主动呼吸控制结合三维适形放疗非小细胞肺癌的初步研究

Primary application of active breathing control system in conformal radiotherapy for patients with non-small cell lung cancer

目的 探讨医科达公司主动呼吸控制（ABC）系统结合三维适形放疗技术治疗非小细胞肺癌（NSCLC）可行性.方法 29例Ⅱ～Ⅳ期未能手术的NSCLC患者分别在自由呼吸（FB）状态和ABC控制下行CT扫描,并在两个重建图像序列中按同样条件分别设计FB和ABC后的三维适形放疗计划.选择屏气触发方式为吸气后屏气,触发阈值设定为呼吸曲线峰值的80%,每次最长屏气时间为25 s.上叶病灶计划靶体积（PTV）为临床靶体积（CTV）外放0.6 cm;中下叶病灶PTV为CTV外放1.0 cm.采用3～5个野进行共面适形治疗.通过剂量体积直方图评价两个计划的大体肿瘤体积（GTV）、CTV、PTV、双肺体积（Vlung）、双肺V20）.和平均肺剂量（MLD）.近期疗效按世界卫生组织肿瘤疗后客观效果评分.正常组织急性反应按美国国家癌症研究所CTC3.0标准评价.结果 除1例患者因经济原因中断治疗,其他患者均顺利完成治疗.使用ABe技术后GTV、CTV、PTV均较FB技术有一定缩小[36.35 cm^3：31.40 cm^3（t=9.70,P〈0.001）、82.33 cm^3：70.83 cm^3（t=8.19,P〈0.001）、230.73 cm^3：197.59 cm^3（t=5.72,P〈0.001）],双肺V20、MLD均低于FB技术[21.66%：18.76%（t=11.16,P〈0.001）、1329.07 Gy：1143.14 Gy（t=13.24,P〈0.001）].总有效率为64%（18例）.急性放射性食管炎发生率1、2级分别为68%（19例）、18%（5例）;急性放射性肺损伤发生率1、2级分别为82%（23例）、7%（2例）;骨髓抑制发生率1、2、3级分别为57%（16例）、25%（7例）、14%（4例）;急性心脏损伤1、2级分别为86%（24例）、14%（4例）.结论 ABC的临床应用可行,靶区定位更为精确,可减少正常肺组织照射剂量,从而减少放射副反应的发生率.

Objective To evaluate the feasibility of active breathing control （ABC） in conformal radiotherapy （CRT） for patients with non-small cell lung cancer （NSCLC）. Methods From Feb 2005 to Mar 2008, 29 patients with inoperable NSCLC （stage II -IV） were evaluated. For each patient, two series of CT scans were obtained with free breathing （FB） and ABC system during simulation, respectively. Then two conformal radiotherapy （CRT） plans were finished based on the two sets of reconstructed images. The pattern of post-inspiratory breath-hold was triggered at 80% of the peak of inspiration curve. The margin of clinical target volume （CTV） to planning target volume （PTV） was 0. 6 cm for lesions of the superior lobe, and 1.0 cm for the lesions of middle and inferior lobes. Three to five coplanar fields were performed in conformal radiotherapy. The gross tumor volume （GTV）, CTV, PTV, volume of the bilateral lungs （Volumelung）, V20 and mean lung dose （MLD） of two plans were evaluated by dose-volume histogram （DVH）. The World Health Organization criteria and National Cancer Institute Common Toxicity Criteria 3.0 （NCI-CTC3.0） scale were used to assess the immediate response and acute slde-effect, respectively. Results Significant differences of GTV, CTV, PTV, Volumlung, V20 and MDL were observed between the two plans （36. 35 cm^3 vs. 31.40 cm^3 ,t =9. 70,P 〈0. 001 ;82. 33 cm^3 vs. 70. 83 cm^3 ,t =8. 19,P 〈0. 001 ; 230. 73 cm^3 vs. 197.59 cm^3 ,t =5.72,P 〈0. 001 ;21.66% vs. 18.76% ,t = 11.16,P 〈0. 001 ;1329.07 Gy vs. 1143.14 Gy, t = 13.24, P 〈 0. 001 ）. With ABC, all patients completed their treatment successfully except one patient for financial problems. The median radiation dose to the GTV was 64 Gy （60 -64 Gy）.The overall immediate response rate was 64% （ 18/28 ）. According to the NCI-CTC 3.0, grade 1 and 2 acute radiation-related toxicities occurred in 68% （19/28） and 18% （5/28） of patients for esophagitis, 82% （23/28） and 7% （2/28） for pneumonitis, respectively. Grade 1, 2 and 3 bone marrow suppression occurred in 57% （ 16/28）, 25% （7/28） and 14% （4/28） of patients, respectively. Grade 1 and 2 acute cardiac injuries occurred in 86% （24/28） and 14% （4/28） of patients. Conclusion During CRT for patients with NSCLC, the use of ABC can decrease the radiation dose and acute complications of normal tissues.