PROSPECTIVELY RANDOMIZED TRIAL OF POSTOPERATIVE ADJUVANT CHEMOTHERAPYIN PATIENTS WITH HIGH-RISK COLON-CANCER

Purpose: This study had two major goals: (1) to asses the effectivenes s of a regimen of fluorouracil (5-FU) plus levamisole plus leucovorin as postoperative surgical adjuvant therapy for patients with high-risk colon cancer, and (2) to evaluate 6 months versus 12 months of chemot herapy. Patients and Methods: Patients with poor-prognosis stage II or III colon cancer were randomly assigned to receive adjuvant chemother apy with either intensive-course 5-FU and levcovorin combined with lev amisole, or a standard regimen of 5-FU plus levamisole. Patients were also randomly assigned to receive either 12 months or 6 months of chem otherapy, which resulted in four treatment groups. Results: Eight hund red ninety-one of 915 patients entered (97.4%) were eligible. The medi an follow-up duration is 5.1 years for patients still alive. There was a difference among the four treatment groups with respect to patient survival, and a significant duration-by-regimen interaction was observ ed. Specifically, standard 5-FU plus levamisole was inferior to 5-FU p lus leucovorin plus levamisole when treatment was given for 6 months ( 5-year survival rate, 60% v 70%; P < .01). Conclusion: There was no si gnificant improvement in patient survival when chemotherapy was given for 12 months compared with 6 months. When chemotherapy was given for 6 months, standard 5-FU plus levamisole was associated with inferior p atient survival compared with intensive-course 5-FU plus levcovorin pl us levamisole. These data suggest that 5-FU plus levamisole for 6 mont hs should not be used in clinical practice, whereas 6 months of treatm ent with 5-FU plus leucovorin plus levamisole is effective. (C) 1998 b y American Society of Clinical Oncology.