CLINICAL CHARACTERISTICS AND SURVIVAL IN PATIENTS WITH HIGHGRADE GASTROENTEROPANCREATIC NEUROENDOCRINE NEOPLASMS

Introduction: High-grade gastroenteropancreatic neuroendocrine neoplasms(GEPNENs) are defined as neoplasms having a high proliferative index with a Ki-67> 20%. They are a highly heterogeneous group, containing tumors that are both well and poorly differentiated. Data on GEP-NENs are limited. We retrospectively studied clinical data GEP-NENs patients. Objective: To characterize patients attended at Federal University Hospital (UNIFESP) between 2000 and 2019. Methods: We retrospectively studied patients with GEP NENs, and divided them into WD-NETs (Ki67≤55%) and PD-NECs (Ki67>55%) according to histological reports. The relationship between baseline characteristics and overall survival(OS) was analysed using the Kaplan Meier logrank test. RESULTS 23 patients were analyzed (14 PD-NEC, 9 WD-NET) with a median follow- up of 18 months. Tumor origin included pancreas (34%) and gastric (26%). The primary tumor was resected in 10 patients. Metastatic disease was evident at diagnosis in 60% (liver metastases: 64%). Median Ki-67 index was 80% (35% in WD-NET and 80% in PD-NECs). Chemotherapy was administered in 12 patients. Platinum-etoposide was the first choice in most of patients(58%). There was a trend in improved survival in the WDNET cohort compared to PD-NECs. Of the entire cohort, an independent effect of Ki67 was demonstrated on risk of mortality (the hazard ratio for death: 8,3; 95% CI, 2-46.3; p:0.004). Ki67>55% was associated with poorer OS compared to lower Ki67 index (median OS 2.4 mo vs 21.2 mo; p < 0.001). Second- line therapy (mainly Platinum- irinotecan) were given in 5 of WD-NET and 1 of PD-NECs patients. Median PFS and OS were 2.5 and 2.7 months respectively after second-line. Conclusions: GEP- NEN patients have a poor prognosis. Ki67>55% was the most negative prognostic factor for survival. Additional clinical and molecular tumor data are needed to individualize future treatment of these patient