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)
OBJECTIVE
Although the benefit from adjuvant chemotherapy has been clearly established in patients with Dukes' C colon cancer, such benefit has been questioned in patients with Dukes' B disease. To determine whether patients with 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 Dukes' stage in four sequential National Surgical Adjuvant Breast and Bowel 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.


METHODS
The four trials included Dukes' B and C patients and were conducted between 1977 and 1990. The eligibility criteria and follow-up requirements were similar for all four trials. Protocol C-01 compared adjuvant semustine, vincristine, and fluorouracil (5-FU) (MOF regimen) with operation 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 compared adjuvant 5-FU and LV with 5-FU and levamisole (LEV) and with the combination of 5-FU, LV, and LEV.


RESULTS
Forty-one percent of the patients included in these four trials had resected Dukes' B tumors. In all four studies, the overall, disease-free, and recurrence-free survival improvement noted for all patients was evident in both Dukes' B and Dukes' C patients. When the relative efficacy of chemotherapy 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 Dukes' B patients as for Dukes' C patients. When data from all four trials were examined in a combined analysis, the mortality reduction was 30% for Dukes' B patients versus 18% for Dukes' C patients. The mortality reduction in Dukes' B patients occurred irrespective of the presence or absence of adverse prognostic factors.


CONCLUSIONS
Patients with Dukes' B colon cancer benefit from adjuvant chemotherapy and should be presented with this treatment option. Regardless of the presence or absence of other clinical prognostic factors, Dukes' B patients seem to benefit from chemotherapy administration.
Mamounas
E
E
National Surgical Adjuvant Breast and Bowel Project Operations and Biostatistical Centers, Pittsburgh, PA 15212, USA.
Wieand
S
S
Wolmark
N
N
Bear
H D
HD
Atkins
J N
JN
Song
K
K
Jones
J
J
Rockette
H
H
D000230:Adenocarcinoma / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery*; D000931:Antidotes / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D017024:Chemotherapy, Adjuvant; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery*; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D002955:Leucovorin / Q000008:administration & dosage; D009367:Neoplasm Staging; D016032:Randomized Controlled Trials as Topic; D012673:Semustine / Q000008:administration & dosage; D016019:Survival Analysis; D014750:Vincristine / Q000008:administration & dosage
D000931:Antidotes; D012673:Semustine; D014750:Vincristine; D002955:Leucovorin; D005472:Fluorouracil