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.

Pathologic outcomes of nonmalignant papillary breast lesions diagnosed at imaging-guided core needle biopsy.

PURPOSE: To determine the upstage rate from nonmalignant papillary breast lesions obtained at imaging-guided core needle biopsy (CNB) and if there are any clinical, imaging, or pathologic features that can be used to predict eventual upstaging to malignancy. MATERIALS AND METHODS: This retrospective case review was institutional review board approved and HIPAA compliant, with a waiver of informed consent. A database search (from January 2001 to March 2010) was performed to find patients with a nonmalignant papillary breast lesion diagnosed at CNB. Of the resulting 128 patients, 86 (67%) underwent surgical excision; 42 (33%) patients were observed with imaging, for a median observation time of 4.1 years (range, 1.0-8.6 years). Chart review was performed to determine pertinent features of each case. RESULTS: Fourteen of 128 patients were subsequently found to have malignancy at excision, for an upstage rate of 11%. Nine (7%) of the 128 patients were subsequently found to have atypia at excision. Comparisons between patients with upstaged lesions and patients whose lesions were not upstaged demonstrated patients with upstaged lesions to be slightly older (65 vs 56 years, P=.01), more likely to have a mass than calcifications at imaging (P=.03), and to have had less tissue obtained at biopsy (three vs five cores obtained, P=.02; 14- vs 9-gauge needle used, P<.01; no vacuum assistance used, P<.01). Most strongly predictive of eventual malignancy, however, was whether the interpreting pathologist qualified the benign diagnosis at CNB with additional commentary (P<.01). CONCLUSION: Given the substantial upstage rate (11%) of papillary lesions diagnosed at imaging-guided CNB, surgical excision is an appropriate management decision; however, careful evaluation in concert with an expert breast pathologist may allow for observation in appropriately selected patients.

Is confidence of mammographic assessment a good predictor of accuracy?

OBJECTIVE: Interpretive accuracy varies among radiologists, especially in mammography. This study examines the relationship between radiologists' confidence in their assessments and their accuracy in interpreting mammograms. MATERIALS AND METHODS: In this study, 119 community radiologists interpreted 109 expert-defined screening mammography examinations in test sets and rated their confidence in their assessment for each case. They also provided a global assessment of their ability to interpret mammograms. Positive predictive value (PPV) and negative predictive value (NPV) were modeled as functions of self-rated confidence on each examination using log-linear regression estimated with generalized estimating equations. Reference measures were cancer status and expert-defined need for recall. Effect modification by weekly mammography volume was examined. RESULTS: Radiologists who self-reported higher global interpretive ability tended to interpret more mammograms per week (p = 0.08), were more likely to specialize (p = 0.02) and to have completed a fellowship in breast or women's imaging (p = 0.05), and had a higher PPV for cancer detection (p = 0.01). Examinations for which low-volume radiologists were "very confident" had a PPV of 2.93 times (95% CI, 2.01-4.27) higher than examinations they rated with neutral confidence. Trends of increasing NPVs with increasing confidence were significant for low-volume radiologists relative to noncancers (p = 0.01) and expert nonrecalls (p < 0.001). A trend of significantly increasing NPVs existed for high-volume radiologists relative to expert nonrecall (p = 0.02) but not relative to noncancer status (p = 0.32). CONCLUSION: Confidence in mammography assessments was associated with better accuracy, especially for low-volume readers. Asking for a second opinion when confidence in an assessment is low may increase accuracy.

Effect of transition to digital mammography on clinical outcomes.

