Low-dose Trifluridine/Tipiracil With Bevacizumab in mCRC

Inclusion Criteria: 1. age over 60 years old, male and female 2. histologically confirmed adenocarcinoma of the colon or rectum 3. patients with metastatic or advanced unresectable diseases who had received two or more previous chemotherapy regimens or intolerance to last regimen 4. with or without measurable lesions 5. ECOG 0 to 2, expected survival time over 3 months 6. Enough organ functions that can tolerate treatment: Absolute neutrophil count (ANC) ≥1.5x109/L, White blood count ≥3.5x109/L, Platelets ≥75x109/L, Hemoglobin (Hb) ≥80g/L, ALT/AST ≤2.5x ULN (for patient with liver metastasis ALT/AST ≤5x ULN), Serum bilirubin ≤1.5x ULN, Serum creatinine ≤1.5x ULN. 7. Signed informed consent and willing to follow the study protocol Exclusion Criteria: 1. symptomatic metastases of central nervous system 2. other primary malignancies 3. uncontrollable comorbidities, such as hypertension, thrombotic diseases, chronic kidney disease 4. organ functions that cannot tolerate study treatment 5. bowel obstruction or other conditions affecting oral administration 6. allergic to study medication 7. other conditions that patients are unsuitable for this study assessed by the investigators