Cutaneous melanoma and endogenous hormonal factors: a large French prospective study.

To assess the role of endogenous hormonal factors on melanoma, the authors conducted a prospective analysis of 91,972 French women, aged 40-65 years at inclusion into the Etude Epidémiologique auprès de femmes de l'Education Nationale (E3N) cohort. Between 1990 and 2005, 460 melanoma cases were ascertained. Relative risks and 95% confidence intervals were computed by using Cox proportional hazards regression models. Risks of melanoma were reduced in women with ≥ 15 years at menarche (relative risk (RR) = 0.67, 95% confidence interval (CI): 0.46, 0.97, compared with 13-14 years), irregular menstrual cycles (RR = 0.52, 95% CI: 0.31, 0.89, compared with regular cycles of 25-31 days), <48 years at natural menopause (RR = 0.70, 95% CI: 0.48, 1.02, compared with 48-51 years), and shorter ovulatory life (RR = 0.51, 95% CI: 0.28, 0.91, for <33 years compared with ≥ 39 years). Modest inverse associations were observed with parity, as well as number of pregnancies and miscarriages. There was no evidence of an association between melanoma risk and age at first birth or pregnancy, age at last birth, time since last birth, breastfeeding duration, age at menstruation regularity, or menopausal status. Results did not significantly differ according to ambient ultraviolet radiation dose and melanoma site or subtype. These findings from a large prospective cohort may suggest a reduced melanoma risk associated with decreased exposure to ovarian hormones.