Clinicopathological Characteristics and Survival Outcomes of Gastrointestinal Neuroendocrine Tumors in a Large Safety...

Background/Objectives: Neuroendocrine tumors (NET) are heterogeneous, rare tumors predominantly of the gastrointestinal (GI) tract. Overall survival (OS) and prognostic factors of GI-NETs remain poorly understood. This study aimed to determine the clinicopathological characteristics and OS outcomes of GI-NETs in a demographically diverse population. Methods: All patients at a large tertiary safety-net hospital with a pathology-proven GI-NET diagnosis from 2001 through 2022 were identified. Demographic and tumor characteristics were collected from medical charts. For survival analysis, the Kaplan-Meier method and Cox regression analysis were used for group comparison. Results: A total of 222 cases were identified: 208 at six primary GI sites and 14 liver metastases only). Of these primary sites, rectum was the most frequent (27.4%). OS was the highest for appendiceal NETs (5-year OS: 95%) and lowest for stomach NETs (5-year OS 76%). Prognostic factors included age (5-year OS: 92% vs. 67% for <65 and ≥65, respectively, p < 0.0001), stage (5-year OS: 89%, 91%, 84% and 50% for stage I, II, III, IV, respectively, p = 0.01), size (5-year OS: 91%, 91% and 75% for <1 cm, 1-2 cm, >2 cm, respectively, p = 0.0025), and grade (5-year OS: 92% and 39% for well/moderately and poorly differentiated, respectively, p < 0.0001). In multivariable analysis, age (hazard ratio (HR) 3.33, p = 0.0002), high tumor stage (HR 2.24, p = 0.02), larger tumor size (HR 2.76, p = 0.0028), and poor grade (HR 6.03, p = 0.0003) were significantly associated with poor OS whereas race and educational level were not significantly associated with OS. Conclusions: In this large, single-site retrospective analysis of GI-NET, we report the anatomical distribution of GI NETs and survival among GI-NETs. Survival among various GI-NETs is generally favorable. These novel findings expand on our knowledge of GI-NET survival and prognostication.