Cancer incidence in a cohort of infertile women who underwent in vitro fertilization.

To assess whether ovarian hyperstimulation and IVF increase the risk for cancer.,Historical cohort analysis. SETTING; IVF units of two medical centers in Israel.,Five thousand twenty-six women who underwent IVF between 1981 and 1992. INTERVENTION(S); Cancer incidence rates were determined through linkage to the National Cancer Registry and were compared with expected rates with respect to age, sex, and place of birth.,Development of cancer.,Twenty-seven cases of cancer were observed, and 35.6 were expected (standardized incidence ratio, 0.76 [95% CI, 0.50-1.10]). Eleven cases of breast cancer were observed, whereas 15.86 were expected (standardized incidence ratio, 0.69 [95% CI, 0.46-1.66]). One case of ovarian cancer and 1 case of cervical cancer were observed, compared with 1.74 and 1.73 cases expected, respectively. The type of infertility, number of IVF cycles, and treatment outcome did not significantly affect risk for cancer.,In a cohort of women treated with IVF, no excess risk for cancer was noted.