The role of oncologic resection and enucleation for small pancreatic neuroendocrine tumors.

Background: Surgical management of small pancreatic neuroendocrine tumors (PNETs) is variable. Patients may undergo formal oncologic resection, encompassing regional lymphadenectomy, or enucleation. This study's aim was to understand if enucleation is adequate treatment for PNETs <2 cm METHODS: The US National Cancer Database (NCDB) from 2004 to 2016 was used to identify patients who underwent oncologic resection or enucleation for PNETs <2 cm. Fisher's exact test, log-rank, and logistic regression were used.

Results: Of 4083 patients, 75.6% underwent oncologic resection with a median (range) number of 8 (0-99) lymph nodes examined, and 24.1% underwent enucleation. Five-year overall survival rate was 89.7% in node-negative patients versus 82.1% in node-positive patients (p < 0.001). No survival difference existed between patients who underwent enucleation versus oncologic resection (5-yr OS of 88.5% vs 88.2%, p = 0.064). According to AJCC classification, 3776 patients were clinically-staged with evidence of node-negative disease. Of these, 75.1% underwent oncologic resection, of which 9.9% had node-positive disease after resection. Tumor grade and size independently predicted nodal upstaging after oncologic resection.

Conclusion: One-tenth of patients with clinically node-negative disease were node-positive after surgery. Although this was not reflected in overall survival, patients who receive enucleation with higher grade and larger size may benefit from enhanced surveillance for locoregional recurrence.