Late xerostomia after intensity-modulated radiation therapy versus conventional radiotherapy

Purpose: To evaluate xerostomia following intensity-modulated radiation therapy (IMRT). Materials and Methods: An institutional review board-approved study of xerostomia was conducted in 210 head and neck cancer patients who were beyond the acute recovery phase (> 1 year) after radiation therapy. Xerostomia was evaluated with the 8-question XQ developed and validated at the University of Michigan. Results: Median XQ scores (normalized so that no xerostomia = 0 and maximum xerostomia = 100) were larynx-only group, 4 points, ipsilateral radiotherapy, 34 points; bilateral radiotherapy, 64 points; IMRT with mean contralateral parotid dose more than 26 Gy, 44 points; and IMRT with mean contralateral parotid dose 26 Gy or less, 32 points (P < 0.05 for all major comparisons). Conclusion: The XQ is an excellent tool for identifying important differences in xerostomia after radiation therapy for head and neck cancer. The authors' IMRT program decreases the severity of xerostomia symptoms compared with what is typically seen after conventional radiation therapy.