Core needle biopsy of synchronous ipsilateral breast lesions: impact on treatment.

OBJECTIVE The purpose of this study was to evaluate the role of core biopsy in the diagnosis of multiple synchronous ipsilateral breast lesions and to determine the impact of this information on patients' management. MATERIALS AND METHODS Of 371 patients who underwent core-needle breast biopsy under stereotaxic (n = 278) or sonographic (n = 93) guidance, 20 (5%) underwent core biopsy of two mammographically separate lesions in the ipsilateral breast on the same date. Fourteen of these 20 patients subsequently underwent surgery. We retrospectively reviewed the medical, radiographic, and histopathologic records in these 14 patients and in 91 patients with single mammographic lesions diagnosed as carcinoma by means of core biopsy during the same period. RESULTS In 11 patients, core biopsy revealed two sites of carcinoma. Core biopsy findings in these 11 patients were two areas of infiltrating ductal carcinoma (n = 5), one infiltrating ductal carcinoma and one infiltrating lobular carcinoma (n = 2), one infiltrating ductal carcinoma and one ductal carcinoma in situ (n = 1), and two foci of ductal carcinoma in situ (n = 3). All 11 patients with two core biopsy-proven foci of carcinoma underwent mastectomy. Patients were significantly more likely to be treated with mastectomy if core biopsy revealed two rather than one site of carcinoma (100% versus 38%, p < .001). CONCLUSION Core-needle biopsy is useful in diagnosing multiple synchronous ipsilateral breast lesions. By showing whether carcinoma is present in one or more sites in the breast, core biopsy can provide information of critical importance in making treatment decisions.