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.
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.
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.
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.