Ovulation induction associated with increased cancer risk

NEW YORK (Reuters Health) - Treatments used to induce ovulation appear to increase the overall risk of cancer, results of a study published in the February 1st issue of the American Journal of Epidemiology suggest.

"Ovulation-inducing drugs are widely used for ovarian follicle stimulation, either as independent therapies or during in vitro fertilization cycles," Dr. Ronit Calderon-Margalit, of Hadassah-Hebrew University, Jerusalem, Israel, and colleagues write. "The scientific literature provides inconsistent information on the association between ovulation induction treatment and cancer incidence."

To investigate further, the researchers examined data from 15,030 women enrolled in the Jerusalem Perinatal Study who gave birth in 1974 to 1976 and participated in a postpartum survey. The cohort was linked with the Israel Cancer Registry to obtain information on cancer incidence through 2004.

A total of 1215 women developed cancer during 424,193 person-years of follow-up. Women who received drug treatment to induce ovulation (n = 567) had increased risks of cancer at any site (multivariate hazard ratio = 1.36; p = 0.017).

Treatment with ovulation-inducing agents was not associated with ovarian cancer (HR = 0.61), but an association was observed for risk of breast cancer (multivariate HR = 1.42; p = 0.058), uterine cancer (HR = 3.39; p = 0.014), and non-Hodgkin lymphoma (multivariate HR = 2.63; p = 0.046).

The use of clomiphene specifically was associated with a significantly increased risk of uterine cancer (multivariate HR = 4.56; p = 0.006) and for malignant melanoma (multivariate HR = 2.56; p = 0.030).

"The potential implications of this study relate firstly to the need of further research and better registries of fertility treatments," Dr. Calderon-Margalit commented to Reuters Health.

"I believe that fertility treatments will continue, but if our findings will be confirmed by others, women who are treated with clomiphene and perhaps other ovulation induction agents will need screening for uterine cancer," she added. "Such studies will potentially shed more light on the hormonal pathogenesis of cancers such as NHL and malignant melanoma."

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