Role of [18F]FDG PET/CT in the management of G1 gastro-entero-pancreatic neuroendocrine tumors
Ludovica Magi, Daniela Prosperi, Giuseppe Lamberti, Matteo Marasco, Valentina Ambrosini, Maria Rinzivillo, Davide Campana, Guido Gentiloni, Bruno Annibale, Alberto Signore, Francesco Panzuto
Abstract
Abstract Purpose Since the role of [ 18 F]FDG PET/CT in low-grade gastroenteropancreatic (GEP) neuroendocrine neoplasia (NET) is not well established, this study was aimed to evaluate the role of [ 18 F]FDG PET/CT in grade 1 (G1) GEP-NETs. Methods This is a retrospective study including patients with G1 GEP-NETs who underwent [ 18 F]FDG PET/CT. Results 55 patients were evaluated, including 24 (43.6%) with pancreatic NETs and 31 (56.4%) with gastrointestinal NETs. At the time of diagnosis, 28 (51%) patients had metastatic disease, and 50 (91%) patients were positive by 68-Ga sstr PET/CT. Overall, 27 patients (49%) had positive findings on [ 18 F]FDG PET/CT. Following [ 18 F]FDG PET/CT, therapeutic management was modified in 29 (52.7%) patients. Progression-free survival was longer in patients with negative [ 18 F]FDG PET/CT compared with positive [ 18 F]FDG PET/CT (median PFS was not reached and 24 months, respectively, p = 0.04). This significance was particularly evident in the pancreatic group ( p = 0.008). Conclusions Despite having low proliferative activity, approximately half of GEP-NETs G1 showed positive [ 18 F]FDG PET/CT, with a corresponding negative impact on patients’ clinical outcomes. These data are in favor of a more “open” attitude toward the potential use of [ 18 F]FDG PET/CT in the diagnostic work-up of G1 GEP-NETs, which may be used in selected cases to detect those at higher risk for an unfavorable disease course.