Irinotecan, continuous 5-fluorouracil, and low dose of leucovorin (modified FOLFIRI) as first line of therapy in recurrent or metastatic colorectal cancer.

Background: Irinotecan, in combination with 5-fluorouracil (5-FU) and a high dose of leucovorin (LV), known as FOLFIRI regimen, has shown activity in recurrent or metastatic colorectal cancer. Therefore, we evaluated the efficacy and safety of irinotecan, 5-FU and a low dose of LV (modified FOLFIRI) as a first line of therapy for patients with relapsed or metastatic colorectal cancer.

Methods: Between January 2002 and October 2004, 44 patients with histologically confirmed recurrent or metastatic colorectal cancer were enrolled. The chemotherapy regimen schedule consisted of 180 mg/m2 of irinotecan being administered intravenously (i.v) on Day 1, 400 mg/m2 of 5-FU via i.v bolus with 600 mg/m2 of continuous infusion for 22 hrs on both Day 1 and 2, and 20 mg/m2 of leucovorin on both Day 1 and 2 , repeated every two weeks.

Results: The overall response rate was 47.8%. Of the 40 evaluated patients, one had CR (2.3%) and 20 had PR (46.5%). Toxicities were mild and easily manageable. Three patients experienced 23 episodes of Grade 3/4 leukopenia., Only one patient developed Grade 3/4 diarrhea. None experienced Grade 3/4 thrombocytopenia.

Conclusion: Modified FOLFIRI with a low dose of LV is an effective and tolerable regimen for patients with recurrent or metastatic colorectal cancer.