Study Of The Predictors For Radiation Pneumonitis In Patient With Non-Small Cell Lung Cancer Received Radiotherapy After Pneumonectomy

Purpose. - To identify the valuable predictors of grade=2 radiation pneumonitis (RP) in patient treated with radiotherapy after pneumonectomy for non-small cell lung cancer (NSCLC); and to construct a nomogram predicting the incidence of grade >= 2 RP in such patients.Patients and methods. - We reviewed 82 patients with NSCLC received radiotherapy after pneumonectomy from 2008 to 2018. The endpoint was grade >= 2 RP. Univariate and multivariate regression analysis were conducted to evaluate significant factors of grade >= 2 RP. Receiver operating characteristic (ROC) curve was used to establish optimal cutoff values and the nomogram was built to make the predictive model visualized. Descriptive analysis was performed on 5 patients with grade 3 RP.Results. - A total of 22(26.8%) patients developed grade 2 RP and 5(6.1%) patients were grade 3 RP. V5, V10, V20, V30, MLD, PTV, and PTV/TLV were associated with the occurrence of grade >= 2 RP in univariate analysis, while none of the clinical factors was significant; V5(OR,1.213;95%CI,1.099-1.339; P<0.001) and V20(OR,1.435;95%CI,1.166-1.765; P=0.001) were the independent significant predictors by multivariate analysis and were included in the nomogram. The ROC analysis for the cutoff values for predicting grade >= 2 RP were V5>23% (AUC=0.819, sensitivity:0.701, specificity:0.832) and V20>8% (AUC=0.812, sensitivity:0.683, specificity:0.811). Additionally, grade >= 3 RP did not occur when V5<30%, V20<13% and MLD<751.2cGy, respectively.Conclusions. - Our study showed that V5 and V20 were independent predictors for grade >= 2 RP in NSCLC patients receiving radiotherapy after pneumonectomy. Grade 3 RP did not occur whenV5<30%, V20<13% and MLD<751.2cGy, respectively. In addition, patient underwent right pneumonectomy may have a lower tolerance to radiation compared to left pneumonectomy. (C) 2020 Societe francaise de radiotherapie oncologique (SFRO). Published by Elsevier Masson SAS. All rights reserved.