Risk of second primary cancer in people with non-melanoma skin cancer: A nationwide cohort study

Purpose Previous western studies have found Caucasians with skin cancer, either melanoma or nonmelanoma skin cancer (NMSC), have an elevated risk of second primary cancer. Our objective was to assess the risk of second primary cancer in Taiwanese with NMSC. Materials and Methods By using data from Taiwan's National Health Insurance Research Database, we conducted a population-based cohort study to assess the risk of incident second primary cancer in Taiwanese affected by NMSC. Results We identified 505 subjects with NMSC and 2,020 matched controls. After adjustment for potential confounders including age, sex, urbanization, and Charlson Comorbidity Index, people who had NMSC had a 1.43-fold (95% confidence interval [CI], 1.05 to 1.96) risk for the development of second primary cancer as compared with control group. Men with NMSC had a 2.99-fold (95% CI, 1.00 to 9.10) risk for second primary cancer involving the lip, oral cavity, and pharynx and a 3.51-fold (95% CI, 1.21 to 10.17) risk for second primary cancer involving the genitourinary organs when compared to the control group. By contrast, women with NMSC did not have an increased risk of second primary cancer. Conclusion This study revealed Asians with NMSC have an increased risk of second primary cancer. Our findings can be a useful reference for health care for people diagnosed with NMSC.