Ovarian stimulation for infertility treatment and cancer risk: An Italian cohort study.

534Background: With the increasing practice of infertility treatments, concerns were raised about the long-term effects of hormonal ovarian stimulation, especially regarding the risk of breast, endometrial and ovarian cancer. We evaluated the long term cancer incidence in women enrolled into fertility programs from 1980 to 2005. Methods: This is a retrospective cohort study of consecutive women entered into fertility programs in 4 italian centers operating in areas covered by Cancer Registries. Eligibility criteria included premenopausal woman aged 20 to 41 years, who received at least 1 cycle of ovarian stimulation in the context of an Assisted Reproductive Technology (ART) treatment. The primary endpoint was breast cancer (BC) incidence; secondary endpoints were incidence of cervical, endometrial and ovarian cancer. Cancer incidence was assessed by linkage with databases of Cancer Registries. The relationship between ovarian stimulation and cancer incidence was assessed using region specific standardize...