Randomized Phase III Study of Folfiri+Avastin Versus Xeliri+Avastin as 1st Line Treatment of CRC

Inclusion Criteria: * Histologically confirmed locally advanced or metastatic colorectal cancer * Measurable or evaluable disease * ECOG performance status ≤ 2 * Age 18 - 72 years * Adequate liver (Bilirubin ≤ 1.5 UNL, SGOT/SGPT ≤ 4 UNL, ALP ≤ 2.5 UNL), renal (Creatinine ≤ 1.5 UNL) and bone marrow (ANC ≥ 1,500/mm3, PLT ≥ 100,000/mm3) function * Patients with history of hemoptysis or with increased risk of thromboembolic events should be observed carefully due to administration of Avastin * Patients must be able to understand the nature of this study * Written informed consent Exclusion Criteria: * Previous 1st line chemotherapy * Adjuvant chemotherapy with Irinotecan regimen with relapse \< 6 months after the completion * Active infection * History of serious cardiac disease (unstable angina, congestive heart failure, myocardial infarction within the previous 6 months, ventricular arrhythmias) * Previous radiotherapy within the last 4 weeks or \> 25% of bone marrow * Patients with unstable CNS metastases * Patients with chronic diarrhea (at least for 3 months) or partial bowel obstruction * Second primary malignancy, except for non-melanoma skin cancer and in situ cervical cancer * Psychiatric illness or social situation that would preclude study compliance * Pregnant or lactating women * Patients \> 65 years with history of arterial thromboembolic, myocardial infarction, unstable angina and pulmonary embolism