Abstract
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Objectives F-18 FDG PET/CT has been proven to be useful in the initial evaluation for nodal and distant metastatic disease in nasopharyngeal carcinoma (NPC). The aim of this study was to evaluate the ability of staging F-18 FDG PET/CT to predict late recurrence of NPC.
Methods The records of 103 patients with NPC who had F-18 FDG PET/CT at our institution were reviewed. Participants without staging F-18 FDG PET/CT and at least 12 month of follow-up were excluded. Recurrence was assessed on follow-up using different imaging modalities, clinical findings and/or histology. Chi-Square, Kruskal-Wallis, Fisher's and two-tailed student-T test were used to analyze the demographics, pathology, clinical staging and different imaging features of PET/CT between the two groups.
Results A total of 38 patients (mean age ± SD: 42.1 ± 13.2) scanned from June 2003 to March 2009 fulfilled the entry criteria. 68% of the participants were men (n=26), 74% were Asian (n=28), 72% were nondrinker (n=27) and 42% were current or past smokers (n=16). The most frequent (n=31) histology was undifferentiated type, WHO 3 classification. Twenty-two patients had stage II or III NPC (58%) compared to IV-A to IV-C (42%). Patients were followed-up for an average of 55.6 months (range: 14.2 - 94.8 months). Only 9 patients had documented recurrence (24%) - group A, while the 29 others (76%) were disease-free - group B, at the time of analysis. There were no statistically significant differences for the median SUVmax (± SD) of the primary tumor (group A: 13.9 ± 6.6 vs. group B: 11.4 ± 4.9, P=0.26) or of the nodal metastases (group A: 8.6 ± 4.0 vs. group B: 12.4 ± 6.2, P=0.13). Moreover, distant metastases on staging F-18 FDG PET/CT (group A: 3 of 9 vs. group B: 3 of 29) did not predict late recurrent disease, P=0.13.
Conclusions Imaging features on staging F-18 FDG PET/CT in patients with NPC can not predict the risk of recurrent disease.