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

Abstract

Purpose 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). Patients and Methods 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 68Ga-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. Results 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 68Ga-DOTATATE PET/CT. 68Ga-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. 68Ga-DOTATATE PET/CT was positive in 9/49 (18.4%) of those with a biochemical and/or clinical suspicion of a NET. Conclusions 68Ga-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.

Bridging the Gap Between Clinical Suspicion of Neuroendocrine Tumors and Diagnosis With PET/CT When Pathology Is Unavailable

“…They conclude that 68 Ga-DOTATATE PET/CT was positive in almost 3 of 4 patients with morphological abnormalities suspicious of NET and in 1/6 of patients with biochemical and/or clinical suspicion of a NET. 6 This study confirms the outstanding performance of 68 Ga-SSA PET/CT in assessing NET patients, despite significant methodological limitations.…”

“…However, in certain indications such as gastroduodenal NETs, there are still insufficient data for supporting with strong evidence the use of 68 Ga-SSA PET/CT. This is illustrated in the recent guidelines by the use of the terms “nonconclusive” or “controversial.” 1–5 Metser et al 6 have prospectively analyzed the value of 68 Ga-DOTATATE PET/CT in a large cohort of patients from a registry suspected of having a NET. Suspicion of a NET was based on ( a ) clinical features with or without elevated biomarkers and negative imaging, or ( b ) abnormalities on morphological imaging not eligible for percutaneous biopsy due to the anatomical location.…”