Selective nonoperative management of patients referred with abnormal mammograms. Screening mammography provides a means of detecting clinically occult breast carcinoma, but the question of whether all abnormal mammograms require biopsy remains unanswered. We retrospectively reviewed records of 214 women referred over an 8-year period for abnormal mammograms. They were selectively assigned to biopsy or mammographic follow-up based on specific mammographic criteria. Of 114 women initially observed mammographically, 2 were later found by biopsy to have carcinoma. Initial assignment to mammographic observation delayed the recommendation for biopsy 3 and 12 months, respectively, in these patients, but no effect on outcome was documented. Because they have benign lesions by clinical and mammographic criteria, 102 women (53%) have been spared biopsy; they continue to be monitored closely. We believe these data support the use of a selective approach to biopsy based on specific mammographic criteria. 