Reduced frequency of non-melanoma skin cancer in 72,739 patients with psoriasis: a retrospective study

Background Chronic inflammatory conditions, such as psoriasis, may pose an increased risk of cancer due to impaired immunosurveillance resulting from chronic inflammation and immunosuppressive medications. Objectives To compare the risk of non-melanoma skin cancer (NMSC) in a retrospective cohort of 72,739 psoriasis patients and 25,956 non-dermatological patients. Materials & methods Arecord linkagewas performed for data on hospitalizations, and the occurrence ofNMSCwas compared by computing the relative risk (RR) and modelled using multiple logistic regression. Results Overall, the occurrence of NMSC was 9.6‰ (95% CI: 8.9-10.3‰) in psoriasis patients and 19.6‰ (95% CI: 18.0-21.4‰) in non-dermatological patients (RR = 0.49; 95% CI: 0.44-0.55). The simultaneous adjustment for gender, age, and phototherapy yielded a RR of 0.84 (95% CI: 0.75-0.95). With regards to phototherapy, the occurrence of NMSC was significantly higher among psoriasis patients who underwent phototherapy relative to those who did not (27.0‰ vs. 9.3‰). Conclusions In this large retrospective study, we found that patients with psoriasis had a 16% lower probability of having NMSC when compared to a group of non-dermatological patients. Further studies, preferably with a prospective longitudinal design to collect more precise data, are needed to corroborate our findings.