Combined FDG PET/CT Imaging in Response Evaluation After Radiochemotherapy in Patients With Locally Advanced Head and Neck Squamous Cell Carcinoma (HNSCC)

To determine if combined \[18F\]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) is performant enough with respect to detecting residual lymph node involvement after chemoradiation in order to omit planned neck dissections in patients with locally advanced potentially operable, N2 and N3 head and neck squamous cell carcinoma (HNSCC). Primary study hypothesis: The lower bound of the 95% confidence interval (CI) of the negative predictive value (NPV) of FDG PET/CT to detect residual malignant lymph node involvement at 12 weeks after completing chemoradiation will exceed 85%.