Intensity-modulated radiation therapy (IMRT) is an exciting new modality in radiation therapy. The head and neck region is an ideal target for this new technology for several reasons. First, IMRT offers the potential for improved tumor control through delivery of high doses to the target volume. Second, because of sharp dose gradients, IMRT results in the relative sparing of normal structures in the head and neck region. Third, organ motion is virtually absent in the head and neck region, so, with proper immobilization, treatment can be delivered accurately. Although this is a relatively new technology, preliminary studies show excellent dosimetric profiles and clinical results. Salivary gland sparing has also resulted in reduced incidence and severity of xerostomia. Early reports of improvement in tumor control with better side effect profiles versus conventional techniques are promising, but will need to be confirmed with longer follow-up.

Radiotherapy planning studies have confirmed dosimetric advantages of intensity-modulated radiation therapy over conventional and conformal radiation therapy. Utilization of intensity-modulated radiation therapy is ideal in head and neck cancer patients. Critical structures can be spared due to sharp dose gradients and limited organ motion with correct immobilization. Initial clinical results have shown excellent locoregional control, in part due to the delivery of high doses to the target volume. Reductions in acute toxicities and xerostomia through parotid sparing have been notable benefits. However, long-term outcomes with regards to local control and late toxicities with intensity-modulated radiation therapy are still lacking. This review focuses on the implementation of intensity-modulated radiation therapy for the treatment of head and neck cancers, with a specific focus on set-up uncertainties, dose prescription and target volume determination and delineation.

No abstract