Number of metastatic organs negatively affects the treatment sequence in patients with EGFR‐TKI failure

Background Several studies have previously demonstrated the survival benefit of both EGFR‐TKI treatment and chemotherapy in patients with non‐small cell lung cancer (NSCLC) harboring EGFR mutations. The aim of the present study was to clarify the factors influencing the treatment sequence after failure of EGFR‐TKI therapy, focusing on the number of organs with metastasis (hereafter, metastatic organs). Methods Between January 2010 and December 2016, consecutive patients with EGFR‐mutated NSCLC who were started on first‐line EGFR‐TKI were reviewed. The factors influencing withholding systemic chemotherapy and the post‐progression survival (PPS) after failure of EGFR‐TKI were investigated. Results A total of 393 patients were started on first‐line EGFR‐TKI during the study period. After excluding patients maintained on EGFR‐TKI or who received osimertinib targeting secondary EGFR T790M, 297 patients were included in the analysis. Among these, 180 (60.6%) received chemotherapy after failure of EGFR‐TKI (TKI‐Ct group), while the remaining 117 (39.4%) received no chemotherapy (TKI‐only group). Multivariate analysis identified older age (≥75 years: odds ratio [OR] = 0.25, 95% confidence interval [CI]: 0.11–0.43, P