Cutaneous melanoma in postmenopausal women after nonmelanoma skin carcinoma: the Women's Health Initiative Observational Study.

BACKGROUND An elevated risk for cutaneous melanoma has been reported in individuals with nonmelanoma skin carcinoma (NMSC), but to the authors' knowledge, this association has not been prospectively studied in a large, multigeographic population of postmenopausal women. METHODS The association between NMSC and the incidence of cutaneous melanoma was assessed in the Women's Health Initiative Observational Study involving 67,030 non-Hispanic white postmenopausal women ages 50-79 years and who were free of prior other cancers at baseline. Cancer history, demographics, and previous and current risk exposures were determined by questionnaires at baseline and follow-up. Participants' reports of incident cutaneous melanoma collected annually were confirmed by physician review of medical records. Cox proportional hazards analyses were used to assess the relation of prior NMSC with incident cutaneous melanoma. RESULTS In age-adjusted analysis, women with a history of NMSC but no other malignancy (n = 5552) were found to be 2.41 times more likely to develop cutaneous melanoma over a mean 6.5 years compared with women who had no history of NMSC (95% confidence interval [95% CI], 1.82-3.20). In a multivariate analysis, women with a history of NMSC and no other cancer history at baseline were 1.70 times more likely to develop cutaneous melanoma compared with women without NMSC (95% CI, 1.18-2.44). CONCLUSION The results of the current study provide evidence and further defines the magnitude of increased risk for cutaneous melanoma in postmenopausal non-Hispanic white women with a history of NMSC.