Weekly MR imaging allows for tumor monitoring during treatment. T2 weighted imaging and distortion-free DW-TSE SPLICE were acquired weekly in 20 patients. Changes in volume and ADC could be followed over the course of (chemo)radiotherapy: volume decreases and ADC increases. Tumor delineation is crucial and becomes increasingly difficult during treatment. For the current patient population, 4 patients developed recurrent disease. However, volume changes measured on T2 weighted imaging and ADC changes did not yet show to be prognostic of tumor recurrence.