Paediatric patients with immune-mediated inflammatory disease harbour a heightened cancer risk

Children and adolescents with an immune-mediated inflammatory disease (pIMID) have an almost double risk of cancer compared with those in whom pIMID is absent, suggested the results of a Danish study. This translated into 1.2 cases of cancer/1,000 patient-years in patients with a pIMID diagnosis and 0.6 cases/1,000 patient-years in controls.

In adults, an increased risk of cancer in patients with inflammatory bowel disease (IBD) has been described, but data regarding the riskof pIMID in children is still limited [1,2]. Therefore, a Danish, case-control study investigated the particular risk of malignancies in paediatric patients with pIMID. The pIMID diagnoses included IBD, autoimmune idiopathic liver disease (AILD), and rheumatic disease [1]. Participants had to be under 18 years of age and have 2 diagnostic codes for pIMID within the National Patient Registry between 1980 and 2018, or 1 entry plus 1 disease-related treatment. Each case was matched with up to 10 controls from the general population.

The study cohort consisted of 13,216 participants with pIMID (5,811 IBD, 329 AILD, 7,241 rheumatic disease) and 114,502 controls. The median age at pIMID diagnosis ranged from 9.9 to 14.9 years and the median follow-up time from 9.0 to 11.6 years.

The researchers identified 207 cases of cancer among the participants with pIMID and 847 among the controls. “We found a 2-fold increased risk of cancer in patients with pIMID compared with the background population,” Ms Andrea Ehrström (Hvidovre Hospital, Denmark) commented on the hazard ratio (HR) of 2.1 (P<0.0001) that was determined by Cox regression. This significantly increased risk varied depending on the type of pIMID: HR 2.4 for IBD, 5.7 for AILD, and 1.6 for rheumatic disease. After stratification according to the cancer site, participants with paediatric IBD and AILD held a significantly increased risk of colorectal cancer, liver cancer, and non-melanoma skin cancer. Furthermore, an about 2-fold risk was seen for melanoma in IBD together with a nearly 5-fold risk for lymphoma (HR 4.8). For participants with rheumatic disease, the augmented hazard of cancer was significant for lymphoma (HR 2.7) and leukaemia (HR 5.7). The investigation also looked at the possible influence of more than 1 pIMID diagnosis on the overall cancer risk and established an HR of 2.8 compared with only 1 pIMID.

“The increased risk of cancer corresponds to 1.2 cancer cases per 1,000 patient-years for pIMID compared with 0.6 cancer cases per 1,000 patient-years among the controls,” Ms Ehrström added in her conclusion.

1. Ehrström A. The risk of cancer in pediatric-onset immune-mediated inflammatory diseases – a nationwide Danish study from 1980-2018. OP22, ECCO 2023, 1–4 March, Copenhagen, Denmark.

2. Wu S, et al. Inflamm Bowel Dis. 2023;29:384–95.

Posted on 4 May 20238 April 2024