Risk Factors for Colorectal Cancer in Patients with Inflammatory Bowel Disease and Management During Cancer Treatment: A Systematic Review

Abstract

Introduction: Inflammatory bowel disease (IBD) is a group of conditions involving inflammation of the gastrointestinal tract. Patients with IBD are at an increased risk of developing colorectal cancer (CRC). Current evidence regarding risk factors for CRC in IBD patients and guidelines for IBD treatment upon cancer diagnosis is inconclusive. A systematic review was conducted to evaluate evidence on risk factors resulting in an increased incidence of CRC among IBD patients and modifications made to IBD management during cancer treatment. Methods: The PubMed database was searched from inception to 2019 with an English-language restriction, and two independent reviewers screened the articles for inclusion according to established criteria. Results: Eight studies (five literature reviews and three retrospective cohort studies) were included. Of the eight articles, six reported several risk factors for CRC in IBD patients such as duration of IBD, extent of IBD, co-existing primary sclerosing cholangitis, family history of CRC, age at IBD onset, vitamin D deficiency, and gender. The other two articles discussed IBD management during cancer treatment in the form of suspending immunosuppressive medications and administering those of an anti-inflammatory nature. Discussion: An individualized, case-by-case approach for IBD patients diagnosed with cancer was recommended. No standardized course of treatment was found. Conclusion: Despite the limitations of this review, numerous potential risk factors for CRC in IBD patients were identified. However, a lack of definitive evidence pertaining to modifications made to IBD management during cancer treatment suggests that additional research is needed to draw material conclusions.