Abstract
1504
Objectives Neuroendocrine tumours (NET) represent a widely heterogeneous group of tumours, with the majority arising from the gastrointestinal tract or lung. This study is aimed at evaluating the clinical utility of 18F-FDOPA PET/CT in suspected or proven NET arising from these sites.
Methods 70 patients with suspected or proven gastroenteropancreatic or thoracic NET were assessed with 18F-FDOPA PET/CT. Patients who had more than one 18F-FDOPA PET/CT scan only had the initial study analysed. The findings at 18F-FDOPA PET/CT were compared to a composite reference standard including conventional anatomical and functional imaging findings, histological results and clinical follow up. The clinical impact of 18F-FDOPA PET/CT findings in patient management was assessed.
Results The overall sensitivity, specificity and diagnostic accuracy of 18F-FDOPA PET/CT in detection of disease was 88%, 100% and 91% respectively. 18F-FDOPA PET/CT correctly identified disease in 43 of 70 patients and was correctly negative in 21 of 70 patients. False negative 18F-FDOPA PET/CT was seen in 6 patients who had a NET arising from the foregut; 2 patients had FDOPA negative metastases and 4 patients had a FDOPA negative primary. There were no false positives. There were 6 patients who had negative findings on conventional anatomical or functional imaging but 18F-FDOPA PET/CT was pursued based on high clinical suspicion of disease. All 6 patients demonstrated FDOPA positive disease. In patients where a primary site was not previously known, 18F-FDOPA PET/CT identified an occult primary in 7 of 14 patients (50%). In 24 of the 70 patients (34%), the 18F-FDOPA PET/CT findings resulted in a relevant change in clinical management.
Conclusions 18F-FDOPA PET/CT is a valuable imaging tool with high sensitivity, specificity and diagnostic accuracy for assessment of gastroenteropancreatic and thoracic NET. It also has high clinical impact and results in a relevant change in management in over a third of patients.