The Study of CIK Plus S-1 and Bevacizumab as Maintenance Treatment for Patients With Advanced Colorectal Cancer

Inclusion Criteria: * Patients who can accept curative operations 18-70 years old * Histologically confirmed with colorectal cancer at stage Ⅳ * Patients who can accept oral drugs; * Eastern Cooperative Oncology Group (ECOG) performance status was 0 - 1. Exclusion Criteria: * Hemoglobin\<8.0 g/dL,White blood cell \<3 X 10\^9/L;Platelet count \<75 X 10\^9/L; alanine aminotransferase, glutamic-oxalacetic transaminase, blood urine nitrogen and creatinine more than normal limits on 3.0 times * Known or suspected allergy to the investigational agent or any agent given in association with this trial * Pregnant or lactating patients * Known history of Human Immunodeficiency Virus (HIV), Hepatitis C Virus (HCV) or TreponemaPallidun (TP) infection * Patients who are suffering from serious autoimmune disease * Patients who had used long time or are using immunosuppressant * Patients who had active infection * Patients who are suffering from serious organ dysfunction * Patients who are suffering from other cancer * Other situations that the researchers considered unsuitable for this study.