Risk of Hematologic Malignancies in Patients with Inflammatory Bowel Disease: A Meta-Analysis of Cohort Studies

Background/Aims: Inflammatory bowel disease (IBD) may contribute to the development of hematologic malignancies. In this study, the potential relationship between IBD and hematologic malignancies was investigated. Methods: We searched the PubMed, Web of Science, Embase, and Cochrane Library databases for all cohort studies comparing the incidence of hematologic malignancies in non-IBD populations with that in IBD patients, and we extracted relevant data from January 2000 to June 2023 for meta-analysis. Results: Twenty cohort studies involving 756,377 participants were included in this study. The results showed that compared with the non-IBD cohort, the incidence of hematologic malignancies in the IBD cohort was higher (standardized incidence ratio [SIR]=3.05, p<0.001). According to the specific types of IBD, compared with the non-IBD patients, the incidences of hematologic malignancies in ulcerative colitis patients (SIR=2.29, p=0.05) and Crohn's disease patients (SIR=3.56, p=0.005) were all higher. In the subgroup analysis of hematologic malignancy types, compared with the control group, the incidences of non-Hodgkin's lymphoma (SIR=1.70, p=0.01), Hodgkin's lymphoma (SIR=3.47, p=0.002), and leukemia (SIR=3.69, p<0.001) were all higher in the IBD cohort. Conclusions: The incidence of hematologic malignancies, including non-Hodgkin's lymphoma, Hodgkin's lymphoma, and leukemia is higher in patients with IBD (ulcerative colitis or Crohn's disease) than in non-IBD patients. (Gut Liver 2024;18:845-856)