Breast-Conserving Surgery in Bilateral Breast Cancer

Bilateral breast cancer (BBC) may present as synchronous (SBC) or metachronous breast cancer (MBC). Optimal surgical management of BBC patients is not well-defined. In this study, we report on histopathology, treatment, and outcomes in BBC patients.

Upon Institutional Review Board approval, we identified BBC patients diagnosed and treated for invasive breast cancer between 1999 and 2007. Retrospective chart review for demographics, histopathology, treatment, and outcomes was performed, and factors associated with BCS choice were collected. Contraindication to BCS was defined as any of the following one-breast findings: multicentric disease, tumor considered too large for BCS, and a patient without a nominal breast size for acceptable cosmetic results. McNemar's test for matched pairs (binary variables) or the paired t test (continuous variables) were used to examine if a pathologic characteristic differed within a cancer pair. Kaplan-Meier methods estimated overall survival (OS).

A total of 203 BBC patients (119 SBC, 84 MBC) comprised our study group. Histopathologic characteristics of the first and second cancers diagnosed in both the SBC and MBC patients were very similar in histologic type and molecular profiles. Overall, 57% of MBC patients underwent breast-conserving surgery (BCS) at initial diagnosis versus 34% of patients with SBC. BCS contraindications were similar in both groups: 16 (34%) MBC patients and 28 (36%) SBC patients. Kaplan-Meier OS estimates at 5 and 10 years were 86 and 78% for MBC, and 87 and 77% for SBC patients, respectively.

OS was excellent for both the MBC and SBC groups. Contraindications to BCS did not differ between groups. However, patients with SBC were less likely to undergo BCS compared with patients with MBC at the time of initial diagnosis.