Background: In the era of biologic therapy, phototherapy and methotrexate (MTX) are still commonly used for treatment in patients with moderate-to-severe psoriasis. However, the skin cancer risk following a combination of MTX and narrowband ultraviolet B (NB-UVB) has rarely been explored.
Objectives: To investigate whether MTX plus NB-UVB increases skin cancer risk in patients with psoriasis.
Methods: We conducted a retrospective cohort study of data in the Taiwan National Health Insurance Research Database from 1997 to 2013. Cumulative incidences and multivariate analysis were investigated using a competing risk regression model, comparing skin cancer risk between cohorts of people having combination therapy and those using NB-UVB alone, matched for relative confounders. We further conducted a sensitivity analysis for those receiving a higher MTX dose. Standardized incidence ratios (SIRs) were calculated for skin cancer risk.
Results: We enrolled 3203 participants in each cohort. No significant differences in skin cancers were noted between the two cohorts for the cumulative incidences (log-rank test, P = 0.28) and for the hazard ratio (HRs) [adjusted HR 0.50, 95% confidence interval (CI) 0.15-1.63, P = 0.247] in the competing risk regression model. There were also no significant differences between those receiving higher-dose MTX and UVB alone in the cumulative incidences of skin cancers (P = 0.23) and the HR (adjusted HR = 0.29, 95% CI 0.04-2.21, P = 0.23) in the multivariate analysis. There was no significant difference in the SIR between the two cohorts compared with the general population.
Conclusions: In the Taiwanese population, MTX does not increase skin cancer risk in patients with moderate-to-severe psoriasis receiving NB-UVB.
© The Author(s) 2023. Published by Oxford University Press on behalf of British Association of Dermatologists.