Intensity-modulated radiation therapy (IMRT): Toward a new standard for radiation therapy of head and neck cancer?

SummaryIntensity-modulated radiation therapy (IMRT) is an evolution of 3D conformal radiation therapy, which is the current standard radiation therapy technique in head-and-neck cancer. Modulating the radiation intensity of each beam by dynamic interposition of the computer-assisted collimator leaves yields dose distributions that are particularly well adapted to head-and-neck tumor volumes. It is thus possible to predetermine dose per element: i.e., the minimum effective dose to be delivered to tumor areas, and the maximum to be safely delivered to organs at risk. The technique thereby enables complex tumoral targets to be optimally covered, while sparing healthy tissue, and salivary glands in particular. In addition, the technique allows dose-escalation, with a higher dose per session delivered to the macroscopic tumor than to other irradiated areas. The first results of ongoing randomized trials confirmed those of earlier comparative studies, showing marked improvement in side effects, including post-radiation xerostomia. Although the positive impact of this technique on tumor control remains to be proven, salivary function conservation currently makes IMRT the standard treatment in most head-and-neck cancer.