Dual 68Ga -DOTANOC and 18F -FDG PET/CT in metastatic gastrointestinal neuroendocrine neoplasms with or without surgical resection of the primary site

Abstract

Abstract Purpose Gastrointestinal neuroendocrine neoplasms (GI-NEN) exhibit heterogeneity in biological behavior, making it difficult to predict prognosis. We established the P Grade based on 68Ga-DOTANOC and 18F-FDG PET dual scans and evaluated the prognostic significance in patients with metastatic GI-NEN who underwent either surgical resection of the primary tumor or medical treatment. Methods The P Grade was categorized based on SSTRI/FDG uptake into P1 (DOTANOC positive/FDG negative), P2 (DOTANOC positive/FDG positive), and P3 (DOTANOC negative/FDG positive). Patients were divided into medical treatment and surgical group. The correlation of P Grade with progression-free survival (PFS) and overall survival (OS) was evaluated using Kaplan-Meier analysis, and performed univariate and multivariate analyzes of relevant clinicopathological variables with PFS and OS. Results 243 patients with metastatic GI-NEN were enrolled. P Grade exhibited significant correlation with OS and PFS in overall cohort on univariate and multivariate analysis (p < 0.01). In surgery group, P Grade demonstrated independent predictive value for OS and PFS (p < 0.01). In medical treatment group, P Grade demonstrated predictive value for PFS (all p < 0.01) and predicted OS (univariate P3vsP1, p < 0.01). Additional predictors of OS and PFS included WHO grade, age at diagnosis, location of primary site, sex and extrahepatic disease, they all had correlation with OS or PFS except sex factors. Conclusion Our study demonstrates that P Grade obtained by combining 68Ga-DOTANOC and 18F-FDG PET is a significant prognostic indicator for patients with metastatic GI-NEN, regardless of whether received medical treatment or surgical resection of the primary site. Prospective research is needed for further verification.