18F-fluorodeoxyglucose-positron emission tomography and bone scintigraphy for detecting bone metastases in patients with malignancies of the upper aerodigestive tract.

The role of 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) in identifying bone metastases in patients with head and neck cancer is not clear. We compared the ability of FDG-PET and bone scintigraphy (BS) to detect bone metastases in patients with upper aerodigestive tract (UADT) malignancies. Patients with histologically confirmed malignancies in the UADT underwent both FDG-PET and BS at initial staging or follow-up. The two methods were compared in patients and in seven skeletal regions. Maximum standard uptake value (SUVmax) on PET was calculated in each lesion and compared between true- and false-positive lesions. This study included 564 eligible patients, of whom 17 had bone metastases. The spine was the most frequently involved site, followed by the lungs and liver. Both FDG-PET and BS had high specificity, accuracy, and negative predictive values for detecting bone metastases (>95% each), and the two methods did not differ in sensitivity, specificity, and predictive values (P>0.05). Both FDG-PET (n=15) and BS (n=14) yielded a significant number of false-positive results, which could be corrected by further work-ups and follow-up imaging. Compared with true-positive lesions, the false-positive lesions on FDG-PET were usually single (86.7% vs. 12.5%, P<0.001) and had lower mean SUVmax (2.4 vs. 5.6, P<0.001). FDG-PET is not more accurate than BS for detecting bone metastasis in patients with UADT cancer. Positive findings on FDG-PET or BS require further confirmation.