Issue 10

Clinical Question

What is the risk of cancer among patients with pediatric-onset IBD?

Editor’s Bottom Line

Pediatric-onset IBD is associated with an increased risk of several cancers. It remains unclear whether this reflects genetic risk, chronic inflammation, treatment exposure, or altered behaviour.

Reference

Elmahdi R, Lemser CE, Thomsen SB, et al. Development of Cancer Among Patients With Pediatric-Onset Inflammatory Bowel Disease: A Meta-analysis of Population-Based Studies. JAMA Netw Open. 2022 Mar 1;5(3):e220595; https://jamanetwork.com/journals/fullarticle/2789513

Synopsis

Researchers in Denmark and the United States performed a meta-analysis of five population-based studies that reported the relative risk of cancer among 19,812 individuals with pediatric-onset IBD, compared to 3,056,282 individuals without IBD.

They found 715 cancer cases in the pediatric-onset IBD population over 283,540 person-years of follow-up, and 11,195 cancer diagnoses in the control population, with statistical analysis showing a significantly increased risk of cancer among patients with pediatric-onset IBD (Pooled relative rates [pRRs], 2.46; 95% Confidence Interval, 2.06–2.93). Patients with both Crohn’s disease (pRR, 2.03; 95% CI, 1.67–2.46) and ulcerative colitis (pRR, 2.61; 95% CI, 2.00–3.40) had a higher risk of cancers, compared to the general population.

Cancers diagnosed at the highest rates among pediatric-onset IBD patients included liver cancers (pRR, 55.45; 95% CI, 19.59–156.99), colorectal cancers (pRR, 20.29; 95% CI, 15.90–25.90), and small bowel cancers (pRR, 16.20; 95% CI, 3.52–74.66). There were a mean 0.3 cases of liver cancer, 0.6 colorectal cancers, and 0.1 cases of small bowel cancer per 1,000 patient years. Other cancers seen at higher rates among the pediatric-onset IBD population compared to the general population included nonmelanoma skin cancer (pRR, 3.62; 95% CI, 1.97–6.66), lymphoid cancer (pRR, 3.1; 95% CI, 1.88–5.1) and melanoma (pRR, 2.05; 95% CI, 1.27–3.29).

Two studies examined cancer by sex and found that males had a significantly higher cancer risk compared to sex-matched non-IBD controls, while females did not (pRR, 3.23; 95% CI, 2.35–4.45 for males and pRR, 2.45; 95% CI, 0.93–6.46 for females). Studies examining cancers by IBD treatment type found no significant association between cancer risk and medication exposure, although the authors noted other publications have found a link between thiopurine use and cancer risk among the IBD population.

Details

Study Design: Meta-analysis

Funding: The Danish National Research Foundation

Allocation: Not applicable

Setting: Multicenter

Level of Evidence: 3a

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.