局部晚期非小细胞肺癌调强放射治疗靶区和剂量学研究

Intensity Modulated Radiation Therapy(IMRT) Target Volume and Dosimetric Planning in Treatment of Locally Advanced Non-small Cell Lung Cancer

目的比较选择性淋巴结照射(ENI)和累及野照射(IFI)调强放射治疗局部晚期非小细胞肺癌(LA-NSCLC)的优劣和剂量学特点。方法应用Varian Eclipse DX计划系统,对经病理证实的27例LA-NSCLC患者设计ENI和IFI两种放疗计划。通过剂量体积直方图(DVH)、靶区适形指数(CI)、肿瘤控制概率(TCP)、正常组织受照射剂量和正常组织并发症概率(NTCP)评价治疗计划优劣。结果 IFI组GTV的最大剂量、最小剂量、平均剂量、CI和TCP均高于ENI组,分别为77.1Gy和73.9Gy、67.3Gy和63.6Gy、70.9Gy和67.1Gy、0.82和0.73、96.7%和93.1%(P<0.05);IFI组肺平均剂量、V20和NTCP均低于ENI组,分别为13.2Gy和16.0Gy、22.1%和24.7%、5.2%和5.8%(P<0.05);IFI组的食管V45低于ENI组,分别为16.3%和21.7%(P<0.05),而LETT45两组间差异无统计学意义(P>0.05);IFI组与ENI组心脏受照平均剂量和脊髓受照最大剂量比较差异无统计学意义(P>0.05)。结论 IFI较ENI提高了靶区的照射剂量和肿瘤控制概率,可降低正常组织受照剂量和正常组织并发症的概率。

Objective To assess elective nodal irradiation（ENI） and involved field irradiation（IFI） target volume and dosimetric distribution and to obtain the optional intensity modulated radiation therapy（IMRT） planning for locally advanced non-small cell lung cancer（LA-NSCLC）.Methods Two different plannings： ENI and IFI were designed to assess the dosimetric distribution of target volume and normal tissues for 27 patients with LA-NSCLC confirmed through pathology.Dose volume histograms（DVHs）,target volume conformal index（CI）,tumor control probability（TCP）,normal tissue irradiation dose and normal tissue complication probability（NTCP） were used to assess the IMRT planning.Results The maximum dose,minimum dose,average dose,CI,and TCP of GTV by IFI and ENI were 77.1 Gy vs.73.9 Gy,67.3 Gy vs.63.6 Gy,70.9 Gy vs.67.1 Gy,0.82 vs.0.73,96.7% vs.93.1%,respectively（P0.05）.The average dose,total lung volume received radiation exceeding 20 Gy（V20） and NTCP of lung were 13.2 Gy vs.16.0 Gy,22.1% vs.24.7%,5.2% vs.5.8%,respectively（P0.05）.The total esophagus volume received radiation exceeding 45 Gy（V45） by IFI and ENI were 16.3% vs.21.7%,however the length of esophagus（total circumference） treated with greater than 45 Gy（LETT45）,average dose of heart and the maximum dose of spinal cord had no different significantly between IFI and ENI respectively（P 0.05）.Conclusion Target volume dosimetric distribution of IFI is significantly better than ENI.Therefore,we suggest IFI in patients with LA-NSCLC.