Epidermal growth factor receptor (EGFR) mutations in a series of non-small-cell lung cancer (NSCLC) patients and response rate to EGFR-specific tyrosine kinase inhibitors (TKIs)

Abstract

INTRODUCTION Epidermal growth factor receptor (EGFR) mutation related to tyrosine kinase inhibitors' (TKIs) responsiveness in non-small cell lung cancer (NSCLC) has become an important issue for therapeutic decision-making in NSCLC patients. MATERIAL AND METHODS Sixty-nine Caucasian NSCLC patients were screened for mutations in the tyrosine kinase (TK) domain of EGFR by direct sequencing from December 2005 to September 2010. RESULTS Activating mutations in the EGFR TK domain were found in 8 of 69 (11.6%) (7 deletions in exon 19 and one L858R mutation in exon 21). Seven of those mutations were found in adenocarcinoma and one mutation in bronchiolo-alveolar carcinoma; five of them in females (one smoker) and three of them in males (one smoker). All patients carrying activating mutations in the TK domain of EGFR were treated with TKIs. Ten patients not carrying an activating mutation in EGFR, who progressed after chemotherapy, were also treated with compassionate use of EGFR-specific TKIs (gefitinib or erlotinib). An objective response (partial response) was observed in all patients carrying an activating mutation in EGFR that received TKIs. Median overall survival for these patients has not been reached, however mean survival has been estimated at 39.5 months (95% CI, 22-57). CONCLUSIONS As previously reported, EGFR TK mutational analysis was a predictive test for response to targeted therapy with EGFR TKIs. The early identification of these patients consistently attains disease response and clearly improves outcomes.