Impacts of radiotherapy fractionation on outcome in squamous cell head and neck cancer (SQC HNC)

Abstract

Although conventional fractionated (CF) radiotherapy (RT) became the most common non-surgical approach delivering 66-70 Gy in 33-35 daily fractions (fx) in 6.5-7 weeks several decades ago due to a good local control (LC) with low normal tissue complication rates, recent decades also brought altered fractionated RT regimens based on better understanding of radiobiology. Of these, split course RT is largely abandoned due to inferior results caused by the treatment gap, which led to inferior local control rates and consequently survival. Hyperfractionated (Hfx) RT and various forms of accelerated (Acc) RT had consistently shown improvement in the treatment outcome, given either alone or with concurrent chemotherapy (CHT). Hfx RT was most consistently superior to CF and frequently to Acc RT, while moderate Acc RT also holds promise to be used more often in daily clinical practice. The use of Hfx RT may face the challenge of applicability in busy radiotherapy departments around the world despite unequivocally having been proven as superior regarding both local/regional tumor control and overall survival. With concurrent CHT, although results favor it, risks of accompanying toxicity rise and should be considered when planning such intensified treatment approach. © 2020, Turkish Society for Radiation Oncology.