Dosimetry、Side Effects And Prognosis Comparison Of IMRT And 3D-CRT In ⅢB Stage NSCLC

ObjectiveConsistent results are lacking as regards the comparative effectiveness of intensity-modulated radiotherapy(IMRT)versus three-dimensional conformal radiotherapy(3DCRT)in patients with locally advanced non-small cell lung cancer(NSCLC).This study was conducted to evaluate the dosimetry,side effects and prognosis between IMRT and 3D-CRT techniques in IIIB NSCLC,and to investigate the prognostic factors of locally advanced NSCLC.MethodsPatients treated with definitive radiotherapy(RT)between 2009.1 and 2013.6 in Shandong Tumor Hospital Affiliated to Shandong University were retrospectively reviewed.Comparison of IMRT and 3D-CRT two groups of related dosimetric parameters,toxicity(radiation esophagitis,radiation pneumonitis,bone marrow suppression),overall survival(OS),progression free survival(PFS).The chi-square test was adopted for dichotomous data comparison between groups.Continuous variables were presented as mean± S and were compared by using the Mann-Whitney U test.The Kaplan-Meier method was used to estimate survival time and follow-up time,and the log-rank test was performed to examine the significance of difference.P<0.05 was considered statistically significant ResultsA total of 133 patients were eligible for analysis,including 58(41.4%)with IMRT and 75(58.6%)with IMRT.IMRT plans decrease the lungs V20,V25,the mean dose,increase the lungs V5 and increase the lungs V10(P<0.05).The lungs V15 under both modes have no statistical significance(P>0.05).The conformal indices(CI)and homogeneity indices(HI)of PTV in IMRT were better than those in 3D-CRT(P<0.05).The cord max dose and the heart mean does in IMRT were low in 3D-CRT(P<0.05).There was a significant reduction of lung toxicity and esophagus toxicity in the IMRT group when compared with the 3D-CRT group.There was no significant difference in the reduction of leukocyte,neutrophile granulocyt and hemoglobin between the two groups.The 1-,2-,3-year survival(OS)of the IMRT group and 3D-CRT group were 84.0%,48.3%,29.3% and 87.9 %,31.8%,22.2%,respectively.The median OS periods of two groups were 11.2 and 9.8 months(P>0.05).The 1-,2-,3-year progression-free survival(PFS)of two groups were 44.8%,12.1%,2.4% and 26.7 %,9.3%,2.7%,respectively.The median PFS periods of two groups were 11.2 and 9.8 months(P>0.05).Both in univariate and multivariate analysis,gender,age,smoking status,histological type,T stage,N stage,radiotherapy dose and lymph node metastasis showed that has no significant influence with the survival.Low KPS score(P=0.029)and weight loss ≥5%(P=0.045)were associated with worse OS.Low KPS score(HR=1.802,P=0.01)was associated with worse PFS.ConclusionIn comparison with 3D-CRT,IMRT has a significant advantage in dosimetry.IMRT may confer comparable OS than can be achieved with 3DCRT in NSCLC,along with the reduction of pulmonary and esophageal toxicity.Weight loss and concurrent chemoradiotherapy were independent prognostic factors in IIIB stage NSCLC.