Outcomes of non-metastatic poorly differentiated gastroenteropancreatic neuroendocrine neoplasms treated with surgery: a real-world population-based study.

Objective: To assess the outcomes of non-metastatic poorly differentiated gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) treated with radical surgery. Methods: Surveillance, Epidemiology, and End Results (SEER) database (1998–2015) was accessed, and patients with non-metastatic poorly differentiated/undifferentiated GEP-NENs were reviewed. Multivariable Cox regression analysis was used to evaluate factors affecting overall survival (OS) and cancer-specific survival (CSS). Patients treated with radical surgery were matched to those who did not undergo surgery through propensity score matching and Kaplan-Meier survival estimates were used to evaluate the impact of surgery in the post-propensity cohort. Results: A total of 1517 patients were included. Within multivariable Cox regression models and compared to no surgery, radical surgery was associated with improved OS (HR: 0.41; 95% CI: 0.34–0.50) and CSS (HR: 0.37; 95% CI: 0.29–0.47). A total of 233 patients who underwent no surgery were then matched to 233 patients who underwent radical surgery. Within the post-propensity cohort, radical surgery was associated with improved OS (P < 0.001). Conclusions: Radical surgery is associated with improved survival outcomes in patients with non-metastatic poorly differentiated GEP-NENs. Further studies are required to better identify the best timing of radical surgery within the context of multimodal management. [ABSTRACT FROM AUTHOR]