Influence of intensity-modulated radiation therapy technique on xerostomia and related quality of life in patients treated with intensity-modulated radiation therapy for nasopharyngeal cancer.

BACKGROUND The purpose of this study was to compare 5-field and 7-field intensity-modulated radiation therapy (IMRT) techniques in terms of xerostomia and related quality of life in patients with nasopharyngeal cancer. METHODS Eight and 23 patients were treated with 5-field (group I) and 7-field (group II) techniques, respectively. The xerostomia was evaluated using the Radiation Therapy Oncology Group (RTOG) scale, stimulated and unstimulated salivary flow (SSF/USF), and xerostomia-related questionnaires (XQs). The assessments were done before and at 3, 6, 12, 18, and 24 months after radiotherapy. RESULTS The mean parotid dose was 45.7 Gy and 29.9 Gy and the ≥G3 toxicity at 24 months was 25% and 19% in group I and II, respectively. Sixty-three percent and 93% of patients recovered at least 25% of SSF pretherapy values. The XQ scores of both groups improved over time but more so in group II. CONCLUSION The 7-field technique decreases the mean parotid dose, reducing xerostomia assessed by the RTOG/XQ score.