The role of combined Ga-DOTANOC and (18)FDG PET/CT in the management of patients with pancreatic neuroendocrine tumors.

PURPOSE The aim of this study was to evaluate the effect of combined (68)Ga and (18)F-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 (68)Ga and (18)FDG 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 (68)Ga imaging, and in 36 of the 49 cases with (18)FDG PET/CT. These results corresponded to sensitivities of 98% for (68)Ga versus 73% for (18)FDG PET/CT. Patients with NET-G1/NET-G2 had a positive (68)Ga and negative (18)FDG PET/CT in 13 cases, whereas both (68)Ga and (18)FDG PET/CT were positive in 27 cases. Patients with NEC-G3 were positive by both (68)Ga and (18)FDG PET/CT in 7 cases and positive only by (18)FDG in 1 case. Another NEC-G3 patient was only positive by (68)Ga PET/CT. The median Ki67 was 7% for (68)Ga PET/CT-positive tumors and 10% for tumors with both (68)Ga and (18)FDG PET/CT positivity (p = 0.130). Half of the patients with a prevalent uptake of (18)FDG (n = 7) had an NEC-G3 compared with 12% of patients with a prevalent uptake of (68)Ga (p = 0.012). There were no significant differences between patients with positive (68)Ga and those with positive (18)FDG with regards to treatment choice. CONCLUSIONS The association of (18)FDG slightly increases sensitivity of (68)Ga PET/CT alone in the diagnosis of PNET. A combined dual tracer PET/CT does not influence the choice of treatment strategy.