Sequential FDG-PET/CT after neoadjuvant chemotherapy is a predictor of histopathologic response in patients with head and neck squamous cell carcinoma.

<bold>Purpose: </bold>To evaluate whether 2-deoxy-2-[(18)F]fluoro-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) more accurately predicts the histopathologic response to neoadjuvant chemotherapy (NAC) than magnetic resonance imaging (MRI) in patients with head and neck squamous cell carcinoma (HNSCC).<bold>Procedures: </bold>Sixteen patients with HNSCC underwent FDG-PET/CT and MRI scans before and after one cycle of NAC, followed by surgical resection. The 26 surgically resected specimens of the 16 patients were analyzed. Decreases in maximum standardized uptake value (SUV(max)) or in tumor maximum size (diameter(max)) were calculated, and their accuracies for the prediction of histopathologic response were evaluated.<bold>Results: </bold>In histopathologic responders (n = 7), percent decreases in SUV(max) were significantly higher (P < 0.001) than in non-responders (n = 19). Applying a cut-off point of 55.5%, the histopathologic response could be predicted with a sensitivity and specificity of 86% and 95%, respectively.<bold>Conclusion: </bold>FDG-PET/CT can predict histopathologic NAC responses with higher accuracy than MRI in HNSCC patients. [ABSTRACT FROM AUTHOR]