Cutaneous melanoma in women. III. Reproductive factors and oral contraceptive use.

Oral contraceptive use and reproductive factors were investigated in a population-based case-control study of 452 women aged 25-59 years who were diagnosed with cutaneous malignant melanoma during the period 1981-1986 and 930 controls. Ever use of oral contraceptives was reported by 72 percent of melanoma patients and 79 percent of control subjects in this San Francisco Bay Area study, although duration of use was slightly longer for women with superficial spreading melanoma (5.5 years) than for controls (4.3 years). While some subgroups had elevated or reduced odds ratios, no consistent association was observed between cutaneous melanoma risk and oral contraceptive use when use was examined by duration, latency, age at diagnosis, age at first use, and time period of first use. Neither number of live births nor age at birth of the first child was associated with risk for cutaneous melanoma; nor was a history of miscarriage, induced abortion, or endometriosis. No association was observed with regularity of menstrual periods or with use of fertility drugs or hormones to regulate menstrual periods. Women who reported experiencing hyperpigmentation of facial skin during a prior pregnancy had a lowered risk for all cutaneous melanoma (odds ratio (OR) = 0.64, 95% confidence interval (CI) 0.44-0.93) and superficial spreading melanoma (OR = 0.54, 95% CI 0.36-0.83). This effect was more pronounced for light-complexioned women (for superficial spreading melanoma, OR = 0.37, 95% CI 0.20-0.70) than for women with a dark or medium complexion (for superficial spreading melanoma, OR = 0.84, 95% CI 0.48-1.5). Women who reported use of acne medication also had a reduced risk of superficial spreading melanoma (OR = 0.55, 95% CI 0.35-0.84). These results indicate an overall lack of effect of oral contraceptives on cutaneous melanoma risk in this population of women. The reduced melanoma risks associated with hyperpigmentation during a prior pregnancy and use of acne medication (or related hormonal indications for its use) should be studied further.