PURPOSE: To determine the effect of transition to digital screening mammography on clinical outcome measures, including recall rate, cancer detection rate, and positive predictive value (PPV). MATERIALS AND METHODS: Institutional review board approval and the need for informed consent were waived for this HIPAA-complaint study. Practice audit data were obtained for three breast imaging radiologists from 2004 to 2009. These data were sorted by time period into the following groups: baseline (2004-2005), digital year 1 (2007), digital year 2 (2008), and digital year 3 (2009). The χ(2) and Fisher exact tests were used to assess differences in proportions among and between years. Clinical outcomes based on lesion type from 2004 to 2008 were also compared. Computer-aided detection was used. RESULTS: The three radiologists interpreted 32 600 screen-film mammograms and 33 879 digital mammograms. Recall rates increased from 6.0% at baseline to 7.1% in digital year 1 (P < .0001) and continued to increase in subsequent years to 8.5%. The cancer detection rate increased from 3.3 at baseline to 5.3 in digital year 1 (P = .0061), and it remained higher than that at baseline in subsequent years. PPV after screening mammogaphy (PPV(1)) increased from 5.6% at baseline to 7.5% in digital year 1 and returned to baseline levels in digital year 3. In contrast, PPV after biopsy (PPV(3)) decreased from 44.5% at baseline to 30.3% in digital year 3 (P = .0021). From 2004 to 2008, 3444 patients with 3493 lesions were recalled. The percentage of recalls for calcifications increased from 13.8% at baseline to a peak of 23.9% in digital year 1 and 17.9% in digital year 2. Both PPV(1) and PPV(3) decreased for calcifications after the digital transition. CONCLUSION: Recall rate and cancer detection rate increase for at least 2 years after the transition to digital screening mammography. PPV(3) is significantly reduced after digital transition, primarily in patients with microcalcifications.

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.

Identifying minimally acceptable interpretive performance criteria for screening mammography.

PURPOSE: To develop criteria to identify thresholds for minimally acceptable physician performance in interpreting screening mammography studies and to profile the impact that implementing these criteria may have on the practice of radiology in the United States. MATERIALS AND METHODS: In an institutional review board-approved, HIPAA-compliant study, an Angoff approach was used in two phases to set criteria for identifying minimally acceptable interpretive performance at screening mammography as measured by sensitivity, specificity, recall rate, positive predictive value (PPV) of recall (PPV(1)) and of biopsy recommendation (PPV(2)), and cancer detection rate. Performance measures were considered separately. In phase I, a group of 10 expert radiologists considered a hypothetical pool of 100 interpreting physicians and conveyed their cut points of minimally acceptable performance. The experts were informed that a physician's performance falling outside the cut points would result in a recommendation to consider additional training. During each round of scoring, all expert radiologists' cut points were summarized into a mean, median, mode, and range; these were presented back to the group. In phase II, normative data on performance were shown to illustrate the potential impact cut points would have on radiology practice. Rescoring was done until consensus among experts was achieved. Simulation methods were used to estimate the potential impact of performance that improved to acceptable levels if effective additional training was provided. RESULTS: Final cut points to identify low performance were as follows: sensitivity less than 75%, specificity less than 88% or greater than 95%, recall rate less than 5% or greater than 12%, PPV(1) less than 3% or greater than 8%, PPV(2) less than 20% or greater than 40%, and cancer detection rate less than 2.5 per 1000 interpretations. The selected cut points for performance measures would likely result in 18%-28% of interpreting physicians being considered for additional training on the basis of sensitivity and cancer detection rate, while the cut points for specificity, recall, and PPV(1) and PPV(2) would likely affect 34%-49% of practicing interpreters. If underperforming physicians moved into the acceptable range, detection of an additional 14 cancers per 100000 women screened and a reduction in the number of false-positive examinations by 880 per 100000 women screened would be expected. CONCLUSION: This study identified minimally acceptable performance levels for interpreters of screening mammography studies. Interpreting physicians whose performance falls outside the identified cut points should be reviewed in the context of their specific practice settings and be considered for additional training.

The impact of breast MRI on surgical decision-making: are patients at risk for mastectomy?

BACKGROUND AND OBJECTIVES: The goal of the current study was to determine whether MRI impacts multidisciplinary treatment planning and if it leads to increased mastectomy rates. METHODS: A retrospective review was conducted of 441 patients treated for breast cancer between January 2005 and May 2008 who underwent breast MRI. Data included number of additional findings and their imaging and pathologic work-up. This was analyzed to determine impact of MRI on treatment planning. RESULTS: Of 441 patients, 45% had > or =1 additional finding on MRI. Of 410 patients with complete records, 29% had changes in the treatment plan, including 36 patients who were initially considered for breast conservation but proceeded directly to mastectomy based on MRI findings of suspected multicentricity. Twenty-three of those patients did not have a biopsy of the MRI lesion, with 87% having unicentric disease on final pathology. Overall, the mastectomy rate was 44%, which was significantly increased compared to patients not undergoing MRI (32%, P < 0.05). CONCLUSIONS: Breast MRI alters the treatment planning for many patients with newly diagnosed breast cancer. Mastectomy rates are increased when MRI results alone direct surgical planning. Biopsy of MRI-identified lesions should be performed to avoid over-treatment.

