Apatinib Mesylate Versus Standard Second-line TKI in the Treatment of Advanced GIST

Inclusion Criteria: 1. Patients were enrolled voluntarily and signed a written informed consent with good compliance and follow-up; 2. Age ≥18 years (calculated on the date of signing the informed consent) for both men and women; 3. Previous first-line TKI (Imatinib/Avatinib) therapy and eventual treatment failure (disease progression or toxicity intolerance during treatment); 4. Subjects who provide pre-C-Kit /PDGFRA test reporting can provide 10ml blood sample and fresh or archived tumor tissue for genetic testing. 5. ECOG score: 0 \~ 1; 6. Predicted survival ≥12 weeks. Exclusion Criteria: 1. Previous molecular targeted therapy other than imatinib/Avatinib for the treatment of gastrointestinal stromal tumor; 2. Toxicity of previous imatinib/Avatinib treatment or other treatments has not recovered or reached NCICTCAE5.0≤ level 1; 3. Patients with clinical symptoms of ascites or pleural effusion who need puncture drainage or who have received thoracic and ascites drainage within 1 month before signing informed consent, except those who only show a small amount of ascites or pleural effusion without clinical symptoms; 4. A second primary malignancy within the last 5 years, except for basal cell carcinoma, squamous cell carcinoma of the skin, or carcinoma in situ of the cervix that has been adequately treated; 5. Gastrointestinal stromal tumor with central nervous system metastasis; 6. Inability to swallow, chronic diarrhea and intestinal obstruction, with multiple factors affecting drug administration and absorption.