Malignancy and Mortality in Pediatric-onset Inflammatory Bowel Disease: A Systematic Review

Background: Cancer and death are the most severe outcomes that affect patients with inflammatory bowel disease (IBD). These outcomes are even more severe if they occur at a young age but are rare, even in the general population. We conducted a systematic review to provide an overview of all reported pediatric (PIBD) patients with severe outcome. Methods: A literature search identified publications that reported development of cancer or fatal outcome in PIBD patients. Studies were eligible for inclusion when (1) article written in English, (2) original data, (3) individual patient information, (4) full text available, (5) study population consisting of patients diagnosed with IBD under the age of 19 years, and (6) who developed malignancy or fatality at any point later in life. Results: A total of 98 included studies comprised data of 271 PIBD patients who developed cancer and/or fatal outcome at any point later in life. Meta-analysis demonstrated an increased risk for cancer in PIBD patients (pooled standardized incidence ratio 2.23, 95% CI: 1.98-2.52). The most frequent type of non-fatal cancer was lymphoma, whereas colorectal carcinomas were the most frequently reported type of fatal cancer in PIBD patients and were particularly associated with primary sclerosing cholangitis. The majority of patients with noncancer-related fatal outcomes were diagnosed with ulcerative colitis and most often died due to infectious complications or severe disease-associated complications. Conclusions: The data in this review confirm that PIBD associated malignancy and mortality are rare and detailed clinical characteristics are limited. Prospective and international collaborations are needed to obtain more detailed patient-specific information, which is necessary to investigate the relationship between severe outcomes in PIBD patients and the currently used therapeutic strategies.