Is there a correlation between ¹⁸F-FDG-PET standardized uptake value, T-classification, histological grading and the anatomic subsites in newly diagnosed squamous cell carcinoma of the head and neck?

¹⁸F-Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET)/CT imaging of squamous cell carcinoma of the head and neck (HNSCC) renders the possibility to study metabolic tumor activity by measuring FDG-uptake expressed as maximum standardized uptake value (SUV_max). A correlation between SUV_max and several factors including T-classification, histological tumor differentiation or different anatomic subsites is of potential interest in HNSCC. The aim of this study was to evaluate how metabolic tumor activity derived from FDG-PET correlates with prognostic clinical and pathological parameters including these factors. 262 patients with HNSCC undergoing PET/CT for initial staging were assessed separately for a potential correlation between SUV_max and T-classification, histological grading, and anatomical subsites of the primary tumor. Nonparametric testing showed a significant correlation between SUV_max and T-classification (P < 0.001). On the contrary, no statistically significant correlation was found between SUV_max and histological tumor grading. Furthermore, no statistical significant correlation between the different anatomical subsites and SUV_max were found. There was no significant correlation of SUV_max and tumor grading after adjustment for T-stage and anatomical localization of the tumor, neither. Conclusion: Metabolic tumor activity correlates with T-stage of HNSCC. However, histological tumor grading does not correlate with SUV_max. The role of primary tumor SUV_max as a predictor of outcome or survival remains unclear. Clinicians should therefore exercise caution in attributing any clinical importance to SUV_max obtained from a single PET/CT exam.