Early assessment of clinical response to concurrent chemoradiotherapy in head and neck carcinoma using fluoro-2-deoxy-d-glucose positron emission tomography

Objectives The aim of this study is to assess the utility of FDG-PET in the evaluation of therapeutic effects at 4 weeks after the completion of the concurrent chemoradiotherapy (CCR) in patients with head and neck squamous cell carcinoma (HNSCC). Methods Thirty-one patients with previously untreated HNSCC were retrospectively investigated about FDG-PET, CT, MRI and biopsies of the carcinoma before and 4 weeks after the treatment. Results The results of pathological examinations after CCR showed 6 residual cases and 25 ones with a pathologically complete response (pCR). The specificity of FDG-PET was 80%, although the sensitivity was limited to 67%. Conclusions FDG-PET has a high specificity but limited sensitivity to discriminate residual cancer from fibrosis or scar at 4 weeks after CCR. FDG-PET at 4 weeks after CCR was too early to perform because of limited sensitivity.