Managing the remaining breast.

Bilateral breast cancer is discussed as to 1) the criteria for determining whether a cancer in the other breast is primary or metastatic; 2) the incidence of simultaneous and subsequent primary cancers in the second breast and the factors that could account for the reported frequency variance by different authors; 3) the influence that a second primary cancer in the contralateral breast makes on the survival of the patient; 4) the psychologic and physical importance of the remaining breast to the patient; and 5) the management of the other breast using preoperative x-rays and random biopsies as added modalities for detection and reserving prophylactic mastectomy of the remaining breast for those patients at high risk for developing cancer in it with a definition of these risk factors. Forty-two simultaneous primary cancers were found in the other breast in a series of 500 (8.4%) patients undergoing primary therapy for cancer in their first breast of which 19 (45.2%) were invasive, and 23 (54.8%) were non-invasive. Two (0.4%) were detected clinically, 16 (3.2%) by x-rays, and 24 (7.5%) by random biopsies in 321 patients. In a series of 846 patients with potentially curable breast cancer, the absolute ten-year survival rate was 63%. They were operated on before the routine use of preoperative x-rays and random biopsies. Eleven (1.3%) had either clinical or x-ray detected simultaneous cancers in the other breast. Of the remaining 835, 48 had prophylactic mastectomies in which 8 (16.6%) unsuspected cancers were found. In the remaining 787, 70 (8.9%) developed subsequent cancers making a total subsequent rate of 78 of 835 (9.3%).