Comprehensive parameters in predicting radiation pneumonitis in advanced stage non-small-cell lung cancer treated with three-dimensional conformal or intensity-modulated radiation therapy

Abstract

Objective To analyze relation of comprehensive parameters of the dose-volume V5,V10 and V20 with radiation pneumonitis (RP) in patients with advanced stage non-small-cell lung cancer (NSCLC) treated with three-dimensional conformal (3DCRT) or intensity-modulated radiation therapy (IMRT).Methods Data of 90 patients with histologically proved NSCLC treated with 3DCRT or IMRT between November 2006 and July 2009 were collected.The median radiation dose of 70 Gy (range, 61 - 80 Gy) was delivered with late-course accelerated hyperfractionated radiotherapy (LAHRT).The V5 ,V10 ,V20,V30 and mean lung dose (MLD) were calculated from the dose-volume histogram system.The RP was evaluated according to the common toxicity criteria 3.0(CTC 3.0).Results The range of V5 ,V10 and V20 was 36% - 98%, 27% - 78% and 19% - 54%, respectively, with a median value of 66%, 48% and 31%, respectively.The RP of grade 1,2,3,4 and 5 was observed in 29,23,5,1 and 1 patients.The V5,V10 ,V20, contralateral V10, GTV,PTV, and numbers of fields were all significantly associated with RP of ≥grade 1 (χ2=2.04, 2.05, 2.01, 4.62, 6.50, 5.61, 5.61, and P= 0.044, 0.043, 0.047, 0.030,0.010,0.020,0.020).The V5, V10, V20, V30, and MLD were all significantly associated with RP of ≥ grade 2 (χ2= 2.05,2.20,2.96,4.96,5.20, and P = 0.040,0.030,0.000,0.030,0.020).In Logistic regression analysis, GTV was the only factor significantly associated with RP of ≥ grade 1 (χ2= 4.06, P =0.044).The V20 was the only factor significantly associated with RP of ≥grade 2(χ2=9.61,P=0.002).The RP of ≥grade 2 was significantly increased when V20 was more than 31%.The RP of ≥grade 2 was significantly increased when V20, V10 and V5 were more than 31%, 48% and 66%, respectively.The RP of ≥ grade 2 was significantly increased when V20 was more than 31% and V5 was more than 66%.Conclusions The comprehensive parameters combined with V5, V10 and V20 are effective in predicting RP. Key words: Carcinoma, non-small cell lung/radiotherapy; Radiotherapy, three-dimensional conformal or intensity-modulated; Radiotherapy, late-course accelerated hyperfraction; Radiation pneumonitis; Dose volume histogram