Phase III study of fluorouracil, leucovorin, and levamisole in high-risk stage II and III colon cancer: final report of Intergroup 0089. Optimum duration of oral adjuvant chemotherapy of HCFU for colorectal cancer; review of 5-year follow-up. Phase III study comparing a semimonthly with a monthly regimen of fluorouracil and leucovorin as adjuvant treatment for stage II and III colon cancer patients: final results of GERCOR C96.1. Prospectively randomized trial of postoperative adjuvant chemotherapy in patients with high-risk colon cancer.
In 1990, fluorouracil (FU) plus levamisole for 1 year became standard adjuvant treatment for patients with high-risk stages II and III colon cancer. Intergroup (INT) 0089 assessed the relative contributions of leucovorin and levamisole in such patients.
                From 1988 to 1992, 3,794 patients were randomly assigned. Experimental treatment consisted of one of three chemotherapy regimens: the low-dose leucovorin plus FU (Mayo Clinic; LDLV) regimen, the high-dose leucovorin plus FU (Roswell Park; HDLV) regimen, and the low-dose leucovorin plus levamisole plus FU (LDLV plus LEV) regimen, each administered for 30 to 32 weeks. The control arm was levamisole plus FU (LEV) for 1 year.
                After a median follow-up of 10 years, of 3,561 eligible patients, 1,691 (47%) have died and 1,330 (37%) have experienced disease recurrence; 137 (10%) of those experiencing recurrence are still alive. A total of 481 patients (13%) died without evidence of recurrence, and 1,723 (48%) are alive and disease free. Although there were toxicity differences among the four arms, none was statistically superior in disease-free or overall survival.
                The 6- to 8-month regimens of LDLV and HDLV without levamisole used in this trial, rather than the previous standard regimen of 12 months of LEV, have become widely used. INT-0089 has long-term follow-up of the largest clinical trial of patients with high-risk colon cancer, documenting not only the durability of the treatment effects, but also the natural history of patients with high-risk colon cancer, and analyses of treatment based on age, race, and comorbid conditions such as obesity, diabetes, and second primary cancers. To investigate the optimal duration of oral HCFU administration for minimization of side effects induced by long-term administration.
                In total, 155 patients allocated to two groups of different duration of the therapy were reviewed: twice or three times per day doses of oral HCFU (8 mg/Kg body weight/day) for 3 months vs. 12 months.
                Though statistically significant difference was not found in cumulative survival and disease-free rates between the groups due to so many violations of duration of therapy, when reanalyzing the variables in order of real duration of therapy, those rates were significantly higher in patients treated for 300 and more days than less than 300 days (g-Wilcoxon test: p < 0.04). No significant difference was observed in the background factors between the groups.
                At least 300 days is suggested to be necessary to obtain the optimal effectiveness of adjuvant chemotherapy for curatively resected colorectal cancer. This randomized, 2 x 2 factorial study compared a semimonthly regimen (fluorouracil [FU] and leucovorin [LV] semi-monthly is LV5FU2) with a monthly regimen of FU and LV (mFU/LV) as well as 24 weeks versus 36 weeks of each regimen as adjuvant treatment of stage II and III colon cancer.
                LV5FU2 was administered semimonthly for 2 days as racemate (dl) or levogyre (l-; 200 or 100 mg/m(2)) as a 2-hour infusion, followed by 400 mg/m(2) FU bolus and a 600-mg/m(2) FU 22-hour continuous infusion. FU and LV were administered monthly (mFU/LV) for 5 days as dl- or l-LV 15-minute infusion, followed by a 400 mg/m(2) FU 15-minute infusion. The primary end point was disease-free survival (DFS).
                Between September 1996 and November 1999, 905 patients with stage II (43%) and III (57%) colon cancer were enrolled. The median follow-up was 6 years. There was no statistically significant difference between mFU/LV and LV5FU2 in terms of DFS (150 v 148 events; hazard ratio [HR],1.01; 95% CI, 0.806 to 1.269; P = .94) and overall survival (OS; 104 v 103 events; HR,1.02; 95% CI, 0.77 to 1.34; P = .91). No statistical difference was observed between 24 or 36 weeks of chemotherapy. Median survival from metastatic relapse was 24 months. The survival of patients with metastatic relapse (n = 243) was significantly longer for patients with a longer time from random assignment to relapse (< 1, 1 to 2, >or= 2 years; log-rank test for trend P, .0497).
                DFS and OS were not statistically different between treatment groups and treatment durations. These data confirm the value of LV5FU2 as control arm in the Multicenter International Study of Oxaliplatin/5FU-LV in the Adjuvant Treatment of Colon Cancer and Pan-European Trials in Adjuvant Colon Cancer studies. This study had two major goals: (1) to assess the effectiveness 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 chemotherapy.
                Patients with poor-prognosis stage II or III colon cancer were randomly assigned to receive adjuvant chemotherapy with either intensive-course 5-FU and leucovorin combined with levamisole, or a standard regimen of 5-FU plus levamisole. Patients were also randomly assigned to receive either 12 months or 6 months of chemotherapy, which resulted in four treatment groups.
                Eight hundred ninety-one of 915 patients entered (97.4%) were eligible. The median 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 observed. Specifically, standard 5-FU plus levamisole was inferior to 5-FU plus leucovorin plus levamisole when treatment was given for 6 months (5-year survival rate, 60% v 70%; P < .01).
                There was no significant 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 patient survival compared with intensive-course 5-FU plus leucovorin plus levamisole. These data suggest that 5-FU plus levamisole for 6 months should not be used in clinical practice, whereas 6 months of treatment with 5-FU plus leucovorin plus levamisole is effective.
The present meta-analysis confirmed that adjuvant chemotherapy of CRC should not last for more than 6 months. Prolonged duration would result in lower benefit to risk ratio. However, the results do not make it possible to favour either 3 or 6 month durations. They should help design a future RCT comparing different durations of continuous treatment.