三维适形放射治疗鼻咽癌的疗效及局部复发的因素分析

背景与目的:鼻咽癌常规二维放射治疗的效果不尽人意,三维适形放射治疗可以得到比二维放射治疗更优的剂量分布。本研究探讨鼻咽癌三维适形放射治疗的效果和意义,并探索影响局部复发的剂量学因素。方法:回顾性分析87例进行三维适形放射治疗的初治鼻咽癌患者,并对7例局部区域复发病例进行剂量学分析。结果:全组共有5例原发灶和2例颈部淋巴结复发,3年局部区域控制率为90.2%,T1、T2、T3和T4的局部控制率分别为95.0%、97.0%、80.1%和100%(P=0.340)。剂量学分析显示大多数患者(5/7)为野外或野边缘复发。无进展生存超过12个月的62例患者3～4级晚期反应的发生率为9.7%。87例患者的3年总生存率和3年无进展生存率分别为88.2%和80.3%,Q92分期Ⅰ期、Ⅱ期、Ⅲ期和Ⅳa期的3年生存率分别为100%、100%、84.7%和47.5%(P<0.001)。结论:初治鼻咽癌的三维适形放射治疗可以取得较好的疗效。靶区勾画范围不足,是导致局部复发的原因之一。

Three-dimensional conformal radiotherapy for primary nasopharyngeal carcinoma and analysis of locoregional recurrence

BACKGROUND & OBJECTIVE: The efficacy of routine two-dimensional radiotherapy for primary nasopharyngeal carcinoma (NPC) is dissatisfied, while three-dimensional conformal radiotherapy (3-D CRT) can optimize irradiation dose distribution. This study was to explore the efficacy of 3-D CRT on NPC, and investigate dosimetric factors of locoregional failure. METHODS: Records of 87 patients with primary NPC, treated with 3-D CRT between Feb. 2001 and Apr. 2004, were retrospectively reviewed. Dosimetric analysis was performed on the patients with locoregional relapse. RESULTS: Of the 87 patients, 5 (5.7%) had local failure, and 2 (2.3%) had regional failure. The overall 3-year locoregional control rate was 90.2%. The 3-year local control rates for stages T1, T2, T3, and T4 patients were 95.0%, 97.0%, 80.1%, and 100%, respectively. Five cases (71%) were marginal or outside failures of the irradiation fields. The occurrence rate of grade 3-4 late complications of the 62 patients progress-freely survived over 12 months was 9.7%. The 3-year overall survival rate and progress-freely survival rate were 88.2% and 80.3%, respectively. The 3-year survival rates were significantly higher in the patients at stages I, II, and III ('92 Fuzhou staging) than in the patients at stage IVa (100%, 100%, 84.7% vs. 47.5%, P<0.001). CONCLUSIONS: Increased locoregional control rate and reduced occurrence of grade 3-4 late complications of primary NPC could be achieved by 3-D CRT through careful delineation of target volumes and design of irradiation fields. Missing of target volumes is a reason of local relapse.