The primary endpoint is to evaluate the TFS (time to failure of strategy).

The primary endpoint is to evaluate the time to failure of strategy, that is the second progression time after induction therapy by the use of XELOX regimen, comparing XELOX regimen chemotherapy combined with or without surgical resection of the primary lesion from the time of randomization to maintenance therapy and reapplication of induction therapy, or time to the use of second line strategy (if no reapplication of induction therapy) or time to no further treatment.

Inclusion Criteria:

1. 18~75 ears old
2. Pathological diagnosis of colon cancer adenocarcinoma
3. No systemic chemotherapy for metastatic tumors
4. ECOG (Eastern Cooperative Oncology Group) 0-1 and expected survival period for 6 months or more
5. At least one measurable objective tumor lesions
6. ANC≥1.5*109/L；PLT≥90*109/L；HB≥90g/L；TBI≤1.5(UNL); ALT、AST≤2.5ULN；Cr≤1.0(ULN) screening within 7 days
7. Primary and metastatic tumors exist at the same time, and distant metastases are not resectable
8. Patients with voluntary participation, and sign the informed consent

Exclusion Criteria:

1. Operation intervention required for perforation, bleeding and obstruction of intestinal cavity
2. With uncontrollable large pleural or peritoneal effusion
3. Alcohol or drug addictions
4. Malignant tumour of the past five years with other organizations to source, but the full treatment of cervical carcinoma in situ and except skin basal cell carcinoma and squamous cell carcinomas
5. With brain metastasis
6. Multiple primary colorectal carcinoma
7. Pregnancy or breast-feeding women
8. There is an important organ failure or other serious diseases, including coronary artery disease, symptomatic cardiovascular disease or myocardial infarction within 12 months; serious neurological or psychiatric history; severe infection; actively disseminated vascula blood coagulation.