Consistency of plasma circulating tumor deoxyribonucleic acid and tumor tissue samples in the mutation detection in non-small cell lung cancer patients and its relationship with prognosis

Objective To investigate the consistency of plasma plasma circulating tumor deoxyribonucleic acid (ctDNA) and tumor tissue samples in the mutation detection in non-small cell lung cancer (NSCLC) patients and its relationship with prognosis. Methods 50 NSCLC patients in our hospital from March 2017 to June 2018 were selected, plasma ctDNA and tumor tissue DNA were extracted, and the mutations of epidermal growth factor receptor (EGFR) gene were detected by amplification refractory mutation system (ARMS) method, and the consistency of the two methods was analyzed. Then the correlation between EGFR gene mutation detected by plasma ctDNA and progression-free survival (PFS) was analyzed. Results The mutation rate of EGFR gene detected by plasma ctDNA in female and non-smoking patients was significantly higher than that in male and smoking patients (P<0.05). The specificity, sensitivity, positive predictive value and negative predictive value of detection of EGFR gene mutation by ctDNA in plasma were 100.00%, 58.82%, 53.33% and 100.00%, respectively. The consistency of ctDNA and tumor tissue in the detection of EGFR gene mutation was good (P<0.05). The plasma ctDNA and tumor tissues showed that the PFS of EGFR mutant patients was significantly longer than that of wild type patients(P<0.05). Conclusion Plasma ctDNA and tumor tissue samples of NSCLC patients have a good consistency in detecting EGFR gene mutation, and plasma ctDNA has a certain predictive value for the prognosis of patients undergoing chemotherapy, which can be used as a laboratory method for clinical detection of EGFR gene mutation and prognosis assessment. Key words: Non-small cell lung cancer; Circulating tumor deoxyribonucleic acid; Epidermal growth factor receptor gene; Gene mutation; Prognosis