Prospective Assessment of Patterns of Failure After High-Precision Definitive (Chemo)Radiation in Head-and-Neck Squamous Cell Carcinoma

Locoregional relapse remains the predominant pattern of failure in head-and-neck squamous cell carcinoma treated with high-precision definitive radiotherapy with the majority of failures occurring “in-field” within the high-dose volume. Marginal failures can occur, particularly in the vicinity of the spared parotid gland. The therapeutic index of high-precision conformal radiotherapy is largely dependent on adequate selection and delineation of target volumes and organs at risk.