Nonpalpable breast lesions: findings of stereotaxic needle-core biopsy and fine-needle aspiration cytology.

Two hundred fifty mammographically detected nonpalpable breast lesions suspicious for malignancy in women who underwent routine screening mammography were stereotaxically localized. Fine-needle-aspiration (FNA) cytologic specimens and needle-core biopsy specimens were obtained before open biopsy in every case. Seventy-six lesions (30.4%) were malignant. Sixty-three (83%) of these 76 cancers were 1 cm long or smaller. Needle-core biopsy alone was used to diagnose conclusively 41% (n = 31) of these cancers, while FNA cytologic study alone was used to diagnose 32% (n = 24). No false-positive results occurred with either test. The same diagnosis was reached in 54% (n = 41) when the combined results of both needle tests were considered. In applying the two needle tests to 125 mammographically defined low-suspicion lesions, 85 (68%) were found to be benign by means of either one or both needle tests; there was one lobular carcinoma in situ. By applying this algorithm, 85 (34%) of 250 patients with abnormal mammograms, or one-third of all patients recommended for open biopsy, might have avoided surgery.