Activity of taxane chemotherapy for metastatic breast cancer (MBC) in BRCA1 and BRCA2 mutation carriers compared to sporadic BC patients.

1020 Background: BRCA1-associated BC is characterized by high differentiation grade and basal-like phenotype, while BRCA2-associated and sporadic BC have similar patterns. Preclinical and small retrospective studies suggest that BC (cells) without functioning BRCA1/2 protein have increased sensitivity to chemotherapy causing dsDNA breaks, and decreased sensitivity to spindle poisons. Clinical data on the activity of taxanes in BRCA1/2-associated BC are scarcely available. Therefore, we assessed the activity of taxane-based chemotherapy in BRCA1- and BRCA2-associated compared to sporadic MBC pts. Methods: From the Family Cancer Clinic database, we selected 32 BRCA1- and 13 BRCA2-associated BC pts treated with taxane chemotherapy for MBC. Sporadic pts (n=90, 1:2 ratio) were matched for year of birth, diagnosis and metastatic disease, and line of chemotherapy. Response rates (RR) were tested by chi-square test, progression-free survival (PFS) was analysed by Kaplan-Meier method. Results: BRCA1 pts significan...