Impact of Sequential Therapy With Osimertinib on the Overall Survival in Patients With EGFR-mutant Non-small Cell Lung Cancer

Abstract Purpose. We conducted a retrospective analysis of the data of patients with epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) to investigate the associations between the available treatment options and the overall survival.Methods. We retrieved the patient data from the medical charts. Patients who were diagnosed as having EGFR-mutant NSCLC and treated with EGFR-tyrosine kinase inhibitors (EGFR-TKIs) between 2007 and 2020 at our institution were included in the analysis.Results. A total of 130 patients were included in the analysis. A log-rank test identified EGFR exon 19 deletion in the tumor, an Eastern Cooperative Oncology Group performance status of 0-1, serum lactate dehydrogenase level, local therapy for brain metastasis, and sequential osimertinib therapy for patients with the T790M mutation acquired after primary EGFR-TKI therapy as being significantly associated with a better overall survival. Analysis using a Cox proportional hazards model identified EGFR exon 19 deletion in the tumor, an Eastern Cooperative Oncology Group performance status of 0-1, serum lactate dehydrogenase level, local therapy for brain metastasis, and sequential therapy with osimertinib as being independently associated with a prolonged overall survival. Conclusion. Our analysis suggested that sequential therapy with osimertinib in patients with acquired drug resistance associated with the appearance of the T790M mutation after the primary EGFR-TKI therapy was associated with prolongation of the overall survival in patients with EGFR-mutant NSCLC in clinical practice settings.