Does CNS metastases reduce systemic therapy lines for NSCLC patients with EGFR mutation?
e21558 Background: The latest generation tyrosine kinase inhibitor (TKI), Osimertinib, targets the epidermal growth factor receptor (EGFR) despite the T790M mutation status in non-small-cell lung cancer (NSCLC). In cases where there is a detected EGFR mutation on the exon 19-deletion and on the exon 21-L858R in the NSCLC population, studies have demonstrated that Osimertinib has a positive benefit in overall survival and delayed progression of central nervous system (CNS) metastases. Methods: From January 2010 to December 2018, 56 patients with the metastatic NSCLC-EGFR mutation, treated with Osimertinib 80 mg once daily, were included in this analysis. Retrospective data was extracted through the internal administrative databases located at Sunnybrook Hospital. All patients had EGFR mutation positivity by cytology, plasma or tissue sampling. The primary endpoint was to evaluate whether NSCLC patients who were exposed to Osimertinib and had brain metastases underwent fewer systemic therapy lines as compared to those who did not have metastases involving the brain. Results: Eligible patients were analyzed and the median age at the initial diagnosis was 65 years old; 50% (n = 28) of the patients had brain metastases. The median of systemic treatment lines for patients without CNS metastasis was two and for those who have metastases to the brain was three. 82,2% of this cohort received Osimertinib in 2nd line, after development of acquired resistance to first or second TKI generation. Conclusions: Results from this study did not demonstrate that EGFR mutated, NSCLC patients with CNS metastases received less systemic therapy lines to those without metastases involving the brain. A larger cohort for further investigation is warranted.