Risk of malignancy in patients with psoriasis receiving systemic medications: A nested case‐control study

Large‐scale, real‐world studies on the side effects of systemic therapies (including biologics) in patients with psoriasis are limited. We aimed to calculate the risk of malignancy in patients with psoriasis who were treated with systemic medications. Nested case‐control analyses were performed among psoriasis patients without a history of malignancy. We recruited 4188 patients with newly diagnosed psoriasis and successive malignancies, and 8376 matched controls from the National Health Insurance Research Database in Taiwan. The therapy duration was within 5 years before malignancy onset and further stratified into two groups according to the duration of medication usage. Multivariate conditional logistic regression adjusted for potential confounders was used to estimate malignancy risk associated with systemic treatments. Among psoriasis patients, long‐term (> 12 months) treatment with cyclosporine increased the risk of malignancy compared with no exposure (odds ratio, 1.57; p = 0.01). Short‐term (≤ 12 months) or long‐term (> 12 months) use of other systemic treatments, including methotrexate, azathioprine, systemic retinoids, mycophenolate mofetil, sulfasalazine, etanercept, adalimumab, and ustekinumab, was not associated with an increased risk of malignancy in patients with psoriasis. Long‐term treatment with cyclosporine increased the risk of malignancy in patients with psoriasis by 1.57‐fold.