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.