Title: Quantitative 68Ga-DOTATOC PET/CT in Patients with Metastatic or Recurrent Neuroendocrine Tumors.
Abstract: 1649 Objectives We aimed to quantitatively evaluate the distribution of [68Ga]DOTA(0)-Phe(1)-Tyr(3)-octreotide (DOTATOC) in tumor lesions and in unaffected organs of patients with metastatic or recurrent neuroendocrine tumors (NETs) using PET/CT imaging. Methods Twenty-six patients (14 male; 63±11 years) with histopathology proven recurrent or metastatic NET, referred for restaging work-up, underwent a standard vertex to mid-thighs PET/CT, acquired approximately 50 min after the IV. administration of 185 MBq of 68Ga-DOTATOC. Radiopeptide uptake was measured using maximum standardized uptake value (SUVmax) obtained by region of interests (ROIs) drawn in lesions with a diameter of at least 1 cm in the CT images. The three lesions with highest uptake per patient were used for analysis. Physiologic 68Ga-DOTATOC uptake was also measured in organs expressing variable density of somatostatin receptors, including the pituitary gland, spleen, unaffected liver and lung. Histopathological features and proliferation indexes were used to define tumor grade. Results Of the 17 patients with G1 NET tumors, 68GaDOTATOC SUVmax was higher than in the 9 patients with G2 tumors, when the lesion with highest uptake was considered (35.5±26 vs 21±10). Similar trend was observed when calculating the average of the 3 lesions with highest uptake (28.8±17.2 vs 16±7), and when comparing control organs, such as the pituitary gland (8±4 vs 6±1.6) and the spleen (26.7±13 vs 18±17). Proliferation index k1-67 was more elevated in G2 tumors when compared to G1 tumors (6.5±4 vs 2.6±4, P Conclusions This pilot study suggests that quantitative 68Ga DOTATOC PET is useful to characterize NET lesions. This information, alongside with the assessment of somatostatin receptors in organs with no evidence of tumor, could be integrated for a more accurate imaging interpretation, and in the treatment decision algorithm.
Publication Year: 2015
Publication Date: 2015-05-01
Language: en
Type: article
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