Post-Menopausal Hormone Replacement Therapy Linked to Increased Ovarian Cancer RiskFeb 16, 2015
New research suggests that there is an increased risk of ovarian cancer among women who use hormone replacement therapy after menopause, even for only a few years. According to a new study published online in The Lancet, women were at a 40 percent increased risk of ovarian cancer if they used hormone replacement therapy for less than five years after menopause.
"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, according to HealthDay. He stated that the risk was small, but statistically significant. The increased risk equates to one extra ovarian cancer diagnosis for every 1,000 women who use hormone therapy for five years from around age 50 and one extra death from ovarian cancer for every 1,700 users.
The study was correlational and does not prove a cause-and-effect relationship. However, Peto and his colleagues believe that hormone therapy had an effect on ovarian cancer. He added that it is unknown exactly how hormone therapy would do this. "We don't know the mechanism," he said.
To conduct the study, researchers pooled data from 52 studies involving more than 12,000 women with ovarian cancer. Roughly half of these women used hormone replacement therapy. The study found a similar increased risk of ovarian cancer in European and American women and between users of an estrogen-progesterone hormone replacement therapy or estrogen alone.
Peto said that the hormone therapy increased the risk of serous and endometrioid ovarian cancer; these are the two most common common among the four total types. His study debunks the notion that there are no dangers associated with short-term use of hormone therapy. "the idea that anything less than five years is safe isn't true." he stated, according to HealthDay.
The American Cancer Society (ACS) estimates that over 21,000 women will be diagnosed with ovarian cancer this year, and 14,000 will die of the disease.
Hormone replacement therapy became popular in the 1990s to alleviate the symptoms of menopause, according to HealthDay. However, use these drugs has dropped dramatically due to safety concerns. In 2002, the Women's Health Initiative study was stopped after researchers found that those taking hormone therapy had a higher risk of heart attack, stroke and blood clots.