Role of Ga-68 DOTANOC positron emission tomography/computed tomography scan in clinical management of patients with neuroendocrine tumors and its correlation with conventional imaging- experience in a tertiary care center in India

Aim of the study was to evaluate the role of ⁶⁸Gallium-DOTANOC positron emission tomography/computed tomography (⁶⁸Ga-DOTANOC PET/CT), a pan somatostatin receptor (SSTR) analog in the clinical management of patients with neuroendocrine tumors (NETs) and its correlation with conventional imaging. We retrospectively evaluated 69 patients of known/suspected NETs who underwent ⁶⁸Ga-DOTANOC PET/CT scan for tumor localization (n = 15), stage modification (primary staging, n = 26 and restaging, n = 25) and therapy monitoring (n = 3). We also compared PET scan with conventional imaging as reference standard and evaluated the impact of PET/CT in the clinical management of patients. The concordant findings on ⁶⁸Ga-DOTANOC PET/CT and conventional imaging seen in 33 and discordant in 36 patients. Among discordant group, disease was upstaged in 32 patients; down staged in 3 patients; no stage change in one patient. PET/CT localized primary tumor in 4 patients. Among patients with raised tumor markers (39/69), PET was positive in 29 and negative in 10 patients. Patients were followed for mean duration of 27 months to assess management. We found strong agreement between positive PET and raised tumor markers (Kappa value = 0.8). Sensitivity and specificity of PET/CT for primary tumor localization, stage modification, and therapy monitoring was >90% (P < 0.05). Study shows that DOTANOC, a broad spectrum SSTRs binding peptide labeled with Ga-68 in PET/CT scan is an excellent modality in the management of NETs patients. (author)