Fruquintinib in the Cross-line Treatment of Refractory mCRC

Inclusion Criteria: \- To be enrolled in this study, patients must meet all of the following criteria: 1. Age ≥18 years, ≤75 years; 2. No gender limitation; 3. Patients with metastatic colorectal cancer confirmed by histopathology had previously received 2-line system therapy with fluorouracil, oxaliplatin, irinotecan, anti-VEGF, anti-EGFR (RAS and BRAF wild type) (treatment with anti-VEGF-TKI is not allowed), and had received fruquinitinib combined with PD-1 inhibitors for third-line treatment. After progression (PD) (confirmed by RECIST 1.1 ), fruquinitinib combined with TAS-102 as fourth-line therapy was received. 4. Expected survival ≥12 weeks 5. Must have at least one measurable lesion (RECIST1.1). 6. Full organ and bone marrow function. Exclusion Criteria: \- Patients will not be admitted to the study if they meet any of the following criteria: 1. Patients with contraindications to study drugs (fruquinitinib, PD-1 inhibitor, TAS-102); 2. allergic to the investigational drug or any of its adjuncts; 3. There are other non-investigational drugs during third-line and fourth-line treatment; 4. Pregnant or lactating female subjects; 5. Patients with a large number of pleural effusion or ascites requiring drainage; 6. Patients considered unsuitable for inclusion in this study by the investigators.