Biologic Therapy Is Associated With Improved Oncologic Outcomes in Crohn's Disease-Associated Colorectal Cancer

BACKGROUND: Patients with Crohn's disease face an elevated risk of colorectal cancer, in part due to underlying chronic inflammation. Biologic therapy is the mainstay of medical treatment; however, the impact of treatment on colorectal cancer-related outcomes remains unclear. OBJECTIVE: To investigate the association between prior exposure to biologic treatment and colorectal cancer-related outcomes in patients with underlying Crohn's disease. DESIGN: Retrospective cohort study. SETTINGS: High volume, tertiary colorectal surgery department. PATIENTS: Adults (older than 18 years) diagnosed with Crohn's disease and colorectal cancer who underwent curative operation between 1998 and 2020. INTERVENTION(S): Exposure to any biologic IBD medication before cancer diagnosis. MAIN OUTCOME MEASURES: Survival and recurrence outcomes. RESULTS: A total of 56 patients were included with a median age of 52.5 years (interquartile range, 18.9 years) at the time of surgery; 19 patients (33.9%) were treated with biologics before surgery; 10 (52.6%) received infliximab, 2 (10.5%) received adalimumab, and 7 (36.8%) received multiple biologics. Rectal cancer (57% vs 43.2%, p = 0.02) and well-differentiated or moderately differentiated tumors (93% vs 50%, p = 0.005) were more common in the biologic exposure group. Exposure to biologics was associated with a higher 5-year disease-free survival rate (80% vs 45%, p = 0.048), whereas the 5-year overall survival (93% vs 57%, p = 0.19) and 5-year recurrence rates (7% vs 31%, p = 0.18) were numerically but not statistically significant. LIMITATIONS: Retrospective, single-center study. CONCLUSIONS: In patients with Crohn's disease and colorectal adenocarcinoma who underwent curative surgery, those previously exposed to biologic therapy were more likely to have well-differentiated or moderately differentiated tumors, which were more likely to be distal to the splenic flexure. Biologic exposure was associated with significantly higher 5-year disease-free survival. These findings suggest that treatment of inflammation in patients with Crohn's disease fundamentally alters carcinogenesis pathways.