(RxWiki News) There are two types of inherited breast cancer genes - BRCA1 and BRCA2. The first of these seems to respond very well to standard chemotherapy before surgery.
Researchers at MD Anderson Cancer Center have discovered that nearly half of all BRCA1 breast cancers disappear after being treated with standard chemotherapy before surgery (neoadjuvant therapy).
"Chemotherapy before surgery works well with BRCA1 breast cancers."
Patients with the BRCA1 gene mutation had what's called a complete pathological response (pCR), which means all evidence of the disease disappeared from both the breast tissue and lymph nodes. This pCR occurred in all stages of the disease after standard neoadjuvant therapy.
The largest observational study to date found that pCR was significantly higher in BRCA1 carriers (46 percent) than in carriers of the BRCA2 mutation (13 percent) and those who do not carry the gene (22 percent).
BRCA1 carriers had better five-year, relapse-free and overall survival rates than the other groups.
BRCA1/2 genes are designed to suppress tumor growth. When there are mutations in these genes, a woman's chance of developing an aggressive form of breast cancer is increased by as much as 80 percent.
This study sought to distinguish the differences in how women with and without these genetic mutations respond to the same treatment.
Researchers worked with 317 women who had different stages of breast cancer, had received neoadjuvant chemotherapy and genetic testing for the BRCA1 and BRCA2 genes between 1997 and 2009. Of this group, 57 women had BRCA1 mutations, 23 were BRCA2 carriers and 237 did not have these mutations.
The majority of participants (256) had mastectomies following chemotherapy.
During the follow-up period of just over three years, 22 percent of patients either had a recurrence of the disease or died.
What this study showed was that the typically more aggressive BRCA1 cancers responded as well to chemotherapy as what's known as sporadic breast cancers.
There is no consensus on the most effective chemotherapy treatment for women with BRCA mutations, according to lead study author, Banu Arun, M.D., professor in the Department of Breast Medical Oncology at MD Anderson.
dailyRx asked Dr. Arun if the standard anthracycline and taxane-based chemotherapy works so well on BRCA1 cancers, why does there need to be a refinement in treatment strategy?
Dr. Arun said, "Good question. 'Works well' is a relative statement. At this point, unfortunately, nothing works 'well' for breast cancer, because are still not able to cure the disease."
"The point here is that BRCA related breast cancers do not respond worse, but given that the pathways involved in BRCA related breast cancer might be different, we can further enhance response and outcome with additional agents; such as targeted drugs," Dr. Arun explained.
The study was funded in part by the Lynn Cohen Breast and Ovarian Cancer Project and the Nellie B. Connally Breast Cancer Research Fund. It was published online in September 6, 2011 edition of The Journal of Clinical Oncology.