Bilateral breast cancer. Risk reduction by contralateral biopsy.

Although survival from primary breast cancer has improved with earlier diagnosis and treatment, the management of the opposite breast is still in question. The risk factors for bilaterality are known, and preoperative mammography is occasionally helpful, but identification of early second breast cancer is very limited. Contralateral biopsy may provide a reasonable answer to the problem. During a 5-year period, 62 elective contralateral biopsies were performed in patients having mastectomies for primary breast cancer. This consisted of either a mirror image biopsy or, more commonly, a biopsy of the upper outer quadrant. Thirteen patients had simultaneous contralateral cancers, of whom two had clinically overt bilateral cancers and 11 (18%) had clinically occult malignancy. Seven of these 11 had both radiologically and clinically normal breasts. Thus, 11.3% had radiologically and clinically occult cancer demonstrated by biopsy. Surgical management consisted of total mastectomy with low axillary dissection for noninvasive cancers and modified radical mastectomy for invasive cancers. Pathologic findings of the dominant breast cancer and the contralateral lesion were: bilateral, noninvasive: three patients; invasive, noninvasive: (seven patients), and invasive, invasive: three patients. Although follow-up is short (median of 40 months), 82% of the patients who had clinically occult second-breast cancer remain free of disease. During a previous 8-year period, 37 of 500 primary breast cancer patients (7.4%) developed metachronous (33) or synchronous (4) second-breast primary cancers primarily diagnosed clinically or radiologically. Of these, 35 were invasive and two noninvasive cancers; 41% had nodal metastases. A selected "favorable group," 28 of these patients who were free of disease 3 years after their first cancer, was analyzed. The analysis showed that only 10 (36%) were surviving free of disease at 7 years; 25% were free of disease at 10 years. Although the incidence of clinically-recognized, second-primary breast cancer is relatively low, development of a second invasive cancer severely impairs patient survival. Contralateral biopsy would appear useful to identify patients with early invasive or preinvasive cancer in the second breast, which appears normal after clinical observation or mammography. It provides opportunity to reduce the risk of invasive cancer in that breast, as well as to provide important diagnostic and prognostic information.