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Fertility drugs, ovarian cancer not linked-study
( 2002-01-25 10:13 ) (7 )

Women who take fertility drugs are not at a higher risk for ovarian cancer, according to an analysis of research on nearly 13,000 women, the largest study of the issue to date, researchers said on Thursday.

"For more than a decade, controversy has surrounded the relationships among infertility, fertility drug use and the risk of ovarian cancer," said Dr. Roberta Ness, associate professor of epidemiology at the University of Pittsburgh Graduate School of Public Health, and principal author of the study.

The study appears in the American Journal of Epidemiology.

The researchers compared women who had fertility problems and took fertility drugs with women who also had fertility problems but did not take fertility drugs. They found that women who had used fertility drugs were not more likely to develop ovarian cancer than those who had never used fertility drugs.

This analysis helps put to rest questions regarding fertility drugs, which have become more popular as women have children at later ages and treatment improves, Ness said.

Women long have been stuck with difficult decisions regarding fertility treatment, she said, "where on one hand they are desperate to have children. They want to do whatever they can to increase their chances. And on the other hand, they're thinking to themselves, 'Oh my God, I'm going to take this drug, and I'm going to increase my risk for developing one of the most terrible cancers known to women.'"

Investigators analyzed interview data on infertility and fertility drug use from eight studies conducted between 1989 and 1999 in the United States, Denmark, Canada and Australia. The studies included 5,207 women with ovarian cancer, and 7,705 women without ovarian cancer.

The results showed that women who spent more than five years trying to conceive, regardless of whether they were taking fertility drugs, were at a 2.7-times higher risk for ovarian cancer than those who tried for less than one year.

"Two things will come from this study," Ness told Reuters. "One is that (women) will be less afraid. They don't have to walk around with anxiety for the next 20 or 30 years.

"And the other thing we've done here is moved the concern from drugs to biology. (We've specified) what it is about the biology that may be the most worrisome," she said.

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The study pointed out a link between ovarian cancer and certain causes of infertility -- specifically, endometriosis and unknown causes of infertility.

Endometriosis is a condition in which cells from the uterine lining, or endometrium, migrate to various sites throughout the pelvis and attach to other organs, causing inflammation and pain, as well as infertility.

In the study, infertility was defined as prolonged unsuccessful episodes of trying to conceive, and by seeking medical help in conceiving.

The study suggested that some women who receive fertility treatments develop ovarian cancer because of underlying conditions that cause infertility, not because of the treatments themselves. Likewise, infertile women who were most likely to develop ovarian cancer were those whose infertility resulted from endometriosis or from unknown causes.

"We are actively working to better understand what are now unknown causes of infertility," said Ness. "Understanding this better will give us a window into the biology behind ovarian cancer and it will help to define the women in this high-risk group."