A new multicenter study is the first to suggest that the prophylactic removal of the ovaries and fallopian tubes may provide a different benefit for women who carry a genetic mutation in the BRCA2 gene than for those who have a BRCA1 genetic mutation.
The results of the study, which are being presented today at the annual American Society of Clinical Oncology meeting, also provide the strongest evidence to date that this surgery significantly reduces the overall risk of BRCA-associated breast and ovarian cancers.
"These findings will help doctors to better counsel women who have an inherited predisposition to ovarian and breast cancers and allow tailoring of risk-reduction strategies depending on what particular mutation a woman has inherited," said the study's lead author Noah D. Kauff, MD, a gynecologist and geneticist at Memorial Sloan-Kettering Cancer Center (MSKCC).
The study followed 886 women over the age of 30 who carry the BRCA1 or BRCA2 genetic mutation. Of this group, 561 opted to have their ovaries and fallopian tubes surgically removed -- a procedure called risk-reducing salpingo-oophorectomy -- while 325 chose to participate in ovarian surveillance. The women were followed for 40 months via questionnaire or medical review.
The results showed that overall the prophylactic surgery reduced the incidence of ovarian and related cancers by 89 percent and decreased breast cancer incidence by 47 percent. When broken down further, the results indicate that none of the women carrying the BRCA2 mutation who had the surgery developed ovarian cancer, while women carrying the BRCA1 mutation who had the surgery decreased their risk of developing ovarian or related cancers by 87 percent.
The study showed that women with BRCA2 mutations also reduced their risk of developing breast cancer by 72 percent, while those with BRCA1 mutations reduced their risk of breast cancer by 39 percent. Why the results of the procedure differ in BRCA1 carriers and BRCA2 carriers is "a question that we are currently exploring and hope to answer in future studies," said Dr. Kauff.