Comparison of 4 modalities for distant metastasis staging in endemic nasopharyngeal carcinoma.

BACKGROUND Endemic nasopharyngeal carcinoma (NPC) commonly metastasizes to the lungs, liver, and bones. This study aims to assess the efficacy of 4 distant metastasis staging modalities, namely (1) conventional work-up comprising chest X-ray, liver ultrasound, and skeletal scintigraphy, (2) CT of the thorax, abdomen, and skeletal scintigraphy, (3) (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET), and (4) integrated FDG-PET/CT. METHODS Seventy-eight consecutive patients diagnosed with NPC were enrolled and followed up for a minimum of 6 months to confirm the staging at diagnosis. RESULTS Six patients (7.7%) had distant metastases at diagnosis. The sensitivities and specificities of conventional work-up, combined CT and skeletal scintigraphy, FDG-PET, and FDG-PET/CT were 33.3%, 66.7%, 83.3%, and 83.3%; and 90.3%, 91.7%, 94.4%, and 97.2%, respectively. The corresponding accuracies were 85.9%, 89.7%, 93.6%, and 96.2%. CONCLUSIONS FDG-PET/CT is the most sensitive, specific, and accurate modality for distant metastasis staging of endemic NPC.