Women who use estrogen-only hormone replacement therapy for a long time increase their risk of developing ovarian cancer. The finding was published this week in the Journal of the American Medical Association, and comes on the heels of another study of hormone replacement therapy that found negative health effects with long-term use.
The women in the latest study of hormone replacement therapy were former participants in the U.S. government's Breast Cancer Detection Demonstration Project.
Researchers at the National Cancer Institute found that 329 of the 44,000 women had developed ovarian cancer since the study ended in 1980. That translated to a 60 percent higher risk of ovarian cancer among women who took estrogen compared to women who never used hormone replacement therapy. Women who used estrogen therapy for twenty years or more were three times more likely to develop ovarian cancer.
John Curtin, who is director of gynecologic oncology at New York University School of Medicine, explains that estrogen is typically given to menopausal women who have had their uteruses removed.
"The number of patients who would be affected by this that is, a woman who would be taking estrogen only and have ovaries, an ovary or both ovaries remaining, is a relatively smaller proportion of the population of post-menopausal women who would be taking estrogen," he said. "Because most women who take estrogen, if they haven't had a hysterectomy, will take estrogen and progesterone."
In the study, researchers did not find any increased risk of ovarian cancer in women with intact wombs who were on estrogen-only hormone therapy.
Kenneth Noller of the Department of Obstetrics and Gynecology at Tufts University in Boston, Massachusetts writes, in accompanying editorial, the possible link between estrogen and ovarian cancer is worrisome. Dr. Noller stresses estrogen should not be prescribed automatically anymore.
"There very well may still be a very few uses but the kind of wholesale, ever body should be on it approach should not any longer be part of clinical medicine," he said.
Last week, U.S. government researchers halted a study of estrogen-progesterone therapy after data showed that the combination therapy, taken over a long period of time, significantly increases the risk of breast cancer, heart disease and stroke.