18F‐FDG PET/CT and MRI in the follow‐up of head and neck squamous cell carcinoma

We evaluated the diagnostic performance of ¹⁸F‐FDG PET/CT and MRI for the assessment of head and neck squamous cell carcinoma (HNSCC) relapse. Since early treatment might prevent inoperable relapse, we also evaluated THE performance of early unenhanced ¹⁸F‐FDG PET/CT in residual tumor detection. The study was prospectively performed on 32 patients who underwent ¹⁸F‐FDG PET/CT and MRI before treatment and at 4 and 12 months after treatment. ¹⁸F‐FDG PET/CT was also performed 2 weeks after the end of radiotherapy. Histopathology or a minimum of 18 months follow‐up were used as gold standard. Before treatment ¹⁸F‐FDG PET/CT and MRI detected all primary tumors except for two limited vocal fold lesions (sensitivity 94%). MRI was more sensitive than ¹⁸F‐FDG PET/CT for the detection of local extension sites (sensitivity 75 vs 58%), but at the cost of a higher rate of false positive results (positive predictive value 74 vs 86%). For relapse detection at 4 months, sensitivity was significantly higher for ¹⁸F‐FDG PET/CT (92%) than for MRI (70%), but the diagnostic performances were not significantly different at 12 months. For the detection of residual malignant tissue 2 weeks post‐radiotherapy, sensitivity and specificity of ¹⁸F‐FDG PET/CT were respectively 86 and 85% (SUV cut‐off value 5.8). ¹⁸F‐FDG PET/CT is effective in the differentiation between residual tumor and radiation‐induced changes, as early as 2 weeks after treatment of a primary HNSCC. For follow‐up, performance of ¹⁸F‐FDG PET/CT and MRI are similar except for a higher sensitivity of ¹⁸F‐FDG PET/CT at 4 months. Copyright © 2011 John Wiley & Sons, Ltd.