Risk of cancer after assisted reproduction: a review of the available evidences and guidance to fertility counselors.

ABSTRACT

OBJECTIVE: Infertile women requiring ovarian stimulation and assisted reproduction techniques (ART) are faced with difficult issues. The fear that using hormones could increase their risk of cancer is the most significant. One of the main challenges for assessing cancer risk after ART is the difficulty to separate it from the underlying condition of infertility per se. The delay or the inability to achieve a pregnancy is an important risk factor for breast, endometrial and ovarian cancer. We analyzed the current literature on the topic. MATERIALS AND METHODS: The published literature in Medline and Cochrane was screened using the following keywords ovulation induction, reproductive techniques, clomiphene, in vitro fertilization, fertility agents, female/adverse effects, female/toxicity gonadotropins/ adverse effects or gonadotropins/toxicity and "neoplasms or cancer". RESULTS: A total of 95 articles were evaluated. Limited evidence suggests that high doses or many cycles of clomiphene citrate could increase the risk of endometrial cancer, although the confounding factors of polycystic ovarian disease and overweight are not always considered. In some studies, ART modestly increased the risk of borderline ovarian cancer. Fertility treatments do not increase the risk of breast, cervical, endometrial and ovarian cancers, thyroid, melanoma and colon cancer. CONCLUSIONS: Women can be reassured that fertility drugs do not appear to significantly increase the risk of invasive ovarian, endometrial, breast or other cancers, while achieving a pregnancy at an earlier age is a significant protective factor.