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

BACKGROUND

The goal of the study was to evaluate the efficacy of tyrosine kinase inhibitors in patients with epidermal growth factor receptor (EGFR)-mutant metastatic non-small cell cancer and to determine the factors that predict objective response.

MATERIALS AND METHODS

In the study, data from metastatic non-small cell lung cancer patients with EGFR mutations treated with tyrosine kinase inhibitors were retrospectively reviewed. Factors predicting objective response were evaluated with logistic regression analysis.

RESULTS

The study evaluated the data of 105 patients. The most common EGFR mutations detected in patients were exon 19 (56.2%) and exon 21 (23.8%). The median progression-free survival (PFS) associated with EGFR tyrosine kinase inhibitors was 20.1 (95% confidence interval [CI], 13.4-26.7) months. The median overall survival (OS) in the post-metastasis period was found to be 30.8 (95% CI, 20.2-41.4) months. Five- and seven-year OS was determined as 28.7% and 22.9%, respectively. Factors predicting the objective response were analyzed. Presence of drug-related toxicity (P = 0.02), histopathologic type (P = 0.01), metastasis burden (P = 0.03), and EGFR mutation type (P = 0.04) were found to be statistically significant in multivariate analysis.

CONCLUSIONS

In our study, we found that EGFR tyrosine kinase inhibitors are effective and safe. Better response to EGFR inhibitors was observed in the presence of drug-induced toxicity, adenocarcinoma histology, low metastasis burden, and exon 19 mutation.