Intensity-modulated radiation therapy for head and neck cancer.

Intensity-modulated radiation therapy (IMRT) involves the delivery of optimized nonuniform beam intensities to the patient. In the head and neck region, there are many critical structures in close proximity to the target, with little influence from internal organ motion. Because IMRT produces tightly conformal doses and steep-dose gradients next to normal tissues, it provides the potential for organ sparing and improved tumor control. The dosimetric superiority of head and neck IMRT over conventional techniques has been demonstrated. The initial results of clinical IMRT studies showed reduction in xerostomia with no compromise in locoregional control if caution and appropriate knowledge are exercised in target determination and delineation.