Definitive radiotherapy for head and neck squamous cell carcinoma: update and perspectives on the basis of EBM

Radiotherapy plays an essential role in the management of head and neck squamous cell carcinoma. Radiotherapy has a distinct advantage over surgical procedures in that it could achieve organ and function preservation with an efficacy similar to that of surgical series. To improve the clinical outcomes achievable by radiotherapy, altered fractionated radiotherapy has been prospectively tested for early and intermediate risk diseases, and was previously shown to be beneficial for local control and survival. Radiotherapy alone is insufficient for locally advanced disease; therefore, concurrent chemoradiotherapy is typically performed and plays an important role. A meta-analysis (Level Ia) revealed that the concurrent use of platinum agents appeared to improve tumor control and survival; however, this was accompanied by increases in the rates of both acute and late toxicities. Regarding radiation techniques, intensity modulated radiotherapy evolved in the 1990s, and has been globally used to treat head and neck squamous cell carcinoma patients. Intensity modulated radiotherapy reduces the exposure of normal tissue to radiation while preserving excellent dose coverage to the target volume; therefore, the rate of late toxicities especially xerostomia is minimized. Small size randomized studies and a meta-analysis have provided evidence to support the benefits of intensity modulated radiotherapy over two-dimensional or three-dimensional radiation therapy. Intensity modulated radiotherapy can also preserve quality of life following definitive chemoradiotherapy. Further improvements using intensity modulated proton therapy are warranted.