| Objective:For the patients with lung cancer who need chest radiation,the incidence of acute radiation pneumonia(ARP)after IMRT was studied,at the same time the clinical and dosimetric factors affecting its occurrence were explored to find a relatively reliable predictors in order to reduce the occurrence of ARP.Methods:This study collected 81 cases of lung cancer who received chest IMRT from April 2016 to June 2017 in Kunming General Hospital of Chengdu Military Region,the patients were diagnosed with lung cancer by pathology.Among them,60 cases were males and 21 cases were females;the average age was 59.7 years(ranged from 28-74 years).The radiation doses were ranged from 60-68Gy,median dose was 63 Gy.The patient's data were collected,including clinical data(age,sex,smoking or not,tumor location,combination with pulmonary disease,pathological type,TNM,the size of GTV,etc),treatment data:the combination with chemotherapy,dosimetric parameters data:V5-V30,absolute volume of the lung spared from 5 Gy(VS5),MLD.By consulting inpatient's records or follow-up the outpatient to understand whether they had the clinical symptoms such as coughing or dyspnea,as well as the patients' CT image of the chest were read in pre-radiotherapy,during the radiotherapy and post-radiotherapy within 3 months,The criteria of radiation therapy oncology group(RTOG)were used for the assessment of Radiation-induced lung injury(RILI),and the ARP>grade 2 was the end point of this study.T test,?2 test,non-parametric test,logistic regression analysis and ROC curve analysis in SPSS 20 software were used to analyze each factors and find out the cut-off point of related predictors.(p<0.05)Results:1.According to the RTOG evaluation criteria,21 of the 81 patients who received chest radiotherapy developed ARP? grade 2,with a total incidence of 25.9%,of which grade 2 was 19.7%(16/81),grade 3 was 6.2%(5/81),grade4 and 5 was 0%(0/81).2.The results of univariate analysis showed that all the clinical data,including age,sex,smoking or not,tumor location,combination with pulmonary disease,pathological type,TNM,irradiation dose,segmentation method,and the combination with chemotherapy were not related to ARP>grade 2(P>0.05).3.The results of univariate analysis showed that the size of GTV,GTV/total lung volume,GTV/contralateral lung volume,GTVyrpsilateral lung volume,and all dosimetric parameters VS5,V5-V30,MLD were related to ARP>grade 2(p<0.05).4.The results of multivariate logistic regression analysis showed that GTV/total lung volume was the independent risk factors of ARP>grade 2(p<0.05).5.By using ROC curve analysis,we got that the AUC of GTV/total lung volume was the maximum,0.983,it had highest predictive value,The cut-off point of the GTV/total lung volume was 4.4%when the sum of sensitivity and specificity was the maximum.While GTV/total lung volume ?4.4%and GTV/total lung volume<4.4%,the rates of ARP ? grade 2 were 75%,5.3%,respectively.6.By using ROC curve analysis,we got that the prediction value of V5 in dosimetric factors was higher,its AUC was 0.804,and the cut-off point was 65.5%.While V5 ?65.5%and V5<65.5%the rates of ARP ? grade 2 were 61.9%,13.3%,respectively.Conclusion(s):1.This study shows that 21 of the 81 patients developed ARP ? grade 2,with a total incidence of 25.9%.2.All the dosimetry parameters,including V5-V30,MLD and VS5,were related to ARP>grade 2,and they had a certain predictive value,in which the predictive value of V5 was higher,the cut-off point was 65.5%.3.The size of GTV,GTV/total lung volume,GTV/contralateral lung volume,GTV/ipsilateral lung volume,were related to ARP>grade 2,and GTV/total lung volume was an independent risk factor for ARP>grade 2,its predictive value was the highest.the cut-off point was 4.4%. |
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