Correlation between core biopsy and excisional biopsy in breast high-risk lesions.

BACKGROUND: The purpose of the current study was to compare the prevalence of invasive or in situ cancer at excisional biopsy in patients with image-guided core needle biopsy (CNB)-proven atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), or lobular carcinoma-in-situ (LCIS). Factors affecting the upgrade rate to malignancy were also identified. METHODS: Patients diagnosed with ADH, ALH, or LCIS on image-guided CNB (stereotactic or ultrasound) from 1995 to 2005 were identified through radiologic and surgical databases. Patients who subsequently underwent excisional biopsy of their lesion were included in the study. The imaging, medical records, and pathology of these patients were reviewed. RESULTS: Ninety-six patients with either ADH (61/96, 63%), ALH (19/96, 20%), or LCIS (16/96, 17%) on image-guided CNB proceeded to excisional biopsy. Malignancy was detected on excisional biopsy in 31% of patients with ADH, 16% of patients with ALH, and 25% of patients with LCIS. There were no significant differences between the 2 groups in terms of age, parity, hormonal status, or previous benign breast biopsies. The presence of a mass on mammography was associated with an increased upgrade rate to malignancy, while biopsies performed using vacuum-assisted devices, larger gauge biopsy needles, and greater number of cores were associated with a lower upgrade rate. CONCLUSIONS: Our data suggest that excisional biopsy is warranted in all patients with CNB diagnoses of ADH, ALH, or LCIS to exclude the presence of cancer.

A survey of breast imaging fellowship programs: current status of curriculum and training in the United States and Canada.

PURPOSE: The Society of Breast Imaging and the Education Committee of the ACR Breast Commission conducted a survey of breast imaging fellowship programs to determine the status of fellowship curricula, help identify strengths and potential areas for improvement, and assess the current demand for fellowship programs. METHODS: In 2012, a two-part survey was emailed to breast imaging fellowship directors from 72 fellowship programs. RESULTS: Of the 66 respondents, a total of 115 positions were identified. There were 90 positions with 9-12 months of breast imaging, and 25 positions with 6 months focused on breast imaging. Approximately two-thirds of programs reported an increase in the number of fellowship applicants, with three-quarters having 3 or more applicants for each position. All programs offered digital mammography, breast MRI, and diagnostic ultrasound services, and nearly all provided experience with interventional procedures. Approximately one-third provided breast screening ultrasound training. More than two-thirds required at least a 1-day rotation with a breast surgeon. Important nonclinical areas of training were not addressed in many programs. Approximately 40% of programs did not offer training related to the practice audit, and one-third of programs did not provide formal training related to quality control. CONCLUSIONS: Breast imaging fellowships are currently in higher demand than in the past. Most fellowship programs provide training in the key imaging modalities and interventional procedures. Potential gaps in training for many programs include the practice audit, quality control procedures, breast positioning, and mammography technical factors.

Scientific Presentation Award: The combination of axillary ultrasound and ultrasound-guided biopsy is an accurate predictor of axillary stage in clinically node-negative breast cancer patients.

BACKGROUND: The study aim was to determine the accuracy of axillary ultrasound (AUS) and fine-needle aspiration biopsy (FNAB)/needle core biopsy in axillary breast cancer staging. METHODS: We reviewed 256 patients with clinically node-negative breast cancer who underwent AUS +/- FNAB/needle core biopsy. AUS-guided FNAB/needle core biopsy was compared with histopathology to determine sensitivity, specificity, negative predictive value, and positive predictive value. RESULTS: AUS-guided FNAB/needle core biopsy and final pathology were positive in 72 of 256 patients (28%). In 125 of 256 cases (49%), the AUS and final pathology were negative. Two of 110 patients had a false-positive FNAB (1.8%); both received neoadjuvant chemotherapy. Nine patients (8%) had a false-negative FNAB/needle core biopsy; the median size of lymph node metastasis was 3 mm. The sensitivity and specificity of AUS-guided FNAB/needle core biopsy was 71% and 99%, respectively, with a negative predictive value of 84% and a positive predictive value of 97%. CONCLUSIONS: AUS-guided FNAB/needle core biopsy is accurate in predicting the status of the axilla in 70% of clinically node-negative breast cancer patients. This technique is minimally invasive with a low complication rate and can obviate the need for staged lymph node procedures.

