Treatment and prognosis after progression in long-term responders to EGFR-tyrosine kinase inhibitor in advanced non-small cell lung cancer

INTRODUCTION The aim of this study was to investigate the treatment and prognosis of advanced non-small cell lung cancer (NSCLC) patients after failure of long-term treatment with epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI). MATERIAL AND METHODS We retrospectively analyzed all NSCLC patients with EGFR-TKI (gefitinib or erlotinib) treatment at our institution between 2011 and 2013 who progressed after at least stable disease on erlotinib or gefitinib for more than 6 months. Survival curves were plotted using the Kaplan-Meier method. The Cox proportional hazard model was used for multivariate analysis. RESULTS In total, 521 patients were administered EGFR-TKI. Of these, 298 patients received EGFR-TKI with progression-free survival less than 6 months (group A), and the other 223 patients more than 6 months (group B). There was a significant difference in overall survival (OS) between group A and group B (7.2 months vs. 5.0 months, p < 0.0001). The median OS for group B patients was 5.0 months. Among the 223 patients in group B, 38 patients received chemotherapy with continued EGFR-TKI after failure of prior gefitinib or erlotinib treatment, 92 with chemotherapy alone and 93 with best supportive care. Patients who continued gefitinib or erlotinib had a significantly longer OS (median: 7.5 months), followed by chemotherapy (5.5 months) and best supportive care (4.0 months) (p < 0.001). CONCLUSIONS The prognosis of advanced NSCLC patients after failure of long-term treatment with EGFR-TKI was poor. Chemotherapy with continued EGFR-TKI beyond progression of long-term responders was feasible and led to prolonged OS in advanced NSCLC patients.