Fertility Drugs and Cancer: Is There a Link?

A common concern among fertility patients is potential risk to their overall health that may result from recommended fertility medications and treatments. There is biologic plausibility to these concerns, especially in regards to hormone responsive cancers that may be stimulated by fertility interventions. Studies to evaluate these concerns are difficult to conduct as large numbers of patients are needed and long term follow-up is required. The literature has slowly become more robust in this area and the American Society for Reproductive Medicine recently published a practice committee guideline regarding the risks of cancer associated with fertility treatment.

Ovarian cancer is the most widely studied cancer in regards to fertility treatment. A 2013 study of over 80,000 women with a diagnosis of infertility compared those who had used fertility drugs in their lifetime with those who received no treatment and found no difference in the rate of invasive ovarian cancer.  Another Danish cohort study in 2009 looked specifically at the use of clomid.  It  also found no difference in ovarian cancer risk between users and non-users.  Finally, a Cochrane review concluded fertility drug exposure was not associated with an increased risk of invasive ovarian cancer.  While the evidence on borderline ovarian tumors is slightly more varied with some studies showing a small increase in the absolute risk in borderline tumors, there is insufficient evidence that any specific fertility medication increases the risk of these tumors.

Other types of hormonally responsive tumors have also been studied, although not to the extent of ovarian cancer. The current available evidence shows no association between fertility medications and either breast or endometrial cancer. Several smaller studies have also suggested no increased risk of thyroid cancer, melanoma, cervical cancer or colon cancer in women who have used fertility drugs in their lifetimes. While we can never guarantee patient outcomes with 100% certainty, this recent ASRM practice committee guideline provides patients reassurance that fertility treatment does not appear to  increase a women’s risk of these specific malignancies.

American Society for Reproductive Medicine. Fertility drugs and cancer: a guideline. Fertil Steril 2016; 106: 1617-26.