Dose-volume histogram parameters for predicting radiation pneumonitis using receiver operating characteristic curve

Abstract

Objective To assess the accuracy (ACC),sensitivity (SEN),and specificity (SPE) of dose-volume histogram (DVH) parameters in predicting the radiation pneumonitis (RP) using receiver operating characteristic (ROC) curve.Methods Complete clinical data of 118 non-small cell lung cancer patients treated with three-dimensional conformal and intensity-modulated radiotherapy plus chemotherapy were included.Chi-square and logistic regression were retrospectively applied to analyze the correlations between DVH parameters [relative lung volume received ≥ 5 Gy (V5),10 Gy (V10),13 Gy(V13),20 Gy (V20) and 30 Gy (V30) and mean lung dose (MLD)] and grade 2 (and above) RP defined by the National Cancer Institute Common Terminology Criteria for Adverse Events,version 3.0.ROC curve was adopted to investigate the predictive ACC,SEN and SPE of potential DVH parameters associated with RP.Results Total lungs V5,V10,V13,V20 and MLD were all correlated to the development of RP (x2 =4.786,5.771,6.366,7.367 and 6.945,P ＜ 0.05) according to univariate analysis.However,total lungs V30,patient characteristics (age,sex,KPS,tumor location,pathology) and treatment factors (prescription dose,radiotherapy technique,chemotherapy method and timing) were not contributors to RP.Logistic regression showed that V20 of both lungs remains tight by associated with RP (x2 =10.96,OR =4.16,95％ CI 1.40 ～ 12.36,P ＜0.05),although significant colinearity was found between V20 and other DVH parameters (r =0.767-0.902,P ＜0.05).ROC curve confirmed that V20 of both lungs could act as a predictor for RP (Z =2.038,P ＜ 0.05).The predictive ACC,SEN,and SPE were 0.645 (95％ CI0.498-0.793),0.650 (95％ CI0.408-0.864),and 0.674 (95％ CI0.571-0.765),respectively.However,the positive predictive value was only 28.9％.Conclusions V20 of both lungs was correlated to the development of RP.It could act as a predictor for RP though the predictability is limited. Key words: Non-small cell lung cancer; Dose-volume histogram; Radiation pneumonitis;