A new study has reported that BRCA1 mutation carriers with triple negative breast cancer have similar survival rates to noncarriers when treated with alkylating chemotherapy. Triple negative breast cancer is a subtype of breast cancer that is estrogen receptor negative (ER-), progesterone receptor negative (PR-), and human epidermal growth factor receptor 2 negative (HER2-) and is associated with early disease relapse and poor outcome. Alkylating chemotherapy drugs such as cyclophosphamide damage the DNA of cancer cell so that they cannot replicate. Women with BRCA1 mutations tend to develop breast cancer with similar pathologic features to sporadic triple negative breast cancer (i.e., breast cancer apparently not directly caused by an inherited genetic defect).
In the study, the outcomes of women with and without BRCA1 mutations who had triple negative breast cancer were compared. The study included 46 BRCA1 carriers and 71 noncarriers, all of whom had stage I to III triple negative breast cancer, received BRCA1 testing within three years of diagnosis, and were treated with alkylating chemotherapy. BRCA1 carriers and noncarriers were compared with respect to sites of metastasis, relapse rates, and survival (median follow-up 75 months).
BRCA1 carriers were found to be younger at diagnosis, with smaller tumors than noncarriers. Five years after breast cancer diagnosis, 76% of BRCA1 carriers were free from distant metastasis compared to 70% of noncarriers, however, the difference was not statistically significant. Sites of distant recurrence also did not vary significantly, although BRCA1 carriers had a tendency toward brain metastases (58% vs 24%). Overall survival at five years also appeared more favorable for BRCA1 carriers (82%) compared to noncarriers (74%), however again the results did not reach statistical significance. BRCA1 mutation status was not found to be an independent predictor of survival after adjusting for age and breast cancer stage. The authors comment that women with BRCA1-related breast cancer may benefit from new treatments that target DNA repair.
Please see our articles on BRCA1 and BRCA2 mutation carriers and the latest research concerning triple negative breast cancer prognosis for more information.