Outcome of right- and left-sided colonic and rectal cancer following surgical resection

Aim To determine the outcome of surgery for colorectal cancer from a single region and to see whether location of the primary cancer influences prognosis. Method Patients with colorectal cancer diagnosed from January 2002 to December 2006, entered into a prospective database were followed until death or to December 2008. Right-sided (caecum to transverse colon) and left-sided (splenic flexure to rectosigmoid junction) colonic cancers and rectal cancers (distal to rectosigmoid junction to the anus) were identified. Statistical analysis was performed using Pearson's chi-square test, Kaplan-Meier (log-rank statistic) and Cox regression analysis with a P-value < 0.05 denoting significance. Results Of 841 patients with solitary colorectal cancers identified (median age 72 [30-101] years; 53% male), 283 (33.7%) were right-sided colonic, 330 (39.2%) were left-sided colonic and 228 (27.1%) were rectal. Respective resection rates were 82.7%, 77.9% and 91.6%, and curative resection rates were 79.9%, 82.9.0% and 85.7%, respectively. There was no significant difference in recurrence rates between right-(16.1%), left-sided (23.0%) colonic and rectal (20.7%) cancers (P = 0.207). Respective mean survival rates were 54.4, 59.8 and 63.6 months (P = 0.007). Conclusion Right-sided colorectal cancers had a worse prognosis than left-sided and rectal cancers, possibly because of more advanced staging and fewer curative resections.