MONDAY, April 4 (HealthDay News) -- Ovarian cancer patients with the BRCA2 gene mutation are more likely to survive than those with the BRCA1 mutation or patients without either mutation, a new study finds.

U.S. researchers analyzed 3,531 cases of epithelial ovarian cancer, including 1,178 patients with BRCA1 mutations, 367 with BRCA2 mutations and 1,986 with neither mutation.

Five-year survival rates were 61 percent for those with the BRCA2 mutation, 46 percent for those with the BRCA1 mutation and 36 percent for those with neither mutation, the investigators found.

The study is to be presented Monday at the annual meeting of the American Association for Cancer Research, in Orlando, Fla. The research is considered preliminary until it is published in a peer-reviewed journal.

"There was some previous evidence that women with ovarian cancer who have mutations in the BRCA genes show improved survival compared to non-mutation carriers. Our study clearly shows that this survival difference is real. We also provide the first solid evidence that BRCA1 and BRCA2 mutations don't have the same impact on ovarian cancer survival," Kelly Bolton, a fellow at the U.S. National Cancer Institute, said in an AACR news release.

Further research is needed to find out why BRCA2 mutations are associated with better survival than BRCA1 mutations or no mutations. The mutations may affect a patient's response to chemotherapy, Bolton suggested.

About 1 in 400 to 1 in 800 women are born with either the BRCA1 or BRCA2 mutations, which increase the risk of ovarian and breast cancer. About 5 percent of ovarian cancer patients have BRCA1 or BRCA2 mutations.

More information

The American Cancer Society has more about ovarian cancer.