Apart from the addition of chemotherapy, treatment modification by intensification of the radiotherapy schedule or by dose escalation has been proven beneficial. Several phase I/II trials explored altered EBRT fractionation schedules that increased the biological effective dose to the primary tumor and reduced local relapse rate. Thereby, two main principles were pursued: reduction of the dose per fraction (≤ 1.8 Gy), giving two or three fractions per day (so-called hyperfractionation), aimed at sparing normal tissues while increasing the dose to the primary tumor; increase of the fraction dose (≥ 2 Gy), combined with a reduction in the total number of fractions (so-called hypofractionation) aimed at increasing the effective tumor dose in less radiation-sensitive primary tumors. On the one hand, hyperfractionation limits the treatment-related side-effects, on the other hypofractionation is attractive for the patient and radiation department as the number of treatment fractions can be reduced.