68GA-DOTA-NOC PET for the evaluation of pulmonary neuroendocrine tumors: preliminary experience

Objective: 18F-FDG PET is of limited value for the assessment of lung neuroendocrine tumours (NET). Sixty-eight Ga-DOTA-NOC, has been reported to be useful for the assessment of gastro-entero-pancreatic NET expressing somatostatin receptors (SSR). To our knowledge, 68Ga-DOTA-NOC has never been studied in patients with lung NET. Aim of the study was to evaluate the role of 68Ga-DOTA-NOC PET for the evaluation of lung NET. Methods: Eleven patients (mean age: 62 years [44–80], M:F=6:5) with pathology proven lung NET were scheduled for 68Ga-DOTA-NOC PET. Indications to perform PET included staging (2), evaluation of equivocal conventional imaging findings (2) and follow-up after surgical excision of the primary tumour (7). PET results were compared with CT and with follow-up data. Results: PET showed at least one positive lesion in 7/11 cases and was negative in 4. Considering all lesions, the mean SUV max was 29.1 [range: 4.4–60.5]. 68Ga-DOTA-NOC PET was concordant with CT in 3/11. Of the remaining eight cases, PET identified a higher number of pathologic areas in 3/8 and excluded the malignant nature of suspicious CT findings in 4/11. In one case a suspicious liver lesion documented by CT and undetected on the PET scan was subsequently excised and immunohistochemistry showed the lack of SSR on tumour cells. Overall, PET provided additional information in 8/11 cases, changing the clinical management in 4/8 and contributing to better evaluate the extent of the disease in 4. Conclusions: Preliminary data show that 68Ga-DOTA-NOC is useful for evaluation of lung NET contributing to more accurate evaluation of disease.