This investigator-initiated study closed to recruitment early due to slower-than-anticipated patient accrual.

pNENs still have a risk of recurrence after radical resection, and the overall recurrence and metastasis rate is as high as 13.7%-36.2% in China. At present, there is no standard adjuvant therapy for pNEN, and prospective studies are still lacking. This study was a randomized, double-blind, placebo-controlled, multicenter clinical trial to explore the efficacy and safety of surufatinib in the adjuvant treatment of pNET, in order to further improve the prognosis of patients and to provide high-quality research evidence for adjuvant therapy.

Inclusion Criteria:

• pNETs lesions pathologically classified as WHO grade 1/ 2/ 3;
• G2/3-NET with at least one high-risk postoperative recurrence factor, including but not limited to lymph node metastasis, neurovascular invasion, pancreatic duct dilation, tumor >4cm, positive resection margin, etc.; or G1-NET with lymph node or remote transfer;
• Complete surgical resection (R0 or R1 was achieved) ;
• Adjuvant treatment was performed within 6-12 weeks after surgery;
• Have received whole-body 68Ga PET-CT examination within the past six months;

Exclusion Criteria:

• Urinalysis shows urine protein ≥ 2+ and 24-hour protein quantity test shows urinary protein ≥1 g;
• Under anti-hypertension treatment, still uncontrolled hypertension, defined as: systolic blood pressure ≥ 150 mmHg or diastolic blood pressure ≥ 100 mmHg;
• Clinically significant cardiovascular disease, including but not limited to, acute myocardial infarction within 6 months prior to enrollment, severe/unstable angina pectoris or coronary artery bypass grafting, congestive heart failure according to the New York Heart Association (NYHA) classification ≥ 2; ventricular arrhythmias which needs drug treatment; LVEF (LVEF) <50%;