Professional and economic factors affecting access to mammography: a crisis today, or tomorrow? Results from a national survey.

BACKGROUND: Objective data and anecdotal reports have suggested that access to mammography may be declining because of facility closures and difficulty in recruiting and retaining radiologists and radiologic technologists. To gain insight into the practice patterns, use of emerging technologies, and concerns of breast imagers in current practice, the Society of Breast Imaging (SBI) conducted a national survey of breast imaging practices in the U.S. METHODS: Between October 2003 and April 2004, the SBI conducted a survey of the SBI membership database, and received completed surveys from 575 breast imaging practices in the U.S. Responses to the survey regarding practice characteristics, the utilization of standard and emerging technologies, staffing, malpractice, finance, and morale were analyzed. RESULTS: Job vacancies for radiologists who read mammograms were reported in 163 practices (29%), 59 of which (10%) had 2 or more openings. A higher proportion of practices with job openings had long appointment waiting times for asymptomatic women when compared with fully staffed practices. Unfilled fellowship positions also were common, with 41 of 65 practices that offer fellowships reporting 47 openings. Among 554 responding practices, 55% reported that someone in their practice was sued because of a mammography related case within the past 5 years, and 50% of practices reported that the threat of lawsuits made radiologist staffing "moderately" or "a lot" more difficult. Of 521 responding practices, 35% reported financial losses in 2002. One in 5 respondents reported that they would prefer to spend less time in mammography, and fewer than 1 in 3 would recommend a breast imaging fellowship to a relative or friend. Emerging technologies, such as breast magnetic resonance imaging and screening ultrasound, currently are being performed in many practices. CONCLUSIONS: The survey results provide support for anecdotal reports that breast imaging practices face significant challenges and stresses, including shortages of key personnel, a lack of trainees, malpractice concerns, financial constraints, increased workload due to emerging technologies, low appeal of breast imaging as a career specialty, and the steady rise in the population of women of screening age.

Survey of radiology residents: breast imaging training and attitudes.

PURPOSE: To investigate the training and attitudes of residents regarding breast imaging. MATERIALS AND METHODS: A telephone survey was conducted with 201 4th-year residents (postgraduate medical school year 5) and 10 3rd-year residents (postgraduate medical school year 4) at 211 accredited radiology residencies in the United States and Canada. Survey topics included organization of the breast imaging section, residents' role in the section, clinical practice protocols of the training institution, residents' personal thoughts about breast imaging, and their interest in performing breast imaging in the future. RESULTS: Of 211 programs, 203 (96%) had dedicated breast imaging rotations; 196 (93%) rotations were 8 weeks or longer; 153 (73%), 12 weeks or longer. Residents dictated reports in 199 (94%) programs. Residents performed real-time ultrasonography (US) in 186 (88%) programs, needle localization in 199 (94%), US-guided biopsy in 174 (82%), and stereotactically guided biopsy in 181 (86%). One hundred eighty-four (87%) residents rated interpretation of mammograms more stressful than they did that of other images, and 137 (65%) believed mammograms should be interpreted by subspecialists. One hundred thirty-five (64%) residents would not consider a fellowship in breast imaging if offered, and 133 (63%) would not want to spend 25% or more of their time in clinical practice on interpretation of mammograms. The most common reasons given for not considering a fellowship or interpretation of mammograms were that breast imaging was not an interesting field, that they feared lawsuits, and that it was too stressful. Fellowships were offered at 53 programs, and at 46 programs, a total of 63 fellows were recruited. CONCLUSION: Residency training in breast imaging has improved in terms of time and curriculum. However, a majority of the residents would not consider a fellowship and did not want to interpret mammograms in their future practices.