Detection of recurrent head and neck squamous cell carcinomas after radiation therapy with 2-¹⁸F-fluoro-2-deoxy-D-glucose positron emission tomography

Objectives/Hypothesis: Fluorodeoxyglucose positron emission tomography (FDG-PET) has been proposed as a sensitive method to diagnose and stage various malignancies. We assessed the efficacy of FDG-PET imaging in distinguishing tumor persistence/recurrence from posttreatment changes following radiation therapy for squamous carcinomas of the head and neck. Study Design: Retrospective analysis of FDG-PET results compared with biopsy results or outcome, or both. Methods: Twenty-eight patients who had undergone radiation therapy with or without surgery for treatment of squamous cell carcinoma were studied with FDG-PET imaging. There was clinical suspicion for recurrence in each patient, but no obvious mass or lesion to biopsy was found on physical examination or anatomic imaging. The results of FDG-PET imaging were compared with those of biopsy or clinical follow-up of at least 6 months, or both. Results: FDG-PET imaging was positive in 13 patients, and the presence of active disease was confirmed in 12. Two thirds of the 12 received further cancer treatment. There were 15 negative FDG-PET images. Thirteen of these were confirmed true-negative images, but two studies were false-negative images. The sensitivity and specificity of FDG-PET were 86% and 93%, respectively, with positive and negative predictive values of 92% and 87%, respectively. The overall accuracy was 89%. Conclusion: FDG-PET imaging is a useful modality to distinguish tumor persistence/recurrence from radiation-induced tissue changes in the neck following treatment for head and neck cancer. FDG-PET can identify patients who may benefit from further treatment, and may lead to improved outcome for individual patients.