The Role of Combined 68Ga-DOTANOC and 18FDG PET/CT in the Management of Patients with Pancreatic Neuroendocrine Tumors

Purpose: The aim of this study was to evaluate the effect of combined 68Ga and 18F-FDG PET/CT on treatment management for patients with pancreatic neuroendocrine tumor (PNET). Methods: Between January 2012 and April 2014, 49 consecutive patients with a cytologically and/or histologically proven diagnosis of PNET underwent combined 68Ga and 18FDG PET/CT on the same day. Results: The study group consisted of 21 males and 28 females with a median age of 59 years. Disease detection was achieved in 48 out of the 49 cases with 68Ga imaging, and in 36 of the 49 cases with 18FDG PET/CT. These results corresponded to sensitivities of 98% for 68Ga versus 73% for 18FDG PET/CT. Patients with NET-G1/NET-G2 had a positive 68Ga and negative 18FDG PET/CT in 13 cases, whereas both 68Ga and 18FDG PET/CT were positive in 27 cases. Patients with NEC-G3 were positive by both 68Ga and 18FDG PET/CT in 7 cases and positive only by 18FDG in 1 case. Another NEC-G3 patient was only positive by 68Ga PET/CT. The median Ki67 was 7% for 68Ga PET/CT-positive tumors and 10% for tumors with both 68Ga and 18FDG PET/CT positivity (p = 0.130). Half of the patients with a prevalent uptake of 18FDG (n = 7) had an NEC-G3 compared with 12% of patients with a prevalent uptake of 68Ga (p = 0.012). There were no significant differences between patients with positive 68Ga and those with positive 18FDG with regards to treatment choice. Conclusions: The association of 18FDG slightly increases sensitivity of 68Ga PET/CT alone in the diagnosis of PNET. A combined dual tracer PET/CT does not influence the choice of treatment strategy.