Intensity-modulated radiation therapy in head and neck squamous cell carcinoma: an adaptation of 2-dimensional concepts or a reconsideration of current clinical practice.

Intensity-modulated radiation therapy (IMRT) for head and neck (HN) tumors refers to a new approach to the whole treatment procedure from patient immobilization to beam delivery. Implementation of IMRT thus requires knowledge of setup uncertainties, adequate selection, and delineation of target volumes based on optimal imaging modalities, appropriate specification, and dose prescription regarding dose-volume constraints and ad hoc quality control of both the clinical and physical aspects of the whole procedure. A large number of issues still need to be resolved and/or further refined, such as the optimal selection and delineation of the target volume, in particular, with the introduction of functional imaging, and a better integration of improved dose distribution into the fractionation strategy. IMRT is associated with a potentially increased incidence of carcinogenesis, although in the HN area this risk is relative to the intrinsic risk of comorbidity and secondary cancer associated with the patient's lifestyle. Currently, the implementation of IMRT into routine clinical practice for HN cancers may not be a straightforward matter and should probably be restricted to selected institutions with adequate resources and experience. This review emphasizes these aspects and provides some recommendations for the future use of IMRT in patients with HN tumors.