The role of PET-CT in diagnosing distant metastasis of nasopharyngeal carcinoma

Abstract

Objective To explore the clinical significance of PET-CT in evaluating distant metastasis and M staging of nasopharyngeal carcinoma(NPC). Methods 257 NPC patients with no prior treatment were investigated with PET-CT and conventional imaging (chest X-ray, abdominal ultrasound, and bone scan). The findings of PET-CT in diagnosing distant metastasis and M staging were compared with those of conventional imaging according to the results of biopsy and follow-up. Results PET-CT disclosed 34 of 39 patients with distant malignancy compared with 22 patients disclosed by conventional imaging. The false positive rate of PET-CT was 12.8 %. On region-based analyses, PET-CT was more effective than bone scan and chest X-ray for detecting mediastinum metastasis (x2=4.063, P =0.041) and bone metastasis (x2=5.939, P=0.015), respectively. Compared with conventional imaging, PET-CT had an impact on the M staging of 19 patients (7.4 %), of which 15 patients were truly staged and 4 patients incorrectly staged. Conclusion PET-CT is superior to MRI in evaluating distant metastasis and M staging of NPC. Key words: Nasopharyngeal neoplasms; Diagnosis; Tomography, emission-computed; Neoplasm metastasis; Neoplasm staging