Lack of an elevated risk of malignant melanoma in relation to oral contraceptive use.

Epidemiologic and laboratory data suggest an effect of oral contraceptives (OC) on the risk of malignant melanoma. This relationship was explored in a hospital-based case-control study of 160 women with malignant melanoma and 640 matched controls, all of whom were white and 20-59 years of age. A total of 63 cases (39%) had used OC compared with 270 controls (42%), yielding a relative risk estimate of 0.9 (95% confidence interval: 0.6-1.3). When a number of potential confounding factors were simultaneously controlled, the relative risk estimate was 0.8 (0.5-1.3). For use that lasted 5 or more years the estimate was 0.9 (0.5-1.6). The level of tumor invasion was not related to OC use. The evidence from this study suggests that OC, even when used for 5 or more years, do not increase the risk of malignant melanoma.