鼻咽癌常规放疗靶体积合理性的初步探讨  

Probe into rational target volume of nasopharyngeal carcinoma having been treated with conventional radiotherapy

作　　者：郑颖洁[1] 赵充[1] 卢丽霞[1] 吴少雄[1] 崔念基[1] 陈福进[2] 

机构地区：[1]中山大学肿瘤防治中心放疗科,广州510060 [2]中山大学肿瘤防治中心头颈科,广州510060

出　　处：《中华放射肿瘤学杂志》2006年第4期257-261,共5页Chinese Journal of Radiation Oncology

基　　金：广东省科技计划项目基金(2003245)

摘　　要：目的分析鼻咽癌常规放疗的局部控制情况和局部复发的剂量学模式,初步探讨照射靶体积确定的合理性。方法共476例初治鼻咽癌患者接受规范化单纯常规根治性放疗。全部病例均采用常规模拟定位,鼻咽靶体积为CI检查所见的原发病灶范围以及可能侵犯的亚临床病灶区域。利用Kaplan-Meier方法计算局部累积复发率；将鼻咽局部复发患者疗前和复发时局部病灶范围(V_(nx)和V_(recur))勾画于三维治疗计划系统,复制首程放疗的射野并按原处方剂量进行计算,根据剂量体积直方图进行剂量学评价：_(recur) B_(95)(95%处方剂量曲线包括的V_(recur))≥95%定义为野内复发,95%＞_(recur)V_(95)≥20%定义为野边缘复发,20%＞_(recur) V_(95)定义为野外复发。结果局部复发共52例,全组1、2、3、4年局部累积复发率分别为0．6%、3．9%、8．7%、11．5%。对42例局部复发的剂量学分析显示野内复发占多数(52%),而大部分野边缘复发和全部野外复发均与射野设置不当、影像学阅片能力欠缺使首程放疗剂量不足有关。结论较好的局部控制率、复发的剂量学模式的分析结果提示该靶体积的设置比较合理。提高影像阅片能力,准确的射野设计,充分利用生物影像学工具,有针对性地提高照射剂量,有望进一步提高局部控制率。Objective To analyze the local control rate and the dosimetric patterns of local recurrence in nasopharyngeal carcinoma（NPC） patients having been treated with standardized conventional radiotherapy and to evaluate the delineation of rational target volume. Methods From Jan. 2000 to Dec. 2000, 476 patients with untreated NTC were treated by standardized conventional radiotherapy alone at the Sun Yat-sen University Cancer Center. The radiation ports were designed on a X-ray simulator. The nasopharyngeal lesion demonstrated by CT scan and the subclinical spread regions adjacent to the nasopharynx were defined as the target volume. Kaplan- Meier method was used to calculate the cumulative local recurrence rate. For patients with local recurrence, the primary and recurrent local tumor volumes（Vnx, Vrecur） were delineated with three-dimensional treatment planning system（3DTPS）, and the dataset of radiation ports and delivered prescription dose to the 3DTPS were transferred according to the first treatment. The dose of radiation received by Vrecur was calculated and analyzed with dosevolume histogram（DVH）. Local recurrence was classified as： 1. ＂in-port＂ with 95% or mere of the recurrence volume （recrtV95） was within the 95% isodose;2.＂marginal＂with 20% to 95% of recurV95 within the 95% isodose; 3.＂outside＂with only less than 20% of recurV95 within the 95% isodose curve. Results With the median followup of 42.5 months （range 8 - 54 months）, 52 patients developed local recurrence. The 1-,2-,3 and 4-year cumulative local failure rate was 0.6%, 3.9%, 8.7 % and 11.5 %, respectively. Among the 42 local recurrent patients who could be analyzed by 3DTPS, 52% were in-port, 40% were marginal and 7% were outside. For most of the marginal recurrence and all the outside recurrence patients, the main reason of recurrence were related to the unreasonable design of the radiation port and inaccuracy in the interpretation image findings. Conclusions The outcome of better local control rate and the

关 键 词：鼻咽肿瘤/放射疗法 肿瘤复发 局部 靶体积 

分 类 号：R739.63[医药卫生—肿瘤]