Malignancy risk in Korean male patients with ankylosing spondylitis.

The objective of this study is to determine the overall and specific cancer risks in male patients with ankylosing spondylitis (AS). From the claims database of the Health Insurance and Review Assessment, male patients with AS without prior cancer history were selected (n = 21,780). Stratified random samples of claims data were used as a reference general male population group (n = 342,361). Incidence rates of overall and types of cancer were presented as number of events per 10,000 person-years with 95% confidence interval (CI). A standardized incidence ratio (SIR) was used to represent the association between AS and cancer, accounting for person-years at risk. Compared to a general male population group, the overall incidence of cancer was increased in male patients with AS (SIR 1.25, 95% CI 1.15-1.36). For specific malignancy types, the risks of male reproductive system malignancy (SIR 1.97, 95% CI 1.59-2.35) and pancreatic cancer (SIR 1.75, 95% CI 1.12-2.37) were increased. Male patients with AS had increased cancer risk, especially for male reproductive system and pancreatic cancer.