Evaluating surgical treatment options for small nonfunctional pancreatic neuroendocrine tumors in the NCDB.

Abstract

645 Background: The role of surgery for small (≤2 cm), nonfunctional pancreatic neuroendocrine tumors (NF-PNETs) remains controversial due to the wide range of tumor aggressiveness. Consensus guidelines of the US, Europe, and Japan offer different recommendations for treatment of small NF-PNETs. The objective of this study is to evaluate the survival benefit of surgical resection for small NF-PNETs. Methods: Patients with NF-PNETs were identified in the National Cancer Database from 2004 to 2018. Small NF-PNETs were divided into two groups: group 1a (tumor ≤1 cm) and group 1b (tumor 1.1 – 2.0 cm). Cox regression models were used to compare the overall survival between resected and unresected small NF-PNETs patients. Interactions between preoperative factors and surgery were estimated using subgroup analyses. Results: We identified 1,278 patients in group 1a and 3,363 patients in group 1b. After adjusting for preoperative factors, surgery was associated with longer survival for patients in group 1b (HR, 0.58; 95% CI, 0.42–0.80; P <0.001), but not for patients in group 1a (HR, 0.68; 95% CI, 0.41–1.11; P = 0.122). Interaction analysis found that age younger than 65 years, fewer comorbidities, treatment at academic institutions, distal pancreatic tumors, and clinical lymph node metastasis were factors associated with longer survival in group 1b by surgery. Conclusions: Findings from this large study support surgical resection for some patients with NF-PNETs (1.1 – 2.0 cm). This, of course, must be taken in context with the patient’s clinical situation. Based on data available for analysis in this study, resection for subcentimeter NF-PNETs does not appear to be of general benefit, but should also be investigated in the context of Ki-67 index.[Table: see text]