Efficacy of chemotherapy in epidermal growth factor receptor (EGFR) mutated metastatic pulmonary adenocarcinoma patients who had acquired resistance to first-line EGFR tyrosine kinase inhibitor (TKI)

Introduction: Salvage chemotherapy is frequently used when tumour epidermal growth factor receptor (EGFR) mutated patients experience disease progression with first-line EGFR-tyrosine kinase inhibitor (TKI) treatment. However, the efficacy of salvage chemotherapy is still unknown. Methods: We retrospectively reviewed the chart records of our pulmonary adenocarcinoma patients between 2010 and 2013. Results: Five hundred and six of the 1240 stage IV adenocarcinoma patients had an EGFR mutation and 338 received first-line EGFR-TKI treatment. In all, 169 patients in this group received salvage chemotherapy after failure of EGFR-TKI, and 102 patients were eligible for this study. The chemotherapy response rate of these 102 patients was 24.5%, with a median progression-free survival (PFS) of 4.5?months, and median survival time was 14.6?months. Patients who received pemetrexed-based chemotherapy had longer PFS and overall survival (OS), although the extent was statistically insignificant. Progression-free survival and OS were longer for patients who received combination chemotherapy than single-agent chemotherapy. Conclusions: Pemetrexed-based combination chemotherapy is preferred before a more efficient treatment strategy is found.