High- versus low-dose leucovorin in 5-fluorouracil-based oxaliplatin- or irinotecan-containing regimen in metastatic colorectal cancer

Abstract

e15054 Background: Although leucovorin (LV) is widely used as a modulator of 5-fluorouracil (5-FU) for the chemotherapy of advanced colorectal cancer, the optimal dose has not yet been established. Low-dose LV appears to be as active as high-dose LV in the several studies. So, we tried to compare the efficacy of high-versus low-dose LV in the commonly used palliative chemotherapy regimen. Methods: Between May 2003 and May 2008, 40 patients with metastatic colorectal cancer were randomly treated with high-LV (200mg/m2/i.v.) or low-LV (20mg/m2/i.v.) in 5-FU based oxaliplatin (FOLFOX-4) or irinotecan (FOLFIRI) containing regimen. The primary endpoint of the study was the comparison of response rates and the secondary endpoint was the assessment of survival and tolerability. Results: The response rate was 40% in low-LV group with 2 CR and 6 PR, and 35% in high-LV group with 2 CR and 5 PR, without any significant difference (P = 0.89). The median overall survival was 24.3 months in low-LV group and 25.2 months in high-LV group, with no difference between treatments. Toxicity mainly consisted of gastrointestinal side effects, which were rare and similar in the two groups. Conclusions: In this randomized phase II study, the low and high doses of LV appeared to be equivalent in palliative chemotherapy of metastatic colorectal cancer although large-scale phase III study are necessary. No significant financial relationships to disclose.