Prognostic factors of epidermal growth factor receptor (EGFR)-mutated advanced non-small cell lung cancer treated with EGFR-tyrosine kinase inhibitor (TKI): a nationwide registry study in China

Background: Epidermal growth factor receptor (EGFR) mutations are the most common oncogenic subtype in non-small cell lung cancer (NSCLC) among Asians. EGFR tyrosine kinase inhibitors (TKIs) have become the mainstay of therapy, significantly improving survival outcomes. However, prognostic factors influencing survival in real-world settings among patients treated with EGFR-TKIs remain underexplored. This study aims to identify prognostic factors in EGFR-TKI-treated patients using data from a nationwide registry. Methods: Patient data were sourced from the "Meina Xinsheng" registry, with survival metrics provided by the China Center for Disease Control. We analyzed the impact of sex, age, disease stage, histology, gene mutation type, and Karnofsky Performance Status (KPS) score on duration of treatment (DoT), overall survival (OS), and the incidence of long-term survival (>5 years), using both univariate and multivariate analyses. A reference cohort of EGFR wild-type patients receiving EGFR-TKI therapy was also included. Results: Among 231,699 patients registered for EGFR-TKI treatment across 3,445 hospitals nationally, 221,788 cases of advanced NSCLC were analyzed. Within the subset of 83,791 patients eligible for survival analysis spanning 2012 to 2018, the median OS was 3.2 years [95% confidence interval (CI): 3.18-3.3], and the median lung cancer-specific survival (LCSS) was 4.1 years (95% CI: 4.02-4.1). At least 7.7% of patients achieved a survival milestone of more than 5 years. Factors associated with improved OS and higher long-term survival rates included female sex, stage IIIb disease, adenocarcinoma histology, EGFR exon 19 deletion, superior KPS scores, prolonged DoT, receiving EGFR-TKI as first-line treatment, and achieving a complete response (CR). Younger patients (