Comparison Of The Clinical Outcome Of Gefitinib For Advanced Lung Adenocarcinoma With Positive Epidermal Growth Factor Receptor Mutated In Exon 21 Or 19 Del Between Patients Treated With First And Second Line Therapy

Objective:Gefitinib,a tyrosine kinase inhibitor(TKI)targeting epidermal growth factor receptor(EGFR),shows excellent clinical benefit in treating advanced non-small cell lung cancer(NSCLC).The aim of this study was to compare the efficacy and toxicity of gefitinib as first and second line therapy for advanced lung adenocarcinoma patients with positive exon 21(L858R)or exon 19 deletion of EGFR mutation.Methods:We retrospectively analyzed the clinical data of 60 EGFR mutated advanced lung adenocarcinoma patients from July 2011 to November 2015,who have received oral gefitinib 250 mg once daily.Gefitinib was taken until disease progression,intolerable toxicity or death.Results:After a median follow-up of 792 days,1 death had occurred.Among the 59 patients who remained survival,17 patients progressed.Overall,the median progression-free survival(mPFS)was 10 months(95%confidence interval(CI):7.53-12.46 months,p<0.05).The response rate(RR)and disease control rate(DCR)were 33.33%and 71.66%,respectively.However,there was longer mPFS in first line therapy than that in second line therapy(p<0.05):in first-line gefitinib therapy,mPFS was 12 months among 41 patients(95%CI:9.58-14.41 months);in the second line therapy,mPFS was 7 months among 19 patients(95%CI:1.31-12.68 months).Furthermore,in subgroup analyses examining different EGFR mutation types,we noted mPFS was significantly longer for patient with exon 19 deletion than that with positive exon 21 in both first line therapy and second line therapy(p<0.05).Major adverse events included rash,abnormal liver functions,dry skin,diarrhoea,fatigue and anemia et al.in the range of Grade 1 and 2.Conclusion:Patients with advanced lung adenocarcinoma who were selected by positive exon 21 or 19 deletion mutations had significantly longer mPFS in first line therapy than that in second line therapy when treated with gefitinib.EGFR mutation types may influence the response to gefitinib therapy.