Surufatinib Plus Gemcitabine and Nab-paclitaxel vs. Gemcitabine Plus Nab-paclitaxel in Neoadjuvant Therapy for High - Risk Resectable or Borderline Resectable Pancreatic Cancer

Inclusion Criteria: * Histologically or cytologically confirmed high-risk resectable or borderline resectable pancreatic cancer; * 18-75 years old (including 18 and 75 years old); * No BRCA1/2 or PALB2 mutation; * No previous pancreatic cancer resection, systemic therapy, or local radiation therapy; * Eastern Cooperation Oncology Group (ECOG) performance status of 0-1; * Life expectancy ≥ 6 months; * At least one measurable lesion according to RECIST version 1.1; * Adequate organ and bone marrow functions; * Women of childbearing age need to take effective contraceptive measures. Exclusion Criteria: * With distant metastasis; * Have received blood transfusion treatment, blood products and hematopoietic factors, such as albumin and granulocyte colony-stimulating factor (G-CSF) within 14 days before enrollment; * Have received any surgery or invasive treatment or operation within 4 weeks before enrollment (except venous catheterization, puncture and drainage, etc.); * Allergic to the study drug or any of its adjuvants; * Researchers judged clinically significant electrolyte abnormalities; * History of serious cardiovascular and cerebrovascular diseases; * With active ulcer, intestinal perforation and intestinal obstruction; * Uncontrollable malignant ascites (defined as ascites that cannot be controlled by diuretics or puncture according to the judgment of the investigator); * Clinically significant electrolyte abnormalities judged by researchers; * With active bleeding or obvious evidence of bleeding tendency; * Hypertension that cannot be controlled by drugs: systolic blood pressure ≥ 150 mmHg and / or diastolic blood pressure ≥ 100 mmHg; * Women who are pregnant or lactating; * Urinary protein ≥ ++, or the 24-hour urine protein quantification is greater than 1.0g; * Concurrent tumors within 5 years (except treated cervical carcinoma in situ, basal cell carcinoma); * Any disease or state that affects the absorption of drugs, or the subject cannot take oral drugs; * Known human immunodeficiency virus (HIV) infection; * History of clinically significant hepatic disease, including, but not limited to, known hepatitis B virus (HBV) infection with HBV DNA positive (copies ≥1×10\^4/ml or \>2000 IU/ml); known hepatitis C virus infection with HCV RNA positive (copies ≥1×10\^3/m); hepatitis and cirrhosis; * Have any other disease, metabolic disorder, physical examination anomaly, abnormal laboratory result, or any other conditions that makes the subject not suitable for enrolling according to the judgment of the investigator.