Detection of recurrent or persistent nasopharyngeal carcinomas after radiotherapy with 18-fluoro-2-deoxyglucose positron emission tomography and comparison with computed tomography

Purpose: The effectiveness of positron emission tomography (PET) with 18-fluoro-2-deoxyglucose (FDG) for detecting suspected recurrence of nasapharyngeal carcinomas (NPC) was evaluated and compared with computed tomography (CT). Patients and Methods: FDG-PET studies were performed on 36 NPC patients 4 months after radiotherapy. The images were interpreted visually and quantitatively by calculating standardized uptake values (SUVs). Results: The sensitivity, specificity, and accuracy of visually interpreted FDG-PET images, for differentiation of recurrent or persistent NPC from benign lesions, were 100%, 96%, and 97%, respectively. Cases with recurrent or persistent NPC (1.6 to 5.8) had significantly higher SUVs than cases with benign lesions (0.8 to 1.5). The sensitivity, specificity, and accuracy of CT for detecting recurrent or persistent NPC were 72%, 88%, and 83%, respectively. Conclusion: FDG-PET is a better tool than CT for the detection of recurrent or persistent NPC. Either visual interpretation or SUV can be used to differentiate benign lesions from recurrent or persistent NPC.