Objective: To determine whether the specific genotype of exon 19 deletion has a better survival outcome than that of exon 21 substitution in advanced lung adenocarcinoma with EGFR mutant patients that were treated with EGFR-TKIs as second-line therapy after first-line chemotherapy.
Methods: Between April 1, 2010 and December 31, 2012, the detailed clinical information of 128 patients was screened from the hospital information database of the First Affiliated Hospital and the Third Affiliated Hospital of Kunming Medical University by inclusion/exclusion criteria. Then, a telephone follow-up and a review of all patients' image data were done to obtain the survival information of all patients. After that, all patients' data were processed by IBM(®) SPSS(®) version 19.0.
Results: There were correlations between EGFR mutation status, gross tumor type and PFS or OS according to the Kaplan-Meier survival analyses and log-rank tests. The exon 19 deletions had significantly better survival outcomes in comparison to exon 21 substitutions (median PFS: 8.1 vs. 6.8 months, P = 0.002; median OS: 17.6 vs. 12.5 months, P = 0.000). Stratification analyses of PFS and OS revealed that exon 19 deletions had a survival superior to exon 21 substitutions.
Conclusion: Compared with L858R mutation, the genotype of exon 19 deletion had a better survival outcome in terms of PFS and OS in patients with advanced lung adenocarcinoma treated with EGFR-TKIs as second-line therapy after first-line chemotherapy.