Nearly half of breast cancer patients carrying the BRCA1 gene mutation experience a complete pathological response (pCR) - the disappearance of all evidence of disease from the breast tissue and lymph nodes - regardless of disease stage after standard neoadjuvent chemotherapy, according to new research from The University of Texas MD Anderson Cancer Center.
The study, published online in The Journal of Clinical Oncology on September 6, is the largest study to date to find that the pCR rate is significantly higher in BRCA1 carriers (46 percent) than in women carrying the BRCA2 mutation (13 percent) and non-carriers (22 percent). Among all the women, researchers did not find a statistical difference in overall survival rates, but noted that BRCA1 carriers who achieved a pCR had better five-year, relapse-free survival and overall survival rates.
BRCA1 and BRCA2 belong to a class of human genes known as tumor suppressors. The mutation is inherited and increases a woman's chance of developing breast cancer with more aggressive features by 80 percent. Researchers aimed to determine whether women with and without the mutations would respond differently to the same treatment.
"While hereditary breast cancers typically carry aggressive tumor features compared to sporadic breast cancers, we found that BRCA1-related tumors were as responsive and sensitive to anthracycline and taxane-based chemotherapy as were sporadic breast cancers," said Banu Arun, M.D., professor in the Department of Breast Medical Oncology at MD Anderson and lead author of the study. "These findings may help physicians determine the best treatment method for this subset of women with unique genetic mutations."