Because of the difficulties of participant enrollment.

Short description for lay public, include brief statement of the study hypothesis

Inclusion Criteria:

• Age : between 20 and 90 years old
• Histologically confirmed adenocarcinoma of the colon or the upper rectum
• Patients with resectable primary colon or upper rectal cancer and unresectable metastatic lesions.
• Patients with no primary cancer related symptoms.
• ECOG performance status of 0 - 2
• Appropriate organ functions (hepatic transaminases - less than 5 times the normal range; bilirubin - less than 2 times the normal range; creatinine serum - less than 1.5 times the normal range; thrombocyte - more than 100,000/µl; neutrophil - more than 1,500/µl)
• ASA score of < 3
• An informed consent form has been signed by the patient.

Exclusion Criteria:

• The patient received adjuvant chemotherapy within the past 6 months.
• The patient received chemotherapy for metastatic colon cancer.
• The patient was planning to have curative surgery for the metastatic lesions.
• The primary cancer is unresectable.
• Patients with peritoneal carcinomatosis.
• Patients with mid and low rectal cancer (< 10cm)
• Patients with primary tumor related complications such as intestinal obstruction, intractable bleeding, and perforation, that needs to be treated.
• ASA score of > 4
• The patient has chronic hepatitis or cirrhosis. An asymptomatic HBV or HCV carrier can participate.
• Patients with an active infection, which need antibiotic therapy, during the randomization period.
• Pregnant or breastfeeding women
• Patients who were enrolled in another clinical trial during the time of enrollment (within the 28 day randomization period).
• Patients with another different malignant tumor during the past 5 years. Patients with treated non-melanoma skin cancer or cervical cancer can be enrolled in this study.