Intensity modulated radiotherapy for head and neck cancer: evidence for preserved salivary gland function.

摘要

BACKGROUND AND PURPOSE: To investigate the salivary gland function following intensity modulated radiotherapy (IMRT) for head and neck cancer. PATIENTS AND METHODS: Seventeen patients with oropharyngeal (n=11) or nasopharyngeal (n=6) carcinoma located adjacent to the major salivary glands were treated with IMRT with an emphasis to spare the salivary glands from high-dose irradiation and to reduce the risk of postirradiation xerostomy. Three patients had stage 2, 4 stage III, and 10 stage IVA cancer. The total basal and stimulated saliva flow rates were measured before the treatment, and 6 and 12 months after radiotherapy. RESULTS: The median basal saliva flow rate measured before radiation treatment was 0.13mL/min, and at 6 and 12 months after the completion of IMRT 0.04mL/min and 0.07mL/min, respectively. The corresponding median stimulated saliva flow rates were 0.49mL/min, 0.33mL/min, and 0.45mL, respectively. The D(50) for an impaired stimulated parotid gland saliva flow rate was 25.5Gy. Only two (12%) patients developed grade 3 and none grade 4 xerostomia during a median follow-up of 24 months (range, 12-40 months). No patients had locoregional cancer recurrence following IMRT. CONCLUSIONS: The results suggest that much of the salivary gland function can be maintained with IMRT without jeopadizing the local control rate in the treatment of locally advanced oropharynx or nasopharynx carcinoma.