Non-melanoma skin cancer and ten-year all-cause mortality: a population-based cohort study

Confounding from comorbidity and socioeconomic status may have biased earlier findings of all-cause mortality among patients with basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). We therefore examined all-cause mortality among 72,295 Danish patients with BCC, 11,601 with SCC, and 383,714 age- and gender-matched population control cohort subjects with extensive control for comorbidity and socioeconomic status. Data on cancer, death, and socioeconomic status were obtained from medical databases and Statistics Denmark. We analysed data using Cox regression analysis, with estimation of 10-year mortality rate ratios (MRRs) and 95% confidence intervals (CI). Mortality was reduced among patients with BCC (10-year MRR = 0.91 (95% CI: 0.89-0.92) and did not vary by age, comorbidity, or socioeconomic status. Mortality among patients with SCC was increased and varied by age, selected chronic diseases, but not socioeconomic status. The reduced mortality observed among patients with BCC and the increased mortality among patients with SCC persisted even after extensive control for comorbidity and socioeconomic status.