Children with inflammatory bowel diseases (IBD) show a 2-fold increase in cancer incidence during adulthood, according to a study published in Gastroenterology.

Researchers from the University of Manitoba in Winnipeg, Canada, assessed the long-term incidence of cancer in patients with pediatric-onset IBD using the population-based University of Manitoba IBD Epidemiology Database and Manitoba cancer registry. According to the researchers, there was minimal nonparticipation because all residents of Manitoba have access to comprehensive universal health insurance.

All patients included in the study had a validated administrative case definition of IBD and were 18 years of age or younger. Patient data was matched with that of control individuals without IBD for age, sex, and region of residence. Study follow ups for each patient continued after database registration, which was as early as April 1984, to December 2018, death, or change in residence.


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Data on patient medications, including thiopurines and anti-tumor necrosis factor (TNF) agents, were available. Hazard ratios (HR) for cancer incidence were calculated using Cox regression analysis. The researchers followed the patients with IBD for 14938 person-years and the matched controls for 132202 persons-years, respectively. Patients in the IBD group were a median of 14 years of age (interquartile range [IQR], 12-16 years) at the time of diagnosis.

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The overall cancer rate was 2-fold higher in the IBD group (114 cases/100 000 person-years) compared to the control group (57 cases/100 000 person-years). In total, 17 cases of cancer arose in 947 patients with IBD compared to 75 cases in 9272 control individuals (HR, 2.00; 95% CI: 1.16-3.43). Patients with IBD were a median of 37 years of age (IQR, 24-45 years) at the time of cancer diagnosis. The cancers reported for these patients included colorectal cancer, non-melanoma skin cancer, lymphoma, leukemia, and urinary bladder cancers.

Of patients with IBD who developed cancer, 576/947 (61%) had Crohn’s disease. This subgroup of patients also had increased risk for developing cancers relative to the control group (HR, 2.47, 95% CI: 1.31-4.66). Similarly, patients with ulcerative colitis (UC, 371/947 [39%]) had increased risk, but this was not statistically significant for developing cancers relative to the control (HR, 1.24; 95% CI: 0.43-3.59).

Comparing patients with IBD who developed cancer with those who did not, cancer events were not associated with exposure (≥2 dispensations) to thiopurines (odds ratio (OR), 0.43; 95% CI: 0.10-1.77) or anti-TNF agents (OR, 0.56; 95% CI: 0.10-3.26).

The authors noted that to protect patient confidentiality, they were not able to report cases of hemophagocytic syndrome or the numbers of other individual cancers (<6 events). The study limitations also included the small number of cancer cases and the possibility of misclassification bias.

Disclosures: Some authors have declared affiliations with the pharmaceutical industry. Please refer to the original study for a full list of disclosures.

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Reference

El-Matary W, Nugent Z, Bernstein CN, Singh H. Long-term cancer risk in patients with pediatric-onset inflammatory bowel diseases in the Canadian population. Gastroenterology. 2020;0(0). doi:10.1053/j.gastro.2020.03.048