Altered fractionation in the treatment of head and neck cancer.

Several altered fractionation schemes have evolved to exploit different aspects of head and neck cancer growth kinetics and normal tissue repair. Hyperfractionation schedules exploit the differential repair abilities of tumor and normal tissue, whereas accelerated fractionation regimens minimize the time of tumor repopulation. Significant clinical data have accumulated that indicate an improvement between 15% and 20% in locoregional control from altered fractionation. Preliminary analysis of a randomized Radiation Therapy Oncology Group trial testing four fractionation schemes confirms the benefit of one altered fractionation approach. Several promising concurrent chemoradiation treatments involving altered fractionation have been reported. Future trials will determine whether the addition of chemotherapy to altered fractionation schemes is warranted in light of the factor of added toxicity.