Predictors of response in EGFR-mutant metastatic non-small cell lung cancer patients treated with tyrosine kinase inhibitors.

Abstract

e21149 Background: EGFR mutations are detected in 15-62% of patients with non-small cell (NSCLC) lung cancer. We can use tyrosine kinase inhibitors (such as erlotinib, gefitinib, afatinib) to treat patients with EGFR-mutant lung cancer. Tyrosine kinase inhibitors improve the survival outcomes of the patients. This study aimed to assess predictors of overall response rate (complete or partial response) in EGFR-mutant non-small cell lung cancer patients treated with EGFR inhibitors. Methods: Data of the EGFR-mutant lung cancer patients were evaluated retrospectively. Clinical, pathological, radiological, and treatment features of the patients were recorded. SPSS 25 version was used for statistical analysis. Kaplan-Meier and Cox-regression methods were used for survival analysis. Also, predictors of overall response were evaluated with logistic regression analysis. Results: 105 patients were included in the study. The female/male patients ratio was 1.25, and the median age was 61 (range, 33-85) years. Adenocarcinoma (90.4%) was the most common histopathological type. The ratios of Exon 19, exon 21, and other (rare or multiple) mutations were 59%, 25%, and 16%, respectively. 89 (84.9%) patients were de-novo metastatic at diagnosis. Before EGFR inhibitor therapy, the patients had received chemotherapy (22.9%) and palliative radiotherapy (40%). The patients received erlotinib (83.8%) or other EGFR inhibitors (16.2%) for treatment. Median overall survival was 30.8 (range 20.2-41.4) months. Overall response rate (complete or partial response) was 61.9%, stable response 11.4%, and progressive disease 26.7%. In logistic regression analysis, we found that age (p = 0.008), number of metastasis sites (p = 0.037), pathological type (adenocarcinoma or other types) (p = 0.001) were statistically significant for the overall response rate. However, gender (p = 0.98), tumor localizations (left or right lung) (p = 0.39), de-novo metastasis (p = 0.81), EGFR mutations type (p = 0.13), and type of EGFR inhibitör (p = 0.30) were not statistically significant. Conclusions: In this study, we showed real-life outcomes of the patients with EGFR-mutant metastatic non-small cell lung cancer. The data of predictors of overall response for EGFR inhibitors is limited. We detected that age, the number of metastatic organs, and histopathological type of tumor were affected the response of treatment.