A Study On Correlation Of Sensitivity To Radiotherapy In Non-small Cell Lung Cancer Based On Mutations Of CtDNA

Objective: Lung cancer is currently one of the most common cancers in the world and causes a major cause of cancer-related deaths,of which approximately 80% of patients die from Non-small Cell Lung Cancer(NSCLC).The early clinical symptoms of lung cancer are not obvious,imaging and tumor markers can not find the lesions in time.The patients sre usually as advanced stages.At the same time,there is also a lack of minimally invasive real-time monitoring of radiation therapy in NSCLC.Therefore,there is a need for a clinical indicator that can assist in early diagnosis and monitoring.As a new diagnostic and prognostic indicator,circulating tumor DNA(ctDNA)is increasingly used in clinical practice.ct DNA contains all the gene mutation information of the patient's tumor cells.Compared with the traditional tissue biopsy,ctDNA has the advantages of easy acquisition and repeated sampling.By detecting ctDNA in peripheral blood,it can help on predicting treatment results,prognosis analysis and tumor load dynamic monitoring.In this study,peripheral blood ctDNA of patients with non-small cell lung cancer was examined by Next-Generation Sequencing(NGS)to determine whether the ctDNA gene mutation characteristic could predict radiosensitivity of non-small cell lung cancer.Methods : Prospectively included the patients with NSCLC who were treated with radiotherapy at Sichuan Cancer Hospital.5ml of antecubital vein blood was collected from the patient before fasting in the early morning,3 ml purified plasma was obtained through purification,and the samples were deeply sequenced by NGS;the clinical efficacy and shrinkage rate of tumor volume after radiotherapy were evaluated,and a comparative analysis was performed.Results: 10 cases of non-small cell lung cancer patients before radiotherapy plasma ct DNA sequencing report total SNV mutations(SNVT),INDEL mutation(DELT),the total number of CNV(CNVC),and the size of the area of CNV(CNVS)in the pathological type,clinical stage,T stage,N stage in no significant predictive significance(P > 0.05).SNVT was of significance in the evaluation of clinical efficacy,and the number of SNVT was 2128 as the cut-off value.The tumor volume regression rate was higher in patients with SNVT>2128 than in patients with SNVT?2128.There was a statistically significant difference(P=0.044).Screening known gene mutations and extracting tumor-driven genes for evaluation revealed that BED4,DNMT1,NCOR2,NR1H2 and TRRAP were significant predictors of radiotherapy(P<0.05).