Risk of metachronous breast cancer after BRCA mutation-associated ovarian cancer

This study sought to estimate the risk of breast cancer (BC) after a diagnosis of ovarian cancer (OC) associated with mutation of the BRCA1/2 (breast cancer, early onset) genes (BRCA-OC).

The Memorial Sloan-Kettering Cancer Center and the University of Pennsylvania, clinical genetics databases were searched to identify women with BRCA-OC who participated in genetic testing and follow-up studies from 1995 to 2009. The primary objective was to determine the risk of developing BC after BRCA-OC. Overall survival (OS) and BC-free survival (BCFS) were determined by the Kaplan-Meier method; patients were censored at the time of last follow-up.

A total of 164 patients had BRCA-OC (115 with BRCA1; 49 with BRCA2). Of these 164 patients, 152 developed OC prior to BRCA testing (median time to testing, 2.4 years [0.01-55 years]). Median follow-up from OC for those not developing BC was 5.8 years (0.25-55.6 years). There were 46 deaths, but none were due to BC. The 5- and 10-year OS were 85% (95% confidence interval [CI] = 0.78, 0.90) and 68% (95% CI = 0.59, 0.76), respectively. There were 18 metachronous BC diagnoses. The 5- and 10-year BCFS were 97% (95% CI = 0.92, 0.99) and 91% (95% CI = 0.82, 0.95), respectively. A subset of 64 women were tested either before or within 12 months of BRCA-OC. In this pseudo-incident subset, 5- and 10- year OS was 71% (95% CI = 0.53, 0.83) and 62% (95% CI = 0.44, 0.75), respectively, and 5- and 10-year BCFS were 100% and 87% (95% CI = 0.56, 0.96), respectively.

OS was dominated by OC deaths. Metachronous BC risk was lower than reported for unaffected BRCA mutation carriers. These results support nonsurgical management of BC risk in women with BRCA-OC.