Preliminary experience on the use of 68Ga-DOTA-NOC PET to study patients with paraganglioma

Objectives to evaluate the role of ⁶⁸Ga-DOTA-NOC PET in patients with paraganglioma.

Methods Eleven patients (mean age: 46ys [26-80], M:F= 7:4) with pathology proven paraganglioma were scheduled for ⁶⁸Ga-DOTA-NOC PET. Indications to perform PET included staging (2), re-staging (8), evaluation before (RIT) radio-immunotherapy (1). PET results were compared with CI (conventional imaging included CT in 5 cases, MRI in 6 cases), and with follow up data.

Results Concordance of PET and CI findings was observed in 6/11 cases. In two patients studied for staging, in three cases studied for re-staging after non-radical surgery, and in one case evaluated before RIT, PET confirmed conventional imaging findings regarding disease extent. PET with 68Ga-DOTA-NOC strongly influenced the clinical management of the two cases with clinical suspicion of relapse (carcinoid syndrome, increased cromogranin). PET confirmed the presence of relapse in one patient with negative CI (that was therefore referred to surgery) and excluded the presence of any malignancy at sites (liver, para-aortic) considered suspicious on CI in one case (that was not further treated). PET also excluded the presence of disease in one case with an unclear CT finding, that was not further treated. In 1/11 case, although PET identified a nodal involvement that was undetected by CI, PET findings did not change the patient management.

Conclusions Our preliminary data show that ⁶⁸Ga-DOTA-NOC PET may provide valuable information on active disease extent and somatostatin receptor expression in paraganglioma patients.