Outcomes of colorectal cancer resection in patients with inflammatory bowel disease: a national population-based analysis in England and Wales.

AIM: The aim was to compare early postoperative outcomes and 2-year cancer-specific mortality following colorectal cancer (CRC) resection in patients with and without inflammatory bowel disease (IBD) in England and Wales. METHOD: Records for patients in the National Bowel Cancer Audit who had major CRC resection between April 2014 and December 2017 were linked to routinely collected hospital level administrative datasets and chemotherapy and radiotherapy datasets. Multivariable regression models were used to compare outcomes with adjustment for patient and tumour characteristics. RESULTS: In all, 63 365 patients were included. 1285 (2.0%) had an IBD diagnosis: 839 (65.3%) ulcerative colitis, 435 (33.9%) Crohn's disease and 11 (0.9%) were indeterminate. IBD patients were younger, had more advanced cancer staging and a higher proportion of right-sided tumours. They also had a higher proportion of emergency resection, total/subtotal colectomy, open surgery and stoma formation at resection, with longer hospital admissions and higher rates of unplanned readmission and reoperation. Fewer rectal cancer patients with IBD received neoadjuvant radiotherapy (24.8% vs. 36.0%, P = 0.005) whilst similar proportions of Stage III colon cancer patients received adjuvant chemotherapy. Ninety-day postoperative mortality was similar, but unadjusted 2-year cancer-specific mortality was significantly higher in patients with IBD (subdistribution hazard ratio 1.35, 95% CI 1.18-1.55). Risk adjustment for patient and tumour factors reduced this association (adjusted subdistribution hazard ratio 1.22, 95% CI 1.05-1.43). CONCLUSION: Patients with IBD and CRC are a distinct patient group who develop CRC at a younger age and undergo more radical surgery. They have worse cancer survival, with the difference in prognosis appearing after the early postoperative period.