Pancreatic neuroendocrine tumors: A population-based analysis of epidemiology and outcomes.

Abstract

401 Background: Pancreatic neuroendocrine tumors (PNETs) are rare neoplasms comprising less than 2% of pancreatic tumors. Outcomes of PNETs vary by stage, grade, and clinical presentation. New therapies may have improved outcomes. We present an analysis of the epidemiology and prognosis of patients (pts) with PNETs evaluating a more recent period than previously reported. Methods: Using data from the SEER registry, we identified adults with PNETs between 2000 and 2013. Cases were identified using a combination of ICD-O-3 site and histology codes. The JMP and SEER*STAT 8.3.2 were used for statistical analysis. Overall survival (OS) was analyzed using the Kaplan–Meier method. The prognostic effect of variables was studied using multivariate Cox proportional hazards models. Results: We identified 5993 pts with PNETs. Over the study duration, there was an increase in the annual incidence from 0.3 to 1.2 per 100.000. This was largely explained by the increase in number of pts with localized disease. The OS for the entire cohort was 54 months (95%; CI 50-58) and 5-year OS rates in localized, locally advanced and metastatic disease were 81.7%, 62% and 26% respectively. New therapies were increasingly implemented after 2008 such as sunitinib, everolimus and capecitabine/temozolomide. OS was better for pts diagnosed after 2008 (HR 0.73; 95% CI, 0.69-0.79; P < 0.0001) and this remained significant after excluding pts with localized disease (HR 0.85; 95% CI, 0.78-0.92; P = 0.0002). Factors found to favorably affect OS included younger age, female sex, early stage, low grade, and surgery. In metastatic disease, pts who had surgery had better OS and this was significant after adjusting for possible confounders (HR 0.36; 95% CI, 0.3-0.45). Conclusions: In this large population-based study, we saw an increase in the annual incidence of PNETs mainly due to an increased number of pts with localized disease. The OS has improved over the study duration likely due to both stage migration and new therapies used in advanced disease. Younger age, female gender, low histologic grade, early stage and surgery were found to be factors that favorably affected survival. Surgery was found to be a predictor of better outcomes in metastatic disease.