Outcomes From IBD-Associated and Non-IBD-Associated Colorectal Cancer: A Surveillance Epidemiology and End Results Medicare Study

BACKGROUND: There is controversy as to whether the clinicopathological features of colorectal cancer in the setting of IBD are distinct from sporadic colorectal cancer. OBJECTIVE: The aim of this study was to compare the characteristics and outcomes between IBD-associated and sporadic colorectal cancer. DESIGN: This retrospective population-based cohort study used the Surveillance, Epidemiology, and End Results Medicare-linked database. SETTINGS: This study was conducted in 6 US metropolitan areas enrolled in Surveillance, Epidemiology, and End Results. PATIENTS: Beneficiaries of Medicare parts A and B identified from the Surveillance, Epidemiology, and End Results database with a diagnosis of IBD-associated or sporadic colorectal cancer who underwent surgical resection were included in the study. MAIN OUTCOMES MEASURES: The main outcome was death. The adjusted risk ratio for death compared patients with IBD-associated colorectal cancer with patients who had sporadic colorectal cancer. RESULTS: Patients with IBD-associated colorectal cancer were more likely to present at an earlier stage, use immunosuppression, and have metachronous colorectal cancer. Although total proctocolectomy was more common among IBD patients with colorectal cancer, the majority (>75%) underwent a segmental resection. Cancer-specific survival was worse for IBD-associated colorectal cancer vs sporadic colorectal cancer (mean, 32.9 months vs 42.4 months). After adjusting for potential confounders, older age, male sex, higher stage, IBD, immunosuppression, neoadjuvant radiation, and metachronous tumor were associated with a higher risk of cancer-specific mortality. Among patients with IBD, there was no difference in cancer-specific survival for segmental colectomy vs proctocolectomy. LIMITATIONS: This is a retrospective cohort study utilizing insurance data dependent on the correct coding of patient claims. CONCLUSION: Older patients with IBD-associated colorectal cancer appear to have a slightly worse outcome than those with sporadic colorectal cancer. The cause of this is multifactorial, but it does not appear to be associated with a more limited surgical resection.