A feasibility study of Irinotecan (CPT-11) by groups of Uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) polymorphisms in patients with metastatic colorectal cancer.

Interventions: Patients receive FOLFIRI with bevacizumab fixed 5mg/kg. (Treatment will be continued unless the disease progression, unacceptable toxicity, or consent withdrawal.) Definision of UGT1A1 polymorphisms groups: The homozygous group is patient with homozygous genotype of UGT1A1*28/*28 or UGT1A1*6/*6, with combined heterozygous genotypes of UGT1A1*28 and UGT1A1*6. The heterozygous group is patient with heterozygous genotype of either UGT1A1*28 or UGT1A1*6. The wild group is patients with no UGT1A1*28 and UGT1A1*6 mutation. CPT-11 dosage is wild and heterozygous:CPT-11 150mg/m2 homozygous:CPT-11 100mg/m2
Primary outcome(s): 1)incidence of adverse events 2)frequency of severe toxicity
Study Design: Single arm Non-randomized