Dual [68Ga]DOTATATE and [18F]FDG PET/CT in patients with metastatic gastroenteropancreatic neuroendocrine neoplasms: a multicentre validation of the NETPET score

Abstract

Background Gastroenteropancreatic neuroendocrine neoplasms (GEPNENs) are heterogeneous in clinical course, biology, and outcomes. The NETPET score predicts survival by scoring uptake on dual [68Ga]DOTATATE and [18F]FDG PET/CT scans. We aimed to validate previous single-centre findings in a multicentre, international study. Methods Dual scans were assigned a NETPET score of P1 (DOTATATE positive/FDG negative), P2–4 (DOTATATE positive/FDG positive), or P5 (DOTATATE negative/FDG positive). NETPET score, histological grade, age at diagnosis, and presence/absence of extrahepatic disease were compared to overall survival/time to progression on univariate and multivariate analysis. Results 319 metastatic/unresectable GEPNEN patients were included. The NETPET score was significantly associated with overall survival and time to progression on univariate and multivariate analysis (all p < 0.01). Median overall survival/time to progression was 101.8/25.5 months for P1, 46.5/16.7 months for P2–4, and 11.5/6.6 months for P5. Histological grade correlated with overall survival and time to progression on univariate and multivariate analysis (all p < 0.01), while presence/absence of extrahepatic disease did not. Age at diagnosis correlated with overall survival on univariate and multivariate analysis (p < 0.01). The NETPET score also correlated with histological grade (p < 0.001). Conclusion This study validates the NETPET score as a prognostic biomarker in metastatic GEPNENs, capturing the complexity of dual PET imaging.

PET Criteria by Cancer Type from Imaging Interpretation to Treatment Response Assessment: Beyond FDG PET Score

“…Furthermore, the score correlated with WHO 2010 histological grade ( p < 0.00001) [ 18 ]. Some years later, the same group of authors validated the grading system in a bigger cohort of 319 metastatic/unresectable gastroenteropancreatic (GEP) NET patients, confirming its prognostic value in terms of OS and time-to-progression as well as with the histological grade [ 43 ]. The impact of NETPET was subsequently evaluated by other studies, and its potential use as a prognostic marker was confirmed [ 44 , 45 ] even in patients with bronchial neuroendocrine neoplasms (NENs) [ 46 ].…”

Use and perceived utility of [18F]FDG PET/CT in neuroendocrine neoplasms: A consensus report from the European Neuroendocrine Tumor Society (ENETS) Advisory Board Meeting 2022

“…Patients were categorised into three cohorts by the so‐called ‘NETPET’ score (P1, P2–4, and P5), representing SST‐positive/FDG‐negative disease, SST‐positive/FDG‐positive disease, and SST‐negative/FDG‐positive disease, respectively). The authors reported that FDG‐positivity (P2‐5) was present in 73% of all cases, while SST‐expression was lacking (P5) in 12% overall but in none, 10% and 41% of G1, G2, and G3 NEN, respectively 11 . These data should, however, be interpreted with caution.…”

“…Besides cost and availability, major arguments against the use of FDG PET/CT in NEN patients are that it may be negative in lower‐grade tumours and that it may not impact management (in patients already studied with SST PET/CT and diagnostic CT/liver MRI). A recently published study included 319 metastatic/unresectable GEP (G1, G2, G3) NEN patients, studied with both SST and FDG PET/CT 11 . Patients were categorised into three cohorts by the so‐called ‘NETPET’ score (P1, P2–4, and P5), representing SST‐positive/FDG‐negative disease, SST‐positive/FDG‐positive disease, and SST‐negative/FDG‐positive disease, respectively).…”

Diagnostic work-up and advancement in the diagnosis of gastroenteropancreatic neuroendocrine neoplasms

“…The NETPET score, a 5-point scoring system for dual PET reporting in subjects with metastatic NENs, summarises the information provided by the two modalities into a single parameter. The NETPET score correlated with histological grade ( p < 0.001), and importantly it was significantly associated with overall survival and time to progression on univariate and multivariate analysis ( p < 0.01) ( 165 ).…”