Feasibility of breast conservation therapy in metachronous or synchronous bilateral breast cancer

Background: The optimal management of contralateral breast cancer (CC) in patients previously treated with breast-conserving therapy (BCT) is unclear, as is whether these patients continue to choose BCT as the preferred treatment of their second breast cancer. Methods: Of 1328 patients treated with BCT at The University of Texas M.D. Anderson Cancer Center between 1958 and 1994, 63 developed a contralateral breast cancer. We reviewed the charts of these patients retrospectively, and standard demographic and treatment variables were evaluated. Survival was analyzed by the Kaplan-Meier method and subgroups by χ² analysis. Results: Twenty-nine percent of the patients had a family history of breast cancer. First breast cancers were detected by patient or physician in 67% of cases and by mammogram in 17% of cases, compared to 59% and 36%, respectively, of CC (P = .04). Median time to development of CC was 61 months. Sixty percent of the initial tumors were AJCC stage 0 or I with a median size of 2 cm, whereas 74% of the CC were stage 0 or I (P = .02), with a median size of 1.5 cm. Eighty-seven percent of patients chose BCT for treatment of CC. There were few treatment-related complications. Recurrence rates were not significantly different from those of patients undergoing BCT for the initial cancer (P = .47), and 5- and 10- year actuarial survival rates after the first cancer were 93% and 76%, respectively. Median follow-up was 134 and 56 months from the time of diagnosis of the initial cancer and CC, respectively. Conclusions: Because contralateral breast cancer often is detected at an early stage, there are few treatment-related complications, and the risk of recurrence is no different from that for the initial cancer, BCT is an acceptable and desirable option for appropriately selected patients with metachronous or synchronous bilateral breast cancers.