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 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.     

Auditing and benchmarks in screening and diagnostic mammography

Radiologists can use outcome data such as cancer size and stage to determine how well their own practice provides benefit to their patients and can use measures such as screening recall rates and positive predictive values to assess how well adverse consequences are being contained. New data on national benchmarks for screening and diagnostic mammography in the United States allow radiologists to evaluate their own performance with respect to their peers. This article discusses recommended outcome values in the United States and Europe, current Mammography Quality Standards Act audit requirements, and Institute of Medicine proposals for future requirements.     

Performance parameters for screening and diagnostic mammography: specialist and general radiologists

PURPOSE: To evaluate performance parameters for radiologists in a practice of breast imaging specialists and general diagnostic radiologists who interpret a large series of consecutive screening and diagnostic mammographic studies. MATERIALS AND METHODS: Data (ie, patient age; family history of breast cancer; availability of previous mammograms for comparison; and abnormal interpretation, cancer detection, and stage 0-I cancer detection rates) were derived from review of mammographic studies obtained from January 1997 through August 2001. The breast imaging specialists have substantially more initial training in mammography and at least six times more continuing education in mammography, and they interpret 10 times more mammographic studies per year than the general radiologists. Differences between specialist and general radiologist performances at both screening and diagnostic examinations were assessed for significance by using Student t and chi(2) tests. RESULTS: The study involved 47,798 screening and 13,286 diagnostic mammographic examinations. Abnormal interpretation rates for screening mammography (ie, recall rate) were 4.9% for specialists and 7.1% for generalists (P <.001); and for diagnostic mammography (ie, recommended biopsy rate), 15.8% and 9.9%, respectively (P <.001). Cancer detection rates at screening mammography were 6.0 cancer cases per 1,000 examinations for specialists and 3.4 per 1,000 for generalists (P =.007); and at diagnostic mammography, 59.0 per 1,000 and 36.6 per 1,000, respectively (P <.001). Stage 0-I cancer detection rates at screening mammography were 5.3 cancer cases per 1,000 examinations for specialists and 3.0 per 1,000 for generalists (P =.012); and at diagnostic mammography, 43.9 per 1,000 and 27.0 per 1,000, respectively (P <.001). CONCLUSION: Specialist radiologists detect more cancers and more early-stage cancers, recommend more biopsies, and have lower recall rates than general radiologists.     

Automated management of screening and diagnostic mammography

We designed an automated system for managing large-scale screening and diagnostic mammography. The system collects coded mammographic findings from the radiologist and records a history directly from the patient. This information is stored in an integrated clinical data base to which the results of subsequent examinations or surgery are added. In addition, the system generates letters to the patient and her physician that describe mammographic findings and letters reminding them of routine screening visits. For patients who have positive results on examinations, it checks for records of biopsy or repeat mammography and generates follow-up letters if appropriate intervention is not found. While this system is part of a comprehensive computerized hospital information system, mammography management tools with most of the features described can be designed for relatively inexpensive microcomputers.     

Compliance with European guidelines for diagnostic mammography in a decentralized health-care setting

PURPOSE: To evaluate the compliance of Danish mammography clinics with requirements concerning organization, activity volume, and assessment procedures from two European guidelines for quality assurance in diagnostic mammography (EUSOMA and EUREF). MATERIAL AND METHODS: We used individual records on all diagnostic mammographies performed in Denmark in 2000, and questionnaires given to Danish mammography clinics in 2000, 2002, and 2004. RESULTS: The study showed a marked centralization of the diagnostic activity from 2000 to 2004 to a smaller number of public breast assessment centers with full multidisciplinary breast assessment. However, a relatively large number of these centers did not comply with the activity volume requirement of 2000 mammograms per clinic per year. The number of private diagnostic mammography clinics performing basic diagnostic mammography has remained fairly stable in the period 2000 to 2004. Compared with public breast assessment centers, the private diagnostic mammography clinics had a lower compliance with activity volume requirements. CONCLUSION: A marked proportion of Danish public breast assessment centers operate with less than optimal activity volume, suggesting that further centralization would be appropriate. The situation in private diagnostic mammography clinics may cause concern, as our study showed that the majority of these clinics did not meet the activity volume requirements.     

