Purpose: Evaluate the predictive and prognostic value of semi-quantitative FDG-PET variables derived from pretreatment FDG-PET images in patients suffering from locally advanced squamous cell carcinoma of the head and neck (SCCHN), treated by means of concomitant radiochemotherapy.
Patients, methods: 40 patients with newly diagnosed SCCHN that were treated with concomitant radiochemotherapy underwent FDG-PET/CT for treatment planning; 18 patients had neck dissection prior to their baseline scan and to receiving radiochemotherapy. FDG-PET images were used to calculate metabolic tumour volumes using region growing and a threshold of 50% (MTV50) of primary lesions and involved lymph nodes as well as the mean and maximum standard uptake value (SUVmean and SUVmax) of the primary tumours.
Results: Neither SUVmean nor SUVmax values of the primary tumour were significantly different between responders and non-responders whereas MTV50 values of the primary tumour proved significantly higher in non-responders. SUVmean, SUVmax and MTV50 of the primary tumour were not predictive for overall or disease free survival. Contrariwise, dichotomized summed MTV50 values (cut-off≥31 cm3) of the primary tumour and involved lymph nodes in patients that didn't have neck dissection prior to radiochemotherapy were predictive for disease free and overall survival in both univariate and multivariate analysis (p≤0.05).
Conclusion: Summed MTV50 values of both the primary tumour and involved lymph nodes provided independent prognostic information on disease free and overall survival.