Clinical trial of low-dose leucovorin plus 5-fluorouracil for patients with metastatic colorectal cancer

BACKGROUND/AIMS: To establish an effective and practical treatment of Japanese patients with metastatic colorectal cancer in an outpatient setting, we conducted a clinical trial using a modified Mayo regimen. METHODOLOGY: A bolus injection of low-dose (20 mg/m2) d,l-leucovorin (LV) was administered, followed one hour later by an intravenous injection of 333 mg/m2 5-fluorouracil (5-FU) for another hour. The two drugs were given on days 1, 2, and 3, and the treatment was repeated every 2 weeks. RESULTS: In the 17 patients enrolled in the study, the tumor response rate was 25%, and time-to-treatment failure and median survival time were 7 and 24 months, respectively. The treatment was well tolerated, with no adverse effects greater than grade 3, and could be completed in all patients in the outpatient setting. One patient with lung, liver, and parailiac lymph node metastasis showed a complete response and survived for more than 6 years with tumor-free status. CONCLUSIONS: These results suggest that although the sample size studied was too small to allow us to draw definitive conclusions, this regimen may be an effective and practical alternative to the Mayo regimen in an outpatient setting for Japanese patients with metastatic colorectal cancer.