Drug Commonly Used to Treat Endometriosis Linked to Ovarian Cancer
By Liza Jane Maltin

March 19, 2002 — A drug used to combat endometriosis may increase a woman’s risk of developing ovarian cancer. Researchers have found that women taking danazol are three times more likely to get the disease than if they take an alternate drug.

The team from the University of Pittsburgh Graduate School of Public Health presented their findings March 17 at a gynecologic oncologists meeting in Miami.

Endometriosis is a painful condition in which pieces of the uterine lining — the endometrium — migrate outside the uterus and grow abnormally.

Roberta B. Ness, MD, MPH, associate professor of epidemiology, and colleagues reviewed pooled data from two studies including more than 1,300 women with ovarian cancer and nearly 2,000 similarly aged healthy women. They looked at the relationship between endometriosis, endometriosis treatments, and ovarian cancer.

In all, 195 of the women with cancer and 195 of the healthy women had been treated for endometriosis. Women with endometriosis were one and a half times more likely than those without endometriosis to have ovarian cancer.

The researchers found that women with endometriosis who’d taken danazol were nearly three times more likely than were women who’d taken another drug to have ovarian cancer. This link held even after taking into account various factors known to influence the risk of getting ovarian cancer including having been on the pill, having had a baby, and having a family history of the disease.

“Our previous studies have found that women with endometriosis are already at a 50% increased risk for ovarian cancer, and treating them with danazol appears to further increase their risk. This new result, even though it is preliminary, may factor into the equation when [doctors] and their patients with endometriosis are deciding on the best treatment,” says Ness in a news release.

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