Methotrexate use for patients with psoriasis and risk of cutaneous squamous cell carcinoma: A nested case-control study

Abstract

An association between methotrexate use and risk of cutaneous squamous cell carcinoma has been reported in patients with rheumatoid and psoriatic arthritis. A nested case-control study was performed to investi-gate if methotrexate use among patients with psoriasis was associated with increased risk of cutaneous squa-mous cell carcinoma. Data were obtained from Swedish registers and included 623 patients with psoriasis and a first cutaneous squamous cell carcinoma from 2010 to 2016. Ten randomly selected patients with psoriasis were matched on age and sex to each case. Among cases, 160 (26%) were ever-users of metho trexate. The corresponding number among the controls was 1,370 (22%), yielding an unadjusted odds ratio (OR) of 1.23 (95% confidence interval (95% CI) 1.02–1.49); p = 0.034. After adjusting for use of other immuno-suppressive drugs the association was close to unity (OR 1.09; 95% CI 0.89–1.34); p = 0.39. The slightly increased risk of cutaneous squamous cell carcinoma associated with methotrexate-exposure in patients with psoriasis does not seem to be associated with metho-trexate, but rather with disease severity, other anti-psoriatic treatments, and ultraviolet exposure.