Adjuvant chemotherapy for stage C colonic cancer in a multidisciplinary setting

Background: In this study of patients undergoing adjuvant chemotherapy for clinicopathological stage C colonic cancer after optimal surgery, the aims were: to describe their immediate experience of chemotherapy, to assess disease-free survival, to compare overall survival with that of a matched untreated historical control group, and to evaluate the associations between previously identified adverse risk factors and survival. Methods: Data were drawn from a comprehensive, prospective hospital registry of resections for colorectal cancer between 1971 and 2004, with retrospective data on adjuvant chemotherapy. The main end point was overall survival. Statistical analysis employed the chi-squared test, Kaplan-Meier estimation and proportional hazards regression. Results: From May 1992 to December 2004, there were 104 patients who received adjuvant chemotherapy. Duration of treatment, withdrawal from treatment, toxicity and other immediate treatment outcomes were similar to those in other equivalent studies. There were no toxicity-associated deaths. Overall survival was significantly longer in the treated patients than in the control group (3-year rates 81% and 66%, respectively, P = 0.009). A significant protective effect of adjuvant therapy was found (hazard ratio 0.5, 95% confidence interval 0.3-0.8, P = 0.001) after adjustment for histopathology features previously shown to be negatively associated with survival (high grade, venous invasion, apical node metastasis, free serosal surface involvement). Conclusions: For patients who have had a curative resection for lymph node positive colonic cancer in a specialist colorectal surgical unit and been managed by a multidisciplinary team, post-operative adjuvant chemotherapy is safe and provides the same survival advantage as seen in randomized trials.