Study objectives: The findings from conventional imaging modalities, such as chest CT, are frequently unreliable in patients with lung cancer. This study was designed to compare the relative diagnostic accuracies and utility of the two most widely used functional imaging examinations, F-18–2-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) and 99mTc depreotide scintigraphy, for the diagnosis and staging of lung cancer.
Design: Prospective, experimental investigation.
Setting: Academic medical center.
Patients: One hundred sixty-six subjects with suspected lung cancer were enrolled in the study.
Interventions: Whole-body and single-photon emission CT imaging of the chest was performed after IV administration of 99mTc depreotide. Attenuation-corrected FDG PET imaging was performed after IV administration of FDG. Image findings were compared with the biopsy results or clinical follow-up.
Measurements and results: In 157 subjects with evaluable lung lesions, the sensitivities and specificities for detecting malignant disease (95% confidence intervals) of FDG PET are 96% (90 to 98%) and 71% (54 to 85%), and of 99mTc depreotide are 94% (88 to 98%) and 51% (34 to 68%). In the 139 subjects with available complete staging data, FDG PET correctly staged 76 of 139 patients (55%), and 99mTc depreotide correctly staged 63 of 139 patients (45%).
Conclusions: The sensitivity for detection of lung cancer in the primary lesion is equally high for FDG PET and 99mTc depreotide. The specificity is superior for FDG PET. The staging accuracy of FDG PET and 99mTc depreotide is similar, but when read with the chest CT neither scintigraphic examination is sufficiently accurate to stage patients with non-small cell lung cancer.