The presence of somatostatin receptors in neuroendocrine tumors allows visualization with radiolabeled somatostatin analogs in vivo. The aim of this prospective study was to compare somatostatin receptor imaging using 99mTc-HYNICTOC with 68Ga-DOTATATE (DOTA-DPhe1,Tyr3-octreotate) with respect to sensitivity, specificity, and impact upon clinical decision making.Methods
Sixty-eight patients (30 men, 38 women; aged 56.4 ± 13.5 years) with disseminated, histologically proven neuroendocrine tumor were enrolled. All patients with previous 99mTc-HYNICTOC (Tektrotyd; POLATOM, Otwock, Poland) underwent 68Ga-DOTATATE PET/CT. Both examinations were compared on a per-patient and per-lesion basis.Results
The sensitivity, specificity, positive and negative predictive values, and accuracy of 68Ga-DOTATATE and 99mTc-HYNICTOC were 100% versus 82%, 85% versus 69%, 97% versus 92%, 100% versus 47%, and 97% versus 79%, respectively.Results
Concordant results were observed in 58 patients (49/68 positive on both 68Ga-DOTATATE and 99mTc-HYNICTOC and 9/68 negative in both examinations). Ten of 68 patients had 68Ga-DOTATATE–positive, 99mTc-HYNICTOC–negative studies. Two hundred eighteen lesions were detected using 99mTc-HYNICTOC, compared with 546 lesions using 68Ga-DOTATATE (P < 0.0001). 68Ga-DOTATATE detected a higher number of lesions in bone and lymph nodes, liver, intestine, and pancreas and had a higher sensitivity for subcentimeter abnormalities than 99mTc-HYNICTOC. 68Ga-DOTATATE led to management change in 23 (34%) of 68 patients.Conclusions
68Ga-DOTATATE has a higher sensitivity than 99mTc-HYNICTOC for the detection of neuroendocrine tumors. 68Ga-DOTATATE proved superior to 99mTc-HYNICTOC in detecting subcentimeter skeletal, lymph node, and liver metastases. 68Ga-DOTATATE PET/CT changed clinical decision making in one third of patients.