Patient characteristics, tumour characteristics including the BRAF mutation status and baseline serum S100B and LDH levels of each patient will be retrospectively determined from the electronical patient file. In each patient, tumour burden and 18F-FDG uptake of the tumour lesions will be measured using multiple standard quantification parameters of the baseline 18F-FDG-PET scan. Tumour burden will also be measured on the baseline contrast enhanced CT scan. The correlation of each FDG-PET parameter with baseline LDH and S100B levels, respectively, will be analyzed using univariate and multivariate regression analysis.
