[Intensity modulated radiation therapy for 90 untreated nasopharyngeal carcinoma].

OBJECTIVE:To observe the clinical results and the toxicities of normal tissues in untreated nasopharyngeal carcinoma (NPC) treated with intensity modulated radiation therapy (IMRT). METHODS:A total of 90 patients with untreated NPC received IMRT. According to the 1992 Fuzhou staging system, 3 patients were in stage I, 29 in stage II, 26 in stage III, and 32 in stage IVa. For IMRT,the prescription dose was 71.94-77.88 Gy/33f for the planning target volume of the gross tumor volume in the nasopharynx (PGTVnx); 69.96 Gy/33f for the positive neck lymph nodes (GTVnd); 60-66 Gy/33f for the planning target volume of the high risk regions (PTV1); and 50.4-56 Gy/28f for the planning target volume of the low risk regions (PTV2). Chemotherapy included concurrent and adjuvant protocols. The overall survival rate, local control rate, and distant metastasis-free survival rate were estimated by Kaplan-Meier method. Cox regression was used for multivariate analysis. Acute and 1ate toxicities were graded according to RTOG radiation morbidity scoring criteria. RESULTS:The median follow-up time was 33 months (12-56 months). The 1-, 2-, 3- and 4-year survival rate was 97.8%, 90.6%, 86% and 80%; the local control tate was 98.8%, 97.5%, 92.1% and 77.4%; and the distant metastasis-free survival rate was 95.3%, 90.7%, 88.4% and 85.8%, respectively. The most serious acute toxicity was irradiated inflammation of mocosa with Grade 1 to 4 of 16.7%, 60%, 23.3% and 0, respectively. In the multivariate analysis, clinical stages were the prognostic factors for the survival rate. The most serious toxicity was salivary gland. The rate of grade xerostomia 1-year after the radiotherapy with Grade 1 to 4 was 18.1%, 9.6%, 0 and 0, respectively. CONCLUSION:IMRT combined chemotherapy can improve the survival rate, and late adverse reaction is obviously decreased. Local recurrence and distant metastasis are the main reasons for low survival rate.