Study of Anlotinib in Patients With Advanced Medullary Thyroid Carcinoma

Inclusion Criteria: * Patients voluntarily joined the study, signed the informed consent, and had good compliance; * Patients ≥18 years of age (at the time of signing the informed consent); Eastern Cooperative Oncology Group Performance Status (ECOG-PS) score: 0-2; Expected survival of more than 3 months; * Patients were pathologically confirmed as inoperable locally advanced or metastatic medullary thyroid carcinoma (MTC), possessing imaging or clinical evidence of disease progression within the first 14 months of enrollment; * Having at least one measurable lesion (assessed by Response Evaluation Criteria In Solid Tumors (RECIST) 1.1); * Major organ functions meet the following criteria within 7 days prior to the treatment: 1. Blood routine examination shall meet the following standards (no transfusion within 14 days) : 1. Hemoglobin (Hb) ≥85g/L; 2. Absolute Neutrophil Count (ANC) ≥1.5×109/L; 3. Platelet (PLT) ≥80×109/L； 2. Biochemical examination shall meet the following standards: 1. Total bilirubin (TBIL) ≤1.5 times the upper limit of normal (ULN); 2. Alanine transferase (ALT) and Aspartate transferase (AST) ≤2.5×ULN; If accompanied by liver metastasis, ALT and AST ≤5×ULN； 3. Serum creatinine (Cr) ≤1.5×ULN or Creatinine clearance rate (CCr) ≥60ml/min； * Female patients of reproductive age should agree that birth control (such as intrauterine device, birth control pills, or condoms) must be used during the study period until six months after completion; Having a negative serum pregnancy test within 7 days prior to study enrollment, and must be non-lactating; Male patients should agree to use contraception during the study period until six months after the end of the study. Exclusion Criteria: * Complicated diseases and history: 1. Patients currently have or had other malignancies within 3 years. Patients with the following two conditions can be included in the group: Continuous 5-year disease-free survival (DFS) was achieved for other malignancies treated with a single operation. Cured cervical carcinoma in situ, non-melanoma skin cancer, and superficial bladder tumors \[Ta (non-invasive tumor), Tis (carcinoma in situ) and T1 (the tumor infiltrates the basal membrane)\]; 2. Major surgical treatment, open biopsy, or significant traumatic injury were received within 28 days before the beginning of the treatment; 3. Subjects with any severe and/or uncontrolled disease, including: 1. Having ≥ grade 2 myocardial ischemia or myocardial infarction or arrhythmia (including QTc ≥450ms (male), QTc ≥470ms (female) and ≥ grade 2 congestive heart failure (classified by New York heart association, NYHA)); 2. Active or uncontrolled severe infection (≥ Common Terminology Criteria for Adverse Events (CTC AE) 2 grade of infection); 3. Renal failure requiring hemodialysis or peritoneal dialysis; * Patients with concomitant diseases that, in the investigator's judgment, may seriously endanger patients' safety or may interfere with the completion of the study, or are deemed unsuitable for inclusion for other reasons. * Patients who have previously used anlotinib hydrochloride capsules or similar Vascular Endothelial Growth Factor- Tyrosine Kinase Inhibitor (VEGFR-TKI) small molecule drugs, such as vandetanib, cabozantinib, lenvatinib, sunitinib, sorafenib, etc.;