Inflammatory bowel disease and risk of adenocarcinoma and neuroendocrine tumors in the small bowel
Menée en Norvège et en Suède sur la période 1987-2016 auprès de 142 008 patients atteints d'une colite ulcéreuse ou de la maladie de Crohn (durée médiane de suivi : 10 ans), cette étude analyse le risque de développer un adénocarcinome de l'intestin grêle (66 cas) ou une tumeur neuroendocrine (57 cas)
Background: Uncertainty prevails about the magnitude of excess risk of small bowel cancer in patients with inflammatory bowel disease (IBD). Patients and Methods: To quantify the risk of small bowel adenocarcinoma and neuroendocrine tumors in patients with ulcerative colitis (UC) and Crohn’s disease (CD), we undertook a population-based cohort study of all IBD-patients diagnosed in Norway and Sweden from 1987 through 2016. Patients were followed through linkage to national registers. We calculated standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) of small bowel adenocarcinomas and neuroendocrine tumors for patients with CD and UC. We excluded the first year of follow-up to reduce reverse causality. Results: Among 142.008 IBD-patients with a median follow-up of 10.0 years, we identified 66 adenocarcinomas and 57 neuroendocrine tumors in the small bowel. The SIR of small bowel adenocarcinoma was 8.3 (95% CI, 5.9-11.3) in CD and 2.0 (95% CI, 1.2-3.1) in UC. The incidence rates of adenocarcinomas were highest in CD with stricturing disease and extent limited to the small bowel, at 14.7 (95% CI, 8.2-24.2) and 15.8 (95% CI, 8.4-27.0) per 100,000 person-years, respectively. The SIR of neuroendocrine tumors was 2.5 (95% CI, 1.5-3.9) in CD and 2.0 (95% CI, 1.4-2.8) in UC. Conclusions: Patients with CD experienced an 8-fold increased risk of small bowel adenocarcinomas, while both UC and CD patients experienced an about 2-fold increased risk of neuroendocrine tumors, and UC patients experienced 2-fold increased risk of small bowel adenocarcinoma. The small absolute excess cancer risk suggests that active surveillance to diagnose small intestinal cancer early is unlikely to be cost-effective.