Abstract
BACKGROUND: The incidence of leptomeningeal metastasis (LM) in patients with advanced non-small cell lung cancer (NSCLC) is increasing gradually. However, it poses therapeutic challenges due to limited effective interventions. Intrathecal Pemetrexed (IP) holds broad application prospects in the therapeutic domain of LM. This study aims to evaluate the efficacy, safety, and optimal combination strategies of IP in NSCLC-LM patients with epidermal growth factor receptor (EGFR) mutation-positive status, with the aim of providing real-world data support for exploring more precise personalized treatment strategies for these patients. METHODS: 104 EGFR-mutated NSCLC-LM patients who received IP treatment at Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School from January 2018 to June 2024 were analyzed retrospectively. Clinical parameters, treatment regimens, and survival outcomes were collected. The overall survival (OS), progression-free survival (PFS), clinical response rate and adverse events (AEs) were evaluated. RESULTS: The cohort demonstrated a median PFS of 9.6 months and OS of 13.0 months with 6-month and 1-year OS rates of 80.8% and 56.5%, respectively. Clinical response was observed in 77.9% of patients. The common AEs were myelosuppression (58.7%) and elevation of hepatic aminotransferases (25.0%). Nine (8.7%) patients experienced grade 4 myelosuppression and recovered to normal after receiving symptomatic treatment. Subgroup analyses revealed prolonged OS in patients with Karnofsky performance status (KPS) ≥60 versus <60 (14.4 vs 9.0 months, P=0.0022) and those receiving Bevacizumab therapy versus not (19.2 vs 10.5 months, P=0.0011). CONCLUSIONS: IP exhibits promising efficacy and manageable toxicity in EGFR-mutated NSCLC-LM patients. When combined with Bevacizumab, it exerts synergistic antitumor effects with the potential to further improve clinical outcomes.