FDG-PET/CT in the Assessment of Treatment Response after Oncologic Treatment of Head and Neck Squamous Cell Carcinoma

BACKGROUND In many centers, (18)F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) is used to monitor treatment response after definitive (chemo)radiotherapy [(C)RT] for head and neck squamous cell carcinoma (HNSCC), but its usefulness remains somewhat controversial. We aimed at assessing the accuracy of FDG-PET/CT in detecting residual disease after (C)RT. METHOD All HNSCC patients with FDG-PET/CT performed to assess treatment response 10-18 weeks after definitive (C)RT at our institution during 2008-2010 were included. The patient charts were reviewed for FDG-PET/CT findings, histopathologic findings, and follow-up data. The median follow-up time for FDG-PET/CT negative patients was 26 months. RESULTS Eighty-eight eligible patients were identified. The stage distribution was as follows: I, n = 1; II, n = 15; III, n = 17; IV, n = 55. The negative predictive value, positive predictive value, specificity, sensitivity, and accuracy of FDG-PET/CT in detecting residual disease were 87%, 81%, 94%, 65%, and 85%, respectively. The corresponding specific figures for the primary tumor site were 91%, 71%, 94%, 59%, and 86% and for the neck 93%, 100%, 100%, 75%, and 94%, respectively. CONCLUSIONS In patients who have received definitive (C)RT for HNSCC, post-treatment FDG-PET/CT has good potential to guide clinical decision-making. Patients with negative scan can safely be followed up clinically only, while positive scan necessitates tissue biopsies or a neck dissection to rule out residual disease.