Cancer Risk in Women Exposed to Diethylstilbestrol in Utero.

ABSTRACT

OBJECTIVE: To evaluate the overall cancer risk, primarily breast cancer, for women exposed to diethylstilbestrol (DES) in utero in France. METHODS: A cohort of 3 436 prenatally DES exposed women and a comparable cohort of 3256 unexposed women were recruited retrospectively from voluntary responses to questionnaires, and cases were ascertained by medical history at the time of recruitment. RESULTS: One hundred ninety-five cancers were observed in exposed women (136 breast cancers, and 59 in other sites) and 141 cancers in unexposed women (90 breast cancers, and 51 others). A significant increase of breast cancers was found in exposed women, with a multivariate incidence rate ratio of 2.10 (95% CI 1.60-2.76) when compared with unexposed women. When exposed women were compared with the general population in France, the standardized incidence ratio was 2.33 (95% CI 1.93-2.72). CONCLUSION: Our results suggest a significant increase of breast cancer in prenatally DES exposed women when compared with unexposed women and with the general population. For other cancers, except clear cell carcinoma of the cervix or vagina, there was a global non-significant increase.