The relationship between xerostomia and radiation dose of parotid in nasopharyngeal carcinoma patients with stereotactic radiotherapy

Objective:To study the relationship between the xerostomia rate and the radiation dose of parotid in nasopharyngeal carcinoma(NPC) patients with stereotactic radiotherapy(SRT). Methods: Sixty one naive NPC patients were treated with SRT,and the target, included the nasopharynx, the space around the parapharyngeal and the area of neck lymph node,were surrounded by 95% isodose curve and by 30-42Gy/10-14f/20-30 days. The parotid were surrounded by 50%-60% isodose curve. All patients were given a questionnaire investigation of clinic regarding xerostomia after 1 year radiotherapy. The relationship between the xerostomia rate and the radiation dose of parotid were studied. Results: The local control rates was 95.08%(58/61), and the 1-,2-,3-year survival rate were 95.08%(58/61),93.22%(57/61),90.16%(55/61) respectively. The radiation dose of left and right parotid were 15.98Gy-31.06Gy(21.21±5.29) and 14.89Gy-26.69Gy(19.01±4.96)respectively.6.56 % (4/61) xerostomia was found. Moderate xerostomia were 3.28%(2/61)and no severe case occurred. Conclusion:The only stereotactic radiotherapy can acquire the same local control rate and the survival rate for nasopharyngeal carcinoma.It also can decrease the rate of xerostomia and improve the quality of life.