Prognostic Analysis Of Patients With Locally Advanced Non-small Cell Lung Cancer Treated With Intensity Modulated Radiatherapy

Objective:To analyze the effiacy and influencing factors of intensity modulated radiotherapy in 130 patients with locally advanced non-small-cell lung cancer（NSCLC）.Methods:Between Oct 2012 to Jun 2019,the clinical data 130 patients with locally advanced non-small cell lung cancer（LA-NSCLC）who received IMRT as initial treatment were reviewed.Evaluated factors included,general clinical data,Karnofsky performance status（KPS）,therapeutic modalities,groupe of gross tumor volume（GTV）、groupe of planning target volume（PTV）,the radiation-induced lung injury（RILI）and radio-dosimetry indexes（more than 10 items such as V₅）.Univariate survival rate analyses were estimated using the Kaplan-Meier method,with comparisons made between groups by the log-rank test.The univariate factors for prognosis with statistical significance were included in the Cox proportional hazards model for multivariate analysis.Chi-square test was used for classification data,T-test or Mann-Whitney U test was used for measurement data,and binary logistic regression was used for multivariate analysis.Then draw the receiver operating characteristic（ROC）curve to the measured data,and find the cutoff value by the area under the curve（AUC）.Result:130 patients had been followed up.The follow-up time was 6-74 months and the median follow-up time was 21 months.In this study,the1-years、3-years、5-years overall survival percentage and the median survival time（MST）were 70.51%、26.91%、8.06%and 19 months.Using univariate analyses,we found that the factors influencing the prognosis were associated with gender,KPS,smoking history,groupe of GTV、PTV and therapeutic modalities.Univariate factors with statistical significance were included in Cox regression model for multivariate analysis（x²:24.230,P<0.000）.The results showed that KPS≥80 scores,PTV<394cm³and concurrent chemoradiotherapy were independent factors affecting the prognosis.We found that RILI grades 2 or highter occurred in37（28.46%）in patients,respectively.The statistically significant factors（all p<0.05）were analyzed by binary logistic regression.We determined that the tumor stages T₂、V₅and V₂₀were the most significant factors associated with RILI grades 2 or highter using multivariate analysis.The AUC of V₅and V₂₀was 0.732 and 0.789,suggesting that the V₅and V₂₀limits could reduce the occurrence of RILI.Conclusion:（1）The results showed that KPS≥80 scores,PTV<394cm³and concurrent chemoradiotherapy were independent factors affecting the prognosis.（2）We determined that the tumor stages T₂、V₅and V₂₀were the most significant factors associated with RILI grades 2 or highter using multivariate analysis.But the cutoff value of V₅、V₂₀needs to be studied further.