TUESDAY, Jan. 24 (HealthDay News) -- Genetic mutations known as BRCA1 and BRCA2 raise the risk of getting ovarian cancer, but new research shows that those same mutations may boost a woman's odds of surviving the deadly disease.

Women with invasive epithelial ovarian cancer who carry the mutations have a better prognosis than women without the genetic variations, according to an analysis of 26 previous studies. The BRCA2 carriers, in particular, had a better five-year survival rate.

"Our paper provides definitive evidence that BRCA1 and BRCA2 carriers have improvement in survival [compared to ovarian cancer patients without the mutations]," said Kelly L. Bolton, lead author of the new analysis and a medical student at the University of California, Los Angeles, David Geffen School of Medicine.

The study, which confirms previous findings, is published Jan. 25 in the Journal of the American Medical Association.

Nearly 23,000 women will get a diagnosis of ovarian cancer this year in the United States, and about 15,500 will die of it, according to the American Cancer Society. Epithelial ovarian cancer, the type Bolton focused on, occurs in the cells on the surface of the ovary.

Germline BRCA1 and BRCA2 mutations are found in up to 15 percent of women with this type of cancer. A germline mutation is a gene change in a reproductive cell that can be passed on to offspring.

Data from more than 1,213 ovarian cancer patients was included in the studies reviewed. Of these, 909 had BRCA1 mutations; 304 had BRCA2 variations.

The studies also included 2,666 women who did not have the genetic mutations.

At the five-year mark, 44 percent of the BRCA1 carriers and 52 percent of the BRCA2 carriers were alive, compared to 36 percent of those without the mutation.

Bolton said the survival differences remained after the researchers took into account such factors as the stage of the cancer and age, although it was less significant among women with a family history of ovarian and/or breast cancer.

Exactly how the mutations may improve survival is not known. However, Bolton and others speculate the BRCA1 or BRCA2 status may modify the response to platinum-based chemotherapy, a common treatment.

The new analysis will have important implications for future research and treatment of ovarian cancer, the authors said. Routine genetic screening of women with high-grade cancer might be warranted, they added.

Dr. Elizabeth Poynor, a gynecologic oncologist and pelvic surgeon at Lenox Hill Hospital in New York City, suggested the findings can help health care providers tailor treatment and more accurately counsel them regarding expected survival.

While not new, the information is valuable, Poynor said. "For a long time, we've known that individuals with BRCA1 or 2 actually have a better prognosis," she said. "This is not new information, it's expanded information. It's reinforcing what we already know."

More research is needed, the authors said, acknowledging some study limitations. For instance, the analysis lacked complete information on types of chemotherapy used, which might also have influenced survival.

Some co-authors reported consultancy fees from Complete Genomics Inc., a company engaged in gene sequencing, and from Merck Sharp & Dohme, Roche, Schering-Plough, Pfizer and other pharmaceutical firms.

More information

Learn how ovarian cancer is diagnosed at the American Cancer Society.