Can PET/CT substitute for bone scintigraphy in assessment of bone metastases in lung cancer patients?

Abstract

7203 Background: Bone is a frequent site of lung cancer metastasis. However, false positive lesions detected by conventional bone scintigraphy often become problematic. We compared the efficacy of whole-body [18F]-2-Fluoro-2-deoxy- D- glucose PET/CT imaging and conventional bone scintigraphy for assessment of bone lesions in lung cancer patients on an individual patient basis. Methods: The study population comprised 106 consecutive patients with suspected or proven lung cancer (73 men and 33 women; age range: 40 to 85 years) who underwent both whole-body PET/CT imaging and conventional bone scintigraphy using 740 MBq of Tc-99m hydroxymethylene diphosphonate for cancer staging. Diagnostic radiologists interpreted and assessed all images on a patient-by-patient basis. Clinical information and the findings of follow-up imaging studies were used as the gold standard for the identification of bone metastases. Results: On the basis of the gold standard, 11 of the 106 patients were identified as having bone metastases. Bone scintigraphy showed a sensitivity of 67% (7/11) while that of PET/CT was 100% (11/11) for detection of bone metastases. Seven of these 11 patients were deemed positive based on both bone scintigraphy and PET/CT. Bone metastases not identified on bone scintigraphy were detected on PET/CT in another four patients. For 39 of 95 patients without bone metastases, the assessment was false-positive for bone scintigraphy but negative for PET/CT. In two of the 39 patients, CT images of PET/CT could identify a benign fracture causing a false positive finding for bone scintigraphy. Conclusions: PET/CT might actually substitute for bone scintigraphy in lung cancer patients because of its superior ability to detect unsuspected bone metastases and to differentiate bone metastases from false positive lesions detected by bone scintigraphy. No significant financial relationships to disclose.