The related factors with radiation pneumonia after intensity modulated radiation therapy for locally advanced non-small cell lung cancer

doi:10.3969/j.issn.1002-7386.2017.04.008

Abstract：Objective To analyze the related factors including dose-volume histogram ( DVH ) with radiation pneumonia ( RP ) after intensity modulated radiation therapy ( IMRT ) for locally advanced non-small cell lung cancer (NSCLC).Methods The clinical data about 60 patients with NSCLC who were treated by IMRT in our hospital from October 2012 to December 2014 were retrospectively analyzed.The PTV prescription dose was over 50~66Gy,1.8~2.4Gy· time-1· d-1, five times a week .All the patients were treated by radiotherapy in whom 19 patients received concurrent chemoradiotherapy . The clinical factors,DVH parameters and grade 2 or higher pneumonitis within 3 months after radiotherapy were observed . Results During follow-up, the incidence rate of grade 2 or higher RP was 30.0% (18/60).The single factor analysis for RP showed that smoking, GTV volume,PTV irradiated volume,V5,V10,V13,V15,V20,V25,V30,mean lung dose (MLD), D35, D50, D75, D95 were closely correlated to the occurrence of RP ( P <0.05).The multi factor analysis showed that V5 only was the independent risk factor of RP ( P <0.05).ROC analysis showed that the area under ROC curve of V 5 was 0.884 ( P <0.01),Taking V5=63%as critical value,the incidence rate of ≥grade 2 RP in V5≥63%group was 54.84%(17/31),however,which in V5<63%group was 3.45%(1/29).Conclusion DVH parameters are closely correlated to the occurrence of RP,in which V5 is an independent factor of predicting RP ,therefor, V5 value should be limited under 63%in order to decrease the volume of low dose irradiation range during IMRT to aviod the occurrence of RP .