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Objective To explore the reasonable radiologic nodal size criterion of retropharyngeal lymph node (RLN) metastasis in patients with nasopharyngeal cancer (NPC).Methods Imaging and clinical data of 817 NPC patients were analyzed retrospectively.The patients with RLN metastasis were classified into two groups according to the nodal size of 5 mm or 6 mm as standard in diagnosis.Overall survival (OS),distant metastasis-free survival (DMFS) and the local-relapse-free survival (LRFS) were assessed between the two groups taking 5 mm or 6 mm as standard in diagnosis of RLN.Results No significant difference was found for OS,DMFS,LRFS between nodal size ＜5 mm group and ≥5 mm group.Difference of OS (P＜0.001),DMFS (P=0.001) were significant statistical and difference of LRFS (P=0.380) had no significant statistical between nodal size ＜6 mm group and ≥6 mm group.OS,DMFS,LRFS were not an independent prognostic factor for NPC.Conclusion Using the minimal axial diameter of 6 mm as the nodal size criterion in diagosis of RLN metastasis in patients with NPC may be more reasonable.
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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.