Preoperative Contrast-Enhanced CT Versus 18F-FDG PET/CT Evaluation and the Prognostic Value of Extranodal Extension for Surgical Patients with Head and Neck Squamous Cell Carcinoma

Background. Extranodal extension (ENE) is a poor prognostic indicator for patients with head and neck squamous cell carcinoma (HNSCC), but pretreatment detection assists with proper treatment planning. This study evaluated whether the ENE of HNSCC is accurately detected by computed tomography (CT) versus fluorine 18-fluorodeoxyglucose (F-18-FDG) positron emission tomography (PET)/CT and whether it has any impact on patient prognosis. Methods. In this study, 186 HNSCC patients were pre-operatively evaluated using contrast-enhanced CT and (18)FFDG PET/CT. The histopathologic findings for the neck dissection samples served as a standard reference. McNemar's test and logistic regression using the generalized estimating equations were used to compare the diagnostic value of CT versus F-18-FDG PET/CT, and Cox proportional hazard regression was used to assess the prognostic value of ENE. Results. Among the 186 study patients, 113 (60.8 %) had a neck metastasis, 44 (23.7 %) had pathologic ENE, and 37 (19.9 %) had macroscopic ENE. Radiologic ENE (rENE) on CT was documented for 48 patients (25.8 %) and 52 neck sides (19.8 %). Using 4.9 as the cutoff value for nodal maximum standardized uptake, F-18-FDG PET/CT documented rENE for 44 patients (23.7 %) and 48 neck sides (18.3 %). Compared with 18 F-FDG PET/CT, CT detected ENE, with a specificity of 92.1 versus 74.4 % (p < 0.001) and an accuracy of 88.6 versus 75.3 % (p < 0.001). However, rENE was not a significant predictor of recurrence or survival (p > 0.05). Conclusion. The findings showed that ENE of HNSCC is more accurately detected by using CT than by using F-18-FDG PET/CT. The accurate pretreatment detection of ENE may help in the planning for HNSCC treatments.