P1228 Cancer incidence in patients with inflammatory bowel disease: A nationwide population-based study from Korea

Abstract Background Inflammatory bowel disease (IBD) is a chronic condition associated with systemic inflammation and potential long-term complications, including an elevated risk of malignancy. While colorectal cancer has been a well-documented concern, data on overall cancer risks in patients with IBD remain limited, particularly in Asian populations. This study aimed to evaluate the incidence of malignancy in Korean patients with IBD compared to the general population. Methods We analysed data from the Korean National Insurance claims database between 2007 and 2022. Cancer occurrence in the general population during the corresponding years was sourced from the National Cancer Registry. Standardized incidence ratios (SIRs), adjusted for age and sex, for each year from 2010 to 2021 were calculated for overall malignancy in patients with IBD and compared with the general population. For visual representation, the SIR values and their 95% confidence intervals were plotted using cubic spline interpolation to create a continuous visualization of annual trends. Results A total of 66,392 patients with IBD were analysed, including 20,503 with Crohn’s disease (CD) and 45,889 with ulcerative colitis (UC). The median follow-up time from IBD diagnosis was 6.6 years (interquartile range, 3.5–10.5) (Table 1). During follow-up, a total of 2,895 malignancy cases occurred in the IBD group. Compared to the expected malignancy cases of 1,837 of the age- and sex-standardized general population, the SIR was significantly increased at 1.576 (95% CI (confidence interval), 1.519–1.634). Further stratification by time periods revealed distinct temporal trends in malignancy risk. During 2010–2015, the SIR was 1.037 (95% CI, 0.950–1.133), reflecting an incidence rate similar to the general population. In contrast, during 2016–2021, the SIR increased significantly to 1.765 (95% CI, 1.696–1.837), indicating a marked rise in the incidence of overall malignancy among patients with IBD in their later follow-up years (Figure 1). Conclusion Korean patients with IBD have a significantly elevated malignancy risk compared to the general population, particularly during their later follow-up years. This highlights the importance of continued cancer surveillance and preventive strategies in this population. References 1.Gordon H, Biancone L, Fiorino G, et al. ECCO Guidelines on Inflammatory Bowel Disease and Malignancies. J Crohns Colitis. 2023;17(6):827-854. doi:10.1093/ecco-jcc/jjac187 2.Scharl S, Barthel C, Rossel JB, et al. Malignancies in Inflammatory Bowel Disease: Frequency, Incidence and Risk Factors-Results from the Swiss IBD Cohort Study. Am J Gastroenterol. 2019;114(1):116-126. doi:10.1038/s41395-018-0360-9 3.Jung YS, Han M, Park S, Kim WH, Cheon JH. Cancer Risk in the Early Stages of Inflammatory Bowel Disease in Korean Patients: A Nationwide Population-based Study. J Crohns Colitis. 2017;11(8):954-962. doi:10.1093/ecco-jcc/jjx040 4.Kim HM, Kim JH, Lee JK, et al. Age- and sex-specific risk of colorectal cancer in incident ulcerative colitis during the first 10 years after diagnosis: a nationwide population-based study. Scand J Gastroenterol. 2021;56(11):1279-1285. doi:10.1080/00365521.2021.1958370