Women who are carriers of one of the "cancer genes" that makes them predisposed to an increased risk for some cancers -- BRCA 1 -- may significantly reduce their risk of developing ovarian cancer if they remove their ovaries by as early as age 35, a new study finds.
The research, which was published in the Journal of Clinical Oncology on Feb. 24, also shows that women with the BRCA1 or BRCA2 mutations who have preventive ovary removal surgery -- known as a prophylactic oophorectomy -- lowered their chance of dying before the age of 70 by 77 percent.
"To me, waiting to have oophorectomy until after 35 is too much of a chance to take," study author Dr. Steven Narod, professor of medicine at the University of Toronto in Canada, said in a press release. "These data are so striking that we believe prophylactic oophorectomy by age 35 should become a universal standard for women with BRCA1 mutations."
BRCA 1 and BRCA 2 are genes that create proteins that limit tumor growth by fixing damaged DNA and making cells more stable. A mutated version of either gene increases the risk of breast, ovarian and other types of cancer.
Angelina Jolie underwent a preventative mastectomy and announced plans to to have her ovaries removed after she found out she was a carrier of the BRCA1 gene. In addition, she had an extensive family history of cancer.
Researchers looked at international data on 5,787 women that had the BRCA1 or BRCA2 mutation. The women were tracked sometime during 1995 through 2011, for an average of 5.6 years.
Out of the subjects, 2,274 women did not have their ovaries removed, while 2,123 had the procedure done before they joined the study. Another 1,390 had the surgery done during the study period.
In total, 186 women ended up with ovarian, fallopian tube or abdominal cancer. The researchers determined that women who had their ovaries removed reduced their risk of ovarian cancer by 80 percent.
For women who had the BRCA1 mutation, waiting until they were 40 to have their ovaries removed increased their chance of developing ovarian cancer by 4 percent. Women who waited until 50 had a 14.2-percent increased risk of getting the disease. For comparison, the incidence of getting ovarian cancer for all women is 1.4 percent.
Previous studies using this same study cohort showed that women
with a BRCA1 mutation who had their ovaries removed had a 48 percent lower
chance of getting breast cancer, and a 70 percent decreased probability of dying
from breast cancer.
About 12 percent of all women will get breast cancer during their lifetime, according to the National Cancer Institute.
BRCA2 mutation carriers had a much lower risk of ovarian cancer than their BRCA1 counterparts. Only one case of ovarian cancer was found in a woman with a BRCA2 mutation before the age of 50. The researchers concluded that there was no increased risk of developing ovarian cancer for women with the BRCA2 before the age of 35, and they can opt to get their ovaries removed at a later age.
As for death risk, 511 women passed away before 70; 333 deaths were due to breast cancer, 68 were due to ovarian, fallopian, or abdominal cancers and the rest were due to other causes.
Having ovaries removed at any age reduced the risk of death by more than three-quarters regardless of which mutation the woman had, due to the fact it lowered the risk of developing related cancers. The 77-percent risk decrease due to the procedure was more effective than undergoing chemotherapy.
According to the National Cancer Institute, BRCA1 and BRCA2 mutations make up between one-fifth and one-fourth of all hereditary breast
cancers, about 5 to 10 percent of all breast cancers. Women who have the
mutations are known to develop breast cancers at an earlier age. About 55 to 65 percent of women with the BRCA1 mutation will
get breast cancer by the age of 70, while 45 percent of women with the BRCA2
mutation will develop the disease.
The gene is also linked to 15 percent of all ovarian cancers. Around 39 percent of the women with a BRCA1 mutation will go on to have ovarian cancer by 70, while 11 to 17 percent with the BRCA2 mutation will be diagnosed with the cancer.
"If you get it, it doesn't tend to end well. This is why, despite the fact that there can be negative consequences, most clinics encourage people to (have an oophorectomy), and a lot of people do consider it," Aletta Poll, a genetic counselor at Women’s College Hospital in Toronto, told the Globe and Mail. She was not involved in the study.
Dr Jamie Bakkum-Gamez, a gynecologic cancer surgeon at the Mayo Clinic who was not involved in the study, told the Toronto Star that this new study can help medical professionals and patients decide the benefits of having the procedure done.
"It provides several tools for care providers of women with the mutation,
as far as risk prediction based on age …. That is something we didn’t really
have before," she added.