Prognostic value of a three-scale grading system based on combining molecular imaging with 68Ga-DOTATATE and 18F-FDG PET/CT in patients with metastatic gastroenteropancreatic neuroendocrine neoplasias

Abstract

We investigated on the added prognostic value of a three-scale combined molecular imaging with 68 Ga-DOTATATE and 18 F-FDG PET/CT, (compared to Ki-67 based histological grading), in gastroenteropancreatic neuroendocrine neoplasia patients. 85 patients with histologically proven metastatic gastroenteropancreatic neuroendocrine neoplasias, who underwent combined PET/CT imaging were retrospectively evaluated. Highest Ki-67 value available at time of 18 F-FDG PET/CT was recorded. Patients were classified according to World Health Organization/European Neuroendocrine Tumor Society histological grades (G1, G2, G3) and into three distinct imaging categories (C1: all lesions are 18 F-FDG negative/ 68 Ga-DOTATATE positive, C2: patients with one or more 18 F-FDG positive lesions, all of them 68 Ga-DOTATATE positive, C3: patients with one or more 18 F-FDG positive lesions, at least one of them 68 Ga-DOTATATE negative). The primary endpoint of the study was Progression-Free Survival, assessed from the date of 18 F-FDG PET/CT to the date of radiological progression according to Response Evaluation Criteria In Solid Tumors version 1.1. Classification according to histological grade did not show significant statistical difference in median Progression-Free Survival between G1 and G2 but was significant between G2 and G3 patients. In contrast, median Progression-Free Survival was significantly higher in C1 compared to C2 and in C2 compared to C3 patients, revealing three distinctive imaging categories, each with highly distinctive prognosis. Our three-scale combined 68 Ga-DOTATATE/ 18 F-FDG PET imaging classification holds high prognostic value in patients with metastatic gastroenteropancreatic neuroendocrine neoplasias. www.oncotarget.com

Dual PET Imaging in Bronchial Neuroendocrine Neoplasms: The NETPET Score as a Prognostic Biomarker

“…To our knowledge, our findings confirm the prognostic value of the NETPET score in bronchial NENs for the first time, extending the findings from previous GEPNEN studies [20,21]. Whilst a similar analysis in bronchial NENs has recently been published and demonstrated a significant proportion of patients with discordant lesions, a different scoring system was used, and the impact of dual PET scoring on overall survival was not reported.…”

“…Given the different roles of these two scans, we proposed a system to interpret the complementary findings of the two scans -the NETPET score [19]. This score was investigated in a group of predominantly GEPNEN patients, showed prognostic significance independent of histological grade, and was subsequently validated in two other patient cohorts [20,21]. As the prognostic impact of the NETPET score had not been formally investigated in bronchial NENs, we aimed to measure this impact in a retrospective study.…”

The Combined Interpretation of 68Ga-DOTATATE PET/CT and 18F-FDG PET/CT in Metastatic Gastroenteropancreatic Neuroendocrine Tumors

“…Chromogranin A is well-established as a correlate of disease volume and is associated with survival in previous NET studies. [16][17][18] It was surprising, however, that WHO grade was not associated with OS from the date of the dual-tracer PET, and this was similar to the analyses performed by Chan et al 14 and Karfis et al 15 To investigate this further, we performed a separate survival analysis calculated from the date of histological diagnosis as opposed to the date of the dual-tracer PET, and this did confirm that WHO grade was associated with OS consistent with previous studies. 1,3 It is possible the long latency between the date of histological diagnosis and the date of dual-tracer PET may explain this discrepancy, given that NETs can demonstrate grade evolution over time.…”

Current status and future of targeted peptide receptor radionuclide positron emission tomography imaging and therapy of gastroenteropancreatic-neuroendocrine tumors

“…Patients with NETs demonstrating FDG avid disease are at a 10 fold increased risk of death[ 43 ]. Other studies have shown similar findings[ 44 , 45 ].…”