A prospective, multicentric clinical study of intensity modulated radiotherapy (IMRT) in nasopharyngeal carcinoma (NPC): A 4-year follow-up report.

Abstract

e16054 Background: To evaluate the treatment efficacy, toxicity and prognostic factors of patients with NPC treated with IMRT. Methods: Between January 2006 and August 2008, 300 patients with pathologically diagnosed NPC from 6 medical center received IMRT. The number of patients with stage I, II, III, IVa-b disease (UICC/AJCC 2002 staging system) was 6, 45,141, and 108, respectively. The prescription doses were as follows: 70~74Gy/30 fraction to GTVnx, 68~70Gy/30 fraction to GTVnd, 60~64Gy/30 fraction to CTV1,50~54Gy /30 fraction to CTV2. Patients with stage III, IVa-b disease also received cisplatin-based chemotherapy. Results: The median follow-up time was 47.1 months (range,11-68 months). There were 18,15 and 42 patients who had developed local, regional recurrence and distant metastasis, respectively. There were 45 patients died. 34 patients died of distant metastasis,6 died of local and regional recurrence, 2 died of re-treatment, one died of hemorrhage complications of nasopharynx,one died of second primary tumor, and the other one died of unknown cause.The 4-year rate of local control (LC), regional control(RC), metastasis-free survival(DMFS),disease-free survival(DFS) and overall survival(OS) was 94.0%, 95.5%, 87.4%, 80.8%, 86.1%, respectively. Multivariate analysis showed that N stage was the only prognostic factor for OS (x2=3.912, p=0.048, HR=14.565), DMFS (x2=5.195, p=0.023, HR=8.737)and DFS (x2=7.613,p=0.006, HR=7.628), in these patients. Mucositis was the most severe acute toxicity, with 18.1% grade 1, 48.6% grade 2, 33.3% grade 3 . No patient suffered from grade 4 mucositis. Xerostomia was the most common seen late toxicity, with 8% grade 0, 50.5% grade 1, 4.6% grade 2. No grade 3-4 xerostomia was observed. Conclusions: IMRT can improve the treatment efficacy of patients with NPC. The acute and late toxicities were tolerated. Distant metastasis becomes the main treatment failure. N stage is a significant prognostic factors.