Is there a role for traditional nuclear medicine imaging in the management of pulmonary carcinoid tumours?

OBJECTIVES: The clinical utility of fluorodeoxyglucose-positron emission tomography (FDG-PET) and somatostatin receptor scintigraphy (SRS) in pulmonary carcinoids staging is unclear. This study aims to determine the role of FDG-PET and SRS in detecting hilar-mediastinal lymph node metastasis from these tumours. METHODS: We retrospectively collected the data of 380 patients who underwent lung resection for primary pulmonary carcinoid in seven centres between 2000 and 2015. Patients without nodal sampling ( n  = 78) were excluded. In 302 patients [35% men, median age 58 (interquartile range 47-68) years] the results of preoperative computed tomography (CT) scan, FDG-PET and SRS were analysed and compared to the pathological findings after resection to determine the respective utility of these two nuclear tests. RESULTS: The sensitivity, specificity and negative predictive value in detecting N1 and N2 disease were respectively 33% and 46%, 93% and 90%, 88% and 95% for computed-tomography-scan, 38% and 60%, 93% and 95%, 88% and 95% for FDG-PET, 22% and 33%, 95% and 98%, 84% and 87% for SRS. The diagnostic accuracy for N1 and N2 disease of CT scan was not significantly different from that of FDG-PET ( P  =   1.0 and P  =   0.37 for N1 and N2 disease respectively) and of SRS ( P  =   0.47 and P  =   0.35 for N1 and N2 disease respectively). The sensitivity and specificity of these imaging tests were also similar when analysed by typical vs atypical histology. CONCLUSIONS: CT scan, FDG-PET and SRS showed similar performance in terms of nodal staging for pulmonary carcinoid. These findings suggest that additional nuclear imaging beyond CT scan is not required as long as a lymphadenectomy or nodal sampling is completed at resection.