The study evaluates the effectiveness of radiotherapy combined with raltitrexed and irinotecan in treating patients who have metastatic or locally recurrent colorectal cancer that has not responded to fluorouracil. The patients will receive radiotherapy combined with raltitrexed and irinotecan, and then the surgeons will evaluate whether they should receive a surgery.

Inclusion Criteria:

• Histologically proven metastatic, advanced, or locally recurrent fluorouracil (5-FU) and oxaliplatin refractory adenocarcinoma of the colon or rectum; Progression of disease within 6 months of receiving adjuvant 5-FU and oxaliplatin chemotherapy OR Progression of disease during or following completion of 5-FU and oxaliplatin chemotherapy for metastatic disease
• Evaluable lesions with indications of radiotherapy
• No other metastatic lesions in the radiation field
• Karnofsky Performance Status>=70
• UGT1A1*28 6/6 or 6/7
• Subject blood routine and biochemical indicators meet the following criteria: hemoglobin ≥ 90g / L; absolute neutrophil count (ANC) ≥ 1.5 × 109 / L; Alanine transaminase (ALT), aspartate aminotransferase (AST) ≤ 2.5 times the upper limit of normal; alkaline phosphatase (ALP) ≤2.5 times the normal upper limit; serum total bilirubin <1.5 times the normal upper limit; serum creatinine <1 times the normal upper limit; serum albumin ≥ 30g / L
• Able to follow the protocol during the study period
• Sign the inform consent

Exclusion Criteria:

• Pregnant or breastfeeding women
• If there is an uncontrolled history of epilepsy, central nervous system disease or mental disorder, the investigator may determine that the clinical severity may hinder the signing of informed consent or affect the patient's oral medication compliance.
• Clinically severe (ie, active) heart disease, such as symptomatic coronary heart disease, New York Heart Association (NYHA) class II or more severe congestive heart failure or severe arrhythmia requiring medication intervention (see appendix 12), or a history of myocardial infarction in the last 12 months
• Organ transplantation requires immunosuppressive therapy
• Severe uncontrolled recurrent infections, or other serious uncontrolled concomitant diseases
• Anyone who is allergic to any research medication