This study is to evaluate the efficacy and tolerability of surgery in selecting patients who can benefit from the synchronous resection of primary pancreatic neuroendocrine tumor and liver metastasis after induction systemic treatment. The willing of participants decide who receive surgery and who will continue to receive standard systemic treatment.

system treatments of metastatic PanNET include SSA, sunitinib, mTOR inhibitor and chemotherapy. For patients achieved PR/SD after system treatment, resection of primary tumor and metastasis maybe a better way to decline tumor burden and get longer survival. this real world study is focused on this group of patients with metastatic PanNET, and to evaluate the efficacy and tolerability of surgery in selecting patients who can benefit from the synchronous resection of primary pancreatic neuroendocrine tumor and liver metastasis after induction systemic treatment.

Inclusion Criteria:

1. Biopsy-proven neuroendocrine tumor
2. primary site in pancreas
3. Advanced disease with lymph node or distant metastases (N1, M1) cannot undergoing cytoreduction by surgery/local ablative therapy at the diagnosis
4. curative intent of all therapies possible
5. ECOG 0-2

Exclusion Criteria:

1. Undifferentiated neuroendocrine carcinoma or mixed neuroendocrine carcinoma secondary tumor
2. functioning NET or advanced carcinoid heart disease
3. part of hereditary syndrome, such as MEN1, VHL
4. do not willing to receive systemic treatment
5. diagnosed with other cancer within 5 years

patients with metastatic pancreatic neuroendocrine tumors in a tertiary referal center