Risk of Skin Cancer in Patients with Pterygium: A Nationwide Population-Based Cohort Study in Taiwan

This study investigated the association between pterygium and skin cancer linking to ultraviolet (UV) radiation using claims data from 1997-2010, obtained from the Taiwan National Health Insurance Research Database. The study included 19,701 patients with pterygium and 78,804 sex-and age-frequency-matched comparison subjects. Multivariate Cox regression analyses were performed to assess the relationship between pterygium and risk of skin cancer by the end of 2010. The incidence rates of malignant melanoma (MM) and nonmelanoma skin cancer (NMSC) in two cohorts and adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) of the diseases were measured. Results showed that the incidences of MM and NMSC were both higher in the pterygium cohort than in the comparison cohort (5.5 vs 3.2 and 32.3 vs 15.0 per 100,000 person years, respectively). After adjusting for age, sex, UV index, occupation, and the other comorbidities, pterygium remained a significant predictor of NMSC (hazard ratio [HR], 1.64; 95% confidence interval [CI], 1.11-2.42), but not MM (HR, 1.46; 95% CI, 0.59-3.65). These results suggest that pterygium patients are associated with an increased risk of NMSC, but not significant for MM.