Epidermal growth factor receptor mutation status and clinical characteristics of advanced lung adenocarcinoma in elderly patients

Abstract

Objective To investigate the epidermal growth factor receptor(EGFR)mutation status and the corresponding clinical characteristics of advanced lung adenocarcinoma in patients over 60 years and the efficacy of first-line therapy. Methods A total of 243 cases aged 60 years and over with histologically confirmed advanced lung adenocarcinoma from January 2011 to December 2015 at Beijing Hospital were included in this retrospective study.The EGFR mutation status was detected by the amplification refractory mutation system.Clinical characteristics including gender, smoking status, and incidence of brain metastasis at initial presentation were recorded.Data for 163 cases aged below 60 years during the same period were collected as controls.The characteristics of EGFR mutation status of elderly patients were analyzed.Besides, differences between the groups in EGFR mutation status, other clinical characteristics and therapeutic efficacy of first-line treatment were compared. Results The EGFR mutation rate was 53.1%(129/243). Basic clinical features were not statistically different between the groups.For elderly patients harboring EGFR mutations, the incidences of the exon 19 deletion and the exon 21 L858R mutation accounted for 46.2%(55/119)and 53.8%(64/119), respectively, whereas for younger patients with EGFR mutations, the prevalence of the exon 19 deletion and the exon 21 L858R mutation were 66.2%(49/74)and 33.8%(25/74), respectively.The proportion with the exon 21 L858R mutation was statistically higher in elderly patients(P=0.007). Eighty-two out of 129 patients with sensitive EGFR mutations received first-line EGFR tyrosine kinase inhibitors, with an objective response rate(ORR)of 62.2%(51/82) and a progression-free survival(PFS)of 8.1 months.For the other 152 patients who received chemotherapy, the ORR was 24.3%(37 cases) and the PFS was 6.0 months.The efficacy of first-line therapy was similar between the groups. Conclusions The incidence of EGFR mutations and clinical characteristics for elderly patients with advanced lung adenocarcinoma are similar to those for younger patients, whereas the proportion of the EGFR exon and the 21 L858R mutation is higher in the elderly.Considering similar benefits from fist-line treatment between different age groups, elderly lung cancer patients should receive similar treatment. Key words: Lung neoplasms; receptor epidermal growth factor; Mutation