J Pediatr Gastroenterol Nutr. 2023 Jul 1;77(1):55-61. doi: 10.1097/MPG.0000000000003781.Epub 2023 Mar 24.

Mikkel Malham ^1 2 3, Sabine Jansson ^1 2, Petter Malmborg ^4 5, Ola Olén ^4 5, Anders Paerregaard ^1 2, Lauri J Virta ⁶, Christian Jakobsen ^1 2, Kaija-Leena Kolho ⁷, Vibeke Wewer ^1 2

Author information

¹From the Department of Paediatric and Adolescence Medicine, Copenhagen University Hospital - Amager and Hvidovre, Hvidovre, Denmark.

²the Copenhagen Centre for Inflammatory Bowel Disease in Children, Adolescents and Adults, Copenhagen University Hospital - Amager and Hvidovre, Hvidovre, Denmark.

³the Department of Paediatric and Adolescence Medicine, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark.

⁴Sachs' Children and Youth Hospital, Stockholm, Sweden.

⁵the Clinical Epidemiology Division, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.

⁶the Research Department, Social Insurance Institution of Finland, Turku, Finland.

⁷Children's Hospital, Helsinki University Hospital, Helsinki, Finland.

Abstract

Objectives: Pediatric-onset inflammatory bowel disease (pIBD) increases the risk of developing several different cancer forms. In this case-control study, we aimed to assess the impact of medical treatment and disease activity on the risk of developing disease-associated cancer (DAC) and treatment-associated cancer (TAC).

Methods: In a previous study, we identified 27 cases of DAC (colorectal cancer, small bowel cancer, and cholangiocarcinoma) and 28 TAC (lymphoma and skin cancer) in 6689 patients with pIBD in Denmark and Finland during the period 1992-2015. In this study, the patient charts were reviewed manually. Cancer-free patients from another population-based pIBD cohort were included as controls. We recorded data on phenotype, medical treatment, surgery, and relapses. Logistic regression was used to estimate adjusted odds ratios (aOR) with 95% confidence intervals (95% CI) to estimate the relative risk.

Results: We included 16 cases with DAC, 21 with TAC, and 331 controls. For DAC, lower frequencies of IBD-relapses were associated with an increased risk of cancer (OR 0.2 [95% CI: 0.04-0.8]). For TAC, we found an increased risk in patients receiving thiopurines at any point during the follow-up period (aOR: 11.7 [95% CI: 2.1-116.2]) and an association with proportion of follow-up time being exposed to thiopurines (aOR 5.6 [95% CI: 1.1-31.5]).

Conclusions: In this nation-wide study, covering all pIBD patients from Denmark and Finland, we found that pIBD patients treated with thiopurines had an increased risk of TAC.