Choosing an Intensity-Modulated Radiation Therapy Technique in the Treatment of Head-and-Neck Cancer

Abstract

With the emerging use of intensity-modulated radiation therapy (IMRT) in the treatment of head-and-neck cancer, selection of technique becomes a critical issue. The purpose of this article is to establish IMRT guidelines for head-and-neck cancer at a given institution. Six common head-and-neck cancer cases were chosen to illustrate the points that must be considered when choosing between split-field (SF) IMRT, in which the low anterior neck (LAN) is treated with an anterior field, and the extended whole-field (EWF) IMRT in which the LAN is included with the IMRT fields. For each case, the gross tumor, clinical target, and planning target volumes and the surrounding critical normal tissues were delineated. Subsequently, the SF and EWF IMRT plans were compared using dosimetric parameters from dose-volume histograms. Target coverage and doses delivered to the critical normal structures were similar between the two different techniques. Cancer involving the nasopharynx and oropharynx are best treated with the SF IMRT technique to minimize the glottic larynx dose. The EWF IMRT technique is preferred in situations in which the glottic larynx is considered as a target, i.e., cancer of the larynx, hypopharynx, and unknown head-and-neck primary. When the gross disease extends inferiorly and close to the glottic larynx, EWF IMRT technique is also preferred. Depending on the clinical scenario, different IMRT techniques and guidelines are suggested to determine a preferred IMRT technique. We found that having this treatment guideline when treating these tumors ensures a smoother flow for the busy clinic.