Risk factors and clinical course of inflammatory bowel disease in patients receiving cancer therapy

Background – Inflammatory bowel disease (IBD) is associated with chronic inflammation and increased malignancy risk; however, data on the effects of cancer therapies on the clinical course of IBD are limited. We evaluated the effects of cancer therapies on IBD activity and oncologic outcomes. Methods – This single-center, retrospective study was conducted at a tertiary care cancer center and included patients with IBD and malignancy who received cancer therapy 2015–2023. Patient characteristics and comparisons between patients who did and did not develop gastrointestinal adverse events (GI AEs) related to cancer therapy are presented. Results – The cohort included 1153 patients, predominantly white (85.3%) and female (51.6%). GI AEs occurred in 296 (25.7%) patients. Those who developed GI AEs had more hematologic malignancies (21.6 vs. 14.6%; P = 0.005), stage III–IV cancer (55.1 vs. 45.6%; P < 0.0001), immune checkpoint inhibitor (ICI) use (19.6 vs. 10.7%; P < 0.0001) and active baseline IBD status before cancer therapy (20.0 vs. 14.5%; P = 0.025). Stage III–IV disease (hazard ratio: 2.9, P < 0.0001), GI AEs (hazard ratio: 1.3, P = 0.008), GI AE-related hospitalization (hazard ratio: 2.1, P < 0.0001), and ICI (hazard ratio: 2.0, P < 0.0001) were associated with decreased survival. Conclusion – Concurrent management of IBD and cancer poses clinical challenges, particularly with the higher risk of GI AEs (25.7%) that is associated with active baseline IBD status and ICI use. These interactions may compromise treatment and survival. Further research is warranted to clarify the long-term impact of cancer therapies on IBD progression and outcomes.