心肺运动试验对放射性肺损伤的预测价值分析

The predictive value of cardiopulmonary exercise testing for radiation-induced lung injury

目的探讨放疗前心肺运动试验(CPET)指标对放射性肺损伤(RILI)的预测价值。方法选取2017至2019年期间在徐州市中心医院拟行放疗的20例肺癌患者作为研究对象,于放疗前1天、放疗结束后次日均进行症状限制性CPET试验及静态肺功能一体化检查,除静息心率(rHR)外,其他指标均取峰值数据。根据放疗结束3个月后随访结果,将患者分为RILI组(发生RILI)及对照组(未发生RILI),同时比较放疗前、后2组患者CPET数据,通过受试者工作特征(ROC)曲线分析CPET指标预测RILI(≥2级)的准确性,并确定最佳cutoff值。结果20例患者中有6例发生RILI(≥2级),发生率为30%。放疗前RILI组与对照组CPET指标比较,发现氧通气当量(EqO2)、潮气末氧分压(PETO2)和潮气末二氧化碳分压(PETCO2)组间差异均具有统计学意义(P<0.05);放疗后2组患者rHR、EqO2及PETO2组间差异均具有统计学意义(P<0.05)。放疗后RILI组rHR、呼吸无效腔与潮气量比值(VD/VT)及二氧化碳通气当量(EqCO2)均较放疗前显著升高(P<0.05);放疗后对照组PETCO2较放疗前明显降低(P<0.05)。放疗前、后2组患者各项静态肺功能指标组间及组内差异均无统计学意义(P>0.05)。经ROC曲线分析,放疗前EqO2曲线下面积为0.917,确定最佳cutoff值为35.85,其敏感度、特异度及准确度分别为83.3%、92.9%和91.7%;放疗前PETO2曲线下面积为0.875,确定最佳cutoff值为117.2,其敏感度、特异度及准确度分别为83.3%、92.9%和87.5%,故认为放疗前EqO2及PETO2指标对RILI(≥2级)具有较好预测价值,且两项指标间存在较强相关性(r=0.853,P<0.01)。结论CPET能客观定量评估肺癌患者放疗前、后整体功能变化情况,于放疗前进行CPET检查能有效预测RILI(≥2级)发生,对指导临床制订个体化放疗方案具有重要意义。

Objective To explore the value of cardiopulmonary exercise testing(CPET)indexes for predicting radiation-induced lung injury(RILI)before radiotherapy.Methods Twenty lung cancer patients scheduled to receive radiotherapy received symptom-limited CPET and a static pulmonary function examination before and after their radiotherapy.Except for the resting heart rate(rHR),the peak values of all the other indexes were recorded.Three months after the radiotherapy,the CPET indexes before and after radiotherapy of those with RILI were compared with the indexes of those without RILI.Receiver operating characteristics(ROC)curves were used to analyze the ability of the CPET indexes to predict the occurrence of grade 2 or above RILI,and the best cutoff values were determined.Results Of the 20 patients,6 patients had RILI of grade 2 or above.Before the radiotherapy,there were significant differences in the ventilatory equivalents for O2(EqO2),end-tidal oxygen partial pressure(PETO2)and end-tidal carbon dioxide(PETCO2)between the two groups.After the radiotherapy there were significant differences in rHR,EqO2 and PETO2 between the two groups.After the treatment,the average rHR,the breathing dead space,the dead-space-to-tidal volume ratio(VD/VT)and EqCO2 of the RILL group were significantly higher than before radiotherapy.However,their average PETCO2 was significantly lower,and significantly lower than the average of the group without RILI.There were no significant differences in static pulmonary function between the two groups before or after the treatment.The ROC curve analysis suggested that an EqO2 value of at least 35.85 and a PETO2 reading of at least 117.2 before radiotherapy could be useful for predicting RILI of grade 2 or above.There was a strong correlation between the two indexes.Conclusions CPET can objectively and quantitatively predict the risk of RILI for lung cancer patients.It deserves wider application in making individualized radiotherapy plans.