Purpose: Methotrexate (MTX) has been described to modulate the activity of fluorouracil (5-FU) in patients with metastatic colorectal cancer. The European Organization for Research and Treatment of Cancer (EORTC) Gastrointestinal Tract Cancer Cooperative Group (GITCCG) conducted a phase III trial to investigate the efficacy and tolarability of the addition of low-dose MTX (40 mg/m2) to high-dose infusional 5-FU (60 mg/kg over 48 hours) given weekly for 4 weeks and thereafter every 2 (for 4 weeks) and 3 weeks.
Patients and methods: Three hundred ten patients were randomized between 1987 and 1992. Eligible patients had measurable advanced or metastatic colorectal cancer and had not been pretreated with antifolates or fluorodinated pyrimidines. All 297 eligible patients were evaluated for survival; toxicity was assessed in 292 patients who received at least one course of treatment. Patients with bidimensionally measurable disease (n = 230) were also evaluated for response according to standard criteria.
Results: The addition of low-dose MTX to high-dose infusional 5-FU led to a doubling of the response rate from 10% to 21% (P = .025). The median survival time also increased from 9.3 to 12.5 months, but this difference was not statistically significant (P = .12). High-dose infusional 5-FU with or without low-dose MTX was well tolerated, with grade 3 to 4 toxicity in greater than 10% of patients only occurring for stomatitis with the combination treatment. Performance status was the sole prognostic factor for survival in a multivariate analysis.
Conclusion: Low-dose MTX effectively modulated high-dose infusional 5-FU in a large, randomized trial in which less than 5% of patients received leucovorin.