Background: Positron emission tomography (PET) combined with computer tomography (CT) using (68)Ga-DOTATATE is a promising method for the evaluation of patients with recognised or suspected neuroendocrine tumours (NET). The aim of this study was to assess the diagnostic value of (68)Ga-DOTATATE PET/CT in the visualisation of the expression of somatostatin receptors (SSTR) and identification of new lesions.
Material and methods: Between December 2009 and January 2011 ninety-seven patients with confirmed (88 cases) or suspected (9 cases) NET underwent (68)Ga DOTATATE PET/CT. The primary, confirmed or suspected, NET localizations were: GEP tumours--71 patients; medullary thyroid carcinoma--4 patients; cancer of an unknown primary--14 patients; and NET in other localisations--8 patients. PET/CT acquisitions were performed using standard techniques, 45 to 60 minutes after the intravenous injection of 111-185 MBq (68)Ga-DOTATATE.
Results: (68)Ga-DOTATATE PET/CT detected the presence of lesions demonstrating the somatostatin receptor affinity in 50 of the 97 patients (51.5%) and was negative in 47 patients (48.5%). Among 14 patients with metastatic unknown primary cancer, in 5 patients (45.5%) the primary tumour site was identified, and in 4 patients with medullary thyroid cancer distant metastases with SSTR expression were localized in only one patient.
Conclusions: Our findings confirm the diagnostic role of (68)Ga-DOTATATE PET/CT as an accurate method of identifying primary tumours and distant metastases. It provides information on tumour cell receptors status, which has a significant bearing on planning target radionuclide therapy. Overall, (68)Ga-DOTATATE PET/CT can be used in staging, re-staging, and in regular follow up of oncology patients.