Surufatinib as Neoadjuvant Treatment for Locally Advanced or Metastatic Differentiated Thyroid Cancer

Inclusion Criteria: * Locally advanced or metastatic thyroid cancer confirmed by histology or cytology, including papillary thyroid carcinoma, follicular thyroid carcinoma, poorly differentiated thyroid cancer, particularly differentiated thyroid cancer. Locally advanced stage refers to: 1) Primary tumor with invasion or adhesion of organs and structures, such as recurrent laryngeal nerve, esophagus, trachea, larynx, encirclement of neck large vessels, mediastinal vessels, extensive invasion of skin, subcutaneous soft tissue or neck muscles; 2). AJCC T4 Stage; 3). Difficult to achieve R0/R1 resection during preoperative assessment; * Age 14-75 years; * At least one measurable lesion (RECIST 1.1); * Eastern Cooperative Oncology Group (ECOG) score 0-1; * Expected survival time ≥ 12 weeks; * The main organ functions meet the following criteria: Absolute neutrophil value (ANC) ≥ 1.5 × 109 / L; Platelet (PLT) ≥80 × 109 / L; Hemoglobin (HB) ≥9g / dL; White blood cell count\> 1.5 × 109 / L; Total bilirubin (TBIL) ≤ 1.5 times the upper limit of normal value (ULN); Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 2.5 ULN, if with liver metastases, ALT and AST ≤ 5 ULN; Serum creatinine (Cr) ≤ 1.5 ULN or creatinine clearance (CCr) ≥ 50ml / min; * Subjects of potential fertility are required to use at least one medically approved contraceptive method (such as an intrauterine device, contraceptive pill, or condom) during the study treatment and for 180 days after the end of the study treatment; The serum HCG test must be negative before the first medication. Exclusion Criteria: * Prior treatment with anti-angiogenic small molecule targeted drugs; * Received other anti-tumor therapy (including but not limited to chemotherapy, radiotherapy, etc.) within 4 weeks prior to treatment, except for TSH suppression treatment; * Allergy to the study drug ; * Have a history of serious cardiovascular and cerebrovascular diseases; * Patients whose imaging showed that the tumor had invaded the important blood vessels or the researchers judged that the tumor was likely to invade important blood vessels during the subsequent study period and caused fatal bleeding; * Patients with hypertension that cannot be well controlled by antihypertensive medication (systolic blood pressure ≥150 mmHg or diastolic blood pressure ≥100 mmHg); * The patient has had other malignant tumors within 5 years (except cured basal cell carcinoma of the skin and carcinoma in situ of the cervix); * The investigator considered that the subject was not suitable to participate in the study due to any clinical or laboratory abnormalities or other reasons.