Long-term experience with reduced planning target volume margins and intensity-modulated radiotherapy with daily image-guidance for head and neck cancer

Background The purpose of this study was to compare outcomes among patients treated by intensity‐modulated radiotherapy (IMRT) with daily image‐guided radiotherapy (IGRT) for head and neck cancer according to the margins used to expand the clinical target volume (CTV) to create a planning target volume (PTV). Methods Three hundred sixty‐seven consecutive patients were treated with IMRT for squamous cell carcinoma of the head and neck. The first 103 patients were treated with 5‐mm CTV‐to‐PTV margins. The subsequent 264 patients were treated using reduced (3 mm) margins. Results The 3‐year locoregional control for patients treated using 5‐mm and 3‐mm CTV‐to‐PTV margins, respectively, was 78% and 80% (p = .75). The incidence of gastrostomy‐tube dependence at 1 year was 10% and 3%, respectively (p = .001). The incidence of posttreatment esophageal stricture was 14% and 7%, respectively (p = .01). Conclusion The use of reduced (3 mm) CTV‐to‐PTV margins was associated with reduced late toxicity while maintaining locoregional control. © 2014 Wiley Periodicals, Inc. Head Neck 36: 1766–1772, 2014