Inflammatory bowel disease-associated colorectal cancer negatively affects surgery outcomes and health care costs.

Background: Inflammatory bowel disease may affect the pathogenesis and clinicopathologic course of colorectal cancer. We sought to characterize the impact of inflammatory bowel disease on outcomes after colectomy and/or proctectomy for a malignant indication.

Methods: Patients diagnosed with colorectal cancer as well as a pre-existing comorbid diagnosis of Crohn's disease or ulcerative colitis between 2018 and 2021 were identified from Medicare claims data. The postoperative textbook outcome was defined as the absence of complications, as well as no extended hospital stay, 90-day readmission, or mortality. Postdischarge disposition and expenditures were also examined.

Results: Among 191,684 patients with colorectal cancer, 4,770 (2.5%) had a pre-existing diagnosis of inflammatory bowel disease. Patients with inflammatory bowel disease-associated colorectal cancer were less likely to undergo surgical resection (no inflammatory bowel disease: 47.6% vs inflammatory bowel disease: 42.1%; P < .001). Among patients who did undergo colorectal surgery, individuals with inflammatory bowel disease were less likely to achieve a textbook outcome (odds ratio 0.64 [95% confidence interval 0.58-0.70]). In particular, patients with inflammatory bowel disease had higher odds of postoperative complications (odds ratio 1.24 [1.12-1.38]), extended hospital stay (odds ratio 1.41 [1.27-1.58]), and readmission within 90 days (odds ratio 1.56 [1.42-1.72]) (all P < .05). Patients with inflammatory bowel disease-associated colorectal cancer were less likely to be discharged to their home under independent care (odds ratio 0.77 [0.68-0.87]) and had 12.2% higher expenditures, which correlated with whether the patient had a postoperative textbook outcome.

Conclusion: One in 40 patients with colorectal cancer had concomitant inflammatory bowel disease. Inflammatory bowel disease was associated with a lower probability of achieving ideal postoperative outcomes, higher postdischarge expenditure, as well as worse long-term survival after colorectal cancer resection.