Background: In phase II trials, irinotecan is active in patients with advanced colorectal cancer, but the survival and clinical benefit of irinotecan compared with second-line fluorouracil by continuous infusion is not known.
Methods: 267 patients who had failed to respond to first-line fluorouracil, or whose disease had progressed after treatment with first-line fluorouracil were randomly allocated irinotecan 300-350 mg/m2 infused once every 3 weeks or fluorouracil by continuous infusion. Treatment was given until disease progression, unacceptable toxic effects, or the patient refused to continue treatment. The primary endpoint was survival, while progression-free survival, response rate, symptom-free survival, adverse events, and quality of life (QoL) were secondary endpoints.
Findings: 133 patients were randomly allocated irinotecan and 134 were allocated fluorouracil by continuous infusion. Patients treated with irinotecan lived for significantly longer than patients on fluorouracil (p=0.035). Survival at 1 year was increased from 32% in the fluorouracil group to 45% in the irinotecan group. Median survival was 10.8 months in the irinotecan group and 8.5 months in the fluorouracil group. Median progression-free survival was longer with irinotecan (4.2 vs 2.9 months for irinotecan vs fluorouracil, respectively; p=0.030). The median pain-free survival was 10.3 months and 8.5 months (p=0.06) for irinotecan and fluorouracil, respectively. Both treatments were equally well tolerated. QoL was similar in both groups.
Interpretation: Compared with fluorouracil by continuous infusion second-line irinotecan significantly improved survival in patients with advanced colorectal cancer.