68Ga-DOTATATE PET/CT in the Initial Diagnosis of Patients With Clinical, Imaging, and/or Biochemical Suspicion of a Neuroendocrine Tumor

The aim of this study was to assess the yield of somatostatin receptor PET in patients with clinical, imaging, and/or biochemical suspicion of a neuroendocrine tumor (NET).This analysis includes patients referred for the initial diagnosis of an unconfirmed NET, as part of a prospective, single-arm registry study (NCT03873870) assessing the utility of 68 Ga-DOTATATE PET/CT in the management of NETs. Inclusion criteria to this cohort consisted of elevated biomarkers and/or clinical presentation suspicious for a NET, with negative conventional cross-sectional imaging, or presence of a lesion suspicious for a NET on conventional imaging, not amenable for biopsy. Patients with histological confirmation of a NET were excluded.There were 220 patients included between April 2019 and March 2022 with a mean age ± SD of 59.5 ± 16.1 years with biochemical, morphological, and/or clinical suspicion of a NET. Overall, 132/220 patients (60%) had a positive 68 Ga-DOTATATE PET/CT. 68 Ga-DOTATATE PET/CT confirmed a type 2 somatostatin receptor overexpressing tumor in 123/171 (71.9%) of patients with a radiographically suspicious abnormality. The positivity rate for pancreatic, small bowel/mesenteric, adrenal, and other sites was 78/96 (81.2%), 38/57 (66.7%), 7/7 (100%), and 1/11 (9.1%), respectively. 68 Ga-DOTATATE PET/CT was positive in 9/49 (18.4%) of those with a biochemical and/or clinical suspicion of a NET.68 Ga-DOTATATE PET/CT is positive in nearly 3 of 4 patients with morphological suspicion of a NET, with the highest yield in those with pancreatic and small bowel or mesenteric masses, and in approximately 1 of 6 patients with biochemical and/or clinical suspicion of a NET.