Large Study Finds That Use Of Infertility Drugs Is Not Generally Associated With Breast Cancer
April 10, 2003
American Society for Reproductive Medicine
A large multi-center case control study coordinated by the Centers for Disease Control has found no general connection between the incidence of breast cancer and the use of drugs to treat infertility. In five large US metropolitan areas, 4,575 patients with primary invasive breast cancer were surveyed along with 4,682 randomly selected, cancer-free controls. The women responded to a standardized questionnaire on reproductive health, family history, use of oral contraceptives, hormones, and infertility drugs. Information on their type of cancer was also obtained from the cancer patients. The researchers calculated the odds of developing breast cancer for those who had taken drugs to help them get pregnant and, overall, they found that women who had used infertility drugs had the same risk of breast cancer as women who had never used such medication.
There was, however, an exception- compared to women who had never used any infertility medication, women who had used human menopausal gonadotropin (hMG) for six or more months or cycles had a two to three times greater relative risk of developing breast cancer. The researchers suggest that the hMG result be viewed with caution as an area that requires further investigation. The number of women surveyed who reported using infertility drugs was rather small and data on infertility medications was self-reported , not confirmed by reference to medical records. Additionally, the mechanism by which hMG might cause cancer is not clear and, in the present analysis, it is difficult to distinguish the effects of infertility, itself, from the effects of its treatment.
"All women are interested in doing everything in their power to reduce their risks for breast cancer. This study, involving over 9,000 women, should be reassuring to most. The increased risk associated with the use of human menopausal gonadotropin needs to be examined more closely, as do the results of other studies with conflicting findings," remarked Sandra Carson, MD, President of the American Society for Reproductive Medicine.
(Burkman, et al, Infertility drugs and the risk of breast cancer: findings from the National Institute of Child Health and Human Development Women's Contraceptive and Reproductive Experiences Study, Vol. 79, No. 4, Fertility and Sterility, April 2003.)
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