PD1-2-2: 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

Abstract

Bone scan and serum alkaline phosphatase concentration are used to detect bone metastasis in malignancy, although whole-body FDG PET/CT is being used increasingly. To compare the usefulness of whole-body FDG PET/CT, bone scan, and serum alkaline phosphatase in detecting bone metastases in patients with newly diagnosed primary lung cancer. The electronic medical record database at our institution was queried to identify all patients with a new diagnosis of lung cancer between January 2004 and December 2005, who had a PET/CT, bone scan, and check of serum alkaline phosphatase concentration before treatment. We retrospectively reviewed all patients’ medical records and radiological reports, and confirmed bone metastases by considering all available clinical information. One hundred eighty-two patients met the inclusion criteria. Bone metastases were confirmed in 30 patients. The average interval between PET/CT and bone scan was 8.5 ± 14.0 days. Forty-nine patients had stage 4 nonsmall cell lung cancer, and seven patients had extensive stage small cell lung cancer. Tabled 1Confirmation criteriaNumber of patientsProgressing bone lesion on follow-up scan (PET/CT or bone scan)2Confirmed bone metastasis by simple radiography, CT, or MRI22Positive initial findings on both bone scan and PET/CT in the same bone lesion with symptoms5Histological confirmation1Total30 Open table in a new tab The sensitivities, specificities and accuracies of PET/CT, bone scan, and serum alkaline phosphatase concentration were noted in following Table. The kappa statistics were calculated for the three modalities. The kappa value was 0.19 between PET/CT and bone scan, 0.03 between bone scan and serum ALP concentration, and 0.15 between serum ALP concentration and PET/CT. The low kappa values suggested poor agreement between the three modalities. FDG PET/CT and bone scan had similar sensitivity, but PET/CT had better specificity and accuracy than bone scan. PET/CT is more useful than bone scan for evaluating bone metastasis. However, in the advanced stage, because of its high specificity, bone scan complemented with serum alkaline phosphatase is a cost-effective modality to avoid having to use PET/CT.