A case–control study of unilateral and bilateral breast carcinoma patients

BACKGROUND Women with unilateral breast carcinoma are at increased risk for developing contralateral disease. The clinical significance of bilateral breast carcinoma has not been fully defined, and the subset of patients who may benefit from medical or surgical risk‐reduction intervention has not yet been characterized. The purpose of this study was to evaluate risk factors and outcomes for bilateral breast carcinoma. METHODS A subject group of 70 bilateral breast carcinoma patients (62% metachronous) was matched by age and survival interval with a control group of 70 unilateral breast carcinoma patients. Median follow‐up was 103 months. RESULTS Eighty‐two percent of the unilateral patients and 80% of the bilateral patients had Stage I or II disease at diagnosis. Median age at presentation was 53 years. In the bilateral group, the contralateral cancer was diagnosed at the same or earlier stage than the first cancer in 87% of cases. Bilateral patients were significantly more likely to have multicentric disease and to have a positive family history for breast carcinoma compared with the unilateral group. There were no significant differences regarding history of exogenous hormone exposure, lobular histology, hormone‐receptor status, or HER‐2/neu expression. Five‐year disease‐free survival was 94% for the unilateral breast carcinoma patients and 91% for the bilateral breast carcinoma patients (P = 0.16). CONCLUSIONS Survival for patients with bilateral breast carcinoma is similar to that of patients with unilateral disease; however, prophylactic risk‐reduction intervention for the contralateral breast should be considered in patients who have multicentric unilateral disease or a positive family history for breast carcinoma. Cancer 2001;91:1845–53. © 2001 American Cancer Society. This case–control study of unilateral versus bilateral breast carcinoma revealed that family history and multicentric disease were significant risk factors for bilateral disease. Survival rates were similar for the two groups of patients.