Fertility drugs and ovarian tumors

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A recent controlled study has indicated that prolonged use of fertility drugs may increase the risk of ovarian tumors. Researchers at the University of Washington and Fred Hutchinson Cancer Center in Seattle decided to look into the matter after case reports suggested that women who undergo fertility treatment may develop tumors at higher than average rates. The scientists wanted to learn whether increased risk was the result of conditions responsible for infertility or by the drugs taken to increase fertility.

The research team examined the records of 3837 women who visited fertility clinics between 1974 and 1986. When they cross-checked the women's names against those in a tumor registry, they discovered that by the end of 1991 four of the women had been diagnosed with ovarian cancer and an additional seven with borderline malignant tumors. The overall risk of ovarian tumors for women who had fertility treatments was 2 1/2 times that of women in general.

The Seattle scientists found that the women who developed ovarian tumors were more likely to have taken one particular fertility drug, clomiphene (Clomid), than were other infertile women. They calculated that although infertility itself did not appear to increase ovarian-tumor risk, taking clomiphene for longer than 12 months increased that risk substantially. Even so, the lifetime risk of ovarian cancer, which increased from about 2% to 4-5% for women in the study, was still relatively slight. Moreover, undergoing clomiphene treatment for less than a year appeared to have no effect on risk whatsoever. The study appeared in the September 22, 1994, issue of the New England Journal of Medicine.

The researchers acknowledged that the study has a few limitations. It did not enable them to detect those women who had ovarian abnormalities, and women who require as many as 12 cycles of clomiphene may have ovulatory difficulties that can signal an increased risk of ovarian cancer. In addition the treatments the Seattle women received may not be representative of fertility therapy nationwide. Specialists tend to substitute another drug, such as Pergonal (human menopausal gonadotropin), if clomiphene isn't successful in a few months, rather than continue clomiphene treatment for as long as a year.

Nonetheless, women who are considering infertility treatment may want to minimize the number of clomiphene cycles. Those who have undergone clomiphene treatment are advised to have annual pelvic exams; beyond that, additional screening tests aren't recommended.

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