Communication in the diagnostic mammography suite: implications for practice and training

RATIONALE AND OBJECTIVES: The diagnostic mammography suite is a microcosm of challenging physician-patient communication in radiology. Little has been written about communication practices in the diagnostic mammography suite, the effect of this communication on both physicians and patients, and implications for radiology training programs. We surveyed radiology residents and staff about communication training, practices, and experiences communicating directly with patients in the diagnostic mammography suite. MATERIALS AND METHODS: We asked the membership of the Association of Program Directors in Radiology to disseminate surveys to radiology residents and staff radiologists in their institutions. We analyzed response frequencies and correlations. RESULTS: We received responses from 142 residents and 120 staff radiologists. More than half of staff respondents spoke personally with every patient who had an abnormal diagnostic mammogram; 37% felt they had inadequate time to do so. Most residents and staff highly rated their own communication skills and confidence in ability to explain results and respond to patients' emotions, but experienced stress doing so. A majority of respondents reported no formal communication skills education after medical school. Twenty-nine percent of staff respondents regularly observed residents' communication with patients and 39% of residents reported receiving feedback about their communication. Residents' opportunities to observe staff communicate with a patient and to receive feedback on their own patient interactions were correlated with self-rated communication skill and confidence in ability to respond to patients' emotions (P < .05). CONCLUSIONS: Radiologists engage in challenging and stressful patient communication interactions. There is a paucity of educational curricula on interpersonal and communication skills in radiology. This has implications for both patient and physician satisfaction and patient outcomes.     

Diagnostic accuracy of Fischer Senoscan Digital Mammography versus screen-film mammography in a diagnostic mammography population

RATIONALE AND OBJECTIVES: To compare the diagnostic accuracy of the Fischer Senoscan Digital Mammography System with that of standard screen-film mammography in a population of women presenting for screening or diagnostic mammography. MATERIALS AND METHODS: Enrollment of patients took place at six different breast-imaging centers between 1997 and 1999. A total of 247 cases were selected for inclusion in the final reader study. All known cancer cases were included (111) from all six participating sites representing 45% of the total cases. The remaining 136 cases (55%) were randomly selected from all available benign or negative cases from three of the six sites. A complete case consisted of both a (unilateral or bilateral) digital and screen-film mammogram of the same patient. Eight radiologists interpreted the cases in laser-printed digital and screen-film hardcopy formats. The study was designed to detect differences of 0.05 in the ROC area under the curve (AUC) between digital and screen-film radiologist interpretation performance. RESULTS: The average AUC for the Senoscan digital was 0.715 for the 8 readers. The average AUC for screen-film was 0.765. The difference AUC of -0.05 falls within the 95% confidence interval (-0.101, 0.002). The average sensitivity was 66% and specificity 67% for SenoScan full-field digital mammography. The average screen-film mammography sensitivity and specificity were 74% and 60%, respectively. CONCLUSION: No statistically significant difference in diagnostic accuracy between the Fischer Senoscan and screen-film mammography was detected in this study.     

Clinical outcome assessment in mammography: an audit of 7,506 screening and diagnostic mammography examinations

PURPOSE: To perform an audit of our routine mammographic practice and to compare our results to performance benchmarks. MATERIALS AND METHODS: We analyzed the outcomes of 7,506 consecutive examinations performed in 1 year. Screening and diagnostic cases were evaluated separately and mammographic assessments were based on the Breast Imaging Reporting and Data System (BI-RADS) classification. RESULTS: In 6,858 (91%) screening and 648 (9%) diagnostic cases, outcomes varied substantially. The recall rate was 10.9%. Estimated sensitivity and specificity were similar (100% vs. 98% and 88% vs. 94%) in the screening and diagnostic groups. Positive predictive values (PPV1, PPV2, and PPV3) were higher in the diagnostic group compared to the screening group (64%, 65%, and 68% vs. 4.9%, 33%, and 39%, respectively). Cancer outcomes in the screening and diagnostic groups were, respectively, as follows: cancer detection rate, 6.1 per thousand vs. 86.4 per thousand; mean invasive cancer size, 15.7 mm vs. 24.5 mm; minimal cancers, 38% vs. 19%; stage 0-1 cancers, 50% vs. 21%; and lymph node negativity, 76% vs. 29%. CONCLUSION: The measures of our screening outcomes were concordant with the literature and the performance benchmarks for screening mammography; however, in our diagnostic group, the reasons for the higher PPV, higher cancer detection rate, and the diagnosis of cancer in a more advanced stage compared to the performance benchmarks should be investigated with more detailed periodic audits.     

