Ovarian Stimulation for IVF Does Not Increase Risk of Endometrial or Colorectal Cancer: Results from a Nationwide Cohort Study
ASRM Office of Public Affairs21 October 2014
Honolulu, Hawaii- Questions about IVF and increased risk of cancer have abounded through the roughly three decades that the treatment has been in use. Tuesday, at the 70th Annual Meeting of the American Society for Reproductive Medicine, researchers from the Netherlands Cancer Institute and Erasmus University Medical Center in Rotterdam share the results of two nationwide cohort studies showing that women who have had ovarian stimulation for IVF are not at increased risk of developing cancer of the colon or endometrium.
The studies focused on 19,158 subfertile women who had received IVF treatment and a comparison group of 5,950 who did not have IVF. The Omega Cohort study was set up in 1996 to examine the risk of cancer in subfertile women receiving ovarian stimulation for IVF.
Medical records provided detailed information on subfertility cause and treatment (types and dosages of ovulation drugs). The women, on average 17 years-post treatment, answered a questionnaire on their reproductive history and lifestyle. Cancer cases were identified through a direct linkage with the Netherlands Cancer Registry.
No statistically significant differences were found in the incidence of colorectal cancer between the women who had had IVF and those who had not, nor was there a difference in risk in either group from that of the general population. The data were also evaluated for trends based on higher numbers of IVF cycles or higher ovulation drug dosages; none emerged.
Endometrial cancer risk was comparable between the women who had undergone IVF and those who had had other fertility treatments. The risk did not differ significantly between those who had had no IVF cycles, one to three cycles, or four or more. There was likewise no difference in risk based on different causes of subfertility. There was a somewhat greater likelihood observed for women who had not had children to develop endometrial cancer.
Kurt Barnhart, MD, President of the Society for Reproductive Endocrinology and Infertility, commented, “Although we’ve been doing IVF for a long time, knowledge of its long-term effects is still incomplete. With their large cohort, connection to a national cancer registry, and long follow-up time, these studies have given us some solid knowledge about cancer and ovulation drugs that should be reassuring to many patients and doctors.”
O-147 M. Spaan et al, “Colorectal Cancer Risk After Ovarian Stimulation for In Vitro Fertilization”
O-149 AW van den Belt-Dousebout et al, “Risk of Endometrial Cancer After Ovarian Stimulation for In Vitro Fertilization”