Lower lymphocyte percentage and higher platelet count as poor prognostic factors for patients with epidermal growth factor receptor–mutated lung adenocarcinoma receiving tyrosine kinase inhibitors as first-line treatment

Background This study evaluated the effect of clinical factors on the treatment outcomes of patients with lung adenocarcinoma with active epidermal growth factor receptor (EGFR) mutations who received tyrosine kinase inhibitors (TKIs) as first-line treatment. Methods Patients with stage IIIb or IV lung adenocarcinoma with mutated EGFR were enrolled retrospectively between March 2010 and December 2017. The effects of various clinical features and hematologic markers on progression-free survival (PFS) and overall survival (OS) were analyzed. Results A total of 190 patients were enrolled in this study. In univariate analysis, the male sex, smoking history, EGFR mutation with L858R, and presentation with malignant pleural effusion at initial diagnosis were significantly associated with shorter PFS or OS. Among hematologic markers, lower lymphocyte percentage and higher platelet count were associated with significantly poor PFS and OS. Stepwise multivariate Cox regression analysis showed that smoking history, EGFR mutation with L858R, and lower lymphocyte percentage were independent poor prognostic factors for PFS and OS. Presentation with malignant pleural effusion and higher platelet count was an independent poor prognostic factor for OS only. Conclusion Patients with lung adenocarcinoma receiving TKIs as the first-line treatment and having hematologic markers with lower lymphocyte percentage, and higher platelet count had poorer prognoses compared with other patients. Additional studies are warranted to elucidate the underlying mechanisms.