XELOX Combined With Fruquintinib and Sintilimab Regimen Conversion Therapy for Gastric Cancer/Gastroesophageal Junction Adenocarcinoma Only With Liver and/or Retroperitoneal Lymph Node Metastasis, a Prospective Single-arm, Multicenter Study

Inclusion Criteria:

1. Age: 18-75 years of age;
2. Understand the steps and content, and written informed consent signed voluntarily;
3. Is confirmed by histopathology and/or cytology her2-negative or HER2 status unknownlate recurrence or stomach esophagus stomach/integration of adenocarcinoma;
4. In this research to define transfer of oligonucleotides definition: the primary lesionand regional lymph node metastasis of process to determine the surgeon can be cut orboundary can be cut, only intrahepatic metastasis and distant metastasis (metastasesnumber 5 or less, a single lesion or less 5 cm in diameter.) And or retroperitoneallymph node metastasis (16a2,16b1,16a1,16b2 metastasis), no other distant metastasis;
5. At least one measurable lesion according to RECIST 1.1 criteria;
6. No previous treatment with VEGFR-targeted drugs and PD-1/PD-L1 monoclonal antibodies.Patients who had relapsed more than 6 months after the completion of postoperativeadjuvant chemotherapy with platinum or paclitaxel or fluorouracil and had no grade 2or higher toxicity were eligible for enrollment.
7. ECOG PS score: 0-1;
8. Expected survival time ≥3 months;
9. The main viscera function is good, namely into groups of related within 14 days beforecheck index meet the following requirements:

(1) hemoglobin ≥80 g/L; (2) neutrophil count >1.5×109/L; (3) platelet count ≥80×109/L; (4)Total bilirubin ≤2.5×ULN (upper limit of normal); (5) serum alanine aminotransferase (ALT)or aspartate aminotransferase (AST) ≤5×ULN; (6) the endogenous creatinine clearance or 60ml/min (Cockcroft - Gault formula); (7) Echocardiography: left ventricular ejectionfraction (LVEF)≥50%; (8) Thyroid function indexes: thyroid stimulating hormone (TSH) andfree thyroxine (FT3/FT4) were in the normal range or only mildly abnormal, without relatedclinical symptoms; (9) A body weight of 40 kg or more, or a BMI > 18.5;

Exclusion Criteria:

1. Patients with other malignant tumors in the past or at the same time, but have beencured of early tumors, including basal cell carcinoma of the skin and carcinoma insitu of the cervix, stage I lung cancer, stage I colorectal cancer and other tumorsthat do not affect the patient's life in the short term according to theinvestigator's judgment can be excluded;
2. Participated in other drug clinical trials within four weeks;
3. Multiple factors affecting oral medication (such as inability to swallow, chronicdiarrhea and intestinal obstruction);
4. Patients with a history of bleeding and any bleeding events of CTCAE5.0 grade 3 orhigher within 4 weeks before screening;
5. Metastasis in other distant sites, including but not limited to lung metastasis, brainmetastasis, bone metastasis, distant lymph node metastasis, and peritoneal metastasis;
6. Patients with hypertension not well controlled by single antihypertensive medication (systolic blood pressure >140 mmHg, diastolic blood pressure >90 mmHg); Patients witha history of unstable angina; Newly diagnosed angina pectoris within 3 months beforescreening or myocardial infarction within 6 months before screening; Arrhythmias (including QTcF ≥450 ms in men and ≥470 ms in women) required long-term use ofantiarrhythmic drugs and New York Heart Association (NYHA) grade ≥II cardiacdysfunction;
7. Long-term unhealed wounds or incompletely healed fractures;
8. Imaging shows that the tumor has invaded the important blood vessels or theinvestigator judges that the patient's tumor has a high possibility of invading theimportant blood vessels during the treatment and causing fatal hemorrhage;
9. Abnormal coagulation function, with bleeding tendency (14 days before enrollment mustmeet: INR in the normal range without anticoagulant or clinically insignificantabnormality); Patients treated with anticoagulants or vitamin K antagonists such aswarfarin, heparin, or their analogues; International standardization in prothrombintime ratio (INR) under the premise of 1.5 or less, allowing purpose to prevent the useof low-dose warfarin (1 mg orally, once per day) or low-dose aspirin (amount does notexceed 100 mg daily);
10. Occurrence of arterial/venous thrombosis events within 6 months before screening, suchas cerebrovascular accident (including transient ischemic attack), deep veinthrombosis (except for venous thrombosis caused by venous catheterization due toprevious chemotherapy and judged by investigators to be cured), and pulmonaryembolism;
11. Urine routine showed urine protein ≥++ and confirmed 24-hour urine proteinquantitation >1.0 g;
12. Previous use of immune-targeted therapy drugs;
13. Have a history of immunodeficiency or other acquired or congenital immunodeficiencydiseases, or have a history of organ transplantation;
14. Patients with infectious pneumonia, non-infectious pneumonia, interstitial pneumoniaand other patients requiring corticosteroids;
15. A history of severe chronic autoimmune diseases, such as systemic lupus erythematosus;He had a history of inflammatory bowel disease such as ulcerative enteritis, Crohn'sdisease, and a history of chronic diarrhea such as irritable bowel syndrome. A historyof sarcoidosis or tuberculosis; Patients with a history of active hepatitis B or C,and HIV infection; Good control of severe autoimmune disease, such as dermatitis,arthritis, psoriasis, etc can be into the group. Patients with hepatitis B virus titer <1000copy/ml were eligible for enrollment.
16. Patients with hypersensitivity to human or murine monoclonal antibodies;
17. Have a history of psychotropic drug abuse and cannot quit or have mental disorders;
18. Patients who do not follow the doctor's advice, do not follow the prescribedmedication, or have incomplete data, which may affect the efficacy or safety judgment;
19. Concomitant diseases that, in the judgment of the investigator, seriously compromisepatient safety or interfere with patient completion of the study.