Imaging and Histopathologic Features of BI-RADS 3 Lesions Upgraded during Imaging Surveillance.

To evaluate imaging and histopathologic differences between screen-detected benign and malignant upgraded lesions initially assessed as BI-RADS 3 at diagnostic evaluation. An IRB approved retrospective review of the mammography data base from January 1, 2004 to December 31, 2008 identified 1,188 (1.07%) of 110,776 screening examinations assessed as BI-RADS 3 following diagnostic evaluation at our academic center (staffed by breast specialists) or our outpatient center (staffed by general radiologists), 1,017 with at least 24 months follow-up or biopsy. Sixty (5.9%) BI-RADS 3 lesions were upgraded to BI-RADS 4 or 5 during imaging surveillance (study population). Prospective reports, patient demographics, and clinical outcomes were abstracted from the longitudinal medical record. Mean patient age was 54.1 years (range 35-85). Lesions consisted of 7 masses, 12 focal asymmetries and 41 calcifications. Fifteen (25%) of 60 lesions upgraded from initial BI-RADS 3 assessment were malignant (1.47% of total; 15/1,017 BI-RADS 3 studies). Malignancy rates by upgraded lesion type showed no significant difference: Thirty-three (73.3%) of 45 benign upgraded lesions were calcifications compared to 8 (53.3%) of 15 malignant upgraded lesions (p = 0.202). Twelve (26.7%) of 45 benign upgraded lesions were masses or focal asymmetries, compared to 7 (46.7%) of 15 upgraded malignant lesions (p = 0.202). Six (85.7%) of 7 malignant upgraded masses/focal asymmetries had no US correlate at initial BI-RADS 3 assessment compared to 7 (58.3%) of 12 benign upgraded masses/focal asymmetries (p = 0.33). Breast-imaging specialists interpreted 21 studies, 3 (14.3%) malignant; general radiologists interpreted 39 studies, 12 (30.8%) malignant (p = 0.218). There was no significant difference in malignancy rate among different types of upgraded mammographic lesions, nor depending on subspecialty interpretation versus nonsubspecialist interpretation. Although calcifications made up a majority of upgraded lesions, most were benign, suggesting that decreased surveillance of calcifications may be appropriate.

Assessment and Management of Challenging BI-RADS Category 3 Mammographic Lesions.

Breast Imaging Reporting and Data System (BI-RADS) category 3 lesions are probably benign by definition and are recommended for short-interval follow-up after a diagnostic workup has been completed. Although the original lexicon-derived BI-RADS category 3 definition applied to lesions without prior imaging studies (when stability could not be determined), in clinical practice, many lesions with prior images may be assigned to BI-RADS category 3. Although the BI-RADS fifth edition specifically delineates lesions that are appropriate for categorization as probably benign, it also specifies that the interpreting radiologist may use his or her discretion and experience to justify a "watchful waiting" approach for lesions that do not meet established criteria. Examples of such lesions include evolving masses or calcifications suggestive of prior trauma and instances when stability cannot be ascertained because of image quality. Although interval change is an important feature of malignancy, many benign lesions also change over time; thus, use of prior imaging studies and ongoing imaging surveillance to demonstrate the evolution of a probably benign lesion is justified. Some examples of common pitfalls associated with inappropriate BI-RADS category 3 assessment include failure to use proper BI-RADS descriptors, failure to perform a complete diagnostic workup, and overreliance on negative ultrasonographic findings. When appropriately used, short-interval follow-up saves many patients from undergoing biopsy of benign lesions, without decreasing the rate of cancer detection. (©)RSNA, 2016.

Patient compliance and diagnostic yield of 18-month unilateral follow-up in surveillance of probably benign mammographic lesions.

OBJECTIVE: The purpose of this study is to determine the patient compliance with and diagnostic yield of 18-month unilateral mammography in surveillance of probably benign (BI-RADS category 3) lesions. MATERIALS AND METHODS: This retrospective study identified lesions prospectively classified BI-RADS 3 in asymptomatic women from January 1, 2004, to December 31, 2008. Surveillance protocol for BI-RADS 3 lesions included 6-month (unilateral), 12-month (bilateral), 18-month (unilateral), and 24-month (bilateral) imaging, with subsequent annual screening. Demographics, surveillance data, BI-RADS upgrades and downgrades, and biopsy results were abstracted from the longitudinal medical record. RESULTS: One thousand one hundred eighty-eight lesions in 1077 patients (mean age, 51.5 years; age range, 26-89 years) had BI-RADS 3 assessment, representing 1.07% of all screening examinations. The compliance rates for follow-up at 6, 12, 18, and 24 months were 83.3%, 75.9%, 54.8%, and 53.9%, respectively. Sixty lesions were upgraded to BI-RADS 4 or 5 during surveillance. Biopsy revealed 15 cancers (cancer yield of 1.47%) from 1017 lesions with either 24-month imaging stability or tissue diagnosis available. Five, six, one, and three cancers were detected at 6, 12, 18, and 24 months, respectively. Cancers were all stage 0 or 1 except for one stage 2A cancer. Seven hundred forty-four of 1188 (62.6%) BI-RADS 3 lesions were downgraded before completing 2-year surveillance. CONCLUSION: Most (11/15 [73%]) breast cancers initially assessed as BI-RADS 3 are diagnosed at up to 12 months' surveillance. Eighteen-month unilateral mammography performed as BI-RADS 3 surveillance contributes minimally to cancer detection and has poor patient compliance.