Association of Nonmelanoma Skin Cancer with Second Malignancy: The Women's Health Initiative Observational Study

BACKGROUND. Heightened risks of second cancers have been reported in patients with nonmelanoma cancer of the skin (NMSC), but this association has not been studied in a large, ethnically diverse, multigeographic population. METHODS. This cross-sectional study assessed the association of NMSC with another malignancy in the Women's Health Initiative Observational Study, a study that was conducted in 40 communities throughout the U.S. and involved 93,676 postmenopausal women ages 50-79 years. Cancer history, demographics, and previous and current risk exposures were determined by questionnaire at a baseline examination. Logistic regression was used to assess the association (odds ratio) of a history of NMSC with a history of other (non-NMSC) cancers controlling for age and potential confounding factors. Complete cancer data were available in 92,658 women. RESULTS. In age-adjusted analyses, women with a history of NMSC (n = 7554 women) were 2.30 times as likely to report a history of another cancer, other than NMSC, compared with women who had no history of NMSC (95% confidence interval [95% CI], 2.18-2.44). In a subgroup analysis, black women with NMSC had 7.46 times the odds (95% CI, 3.08-18.0) of reporting a second malignancy compared with black women without NMSC. CONCLUSIONS. This study provides additional evidence of an association between NMSC and another malignancy in a large, multiethnic population.