7%, the estimated AW/ACD increased from 80 to 132, which rendered it the highest desirable target recall rate. At a recall rate of 12.3%, the estimated AW/ACD was 304, which suggests little benefit for any higher recall rate.

CONCLUSION

Recall rates of 10.0% for first and 6.7% for subsequent mammograms are recommended targets on the basis of their AW/ACD rates (less than 100).

Computed Tomography Reflects Lower Airway Inflammation and Tracks Changes in Early Cystic Fibrosis

RATIONALE

Detecting and tracking early cystic fibrosis (CF) lung disease are difficult due to lack of sensitive markers of airway dysfunction.

OBJECTIVES

The goals were to detect regional distribution of airway disease through high-resolution computed tomography, correlate abnormalities to lower airway inflammation/infection, and compare computed tomography findings before and after intravenous antibiotic therapy in children with CF younger than 4 years experiencing a pulmonary exacerbation.

METHODS

High-resolution computed tomography was performed in 17 children scheduled for bronchoscopy. The radiologist identified the lobes with the "greatest" and "least" disease based on computed tomography, and bronchoalveolar lavage was performed in these areas. In 13 subjects, imaging was repeated after antibiotic completion. Modified Brody scores were assigned by two radiologists.

MEASUREMENTS AND MAIN RESULTS

The lobe with greatest disease was predominantly localized to the right and had higher modified Brody scores, indicating more severe abnormalities (p < 0.01), compared with the lobe with least disease. The total modified Brody score (p < 0.01), hyperinflation subscore (p < 0.01), and bronchial dilatation/bronchiectasis subscore (p < 0.01) improved after antibiotics and intensified airway clearance. Interleukin-8 levels (p < 0.01) and % neutrophils (p = 0.04) were increased in the lobe with greatest disease compared with the lobe with least disease.

CONCLUSIONS

These results indicate that, in young children with CF experiencing a pulmonary exacerbation, computed tomography detects regional differences in airway inflammation, may be a sensitive outcome to evaluate therapeutic interventions, and identifies early lung disease as being more prominent on the right.

Performance benchmarks for screening mammography

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.

Improving the concordance of mammography assessment and management recommendations

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.

Prospective breast cancer risk prediction model for women undergoing screening mammography

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.

Epidemiology of breast cancer in young women

Breast cancer is a rare disease in young women, yet is the leading cause of cancer deaths in all ethnic groups in the United States and many parts of the world. The epidemiology for breast cancer in young women is reviewed, focusing on women under 40, prior to the recommended screening age. Specific age comparison groups used and results for young women vary in the literature, yet there are some common results. Young women have low incidence rates of breast cancer compared to older women. However, cancer incidence increases at a faster rate with increasing age in young women. Their cancers tend to be larger and higher grade with poorer prognostic characteristics, resulting in a higher risk of recurrence and death from breast cancer when compared to older women. Many of the usual risk factors for breast cancer in older women also increase risk in younger women including increasing age, Black race, family history, later age at first birth and menarche, radiation exposure and lack of physical activity. Risk factors that have specific relevance to young women include reproductive factors, history of induced abortion or miscarriage, oral contraceptive use, smoking, and radiation exposure, most specifically for treatment of Hodgkin Disease.

Association of stellate mammographic pattern with survival in small invasive breast tumors

OBJECTIVE

We tested whether the stellate mammographic pattern of presentation of small breast tumors is a better indicator of survival than other patterns.

MATERIALS AND METHODS

Patients with primary invasive breast cancer diagnosed in 1993-1997 were grouped according to the size of the lesion: 0.1-0.9 cm and 1.0-1.4 cm. Each tumor was placed in one of five mammographic prognostic categories: stellate without calcifications; circular without calcifications; and calcifications with or without tumor mass in a casting, crushed-stone, or other (powdery, punctuate, or round) pattern. To assess reproducibility, a second radiologist gave an independent interpretation in the first 109 cases. Descriptive data were stratified by tumor size, and tests of association were done with an extension of Fisher's exact test. Odds ratios and confidence intervals were computed. Weighted log-rank test and Kaplan-Meier survival curves were used to compare breast cancer survival in the stellate group compared with the other groups.

RESULTS

Two hundred one consecutive patients with a median follow-up period of 7.4 years were identified. There were nine breast cancer deaths. The stellate morphologic pattern was most common (91 [45.3%] of 201 cases), yet there was only one breast cancer death in this group (survival rate, 98.9%; 95% confidence interval [CI], 96.7-100%). In the group of stellate lesions smaller than 1.0 cm, 67.6% (25/37) of the tumors were well-differentiated without lymph node metastasis (30 [96.8%] of 31 cases), and there were no deaths. In the group of stellate lesions measuring 1.0-1.4 cm, 66.7% (36/54) of the tumors were well-differentiated with a 19.6% risk of lymph node metastasis, one death, and a survival rate of 98.1% (52/53; 95% CI, 94.4-100%). Circular tumors accounted for 29.9% (60/201) of tumors and 55.6% (5/9) of breast cancer deaths. Casting and crushed-stone microcalcifications were associated with 33.3% (3/9) of disease-specific deaths. A weighted kappa value of 0.89 (CI, 0.83-0.94) indicated very high agreement of pattern assignment.

