Raltitrexed-based Chemotherapy Plus Bevacizumab in Retreated Patients With Advanced Colorectal Cancer

Inclusion Criteria:

* 18-70 years;
* histological and/or cytological confirmation of ACC;
* disease progression while on first-line palliative fluoropyrimidine-based chemotherapy or relapse within 6 months after adjuvant chemotherapy;
* at least one measurable objective tumor lesion by spiral CT examination, the maximum diameter ≥ 1cm（according to RECIST 1.1）
* ECOG performance status 0-1
* life expectancy of at least 3 months
* satisfactory main organ function，laboratory test must meet the following criteria: hemoglobin (HGB) ≥90g/L, neutrophil count（ANC） ≥1.5×109/L, platelet count（PLT） ≥80×109/L, Serum creatinine（CR）≤1.5 upper normal limitation (UNL)，total bilirubin (TBil) ≤1.5 upper normal limitation (UNL), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤2.5 UNL (For patients with liver metastasis, the AST/ALT must be ≤5.0 UNL), Alkaline phosphatase（ALP）≤3 UNL(For patients with liver metastasis, the ALP must be ≤5.0 UNL);
* written informed consent

Exclusion Criteria:

* prior exposure to raltitrexed;
* Clinically significant cardiovascular disease, for example symptomatic coronary artery disease, myocardial infarction (\<=6 months before treatment start),congestive heart failure （New York Heart Association ，NYHA\>= grade 3）,stroke or transient ischemic attack
* Accept kidney dialysis treatment now
* chronic enteropathy on unresolved bowel obstruction;
* previous malignant disease other than carcinoma in situ of the cervix or basal cell carcinoma of the skin;
* the UGT1A1 \*28（7/7）\*6（A/A） gene type;
* pregnant or lactated women;
* Unsuitable for the study or other chemotherapy determined by investigator.