Informing patients of diagnostic mammography results: mammographer's opinions

PURPOSE: The authors' purpose was to determine mammographers' practices and attitudes regarding disclosing results of diagnostic mammograms to patients. MATERIALS AND METHODS: In 1995, the authors mailed a questionnaire to 500 members of the Society of Breast Imaging; 399 (80%) responded to the survey. RESULTS: Three-quarters of respondents stated that mammographers should disclose results to their patients, and approximately half were already doing so (52% for normal results, 51% for abnormal results). A sizable minority (25%) said that not telling patients was the best practice and identified several barriers to direct disclosure, including lack of time. Although bivariate analysis showed direct disclosure to be more common among female mammographers, the sex difference did not persist in multivariate analysis. In both bivariate and multivariate analyses, reading more than 100 mammograms per week and having a radiology practice in a university or academic setting were each strongly associated with direct disclosure. CONCLUSION: Implementation of the Mammography Quality Standards Reauthorization Act of 1998 may not require a major change in mammographers' current practice. It remains critical to establish systems that help radiologists disclose results and communicate with referring physicians efficiently and effectively.     

The positive predictive value for diagnosis of breast cancer full-field digital mammography versus film-screen mammography in the diagnostic mammographic population

RATIONALE AND OBJECTIVES: Diagnostic mammography is performed on women with clinical symptoms that suggest breast cancer or women for whom further mammographic evaluation has been requested because of an abnormal screening mammography. We assessed whether the use of full-field digital mammography would improve the positive predictive value (PPV) for the diagnosis of breast cancer in a diagnostic population compared with film-screen mammography. MATERIALS AND METHODS: From January 2002 to December 2003, 11,621 patients underwent diagnostic mammography at the University of North Carolina Hospital, Chapel Hill. Among these 11,621 patients, 1400 lesions in 1121 patients underwent biopsy. We included the biopsy-performed lesions, so PPV3 was used for comparison of PPVs between film-screen mammography and full-field digital mammography. Six breast radiologists interpreted the images using the Breast Imaging Reporting and Data System of the American College of Radiology. PPV3s were compared between film-screen and full-field digital mammography in the entire study cohort and in specified subgroups according to different radiologists, breast density, and lesion type on mammography. The chi(2) and Fisher's exact tests were used for comparison of PPV3s between two modalities of mammography with the Bonferroni procedure for subgroup analysis. RESULTS: In the entire study cohort, PPV3s of full-field digital mammography and film-screen mammography were similar (difference in PPV3,-0.007; 95% confidence interval, -0.081 to 0.068; P = .8602). In predefined subgroups, there was no difference in PPV3 by the radiologist, breast density, or lesion type between two modalities of mammography (P > .005). CONCLUSION: There is no improvement in PPV for the diagnosis of breast cancer with full-field digital mammography compared with film-screen mammography in a large diagnostic population.     

Breast tomosynthesis: A diagnostic addition to screening digital mammography

Objectives

Comparison between digital mammography alone and with adding digital breast tomosynthesis in breast cancer screening.

Rates and causes of disagreement in interpretation of full-field digital mammography and film-screen mammography in a diagnostic setting

