Abstract
BACKGROUND: The prognosis of patients with epidermal growth factor receptor (EGFR) mutation-positive lung cancer has improved significantly since the advent of EGFR tyrosine kinase inhibitors (EGFR-TKIs). We aimed to investigate the relationship between patient characteristics, EGFR genotype, therapeutic agents, and the prognosis of the patients with EGFR mutation-positive lung cancer. METHODS: This retrospective cohort study analyzed 198 Japanese patients with unresectable EGFR mutation-positive lung cancer who were treated with EGFR-TKIs at Toho University Sakura Medical Center from April 2006 to December 2021. Factors associated with overall survival (OS) were analyzed using Cox proportional hazards analysis. RESULTS: Patients who received osimertinib had a significantly longer OS than did those not receiving it (median OS, 36.2 versus 20.7 months; p < 0.001).There were significant differences in OS between patients with EGFR mutation who received osimertinib as first-line treatment, T790M-positive patients who received osimertinib as second- or later-line treatment, and those who did not receive it (median OS, 28.2 versus 40.2 versus 20.7 months; p = 0.003). However, in T790M-negative patients, no significant difference in OS was noted between those who did and did not receive osimertinib as post-treatment (median OS, 28.0 versus 40.0 months; p = 0.619). Multivariate Cox proportional hazards analysis showed that osimertinib treatment was associated with longer OS (hazard ratio, 0.480; 95% confidence interval, 0.326-0.707; p < 0.001). CONCLUSION: The patients who were T790M-positive in the first-line treatment with first or second-generation EGFR-TKIs and were given osimertinib as the second or later line treatment had a better prognosis than the patients who were T790M-negative in the first-line treatment with first or second-generation EGFR-TKIs and could not receive osimertinib.