Efficacy of fluoro-2-deoxy- d -glucose positron emission tomography to evaluate responses to concurrent chemoradiotherapy for head and neck squamous cell carcinoma

Abstract Objective This study evaluates the utility of fluorodeoxyglucose-positron emission tomography (FDG-PET) in patients with head and neck squamous cell carcinoma (HNSCC) who received concurrent chemoradiotherapy (CCRT). Methods Sixty-five patients were recruited for this study between November 2002 and April 2007. The FDG-PET scan was performed before treatment and 4–6 weeks after treatment. Results The mean of maximum standardized uptake value (SUVmax) before treatment at the primary tumor site was 8.1 (range, 2–22). The sensitivity of FDG-PET for the diagnosis of primary tumor site was 98%. The mean of SUVmax after treatment was 2.6 (range, 2–5). The sensitivity, specificity, and accuracy of FDG-PET for the diagnosis of primary tumor site after treatment were 100%, 40%, and 46%, respectively. The mean of SUVmax before treatment at the nodal site was 4.7 (range, 2–16). The mean of SUVmax after treatment was 2.0 (range, 2–6.7). The pre-treatment SUVmax of T2, T3, and T4 stages were significantly higher than that of the T1 stage. The N stage had no correlation in terms of the pre-treatment nodal site SUVmax. Conclusion Our results indicate that FDG-PET is a useful imaging method for evaluating the response of CCRT in patients with HNSCC. However, performing FDG-PET 4–6 weeks after treatment may be too early as it may give false-positive results due to fibrosis and scarring.