BRCA Breast Cancers Aren't More Deadly
Study Shows Mutations in BRCA Genes Don't Influence Survival Rates
July 11, 2007 -- It appears that breast cancer patients with BRCA mutations are as likely to survive their disease as women who don't carry the inherited breast cancer genes.
Researchers compared cancer-specific survival outcomes among Israeli women with BRCA1 or BRCA2 gene mutations to women without the genes in the new study, published in the July 12 issue of The New England Journal of Medicine.
They found no difference in survival among the two groups, challenging the common belief that breast cancers occurring among BRCA carriers are more deadly than cancers in noncarriers.
"We know that women with BRCA1 and BRCA2 mutations tend to show up with bad prognostic factors -- characteristics that suggest they are at very high risk," researcher Gad Rennert, MD, PhD, tells WebMD. "But our results suggest the outcomes among these women are often much better than would be expected."
BRCA Mutations Uncommon
Inherited gene mutations account for just 5% to 10% of all breast cancers diagnosed in the U.S. BRCA1 and BRCA2 mutations are the most common ones linked to hereditary breast cancer and ovarian cancer, but the lifetime risk of developing breast cancer is between three times and seven times higher for carriers than noncarriers, according to the National Cancer Institute.
People of Ashkenazi Jewish descent are five times more likely to have inherited BRCA mutations than the general population.
Because Israel has a very high concentration of Ashkenazi Jews as well as a national breast cancer registry, Rennert and colleagues from the nation's National Cancer Control Center were able to compare long-term breast cancer outcomes among a large group of BRCA carriers and noncarriers.
The researchers first tested DNA from stored tumor specimens obtained from breast cancer patients treated in Israel in 1987 and 1988 to determine the incidence of BRCA mutations.
They then reviewed the medical records of the women from whom the specimens were collected for a minimum of 10 years after diagnosis.
A BRCA1 or BRCA2 mutation was identified in 10% of the samples tested from women who were of Ashkenazi Jewish descent, and the 10-year follow up revealed that women who carried a BRCA mutation and women who were not carriers had similar survival rates.