Higher Risk for Hematological Malignancies in Inflammatory Bowel Disease: A Nationwide Population-based Study in Taiwan

Objectives: The relationship between inflammatory bowel disease (IBD) and cancer remains unclear especially in Asian populations. Therefore, we conducted a nationwide population-based study in Taiwan to reveal the cancer risk in patients with IBD. Methods: Using the national health database of Taiwan, we identified 3,348 IBD patients without previous cancer, including 685 with Crohn's disease (CD) and 2,663 with ulcerative colitis (UC), as a cohort from 1998 to 2012 and followed them up until 2013. Standardized incidence ratios (SIRs) of overall and site-specific cancers in CD and UC patients in comparison with the general population were analyzed. Results: Regarding overall cancer risk analysis, both CD (SIR 1.4, 95% confidence interval (CI) 0.9-2.1) and UC (SIR 0.93, 95% CI 0.7-1.1) patients did not have a higher risk. In site-specific cancer risk analysis, CD (SIR 14.08, P<0.01) and UC (SIR 2.51, P=0.02) patients had a higher risk of hematological malignancies. The risk of colorectal cancer (CRC) did not increase significantly in either CD (SIR 0.96, P=0.7) or UC (SIR 1.39, P=0.22) patients. Conclusions: This first nationwide population-based study in Asia reveals a significantly higher risk for hematological malignancies in IBD patients. This finding may highlight the importance of screening for hematological malignancies in patients with IBD in the future.