Study On The Changes Of Plasma T790M Gene Mutation After TKI Therapy In Patients With Advanced Non-small Cell Lung Cancer

Objective: To observe the changes of plasma T790 M gene mutation in patients with advanced non-small cell lung cancer after oral administration of a generation of TKIs,and to explore the time point of T790 M resistance after the first generation of targeted drug resistance and the clinical characteristics of patients with T790 M resistance gene,so as to provide reference basis for the treatment of patients with non-small cell lung cancer after targeted treatment.Methods:The clinical data of 34 patients with EGFR classical mutation in advanced non-small cell lung cancer confirmed by pathology in the third Clinical Medical College of Xinjiang Medical University(affiliated Cancer Hospital)from January1,2016 to December 31,2017 were collected.According to T790 M gene,the patients were divided into T790 M positive group and T790 M negative group.The time point of T790 M drug resistance gene was dynamically observed to explore the characteristics of molecular progress.To explore the time relationship between the occurrence of plasma T790 M resistance gene and imaging progression,to observe the time interval between molecular progression to clinical progression,and to analyze the correlation between plasma T790 M gene mutation and PFS time.Results:The median progression-free survival time((Progress free survival,PFS)of EGFR mutation positive NSCLC patients after oral administration of first-generation EGFR-TKIs was 10.8(7.0,13.9)months.The median PFS of T790 M mutation positive group was 12.9 months(9.2,16.9 months),while that of T790 M mutation negative group was 7.2months(6.3,11.5 months).In the T790 M mutation positive group,the median time that T790 M gene could be detected was 11.3 months(8.3minutes 14.8 months),which was 1.6 months earlier than the median time of PFS in imaging.There was a significant correlation between the length of PFS and T790 M gene mutation after oral administration of the first generation EGFR-TKIs.Conclusion: In thepatients with advanced NSCLC with positive EGFR gene,the patients with positive T790 M gene mutation had longer progress-free survival time than those with negative T790 M gene mutation,and the long PFS was closely related to the T790 M mutant gene.The longer the PFS was after oral administration of the first generation of EGFR-TKIs,the more likely it was to have T790 M mutation gene.The time of detection of T790 M gene mutation in blood of patients with T790 M gene mutation was earlier than that of imaging progression,and the median time was 1.6 months earlier.