[Sequential methotrexate-5-fluorouracil (MTX-5-FU) treatment of patients with advanced gastric and colorectal cancer. Sequential Methotrexate-5-FU Study Group].

A multicenter cooperative study was conducted from July 1984 to March 1986 to evaluate the clinical efficacy of sequential MTX-5-FU treatment in 96 cases of advanced gastric cancer and 39 cases of colorectal cancer. 5-FU 600 mg/m2 i.v. was given and MTX 30 mg/m2 (A), 100 mg/m2 (B) and 300 mg/m2 (C) i.v. were given, and the administration interval between MTX and 5-FU was 1 to 3 h for the gastric cancer group, and 7 h for the colorectal cancer group. Leucovorin rescue of 10 mg/m2 p.o. was given 24 h after MTX administration. In the gastric cancer group, the response rate for Regimen A was 23.2% (CR 1 and PR 12) out of 56 evaluable cases, and for Regimen B, 40.5% (CR 1 and PR 14) out of 37 evaluable cases. In the colorectal cancer group, the response rate for Regimen A was 28.6% (PR 6) out of 21 evaluable cases and for Regimen B, 20.0% (PR 3) out of 15 cases. Median survival time for the gastric cancer group was 5.5 months with Regimen A and 7.6 months with Regimen B, and for the colorectal cancer group 10.9 months with Regimen A and 7.9 months with Regimen B. Main adverse effects were marrow impairment and gastrointestinal symptoms such as nausea, diarrhea, and stomatitis. In this study Regimen B showed relatively good results. In order to evaluate the biochemical modulation occurring with sequential MTX-5-FU treatment, a further phase III study in gastric cancer patients should be conducted.