Clinical Study Of Late Course Three Dimentional Conformal Radiotherapy For Early-Stage Nasopharyngeal Carcinoma To Preserve Parotid Function

Objective: With late course three Dimensioal conformal Radiotherapy (3D-CRT) for early nasopharyngeal carcinoma with not treated previously to preserve the parotid, Compare the parotid dysfunction, Local control rate and complications with conventional fraction Radiotherapy(CF).Methods: Forty early(T_1-2N_0-1M₀) nasopharyngeal carcinoma cases with not treated previously which diagnised by imaging and pathology were treated in our department between November 2004 to December 2006. They were randomly divided into two groups. The CF group included 20 cases received routine radiotherapy to a total dose of 72Gy. While the late-course 3D-CRT group included 20 cases irradiated with bilateral faciocervical portal to a total dose of 30Gy in early course, and then irradiated with 3D-CRT to preserve the contralateral parotid to another dose of 42Gy, the total dose are 72Gy too. All patients were received ^99mTco₄^- dynamic raster display to test the Uptake Index(UI) and Excretion Index(EI) of the bilateral parotid before radiation and one month and six month after radiation. Nasopharyngeal mass were evaluated with WHO Response Evaluation criteria in Solid Tumors. During radiation, we record the degree of dry mouth. We evaluat the Oral mucositis with American Radiation Ocolgy group(RIOG) criteria.Results: 1.The median dose received by the parotid of two group and the parotid dysfunction: The parotids of CF group were received a median dose of 66.97Gy(61.9-71.8Gy). While the contealateral parotid of late cours 3D-CRT group were recoived a median dose of 36.24Gy(31.9-39.4Gy). The UI and EI of both one month or six month after radiation in two group were lower than which of both group before radiation(p<0.05). And the UI and EI of both group after one month were not different (p>0.05). But the UI and EI tested six month after radiation of CF group were lower than that of late cours 3D-CRT group,UI (4.06±1.40VS 6.03±1.85),EI(0.0935±0.0252 VS 0.19±0.0281)(P<0.01).2. Xerothermic: Most of patients have only grade (Ⅰ～Ⅱ) xerothermic ,gradeâ…¢xerothermic of late cours 3D-CRT group were significant lower than that of CF group (P<0.05).3. Recently Response: The CR, PR, SD, DR in late cours 3D-CRT group were 90%(18/20), 5%(1/20), 5%(1/20),95%(19/20), respectively; and that in the CF group were 85%(17/20), 10%(2/20), 5%(1/20), 95%(19/20), respectively. there were no significant differences of response rate(P>0.05).4. Oral mucositis: oral mucositis take place in group were low gradeⅠ～Ⅱ,But gradeâ…¢-â…£oral mucositis were significantly lower than thai of CF group (P<0.05).Conclusion: On the basis of ensure the Local Control rate and Overal response rate, Late course late cours 3D-CRT for early nasopharyngeal carcinoma can preserve the parotid function, reduce xerothermic and oral mucositis induced radiation.