Hormone replacement therapy tied to ovarian cancer

NEW YORK (Reuters Health) - New research suggests that no matter how hormone replacement therapy is given, it increases the risk of ovarian cancer.

Hormone replacement therapy, consisting of estrogen, progesterone, or both, and used to relieve the symptoms of menopause, has been linked to breast cancer, Dr. Lina Steinrud Morch, from Rigshospitalet, Copenhagen, Denmark, and colleagues note in their study. Some studies have suggested that it could raise the risk of ovarian cancer.

Morch's team studied more than 900,000 Danish women who were 50 to 79 years of age from 1995 to 2005. None of them had tumors that grew in response to hormones, and none had had their ovaries removed during a hysterectomy or for other reasons.

During the study's follow-up period (an average of eight years), doctors found more than 3,000 ovarian tumors, they report in the Journal of the American Medical Association. Women who were currently using hormones were almost 40 percent more likely to develop such tumors.

The rate of ovarian cancer in current hormone users was 0.52 per 1000 years versus 0.40 per 1000 years in never users. This translates into roughly 1 extra case of ovarian cancer per 8300 women who use hormone therapy each year, the authors state.

As noted, the link between hormone therapy and ovarian cancer was apparent regardless of the type of hormones used, or how long they were used.

"The risk of ovarian cancer," the authors conclude, "is one of several factors to take into account when assessing the risks and benefits of hormone use."

SOURCE: Journal of the American Medical Association, July 15, 2009.