Outcome After Surgery for Colon Cancer in a National Cohort of Patients With and Without Inflammatory Bowel Disease.

[AIMS] To estimate the impact of inflammatory bowel disease on survival in a national cohort of patients following surgical resection for colon cancer, and to describe the surgical treatment of colon cancer in patients with inflammatory bowel disease.

[METHODS] Using the Colorectal Cancer Database, we included all patients ≥ 15 years of age with a diagnosis of stages I-III colon cancer treated with curative intent 2007-2021. We used Cox proportional hazards models to compare overall survival, recurrence-free survival and cancer-specific survival between patients with and without inflammatory bowel disease. Multivariable analyses were adjusted for sex, age, date of colon cancer surgery, Charlson Comorbidity Index and primary sclerosing cholangitis.

[RESULTS] Among 35,640 patients with colon cancer, 675 (1.9%) had inflammatory bowel disease. Median age at colon cancer diagnosis was 68 years in patients with inflammatory bowel disease and 75 in those without; proportions of male sex were 55% and 49%, respectively. In patients with inflammatory bowel disease, surgical therapy was proctocolectomy in 10%, subtotal colectomy in 29% and segmental resection in 61%. From adjusted analyses, patients with inflammatory bowel disease had worse overall survival (HR = 1.38; 95% CI: 1.21-1.57), recurrence-free survival (HR = 1.33; 95% CI: 1.18-1.50) and cancer-specific survival (HR = 1.46; 95% CI: 1.23-1.73) than patients without.

[CONCLUSION] Inflammatory bowel disease negatively influences the prognosis of colon cancer. Proctocolectomy was performed only in a minority of those with inflammatory bowel disease. Outcomes need to be improved in patients with inflammatory bowel disease developing colon cancer.