Comparative efficacy of adjuvant chemotherapy in patients with Dukes' B versus Dukes' c colon cancer: Results from four national surgical adjuvant breast and bowel project adjuvant studies (C-01, C-02, C-03, and C-04)

Purpose: Although the benefit from adjuvant chemotherapy has been clearly e stablished in patients with Dukes' C colon cancer, such benefit has been qu estioned in patients with Dykes' B disease. To determine whether patients w ith Dukes' B disease benefit from adjuvant chemotherapy and to evaluate the magnitude of the benefit, compared with that observed in Dukes' C patients , we examined the relative efficacy of adjuvant chemotherapy according to D ukes' stage in four sequential National Surgical Adjuvant Breast and Dowel Project trials (C-01,C-02, C-03, and C-04) that compared different adjuvant chemotherapy regimens with each other or with no adjuvant treatment. Patients and Methods: The four trials included Dukes' B and C patients and were conducted between 1977 and 1990. The eligibility criteria and follow-u p requirements were similar for all four trials. Protocol C-01 compared adj uvant semustine, vincristine, and fluorouracil(5-FU) (MOF regimen) with ope ration alone. Protocol C-02 compared the perioperative administration of a portal venous infusion of 5-FU with operation alone. Protocol C-03 compared adjuvant 5-FU and leucovorin (LV) with adjuvant MOF. Protocol C-04 compare d adjuvant 5-FU and LV with 5-FU and levamisole (LEV) and with the combinat ion of 5-FU, LV,and LEV. Results: Forty-one percent of the patients included in these four trials ha d resected Dykes' B tumors. In all four studies, the overall, disease-free, and recurrence-free survival improvement noted for all patients was eviden t in both Dukes' B and Dykes' C patients. When the relative efficacy of che motherapy was examined, there was always an observed reduction in mortality , recurrence, or disease-free survival event, irrespective of Dukes' stage, and in most instances, the reduction was as great or greater for Dykes' B patients as for Dykes' C patients. When data from all four trials were exam ined in a combined analysis, the mortality reduction was 30% for Dukes' B p atients versus 18% for Dykes' C patients. The mortality reduction in Dukes' B patients occurred irrespective of the presence or absence of adverse pro gnostic factors. Conclusion: Patients with Dukes' B colon cancer benefit from adjuvant chemo therapy and should be presented with this treatment option. Regardless of t he presence or absence of other clinical prognostic factors, Dukes' B patie nts seem to benefit from chemotherapy administration. J Clin Oncol 17:1349- 1355. (C) 1999 by American Society of Clinical Oncology.