OBJECTIVE: This study was performed to determine the rates and causes of disagreements in interpretation between full-field digital mammography and film-screen mammography in a diagnostic setting. SUBJECTS AND METHODS: Patients undergoing diagnostic mammography were invited to participate in the digital mammography study. Three views, selected by the radiologist interpreting the film-screen mammography, were obtained in both film-screen mammography and digital mammography. Radiologists independently assigned a Breast Imaging Reporting and Data System (BI-RADS) category to the film-screen mammography and the digital mammography images. The BI-RADS categories were grouped into the general categories of agreement, partial agreement, or disagreement. A third and different radiologist reviewed all cases of disagreement, reached a decision as to management, and determined the primary cause of disagreement. RESULTS: Six radiologists reviewed digital mammography and film-screen mammography diagnostic images in a total of 1147 breasts in 692 patients. Agreement between digital mammography and final film-screen mammography assessment was present in 937 breasts (82%), partial agreement in 159 (14%), and disagreement in 51 (4%), for a kappa value of 0.29. The primary causes of disagreement were differences in management approach of the radiologists (52%), information derived from sonography or additional film-screen mammograms (34%), and technical differences between the two mammographic techniques (10%). CONCLUSION: Significant disagreement between film-screen mammography and digital mammography affecting follow-up management was present in only 4% of breasts. The most frequent cause of disagreement in interpretation was a difference in management approach between radiologists (interobserver variability). This source of variability was larger than that due to differences in lesion visibility between film-screen mammography and digital mammography.     

Computer-aided detection in diagnostic mammography: detection of clinically unsuspected cancers

OBJECTIVE: We had two objectives: to determine the percentage of women presenting with clinical findings whose diagnostic mammogram led to detection of a breast cancer at a site distant from the original clinical complaint and to assess the performance of computer-aided detection (CAD) on diagnostic mammography. MATERIALS AND METHODS: Three institutions contributed consecutive cases in which a mammogram was obtained to evaluate a clinical finding, after which a histologic diagnosis of breast cancer was made. Clinical data and the mammograms were reviewed to determine the nature of the clinical findings and to document the location and characteristics of 212 biopsy-proven cancers in 197 patients who met the study criteria. Standard four-view breast mammograms were then analyzed by a CAD system. RESULTS: The most common clinical finding was a palpable mass (90%, 177/197), with nipple discharge (5%, 9/197), focal tenderness or pain (2%, 5/197), and miscellaneous complaints (3%, 6/197) also noted. Two separate cancers were found in 7.6% (15/197) of the cases. In another 7.6% (15/197) of the cases, the single diagnosed cancer was not at the location of the specific clinical finding. The CAD system correctly marked 87% (26/30) of those cancers that were clinically unsuspected (i.e., not at the location of the clinical finding). CONCLUSION: Breast cancers occurred at locations other than the site of the presenting clinical finding in 15% (30/197) of patients undergoing diagnostic mammography in whom a cancer was detected. CAD identified 87% of these incidentally detected cancers and may therefore be useful as a detection aid to the radiologist when interpreting diagnostic mammograms.     

Performance comparison of single-view digital breast tomosynthesis plus single-view digital mammography with two-view digital mammography

Objective

To determine the performance of combined single-view mediolateral oblique (MLO) digital breast tomosynthesis (DBT) plus single-view cranio-caudal (CC) mammography (MX) compared with that of standard two-view digital mammography.

Methods

A multi-reader multi-case (MRMC) receiver-operating characteristic (ROC) study was conducted, involving six breast radiologists. Two hundred fifty patients underwent bilateral MX and DBT imaging. MX and DBT images with the adjunct of the CC-MX view from 469 breasts were evaluated and rated independently by six readers. Differences in mean areas under the ROC curves (AUCs), mean sensitivity and mean specificity were analysed by analysis of variance (ANOVA) to assess clinical performance.

Results

The combined technique was found to be non-inferior to standard two-view mammography (MX_(CC+MLO)) in mean AUC (difference: +0.021;95 % LCL = ?0.011), but was not statistically significant for superiority (P?=?0.197). The combined technique had equivalent sensitivity to standard mammography (76.2 % vs. 72.8 %, P?=?0.269) and equivalent specificity (84.9 % vs. 83.0 %, P?=?0.130). Specificity for benign lesions was significantly higher with the combination of techniques versus mammography (45.6 % vs. 36.8 %, P?=?0.002).

Conclusion

In this enriched study population, the combination of single-view MLO tomosynthesis plus single-view CC mammography was non-inferior to that of standard two-view digital mammography in terms of ROC curve area, sensitivity and specificity.

Key Points

? Breast tomosynthesis (DBT) has emerged as a valuable adjunct to mammography (MX). ? Combination DBT/MX demonstrated non-inferior clinical performance to standard two-view MX. ? Combination DBT/MX was superior to two-view MX in recognising benign lesions. ? Combination DBT/MX reduced variability compared with two-view MX.