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

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). <b>Methods:</b> 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. <b>Results:</b> 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 (<i>P</i> = 0.18). ¹⁸F-DOPA PET/CT detected a higher number of abnormal subdiaphragmatic nodes (<i>P</i> = 0.009). Regarding mesenteric nodes only, ¹⁸F-DOPA PET/CT detected more positive regions (<i>P</i> = 0.005) and nodal lesions (<i>P</i> = 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 (<i>P</i> < 0.001), peritoneal (<i>P</i> < 0.001), and lung metastases (<i>P</i> < 0.001). <b>Conclusion:</b> 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.