A Retrospective Study Of Stage Ⅲ Non-small Cell Lung Cancer Elderly Patients Receiving Different Radiotherapy Techniques

Objective: To compare the dosimetric parameters,tumor markers,clinical outcome and treatment-related side effects of Helical Tomotherapy(TOMO),Intensity Modulated Radiation Therapy(IMRT),Three-Dimensional Conformal Radiation Therapy(3D-CRT)in elderly patients with stage III non-small cell lung cancer(NSCLC),and further to evaluate the best benefit of different radiotherapy techniques in the treatment of senile stage III NSCLC.Methods: The clinical data of elderly patients(≥70 years old)with stage III NSCLC who received radiotherapy in Yantai Yuhuangding Hospital from 2010 to 2016 were retrospectively analyzed.Radiotherapy techniques implemented in our research include TOMO,IMRT and 3D-CRT.The dosimetric parameters,short-term efficacy,side effects,tumor markers and long-term efficacy of the three radiotherapy techniques were compared.Dosimetric parameters were evaluated according to conformity index(CI),homogeneity index(HI),and mean dose(Dmean)of target area.Short-term efficacy was evaluated according to RECIST 1.0.Long-term efficacy was evaluated according to median survival,1-year and 2-year survival rates.Treatment toxicity was evaluated according to RTOG standard.SPSS 24.0 software was used for statistical analysis.Chi-square test,Kaplan-Meier,Cox survival analysis,Log-rank and so on were used in the study.Results: A total of 147 patients were enrolled in this study,of which 51 patients in 3D-CRT group,64 patients in IMRT group and 32 patients in TOMO group.Dosimetric data: Significant differences were seen in mean dose,CI,and HI of tumor target(TOMO group>IMRT group >3D-CRT group).Compared to 3D-CRT,significant advantages were also seen in V20、V30、Dmean of lung,V55、Dmean of esophagus,max dose of spinal cord,V40、Dmean of heart in IMRT and TOMO group.What’s more,V5 of lung in 3D-CRT group was significant lower than IMRT and TOMO group.Short-term efficacy: The response rates of total patients was 60.54%(3D-CRT group:47.05%;IMRT group: 65.63% and TOMO group: 71.88%,P=0.043).Tumor markers: Significant diclines of CEA、SCC、Cyfra21-1、CA125 were seen in the three grous.Cyfra21-1 and CA125 level after radiotherapy in Tomo and IMRT group were significantly lower than 3D-CRT group,in regrads to CEA and SCC,no significant diffenrences were seen in the research;no significant differences of all tumor markes were seen between TOMO and IMRT grous.Significant declines of the four tumor markers were seen in the response grous(CR+PR),and upward tendency of the four tumor markers were also seen in the non-response grous(SD+PD),however,no significant data were seen.Long-term outcome: The overall survival(OS)of the whole group was 13.10 months,and the median survival time of 3D-CRT,IMRT and TOMO groups were 11.9,13.3 and 13.9 months,respectively(P=0.296);1 and 2-year survival rates were 49.01%,57.81%,62.50%(P=0.272),15.68%、16.15%、18.75%,(P=0.361)respectively.In terms of toxicity,the incidence rates of ≥2grade radiation oesophagitisin 3D-CRT group,IMRT group and TOMO group was 52.90%,34.40%,28.10%,P=0.043;and incidence rates of ≥ grade 2 radiation pneumonits was 37.30%,18.8%,15.6%,(P=0.038),respectively.No significant difference was found in ≥grade 2 myelosuppression in the three groups.Multivariate analysis showed that KPS score and target dose were independent factors affecting survival.Conclusion: Dosimetric advantages were seen in IMRT and TOMO group,which in further improving the short-term effect,declining the incidence rates of ≥grade 2 radiation oesophagitisin and pneumonits in stage III eldly patients received these two treatment techniques.CEA、SCC、Cyfra21-1、CA125 acts as important markers for predicting short-term efficacy.KPS score and radiation dose were significant independent factors affecting prognosis.