Simultaneous bilateral breast carcinomas: a retrospective review of 149 cases

To evaluate clinical and biological characteristics as well as treatment outcome in simultaneous bilateral breast carcinomas.

Between 1981 and 1990, 149 patients were diagnosed to have simultaneous bilateral breast carcinoma, defined as tumor arising in both breasts within a maximum of a 6-month interval, in the absence of distant metastases. The median age was 58. Out of a total of 298 tumors, the clinical tumor size was T0-T1 in 40%, T2 in 45%, and T3-T4 in 15% of tumors. The majority of patients (83%) were clinically node negative. Seventy-eight percent of all tumors were classified ductal invasive; 6% were invasive lobular carcinomas; in situ tumors were present in 9%. More than two-thirds of all tumors were well or moderately well differentiated. Tumors were estrogen positive in 86% and progesterone positive in 69% of 62% of patients for whom this information was available in both tumors. Treatment had been by bilateral mastectomy in 43%, by exclusive irradiation in 16%, and by combined surgery and radiation in 41%.

Median follow-up was 68 months (11-141). A number of positive correlations existed between the tumors in both breasts more often than by chance alone: These were the presence of lobular carcinomas in both breasts (p = 0.06), the same histological grade (p = 0.002), similar ER (p = 0.03) and PR (p = 0.01) status. Five-year rates for survival and disease-free interval were 86% (80-92) and 70% (62-78), respectively. For each patient the stage of the largest tumor at diagnosis was defined as maximum stage. When survival figures were compared between each maximum stage and matched stages of a group of unilateral breast cancer patients treated during the same time interval in our institute, bilateral breast cancer fared not worse than unilateral breast tumors. Treatment related complications occurred in eight patients (5%).

Simultaneous bilateral breast carcinomas have similar biological, but not clinical, features more frequently than would be predicted by chance alone. So far, the number of patients is too small, and the follow-up is too short to determine whether or not the prognosis is equivalent to that of unilateral breast cancer patients of equal stage. Bilateral conservative treatment is feasible with acceptable cosmetic results and toxicity by using carefully designed radiotherapy techniques.