Overall increase is small, though, adding 1 cancer per 1,000 women treated
WebMD News from HealthDay
By Kathleen Doheny
HealthDay Reporter
THURSDAY, Feb. 12, 2015 (HealthDay News) -- Women who use hormone therapy after menopause -- even for just a few years -- may have an increased risk of ovarian cancer, according to new research.
The new study found that when women used hormone replacement therapy for less than five years after menopause, the risk of ovarian cancer increased by about 40 percent.
"We have evidence, proof, that there is a small but real excess risk of cancer of the ovaries with hormone therapy use," said study researcher Sir Richard Peto, professor of medical statistics and epidemiology at the University of Oxford, in England.
Peto said the increased risk was significant from a statistical standpoint but emphasized that the risk is a small one. It would mean that for women who take hormone therapy for five years from around age 50, one extra ovarian cancer diagnosis for every 1,000 users would be expected, and one extra ovarian cancer death for every 1,700 users, the study found.
It's also important to note that the current study wasn't designed to definitively show a cause-and-effect relationship between hormone replacement therapy and ovarian cancer.
However, Peto and his colleagues contend that the use of the hormone therapy likely did contribute to the ovarian cancers. But it's not clear how hormone therapy might raise the risk of ovarian cancers, he added. "We don't know the mechanism," he said.
The study was published in the Feb. 13 online edition of The Lancet.
In the United States this year, more than 21,000 women will be diagnosed with ovarian cancer, according to the American Cancer Society (ACS). And about 14,000 women will die of the disease, the ACS estimates.
The use of hormone replacement therapy to help ease the symptoms of menopause rose dramatically in the 1990s. However, after the Women's Health Initiative study was halted in 2002 because researchers found increased risk for heart attack, stroke and blood clots in hormone therapy users, the use of the treatment plummeted. Even so, about 6 million women in the United Kingdom and the United States alone still take hormone therapy, according to background information in the study.
source : Study Ties Hormone Therapy to Increased Ovarian Cancer Risk
