Ovary removal for gene carriers greatly cuts risk of early death: study
Angela Mulholland, CTVNews.ca
Published Monday, February 24, 2014 4:06PM EST
Last Updated Tuesday, February 25, 2014 7:30AM EST
Women with a key gene mutation that puts them at higher risk of breast and ovarian cancer appear to significantly cut their risk of dying of the diseases by having their ovaries removed, a new study led by Canadian researchers has found.
The study found women with either the BRCA1 or BRCA2 gene mutation who underwent the surgery had a 77 per cent lower risk of death than those who did not have the surgery.
BRCA1 is the same gene mutation that Hollywood actress Angelina Jolie learned she had before deciding to undergo a double mastectomy and ovarian removal.
The mutation is known to increase the risk of ovarian cancer, which is often called a “silent killer” because it typically presents no symptoms until the cancer is well advanced. In Canada, 2,600 women were diagnosed with ovarian cancer in 2013 and 1,700 women died of it.
Research has long shown that surgery to remove the ovaries -- technically called an oophorectomy -- reduces the risk of ovarian and breast cancers in women with these gene mutations. But the optimum age for having the surgery has not been studied, nor has it been clear whether the surgery cuts the risk of an early death.
So researchers with the Toronto-based Women’s College Research Institute took part in a study that looked at nearly 5,800 women around the world with one of the BRCA gene mutations. The researchers tracked the women’s health for an average of 5.6 years, when some of the women opted to have an oophorectomy.
They found having the surgery was associated with:
- A 77 per cent lower risk of death from all causes by age 70;
- An 80 per cent reduction in the risk of ovarian and fallopian tube cancer, as well as cancer of the peritoneum, a membrane in the abdomen;
- A 68 per cent lower risk of death from all causes in women who previously had breast cancer.
Dr. Steven Narod, the study’s lead author and a scientist with WCRI, says even he was surprised by the results.
“The size of the reduction was much larger than we expected. We saw a 77 per cent reduction of dying of any cause… I was expecting to see more like 30 per cent,” he told CTV News.
Researchers also found that women with the BRCA1 mutation who had ovary removal surgery by 35 had a much lower risk of developing or dying from cancer than women who waited until they were older.
The risk of ovarian cancer in the average population is just 1.4 per cent. But women with the mutation who delayed surgery until age 40 saw their risk of developing ovarian, fallopian tube or peritoneal cancers jump to 4 per cent. If they waited to age 50, the risk jumped to 14.2 per cent.
Women with a BRCA2 mutation, however, did not appear to be at an increased risk of ovarian cancer by 35, suggesting they can delay this procedure until later.
The findings are published in the Journal of Clinical Oncology.
Dr. Narod says he would encourage women with the BRCA1 mutation to have the procedure done as early as possible.
"To me, waiting to have oophorectomy until after 35 is too much of a chance to take," he said in a statement.
The researchers note that while oophorectomy can cut the risk of ovarian cancer in women with the BRCA1 mutation, the surgery comes with side effects, most notably premature menopause.
The researchers say it will be important to study how that affects women’s health, since early menopause has been linked to cardiovascular risks and osteoporosis.
“After an oophorectomy, the long-term effects on a woman’s cardiovascular health and her bone health are less well known, and further research is needed,” said study co-author Amy Finch, of Women’s College Hospital.
The likelihood of having a BRCA mutation is about 1 in 400. But in women who develop ovarian cancer, the likelihood rises to one in eight, and in women who develop breast cancer before age 40, it rises to one in 10.
Currently, most women who learn they have the BRCA1 mutation choose to have their ovaries removed. But Dr. Narod says most women with the mutation don’t know they have it.
“Our biggest challenge is to identify all the women who might benefit (from testing),” he says. “Probably only one in 20 women in Ontario with a BRCA mutation knows it at age 35, so our biggest challenge… is how do we get that information out.”
With a report from CTV medical specialist Avis Favaro and producer Elizabeth St. Philip