The Role of ⁶⁸Ga-DOTATATE PET/CT in Suspected Neuroendocrine Tumors

Abstract

In patients with suspected but yet not localized neuroendocrine tumors (NETs), early diagnosis or reliable exclusion is crucial for optimal individual prognosis and therapy. Despite recourse to several imaging modalities, the definite diagnosis of NET can be challenging. Therefore, we tested 68 Ga-DOTATATE PET/CT as a tool for improved diagnosis in a cohort of patients with suspected, nonlocalized NET. Methods: 68 Ga-DOTATATE PET/CT recordings were obtained in 104 consecutive patients meeting at least one of the following criteria: clinical suspicion of NET (n 5 70), elevated blood levels of tumor markers (n 5 49), and image-based suspicion of NET (n 5 53). The presence of NET was validated by histopathology (n 5 49) or clinical follow-up of 107 6 59 wk (n 5 55). Results: In 36 of 104 patients (35%), NET was histologically verified, most frequently located in the small bowel (10/36), pancreas (8/36), lung (5/36), and stomach (2/36). Twelve patients had tumors of nonneuroendocrine origin, and 7 patients had benign tumors. 68 Ga-DOTATATE PET/CT identified NET in 29 of the 36 cases and excluded the presence of a NET in 61 of the 68 non-NET patients, indicating a sensitivity of 81% and specificity of 90%. The PET/CT gave a false-positive result in 7 patients and a false-negative in another 7 patients, indicating positive and negative predictive values of 81% and 90%, respectively, and an accuracy of 87%. Chromogranin A levels were significantly higher in both PET-positive patients (1,841 vs. 342 ng/mL; P , 0.05) and patients with verified NET (2,214 vs. 524 ng/mL; P , 0.05). Conclusion: In patients with suspected NETs due to clinical symptoms, elevated levels of tumor markers, or indeterminate tumors suggestive of NET, 68 Ga-DOTATATE PET/CT is highly accurate, thus supporting its use in clinical routine diagnostics.

Comparison of the Impact of 68Ga-DOTATATE and 18F-FDG PET/CT on Clinical Management in Patients with Neuroendocrine Tumors

“…Detection of a higher number of lesions is nevertheless not always followed by a change in disease stage and, most importantly, does not always affect the therapeutic approach. Although several studies have demonstrated the clinical impact of 68 Ga-DOTA peptides, few have compared the clinical impact of both PET tracers in NET patients (24)(25)(26)(27).…”

64Cu-DOTATATE PET for Neuroendocrine Tumors: A Prospective Head-to-Head Comparison with 111In-DTPA-Octreotide in 112 Patients

“…However, because of the better sensitivity, spatial resolution, and inherently quantitative nature of PET, somatostatin receptor imaging (SRI) with PET is increasingly used. Most common is the use of the 68 Ga-labeled somatostatin analogs, for example, 68 Ga-DOTATATE (6)(7)(8)(9), 68 Ga-DOTATOC (10)(11)(12), and 68 Ga-DOTANOC (13). However, the high positron energy of 68 Ga limits spatial resolution and the short half-life of 68 min may be challenging logistically, because production has to be aligned with patients and to be repeated several times a day.…”

GEP-NETs update: Functional localisation and scintigraphy in neuroendocrine tumours of the gastrointestinal tract and pancreas (GEP-NETs)

“…68 Ga-DOTATATE has a high affinity for sst 2(a) , 68 Ga-DOTATOC has a high affinity for sst 2(a) and sst 5 and 68 Ga-DOTANOC is sst 2(a) , sst 3 and sst 5 specific (13,31,32,33,34). Somatostatin receptor PET/CT using 68 Ga-DO-TANOC, 68 Ga-DOTATATE or 68 Ga-DOTATOC is superior to SRS SPECT-CT showing higher sensitivities for GEP-NET lesion detection (more than 90%), particularly due to a better special resolution or better sst affinities (13,31,32,33,34). These compounds are also more 'patient friendly', as they allow for imaging 1-3 h within i.v.…”

“…Three different 68 Ga-DOTA-labelled SSAs are used in clinical practice: DOTANOC, DOTATATE and DOTATOC (13,31,32,33,34). These compounds differ with regard to their individual affinity for the different ssts.…”

“…These compounds are also more 'patient friendly', as they allow for imaging 1-3 h within i.v. injection (13,31,32,33,34). New 68 Ga-DOTA-labelled SSAs for PET imaging include 68 Ga-DOTAVAP and 68 Ga-DOTALAN (27).…”