Abstract 72P
Background
Compared to exon 19 deletions, the epidermal growth factor receptor (EGFR) exon 21 L858R (21L858R) mutation is associated with a poorer prognosis in non-small cell lung cancer (NSCLC), particularly in patients with brain metastases (BM). However, there is a notable lack of prospective or retrospective clinical studies focusing on this specific population. This study aims to evaluate the efficacy of different first-line treatment strategies using EGFR-tyrosine kinase inhibitors (TKIs) in NSCLC patients harboring 21L858R and BM while providing insights into concurrent mutations and resistance mechanisms.
Methods
We analyzed clinical data from 331 patients diagnosed with EGFR 21L858R mutation and BM who received first-line EGFR-TKI treatment at Sun Yat-sen University Cancer Center between April 2014 and June 2023. The efficacy was evaluated through intracranial progression-free survival (iPFS), PFS, and overall survival (OS).
Results
Compared to the first-generation and second-generation cohorts, the third-generation EGFR-TKI cohort demonstrated significant improvements in iPFS (20.6 m, p=0.002), PFS (18.6 m, p < 0.001), and OS (41.2 m, p=0.016). Within the third-generation EGFR-TKI group, the combination chemotherapy cohort exhibited most favorable outcomes, with marked extensions in both iPFS (not reached, p=0.037) and PFS (28.0 m, p=0.049), alongside a trend towards increased OS (p=0.090). Multivariate analyses identified the treatment regimen of third-generation TKIs combined with chemotherapy as an independent prognostic factor for improved iPFS (p=0.013). Compared to treatment regimens containing first-generation or second-generation EGFR-TKIs, patients with TP53 mutations derived greater benefit from treatment regimens containing third-generation EGFR-TKIs (iPFS, p < 0.001; PFS, p < 0.001; OS, p < 0.001).
Conclusions
The combination of third-generation EGFR-TKIs with chemotherapy shows enhanced efficacy in patients with EGFR 21L858R mutation and BM compared to other treatments. Future prospective clinical trials are essential to assess this combination’s effects in this population.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.