18F-DOPA PET/CT at the Forefront of Initial or Presurgical Evaluation of Small-Intestine Neuroendocrine Tumors

J Nucl Med. 2022 Dec;63(12):1865-1870. doi: 10.2967/jnumed.122.263984. Epub 2022 May 19.

Abstract

Our objective was to compare the respective value of 68Ga-DOTATOC and 18F-DOPA PET/CT for initial staging or presurgical work-up of patients with small-intestine neuroendocrine tumors (SiNETs). Methods: This was a retrospective, multicenter, noninterventional investigation involving 53 non-surgically treated SiNET patients who underwent both 68Ga-DOTATOC and 18F-DOPA PET/CT within a 6-mo interval without surgical intervention or therapeutic change between the 2 PET/CT studies. Percentage detection rate was calculated according to per-region and per-lesion analyses. Sensitivity for primary tumor detection was assessed in 37 surgically treated patients, taking surgical results (76 SiNETs) as the diagnostic gold standard. Results: 68Ga-DOTATOC PET/CT and 18F-DOPA PET/CT individually identified at least 1 primary SiNET in 92% (34/37) of the patients. Intestinal tumor multifocality was confirmed by histology in 8 patients. 68Ga-DOTATOC and 18F-DOPA PET/CT were concordantly positive for tumor multifocality in 5 patients, discordantly positive in 2 patients, and concordantly negative in 1 patient. The detection rate for subdiaphragmatic nodal metastases on per-region-based analysis was 91% and 98% for 68Ga-DOTATOC and 18F-DOPA PET/CT, respectively (P = 0.18). 18F-DOPA PET/CT detected a higher number of abnormal subdiaphragmatic nodes (P = 0.009). Regarding mesenteric nodes only, 18F-DOPA PET/CT detected more positive regions (P = 0.005) and nodal lesions (P = 0.003) than 68Ga-DOTATOC PET/CT, including nodes at the origin of mesenteric vessels. For detection of distant metastases, 68Ga-DOTATOC and 18F-DOPA PET/CT performed equally well on a per-region-based analysis. As compared with 68Ga-DOTATOC, 18F-DOPA PET/CT detected more hepatic (P < 0.001), peritoneal (P < 0.001), and lung metastases (P < 0.001). Conclusion: 18F-DOPA PET/CT detected more lesions than 68Ga-DOTATOC PET/CT in the studied patients. The respective roles of the two should be discussed in terms of disease staging and treatment selection.

Keywords: 18F-DOPA; 68Ga-DOTATOC; PET; carcinoid; neuroendocrine; small intestine; staging.

Publication types

  • Multicenter Study

MeSH terms

  • Gallium Radioisotopes
  • Humans
  • Intestinal Neoplasms*
  • Intestines / pathology
  • Neuroendocrine Tumors* / pathology
  • Octreotide
  • Organometallic Compounds*
  • Positron Emission Tomography Computed Tomography / methods
  • Retrospective Studies

Substances

  • fluorodopa F 18
  • Gallium Radioisotopes
  • Organometallic Compounds
  • Octreotide