Long-Term Outcomes After Colorectal Surgery in Patients with Ulcerative Colitis-Associated Colorectal Cancer Versus Sporadic Colorectal Cancer

Background Ulcerative colitis is associated with a higher risk for developing colorectal cancer. It is unknown whether this translates into a worse prognosis when malignancy occurs. The goal of this study was to compare long-term outcomes between patients with ulcerative colitis-associated colorectal cancer and sporadic colorectal cancer. Methods All patients who underwent surgery with curative intent for colorectal cancer in Denmark between January 2004 and June 2016 were included in the study. Patients diagnosed with ulcerative colitis were identified and matched 1:5 with patients with sporadic colorectal cancer using propensity score matching. The primary outcome was disease-free survival, with recurrence-free survival and all-cause mortality as secondary outcomes. In order to relate the results of the study to the existing literature, a systematic review with meta-analysis was conducted. Results A total of 1332 patients, 222 with ulcerative colitis and 1110 with sporadic colorectal cancer were included in the study. Disease-free survival was similar between the two groups with a hazards ratio (HR) 1.06 [95% confidence interval (CI) 0.85-1.32], as was recurrence-free survival HR 1.14 (95% CI 0.86-1.53) and all-cause mortality HR 1.15 (95% CI 0.89-1.48). The results of the systematic review identified seven other relevant studies. Meta-analysis showed a HR 1.67 (95% CI 0.61-4.56) for recurrence-free survival and HR 1.21 (95% CI 0.93-1.56) for all-cause mortality. Conclusions There were no significant differences in long-term outcomes between ulcerative colitis-associated and sporadic colorectal cancer. However, the current results are limited by possible residual confounding and the meta-analysis by heterogeneity in confounding adjustment.