Malignancy rates in a large cohort of patients with systemically treated psoriasis in a managed care population.

BACKGROUND: Moderate to severe psoriasis often requires treatment with systemic agents, many of which have immunosuppressive properties and could increase cancer risk, including nonmelanoma skin cancer (NMSC). OBJECTIVE: We sought to estimate the overall malignancy rate (excluding NMSC) and NMSC rate among 5889 patients with systemically treated psoriasis. METHODS: We identified a cohort of adult Kaiser Permanente Northern California health plan members with psoriasis diagnosed from 1998 to 2011 and treated with at least 1 systemic antipsoriatic agent and categorized them into ever-biologic or nonbiologic users. Malignancy rates were calculated per 1000 person-years of follow-up with 95% confidence intervals (CI). Crude and confounder-adjusted hazard ratios (aHRs) were calculated using Cox regression. RESULTS: Most biologic-exposed members were treated with TNF-alfa inhibitors (n = 2214, 97%). Overall incident cancer rates were comparable between ever-biologic as compared to nonbiologic users (aHR 0.86, 95% CI 0.66-1.13). NMSC rates were 42% higher among individuals ever exposed to a biologic (aHR 1.42, 95% CI 1.12-1.80), largely driven by increased cutaneous squamous cell carcinoma risk (aHR 1.81, 95% CI 1.23-2.67). LIMITATIONS: No information was available on disease severity. CONCLUSION: We found increased incidence of cutaneous squamous cell carcinoma among patients with systemically treated psoriasis who were ever exposed to biologics, the majority of which were TNF-alfa inhibitors. Increased skin cancer surveillance in this population may be warranted.