This study was done to explore whether treatment with osimertinib leads to the improved OS for patients with EGFR-mutated NSCLC with LM compared with those not treated with osimertinib.


Patients with EGFR-mutated NSCLC and cytologically confirmed LM were retrospectively analyzed for OS according to osimertinib treatment and T790M mutational status. The OS was defined as the time from the diagnosis of LM to death.

351 patients with LM were included in the analysis. T790M mutation was detected in 88 of 197 patients tested, and a total of 110 patients were treated with osimertinib after LM. No difference in mOS according to T790M mutational status was found. Nevertheless, patients treated with osimertinib had a superior OS of 17.0 months compared with those not treated with osimertinib who had an mOS of 5.5 months, regardless of T790M mutational status. This was also considerably longer even than the mOS of 8.7 months of those who were never treated with osimertinib but had first- or second-generation EGFR tyrosine kinase inhibitors.

The study concluded that osimertinib is a promising treatment option for EGFR-mutated NSCLC with LM regardless of T790M mutational status.