A Clinical Study Of The Effect Of EGFR Mutations On Targeting Therapy As Second Line Treatment In Advanced Non-small Cell Lung Cancer(NSCLC)

Objective: This essay was a retrospective analysis of132cases ofpatients with advanced NSCLC from Liaoning Provincial Tumor Hospitalwho EGFR mutation status is known treated with gefitinib or chemotherapyas second-line therapy, to explore the effect of gene mutations of epidermalgrowth factor receptor (EGFR) on targeting therapy as second-line treat-ment in advanced non-small cell lung cancer (NSCLC).Methods: Collect132patients with NSCLC from Liaoning ProvinceTumor Hospital between2010.6.1-2013.6.30that confirmed stage IIIB/IV(AJCC7th edition TNM stages) retrospectively, both of them had diseaseprogression after platinum-based first-line chemotherapy and had thedetection of EGFR and accepted second-line therapy. according to theresults of testing and therapy，the patients were divided into EGFR mutantgefitinib group (35cases), EGFR mutant chemotherapy group (chemo-therapy as pemetrexed or docetaxel)(30cases), EGFR wild-typegefitinib group (32cases), EGFR wild-type chemotherapy group(chemotherapy as pemetrexed or docetaxel)(35cases), analyze theclinical features, efficacy, survival and toxicity of the4groups of patients.Using SPSS19.0statistical software for statistical analysis, evaluation ofthe general clinical characteristics of the4groups, efficacy and adver sereactions with χ2test, the progression-free survival and survival time useKaplan-Meier method, comparing with the survival use the Log-rank testing, multivariate analysis use COX regression model. Determine P <0.05to have significant differences.Results: EGFR mutation rate in terms of gender (P=0.026), histologicaltype (P=0.010), smoking status (P=0.026) has significant differences,butin the terms of age (P=0.452), disease stage (P=0.925), PS score (P=0.214) has no significant difference. EGFR mutation rate is higher infemale, adenocarcinoma, non-smokers than the corresponding group;EGFR mutant gefitinib group: complete response (CR)5.7%, partialresponse (PR)45.7%, stable disease (SD)37.1%, progressive disease(PD)11.5%; EGFR mutant chemotherapy group: CR0%, PR30.0%, SD36.7%, PD33.3%; EGFR wild-type oral gefitinib groups: CR0%, PR9.4%,SD46.9%, PD43.7%; wild-type chemotherapy group: CR0%, PR28.6%,SD37.1%, PD34.3%. The objective response rate (ORR) of4groups are51.4%,30.0%,9.4%and28.6%respectively; the disease control rate(DCR) are88.5%,66.7%,56.3%and65.7%respectively, the re are signify-cant differences (all P <0.05). The median progression-free survival (PFS)of4groups are9.40,4.82,2.89,3.48months respectively, P <0.001, thereis significant difference. Pairwise comparison: EGFR mutant gefitinibgroup with EGFR mutant chemotherapy group, the EGFR wild-type oralgefitinib group with wild-type chemotherapy group, EGFR mutant oralgefitinib group with EGFR wild-type oral gefitinib, the PFS also aresignificant differences(all P <0.05). The median survival time (OS) of the4groups are14.45,16.87,14.90,12.90months respectively, P=0.103, there isno significant difference. Pairwise comparison:EGFR mutant gefitinibgroup with mutant chemotherapy group, EGFR wild-type gefitinib groupwith wild-type chemotherapy group, EGFR mutant gefitinib group withEGFR wild-type gefitinib group, there are no significant differences in OS(all P≥0.05). The patients treated with gefitinib has higher incidence ofrash and diarrhea than chemotherapy,59.6%vs10.8%,16.3%vs4.6%respectively,but in bone marrow supp ression、 nausea and vomiting，chemotherapy group have higher incidence than gefitinib group，which are97.0%vs26.9%,72.3%vs22.4%,15.4%vs4.8%respectively. In additionto the2patients in chemotherapy group can not tolerate chemotherapy because of IV grade of bone marrow suppression, the rest of patients allhave improvement by symptomatic treatment,and no person need to stopchemotherapy or gefitinib due to serious side effects.’Conclusions: EGFR mutation rate is related to gender, histologicaltype, smoking status, and unrelated to age, PS score and disease staging.EGFR mutation rate is higher in females, adenocarcinoma, non-smokersthan the corresponding group.The patients with EGFR mutation treated withgefitinib has the better ORR, DCR than the other three groups of patients,For EGFR mutant patients treated with gefitinib has longer PFS thanchemotherapy, for EGFR wild-type patients treated with chemotherapy issuperior to gefitinib in PFS. For patients who EGFR mutant gefitinib grouphas longer PFS than EGFR wild-type gefitinib group. Thus, the EGFRmutations can be used as an important indicator of advanced NSCLC insecond-line targeted therapy.