Abstract
Background Psoriasis is a chronic inflammatory skin disorder which may result in an increased cancer risk due to defects of immune surveillance. The relationship between psoriasis and risk of non-melanoma skin cancer (NMSC) has not yet been fully determined. The aim of this study was to update the evidence on the association between psoriasis and risk of NMSC. Methods We conducted an extensive literature search of publications in Pubmed, EMBASE, and Cochrane Library without restrictions on language from inception through August 2019 using predefined keywords. Eligible observational studies were selected if they assessed the risk ratio of NMSC in patients with psoriasis. Data from included studies were extracted, and meta-analysis was performed using random-effects models. Results Sixteen cohort studies involving 16,023,503 participants published between 1999 and 2019 met inclusion criteria and were included in this systematic review. Meta-analysis demonstrated that compared with patients without psoriasis, patients with psoriasis had 1.72 times higher risk of developing NMSC (RR, 1.72, 95% CI 1.46 to 2.02). Patients with moderate to severe psoriasis had higher risk of NMSC (RR, 1.82, 95% CI 1.38 to 2.41) than those had mild psoriasis (RR, 1.61, 95% CI 1.25 to 2.09) (P for interaction<0.001). Moreover, patients with psoriasis had significantly higher risk of squamous cell carcinoma (RR, 2.08, 95% CI 1.53 to 2.83) than that of basal cell carcinoma (RR, 1.28, 95% CI 0.81 to 2.00) (P for interaction<0.001). Conclusions Current evidence suggests that patients with psoriasis may have a higher risk of NMSC than psoriasis-free patients. Periodic screening for specific cancer risk is warranted in patients with psoriasis.