Probably benign breast masses at US: is follow-up an acceptable alternative to biopsy?

PURPOSE: To retrospectively determine whether nonpalpable solid breast masses that were partially or completely obscured at mammography and diagnosed as probably benign only at ultrasonography (US) can be safely managed with follow-up. MATERIALS AND METHODS: The local ethics committee approved this study; informed consent was not required. In 409 women, 448 nonpalpable solid masses were identified and classified as probably benign at US; at mammography these masses were either partially or completely obscured by dense fibroglandular tissue. Of the 448 masses, 445 were followed up, while biopsy was performed after initial imaging in the remaining three. False-negative rates, negative predictive values (NPVs), and exact 95% confidence intervals (CIs) were calculated. RESULTS: Of the 445 masses, 442 remained stable at follow-up (range, 2-5 years; mean, 3.3 years). Two masses increased (fibroadenomas at biopsy). One mass became palpable, and cancer was diagnosed at biopsy. The three masses in which initial biopsy was performed were fibroadenomas. The false-negative rate was 0.2% (one of 448; NPV, 99.8%; 95%CI: 0.0%, 1.23%). CONCLUSION: Follow-up US appears to be an acceptable alternative to biopsy for solid masses with benign morphologic features seen at US owing to the extremely high NPV (99.8%).

Follow-up of palpable circumscribed noncalcified solid breast masses at mammography and US: can biopsy be averted?

PURPOSE: To determine whether palpable noncalcified solid breast masses with benign morphology at mammography and ultrasonography (US) can be managed similarly to nonpalpable probably benign lesions (Breast Imaging Reporting and Data System [BI-RADS] category 3)-that is, with periodic imaging surveillance-and to determine whether biopsy can be averted in these lesions. MATERIALS AND METHODS: No institutional review board approval or patient consent was required. This retrospective analysis, based on final imaging reports, included 152 patients (age range, 28-77 years; mean age, 48.3 years) with 157 palpable noncalcified solid masses that were classified as probably benign at initial mammography and US. Of 152 patients, 108 underwent follow-up with mammography and US (6-month intervals for 2 years, then 12-month intervals). The remaining 44 patients underwent surgical or needle biopsy after initial imaging. Lesions were analyzed at initial and follow-up examinations. Statistical analysis included Student t test and corresponding exact 95% confidence intervals. RESULTS: In 108 patients who underwent follow-up only, 112 lesions were palpable. In 102 (94.4%) of 108 patients, masses remained stable during follow-up. Lesions were followed for at least 2 years (mean, 4.1 years; range, 2-7 years). In six (5.6%) patients, palpable lesions increased in size during follow-up; these lesions were benign at subsequent open biopsy. No breast carcinoma was diagnosed in the 44 patients with 45 palpable lesions who underwent biopsy after initial imaging. Of 157 lesions, no malignant tumors were observed (exact one-sided 95% confidence interval: 0%, 1.95%). CONCLUSION: The data strongly suggest that palpable noncalcified solid breast masses with benign morphology at mammography and US can be managed similarly to nonpalpable BI-RADS category 3 lesions, with short-term follow-up (6-month intervals for 2 years). More data, based on a larger series, are required to determine whether this conclusion is correct.