The aim of this trial is to evaluate the value of palliative primary tumor resection in colon cancer patients with initially unresectable metastases and a positive response to induction chemotherapy which depends on gene testing. The primary endpoint is to evaluate overall survival.

Inclusion Criteria:

• 75 years old
• ECOG (Eastern Cooperative Oncology Group) 0-1 and expected survival period for 6 months or more
• Pathological diagnosis of colon cancer adenocarcinoma
• At least one measurable objective tumor lesions which could be evaluated.
• Primary and metastatic tumors exist at the same time, and distant metastases are not resectable
• 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
• No systemic chemotherapy
• Patients with voluntary participation, and sign the informed consent

Exclusion Criteria:

• Operation intervention required for perforation, bleeding and obstruction of intestinal cavity
• Multiple primary colorectal carcinoma
• Malignant peritoneal effusion or metastatic carcinoma of the peritoneum
• Uncontrolled pleural effusion
• 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
• With brain metastasis or meningeal metastasis
• Pregnancy or breast-feeding women
• Alcohol or drug addictions
• 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