Surgical Management of Pancreatic Neuroendocrine Tumors (PNETs)
Surgical resection is the primary and potentially curative treatment for localized pancreatic neuroendocrine tumors (PNETs), with specific surgical approaches determined by tumor size, location, functionality, and grade. 1
Preoperative Management
Before surgical intervention, symptoms of hormonal excess must be controlled:
- Insulinomas: Stabilize glucose levels with diet and/or diazoxide; octreotide should be used with extreme caution as it can worsen hypoglycemia 2
- Gastrinomas: Treat gastrin hypersecretion with proton pump inhibitors 2
- Glucagonomas: Manage hyperglycemia and diabetes; consider total parenteral nutrition for severe weight loss 2
- VIPomas: Control electrolyte imbalances and diarrhea 2
All patients who might require splenectomy should receive preoperative trivalent vaccine (pneumococcus, haemophilus influenzae b, meningococcus group c) 2
Surgical Approach Based on Tumor Type
Non-functioning PNETs:
Tumors ≤1 cm:
Tumors 1-2 cm:
- Surgical resection with lymph node dissection due to risk of lymph node metastases 2
Tumors >2 cm or malignant-appearing:
- Complete resection with negative margins (including adjacent organs if necessary)
- Regional lymph node removal 2
Functioning PNETs:
Insulinomas:
- Primarily benign (90%)
- Surgical approach: Enucleation for exophytic or peripheral tumors 2
- If enucleation not possible: Pancreatoduodenectomy for head tumors or distal pancreatectomy with spleen preservation when feasible 2
Gastrinomas:
- Occult gastrinomas: Exploratory surgery with duodenotomy and intraoperative ultrasound; enucleation or local resection if identified 2
- Duodenal gastrinomas: Duodenotomy with local resection/enucleation and periduodenal node dissection 2
- Head of pancreas gastrinomas:
- Exophytic/peripheral: Enucleation with periduodenal node removal
- Deep/invasive/close to pancreatic duct: Pancreatoduodenectomy 2
- Distal pancreas gastrinomas: Distal pancreatectomy with or without splenectomy 2
Glucagonomas:
- Mostly malignant, often located in pancreatic tail
- Surgical approach: Distal pancreatectomy with lymph node resection and splenectomy 2
- Consider perioperative anticoagulation due to increased risk of pulmonary emboli 2
VIPomas:
- Distal VIPomas: Distal pancreatectomy with lymph node resection and splenectomy
- Head of pancreas VIPomas: Pancreatoduodenectomy with peripancreatic node dissection 2
- Small peripheral tumors (<2 cm): Consider enucleation or local excision with lymph node dissection 2
Surgical Techniques
Standard resections:
- Pancreatoduodenectomy (Whipple) for head/uncinate process tumors
- Distal pancreatectomy for body/tail tumors
- Total pancreatectomy for diffuse disease
Parenchymal-sparing techniques:
- Enucleation for small, superficial tumors away from pancreatic duct
- Central pancreatectomy for appropriate mid-body tumors
Management of Advanced Disease
For patients with limited hepatic metastases:
- Consider surgical excision of both primary tumor and liver metastases when possible 2
- Staged approach: Consider hepatectomy before pancreatic resection to reduce risk of perihepatic sepsis 2
- Cytoreductive surgery may provide clinical benefit, though most patients will experience recurrence 2
Post-Surgical Surveillance
- Follow-up 3-12 months after resection, or earlier if symptomatic
- Continue surveillance every 6-12 months with appropriate tumor markers and imaging studies
- Disease recurrence occurs in 21-42% of patients, sometimes after many years 2
Special Considerations
- MEN1 syndrome patients: Often have multiple tumors requiring specialized surgical approach
- Borderline/locally advanced PNETs: Pancreatectomy with vascular resection may be considered for portal/superior mesenteric vein invasion 2
- High-grade PNETs (G3): Role of surgery is controversial; upfront surgery may not provide clear survival benefit 2
Surgical management of PNETs requires a multidisciplinary approach in specialized high-volume centers to achieve optimal outcomes while minimizing complications.