Effect of a 3-hour interval between methotrexate and 5-fluorouracil in the treatment of metastatic colorectal cancer.

Objective: This phase II study was designed to evaluate the efficacy and toxicity of 3-h interval sequential methotrexate (MTX) and 5-fluorouracil (5-FU) with leucovorin (LV) rescue in the treatment of patients with metastatic colorectal cancer.

Methods: Forty-two patients with histologically confirmed metastatic colorectal cancer and at least one two-dimensionally measurable lesion, aged 30-74 years old, with performance status < or =2 and no or one prior chemotherapy were selected. Patients received sequential MTX 100 mg/m2 by bolus injection and 5-FU 600 mg/m2 at 3 h followed by LV rescue initiated after 24 h (15 mg per body every 6 h for six doses).