The role of whole-body FDG PET/CT, Tc 99m MDP bone scintigraphy, and serum alkaline phosphatase in detecting bone metastasis in patients with newly diagnosed lung cancer

Bone scan (BS) and serum alkaline phosphatase (ALP) concentration are used to detect bone metastasis in malignancy, although whole-body fluoro-D-glucose positron emission tomography computed tomography (FDG PET/CT) is being used increasingly. But BS is still used for the detection of metastatic bone lesion. So we compared the usefulness of PET/CT, BS, and serum ALP in detecting bone metastases in patients with newly diagnosed lung cancer. The medical record database was queried to identify all patients with a new diagnosis of lung cancer between January 2004 and December 2005, who had a PET/CT, BS, and serum ALP before treatment. We retrospectively reviewed all patients' records and radiological reports. One hundred eighty-two patients met the inclusion criteria. Bone metastases were confirmed in 30 patients. The sensitivity values were 93.3% for PET/CT, 93.3% for BS, 26.7% for serum ALP concentration, and 26.7% for BS complemented with serum ALP concentration. The respective specificity values were 94.1%, 44.1%, 94.1%, and 97.3%. The kappa statistic suggested a poor agreement among the three modalities. FDG PET/CT and BS had similar sensitivity, but PET/CT had better specificity and accuracy than BS. PET/CT is more useful than BS for evaluating bone metastasis. However, in the advanced stage, because of its high specificity, BS complemented with serum ALP is a cost-effective modality to avoid having to use PET/CT.