Efficacy and safety of cytotoxic drug chemotherapy after first-line EGFR–TKI treatment in elderly patients with non-small-cell lung cancer harboring sensitive EGFR mutations

Purpose Epidermal growth factor receptor–tyrosine kinase inhibitor (EGFR–TKI) is effective as first-line chemotherapy for patients with advanced non-small-cell lung cancer (NSCLC) harboring sensitive EGFR mutations. However, whether the efficacy of second-line cytotoxic drug chemotherapy after first-line EGFR–TKI treatment is similar to that of first-line cytotoxic drug chemotherapy in elderly patients aged ≥ 75 years harboring sensitive EGFR mutations is unclear. Therefore, we aimed to investigate the efficacy and safety of cytotoxic drug chemotherapy after first-line EGFR–TKI treatment in elderly patients with NSCLC harboring sensitive EGFR mutations. Methods We retrospectively evaluated the clinical effects and safety profiles of second-line cytotoxic drug chemotherapy after first-line EGFR–TKI treatment in elderly patients with NSCLC harboring sensitive EGFR mutations (exon 19 deletion/exon 21 L858R mutation). Between April 2008 and December 2015, 78 elderly patients with advanced NSCLC harboring sensitive EGFR mutations received first-line EGFR–TKI at four Japanese institutions. Baseline characteristics, regimens, responses to first- and second-line treatments, whether or not patients received subsequent treatment, and if not, the reasons for non-administration were recorded. Results Overall, 20 patients with a median age of 79.5 years (range 75–85 years) were included in our analysis. The overall response, disease control, median progression-free survival, and overall survival rates were 15.0, 60.0%, 2.4, and 13.2 months, respectively. Common adverse events included leukopenia, neutropenia, anemia, thrombocytopenia, malaise, and anorexia. Major grade 3 or 4 toxicities included leukopenia (25.0%) and neutropenia (45.0%). No treatment-related deaths were noted. Conclusion Second-line cytotoxic drug chemotherapy after first-line EGFR–TKI treatment among elderly patients with NSCLC harboring sensitive EGFR mutations was effective and safe and showed equivalent outcomes to first-line cytotoxic drug chemotherapy.