Impact of Gallium-68-DOTA-NOC PET/CT on Management Of Neuroendocrine tumors

Methods Overall 40 patients (25 men and 15 women, age: 50±9 years) with clinical / biochemical suspicion or histologicaly proven Neuroendocrine tumors underwent ⁶⁸Ga-DOTA-NOC PET/CT. 21 patients (52.5%) came with recently diagnosed primary NET. 17 patients (42.5%) presented with NET metastases from carcinoma of unknown primary site (CUPS). 2 patients presented with raised gastrin levels.

Results Ga-68-DOTA-NOC PET/CT showed sensitivity and specificity of 85% and 92.5%, respectively, for primary tumor and 98.5% and 100% for metastases. It was better than a conventional imaging modality for the detection of both primary tumor (p < 0.001) and metastases (p < 0.0001). It changed the management strategy in 22 patients (55%). On the basis of the results, 11 patients (27.5%) underwent surgery for primary lesions for surgically resectable loco regional disease. Five patients (12.5 %) detected with advanced stage of disease on PET were spared unnecessary surgery. Six patients (15%) with poor 68Ga-DOTA-NOC uptake were spared unnecessary octreotide therapy and were started on systemic chemotherapy. In addition, the detection of the expression of somatostatin receptors led to octreotide-based treatments in 25 patients.

Conclusions 68Ga-DOTA-NOC PET/CT provides incremental diagnostic information compared to conventional imaging. It has significant impact in management of patients with neuroendocrine tumors. Extent of disease defined by Ga-68-DOTA-NOC PET/CT can alter the surgical management of these patients. The detection of a high degree of somatostatin receptor expression can be exploited to treat patients with octreotide therapy and peptide receptor radionuclide therapy and, conversely, a negative finding on 68Ga-DOTA-NOC PET/ CT can guide the treating physician to choose an alternate form of treatment. Additional benefit of 68Ga-DOTA-NOC PET/CT include patient convenience with short time acquisition and lower radiation exposure signifying the important role of 68Ga-DOTA-NOC PET CT in clinical practice of neuroendocrine malignancies.