TAS-102 Combined With Bevacizumab and Tislelizumab Third-line or Above in the Treatment of Liver Metastasis in Colorectal Cancer

Inclusion Criteria:

* Patients who provided informed consent and voluntarily enrolled
* Patients with liver metastasis of advanced colorectal adenocarcinoma with MSS confirmed by pathology;
* 18-75 years old;
* Measurable target lesions according to RECIST V1.1 assessment criteria;
* Progression after standard second-line treatment (irinotecan, oxaliplatin, or fluorouracil);
* 0 \~ 2 points according to ECOG quality of life score;
* Drugs can be taken orally
* Estimated survival ≥3 months;
* Women of childbearing age should comply with contraceptive measures if pregnancy test is negative;
* Ascites with no obvious symptoms and no clinical intervention;
* Adequate organ and bone marrow functions, ecg, blood, biochemical and other basic tests are not contraindications of chemotherapy;
* Adherence to scheduled visits, treatment plans, laboratory tests, and other study procedures Willingness and ability.

Exclusion Criteria:

* Previous application of TAS-102;
* Pregnant or lactating women;
* No contraception during the reproductive period;
* patients known to have a history of allergy to any study drug, similar drug or excipient;
* Patients with risk of massive gastrointestinal bleeding or gastrointestinal obstruction;
* Patients with a history of thromboembolism, except those caused by PICC;
* Patients with active infection;
* Patients with uncontrolled hypertension (systolic blood pressure ≥160 mmHg and diastolic blood pressure ≥90) MmHg);
* Patients with brain metastases with clinical symptoms or imaging evidence;
* Contraindications for treatment of other chronic diseases;
* Previous immunotherapy-related myocarditis, pneumonia, colitis, hepatitis, kidney Inflammation and other conditions, the current AE is still ≥2;
* According to THE NCI CTCAE 5.0 assessment criteria, there are all types of existing cases due to previous treatment Patients with grade ≥2 toxic reactions;
* Other conditions that the investigator determines are not suitable for inclusion in the study.
* Received any anti-tumor therapy and participated in other clinical studies within 4 weeks prior to enrollment.