Are IBD patients at risk of extraintestinal cancers?
Inflammatory bowel disease is associated with an increased risk of various extraintestinal cancers. However, it remains unclear whether this association reflects cumulative inflammatory burden, drug exposure, common genetic risk factors, or other confounding behaviours.
Lo B, Zhao M, Vind I, et al. The Risk of Extraintestinal Cancer in Inflammatory Bowel Disease: A Systematic Review and Meta-analysis of Population-based Cohort Studies. Clin Gastroenterol Hepatol. 2021;19(6):1117–38.e19; https://linkinghub.elsevier.com/retrieve/pii/S1542-3565(20)31124-1
This meta-analysis included 15 population-based studies examining the prevalence or incidence of extraintestinal cancers in inflammatory bowel disease (IBD) patients. A systematic review identified 15 additional population-based studies on the topic, totalling 882,622 IBD patients and 5.1 million patient years.
The authors found that, compared to the general population, Crohn’s disease (CD) patients—particularly those with ileocolonic disease or pediatric onset CD—had a higher risk of extraintestinal cancers (Incidence Rate Ratio [IRR]: 1.43; 95% Confidence Interval [CI], 1.26–1.63). The risk of extraintestinal cancers was also higher among those ulcerative colitis (UC) patients (IRR: 1.15; 95% CI, 1.02–1.31).
More specifically, the risk of skin cancer was elevated among both CD and UC patients (IRR for CD: 2.22; 95% CI, 1.41–3.48 and IRR for UC: 1.38; 95% CI, 1.12–1.71), with the risk of non-melanoma skin cancer higher among both groups and the risk of melanoma higher only among CD patients. The risk of hepatobiliary malignancies was higher among both CD and UC patients (IRR for CD: 2.31; 95% CI, 1.25–4.28 and IRR for UC: 2.05; 95% CI, 1.52–2.76), and CD patients had an additional risk of hematologic cancers (IRR: 2.40; 95% CI, 1.81–3.18) and lung cancers (IRR: 1.53; 95% CI, 1.23–1.91).
Several studies identified a correlation between risk of non-Hodgkin lymphoma and use of immunosuppressive agents, with a further elevated risk of non-Hodgkin lymphoma when an immunosuppressive agent was used with an anti-tumor necrosis factor agent. There was no elevated risk of urologic or nephrologic cancers or of cancers of the reproductive organs among IBD patients.
Study Design: Systematic review and meta-analysis
Funding: Not stated
Setting: Database analysis
Level of Evidence: 2a
The summary and conclusion in this issue of E-mentoring in IBD pertains to the manuscript(s) being reviewed, and should be considered in the context of what is already known surrounding the topic and incorporated into practice as deemed appropriate by the individual learner.