Results of the study, which was in part funded by the National Institutes of Health of the USA, were presented on 30 June 2014 at the Annual Meeting of ESHRE by Dr Humberto Scoccia from the University of Illinois at Chicago, USA.
There is “little evidence” that the use of conventional fertility hormones used for ovarian stimulation in the treatment of infertility increases the long-term risk of breast and gynecological cancers, according to the results of a substantial 30-year follow-up study. However, the extended use of clomiphene citrate was associated with a higher risk of breast cancer among women who had used the fertility drug for 12 cycles or more. Gonadotrophins, more commonly used for ovarian stimulation today, were not generally associated with any increased risk, except in a sub-group of women who remained childless after treatment.
Previous studies of fertility drugs and breast and gynecological cancers present a mixed picture, with some showing increases in risk, others decreases, and still others showing no substantial associations. “However, most of these studies had small numbers with relatively short follow-up periods, and were unable to control for other cancer predictors.