CONCLUSION

Stellate tumors had a significantly better survival prognosis than tumors with other patterns even though there were no differences in treatment. By recognizing these small malignant lesions, trained radiologists may be able to identify tumors that pose negligible risk of breast cancer death.

Diagnostic mammography performance and race: outcomes in Black and White women

BACKGROUND

A previous study compared the performance (sensitivity, specificity, positive predictive value, and cancer detection rate) of screening mammography in Black and White women. No study, to the authors' knowledge, has evaluated the difference in the performance of diagnostic mammography between Black and White women.

METHODS

Univariate analysis was used to evaluate differences in characteristics and cancers between Black and White women. Stratified and adjusted logistic regression analyses were used to test the association of Black and White race with performance measures of diagnostic mammography.

RESULTS

The sensitivity of diagnostic mammography was higher (91% vs. 84%) and specificity was lower (86% vs. 90%) among Black women compared with White women. After controlling for age, density, self-reported breast problems, and previous mammography, sensitivity was significantly higher (odds ratio [OR] = 1.82, 95% confidence interval [CI] = 1.22-2.80) and specificity was significantly lower (OR = 0.75, 95% CI = 0.70-0.81) among Black women. The crude cancer detection rate of mammography was higher for Black women (42.6/1000) than for White women (31.0/1000) and Black women had a higher proportion of cancers that were > 2.0 cm (57.4% vs. 46.2%) that were more often poorly differentiated (61.7% vs. 49.3%) and were more often estrogen-receptor and progesterone-receptor negative.

CONCLUSIONS

Black women have lower specificity of diagnostic mammography and, consequently, more unnecessary workups than White women. Black women have higher sensitivity of diagnostic mammography, with cancers that are larger and more advanced than White women. Delay in responding to signs and symptoms would explain the size and later stage. However, more research is needed to understand the biologic differences of breast cancer characteristics between Black and White women.

Methodological issues in international comparison of interval breast cancers

International comparisons of interval cancers (IC) are important to better understand the relationship between programmes' performance and screening practices. In this respect, differences in (i) definition, (ii) identification and (iii) quantification of IC have received little attention. To examine these 3 comparability issues and activities involving IC, an assessment was conducted among member countries of the International Breast Cancer Screening Network, and the impact of accuracy of identification and quantification practices was estimated using 1996-98 data from the Dutch breast cancer screening programme. Information was obtained from 19 screening programmes in 18 countries, 16 of which acknowledged the coexistence of opportunistic screening. IC data were collected to evaluate performance of the screening programme (100% of programmes) and the radiologists (89%); 53% of programmes had a designated review process for IC. Most programmes (84%) agreed with the European Guidelines definition of IC, but a case situation exercise evidenced substantial discrepancy in classification of cancers that occurred after a positive screen. Completeness of identification of IC appears to contribute most to international variation, and cannot be easily controlled for in methodologically rigorous comparisons. Statistically significant differences of about 4% were measured between quantification methods for IC. An operational definition of IC is proposed to enhance international comparability. Valid comparisons of IC are possible with careful attention to the definition but true differences in IC frequency across screening programmes should exceed 10% to be possibly indicative of real differences between programmes.

Screening mammography after breast cancer treatment: patterns in community practice

BACKGROUND

Guidelines for screening women post-breast cancer treatment are generally lacking. This study was conducted to review the literature on guidelines for this population and to evaluate whether there is a common practice in the community for following these women.

METHODS

The literature was reviewed for presence of published or inferred guidelines. Data were then used from the Carolina Mammography Registry (CMR) to see if patterns exist in community practice. For the years 1995-1999, 3081 women with a new diagnosis of unilateral breast cancer and a post-treatment screening mammogram in CMR were included. Recommendations for initial mammographic examination and intervals of subsequent mammograms post-treatment were described and tested for patterns of follow-up time.

RESULTS

The only evidence-based guidelines found for post-treatment mammographic examinations were from the American Society of Clinical Oncology. They recommend 6 month follow-up initially followed by 12 month follow-up if findings remain stable. Among the 3081 women included in the study, 17.4% were recommended to return at 6 months post-treatment following their initial mammogram. Of the women who had at least three post-cancer mammograms (1592/3081), 82.6% were recommended for 12 month intervals at all three visits; only 2.1% of women were recommended for 6 month intervals at all three visits.

CONCLUSIONS

This study found that most community-based radiologists included in our study recommend following women at 12 month intervals post-treatment. Whether this 12 month screening interval is optimal for detecting recurrent cancers is not known and should be the focus of future research.