Risk of malignancy in patients with psoriasis: a 15-year nationwide population-based prospective cohort study in Korea.

ABSTRACT

BACKGROUND: The association between psoriasis and risk of malignancy has not been thoroughly evaluated in a large longitudinal cohort of Asian population. OBJECTIVE: To determine the long-term risk of malignancy in Korean adult patients with psoriasis. METHODS: We conducted a nationwide population-based prospective cohort study with a 15-year observational period. During the baseline period (1997-2000), total 1 773 786 Korean subjects who received health insurance from the National Health Insurance System were enrolled and 5788 subjects were defined as a psoriasis group. The number of new-onset malignancy was collected during the observational period (2001-2015). RESULTS: Patients with psoriasis had a higher adjusted hazard ratio (aHR) for development of overall malignancy [aHR 1.08, 95% confidence interval (CI) 1.00-1.18] and gastric cancer (aHR 1.31, 95% CI 1.08-1.58) compared to controls. The risks of non-Hodgkin lymphoma and non-melanoma skin cancer were significantly increased only in patients with psoriasis who received systemic treatments (aHR 2.86, 95% CI 1.07-7.61 and aHR 3.93, 95% CI 1.47-10.47, respectively). CONCLUSION: Psoriasis is associated with long-term risk for overall malignancy in Koreans, which was primarily driven by the increased risk of gastric cancer.