To study safety and efficacy of intravenous pump of recombinant human endostatin combined with XELOX-treated and also investigate the potential value of CECs level for the prediction of PD and outcomes in patients with advanced colorectal cancer.

Inclusion Criteria:

• Clear pathology diagnosis of stage for the Ⅳ period of advanced colorectal cancer.
• There are at least 1 imaging examinations according to the standard of RECIST（the longest diameter is at least 10mm with spiral CT and 20mm with ordinary CT）.
• Male or female , age 18～75
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
• The patients had to have a life expectancy of at least 3 months.
• A white blood count (WBC) greater than 3000/mm3, platelets greater than 100 000/mm3, and normal coagulation values.
• Aspartate aminotransferase (AST) and adenosine triphosphate (ALT) values were to be less than 2.5 times the upper limit of normal;a bilirubin level of less than 25 lmol/l；a creatinine value less than 130 lmol/l.
• Informed consent was obtained from all patients.

Exclusion Criteria:

• Patients having a brain tumor or brain metastases, a bleeding disorder, receiving anti-coagulant therapy.
• a history of myocardial infarction or angina pectoris in the last 6 months or uncontrolled congestive heart failure, having an active infection or receiving radio- or chemotherapy within 4 weeks before study.
• patients with uncontrolled serious medical or psychiatric illness or having any other condition that was likely to interfere with regular follow-up.