Clarifying the Role of Observation in the Management of Poorly Differentiated Pancreatic Neuroendocrine Tumors

Abstract

Introduction: The management of pancreatic neuroendocrine tumors (PNET) varies between observation (O), pancreatic resection (PR) and enucleation (E). Currently, size, grade and location are used to determine which treatment strategy may be employed. We sought to evaluate each strategy and further clarify the role for surgery with regards to patients with poorly differentiated (PD) PNET. Method: Utilizing the National Cancer Database we identified patients with poorly differentiated PNET and stratified based upon size and management. Pearson’s Chi-square test was used to compare categorical variables. Survival analyses were performed using the Kaplan-Meier method. Multivariate analysis (MVA) was performed to identify predictors of survival. A p-value of <0.05 was considered significant. Results: We identified 3,187 patients diagnosed with poorly differentiated pancreatic neuroendocrine tumors. The median age of the cohort was 61 (18-90). Patients with tumors > 2cm demonstrated a higher incidence of node positivity compared to other cohorts p=0.01. Patients with <2cm tumors demonstrated a 5-year survival of 65% in those undergoing surgery vs 16% in those who did not, p<0.001. There was no difference in survival in those patients undergoing pancreatic enucleation vs those undergoing pancreatic resection, (median survival 102.2 months PR, vs 107.9 months PE, p=0.16). Multivariate analysis revealed age, tumor location, size, surgery, and clinical stage were predictors of survival. Conclusions: Poorly differentiated pancreatic neuroendocrine tumors exhibit high incidence of node positivity. Surgery improves survival in all patients with poorly differentiated PNET. Thus, observation has no role in the management of PD PNET.