Pathology and treatment of impalpable breast lesions.

With the increasing use of mammography, more needle-localized breast biopsies (NLBB) are being done. The purpose of this study was to analyze the pathology of impalpable breast lesions and the impact of NLBB on treatment strategies. From 1985 to 1990, 1,605 NLBB were performed, of which 321 (20%) were malignant. Twenty-five percent of malignant biopsies demonstrated in situ disease only. The average size of all lesions detected was 16 mm, and, for invasive cancer, 12 mm. Eighteen percent of invasive cancers had metastasized to the axillary lymph nodes. Surgical management consisted of mastectomy in 74% of patients and breast conservation treatment (BCT) in 26%. No significant difference in surgical management for women 50 years of age or younger compared with those older than 50 years of age was noted. Although the use of BCT for eligible women is recommended by the National Institutes of Health, it is not widely practiced, possibly reflecting less physician acceptance of BCT. These observations suggest that the detection of smaller, impalpable breast cancers has had no impact on treatment strategies.