Survival outcome assessed according to tumor burden and progression patterns in patients with epidermal growth factor receptor mutant lung adenocarcinoma undergoing epidermal growth factor receptor tyrosine kinase inhibitor therapy.

BACKGROUND: Mutations in the epidermal growth factor receptor (EGFR) have been associated with a marked therapeutic response to EGFR-tyrosine kinase inhibitors (TKIs) in patients with advanced non-small-cell lung cancer (NSCLC). However, the clinical predictors of the survival benefit of EGFR-TKI therapy for NSCLC with EGFR-activating mutations have not been well elucidated. Therefore, the present study evaluated the clinical predictors of survival outcome in patients with EGFR-mutant NSCLC who had been treated with EGFR-TKIs.

MATERIAL AND METHODS: The data from 224 patients with EGFR-mutant lung adenocarcinoma treated with EGFR-TKIs were retrospectively reviewed. The treatment outcomes were evaluated according to the clinical factors, number of metastasis sites, and progression patterns.

RESULTS: The clinical factors associated with reduced progression-free survival (PFS) and overall survival (OS) on univariate analysis were Eastern Cooperative Oncology Group (ECOG) performance status (PS) ≥ 2, intra- and extrathoracic metastasis, extrathoracic metastasis, a high number of metastatic sites, metastasis to the liver or adrenal gland at baseline, and rapid progression at the diagnosis of progressive disease (PD). On multivariate analysis, the factors that remained significantly associated with a shorter PFS were ECOG PS ≥ 2 (odds ratio [OR], 2.189; 95% confidence interval [CI], 1.374-3.437; P < .001) and rapid tumor progression at PD (OR, 1.800; 95% CI, 1.059-3.058; P = .030).

CONCLUSION: Thus, the tumor burden, expressed as the number of metastatic sites at EGFR-TKI treatment, and rapid tumor progression at PD were predictive of inferior survival in patients with lung adenocarcinoma with activating EGFR mutations.