不同肺容积方法定义的剂量学参数预测放疗后非小细胞肺癌患者放射性肺炎的效能比较

Comparison of the efficacy of dosimetric parameters defined by different lung volume methods in predicting radiation pneumonitis in patients with non-small cell lung cancer

目的比较不同肺容积方法定义的剂量学参数预测放疗后非小细胞肺癌患者放射性肺炎(RP)的效能。方法选择接受调强放疗的92例非小细胞肺癌患者为研究对象,使用CT扫描记录患者全肺容积、计划靶区容积(PTV)和计划大体肿瘤靶区容积(PGTV),采用3种肺容积方法[全肺容积、PTV和PGTV]定义剂量学参数,包括正常肺组织接受放射剂量高于5 Gy照射的体积百分比(V_(5))、正常肺组织接受放射剂量高于20 Gy照射的体积百分比(V_(20))和平均肺剂量(MLD),本研究的主要终点事件为症状性RP。采用Logistic回归分析探讨症状性RP和剂量学参数(V_(5)、V_(20)、MLD)的相关性,并采用受试者工作特征曲线下面积(AUC)评估MLD预测症状性RP的性能。结果92例患者中,13例患者治疗后3个月内出现急性症状性RP。症状性RP和非症状性RP患者采用PTV方法定义的V_(5)、V_(20)、MLD比较,差异有统计学意义(P<0.05)。Logistic回归分析显示,PTV方法和PGTV方法定义的MLD与症状性RP的发生率相关(P<0.05)。在预测症状性RP方面,PTV定义的MLD具有最高AUC值(0.798),高于PGTV(0.699)和全肺容积(0.605)的AUC值(P<0.05)。结论采用PTV定义的剂量学参数在预测接受调强放疗肺癌患者的症状性RP方面具有较高价值。

Objective To compare the efficacy of dosimetric parameters defined by different lung volume methods in predicting radiation pneumonitis(RP)in patients with non-small cell lung cancer after radiotherapy.Methods A total of 92 patients with non-small cell lung cancer who received intensity-modulated radiotherapy were selected as study objects.Total lung volume,planned target volume(PTV)and planned gross tumor target volume(PGTV)were recorded by CT scan.Dosimetric parameters including volume percentage of normal lung relative volume receiving greater than 5 Gy(V_(5)),volume percentage of normal lung relative volume receiving greater than 20 Gy(V_(20))and mean lung dose(MLD)were defined by three lung volume methods(total lung volume,PTV and PGTV).The primary endpoint was symptomatic RP.The correlations of symptomatic RP with dose parameters(V_(5),V_(20)and MLD)were analyzed by Logistic regression,and the performance of MLD in predicting symptomatic RP was assessed using the area under the receiver operating characteristic curve(AUC).Results Of 92 patients,13 developed acute symptomatic RP within 3 months after treatment.There were significant differences in V_(5),V_(20) and MLD defined by PTV in symptomatic RP compared with non-symptomatic RP patients(P<0.05).Logistic regression analysis showed that MLD defined by PTV method and PGTV method was associated with the incidence of symptomatic RP(P<0.05).In predicting symptomatic RP,MLD defined by PTV had the highest AUC value(0.798),which was significantly higher than 0.699 by PGTV and 0.605 by whole lung volume(P<0.05).Conclusion Dosimetric parameters defined by PTV have high value in predicting symptomatic RP in lung cancer patients undergoing intensity-modulated radiotherapy.