Extracapsular spread in hypopharyngeal squamous cell carcinoma: Diagnostic value of FDG PET/CT

Background: The purpose of this study was to evaluate the use of fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT for the identification of extracapsular spread (ECS) with supporting histologic correlation in hypopharyngeal cancer. Method: We retrospectively reviewed the medical records of 57 patients who underwent FDG PET/CT for hypopharyngeal cancer. Results: ECS was present in 79% dissected necks (45 of 57 patients) and in 64% dissected cervical levels (55 of 86). A significant difference in standardized uptake value maximum (SUV_max) values was found between cervical lymph nodes with and without ECS (6.10 ± 3.51 vs 1.75 ± 1.46, respectively; p <.001). The cutoff value of SUV_max for differentiating with and without ECS was 2.65 with a sensitivity of 80% and a specificity of 74%. The presence of ECS and median SUV_max were found to have a significant adverse effect on 5-year disease-specific survival. Conclusion: Median FDG PET/CT SUV_max cutoff values of 2.65 or greater are associated with a greater risk of ECS in cervical lymph node metastasis from hypopharyngeal squamous cell carcinoma (SCC).