We assessed the efficacy of taxane chemotherapy in BRCA1- and BRCA2-associated patients compared with sporadic metastatic breast cancer patients.
Response rates (RRs) to and progression-free survival (PFS) after taxane chemotherapy of 35 BRCA1-associated and 13 BRCA2-associated metastatic breast cancer patients were compared with those outcomes in 95 matched (1:2) sporadic patients. Matching was performed for age at and year of diagnosis of primary breast cancer, year of metastatic disease, and line of therapy (first vs second or third).
Among BRCA1-associated patients, the RR was worse (objective response [OR], 23% vs 38%; progressive disease [PD], 60% vs 19%; P < 0.001); and the median PFS shorter (2.2 vs 4.9 months; P = 0.04) compared with sporadic patients. In the subgroup of hormone receptor (HRec)-negative patients, BRCA1-associated patients (n = 20) had a worse RR (OR, 20% vs 42%, respectively; PD, 70% vs 26%, respectively; P = 0.03) and a shorter PFS (1.8 vs 3.8 months; P = 0.004) compared with sporadic patients (n = 19). These outcomes in HRec-positive patients were similar in BRCA1-associated (n = 11) and sporadic (n = 61) patients (OR, 36% vs 38%; PD, 28% vs 20%; median PFS, both 5.7 months). In BRCA2-associated patients, who were mainly HRec-positive, the OR was higher than in sporadic patients (89% vs 38%, respectively; P = 0.02), whereas the median PFS was not significantly different (7.1 vs 5.7 months, respectively).
BRCA1-associated, HRec-negative metastatic breast cancer patients were less sensitive to taxane chemotherapy than sporadic HRec-negative patients. HRec-positive BRCA1- and BRCA2-associated patients had a sensitivity to taxane chemotherapy similar to that of sporadic patients.