O11. The results of gefitinib in front line treatment of Caucasian patients with NSCLC in the Czech Republic: analysis according to activated mutations location

Background: This study evaluates treatment outcomes in 127 non-small cell lung cancer (NSCLC) patients from Czech Republic according to activated mutations located in exons 19 (Del19) and 21 (L858R).

Methods: NSCLC patients with epidermal growth factor receptor (EGFR) activated mutations were treated with gefitinib in first line between February 2010 and March 2014 in 10 institutions. Retrospective analyses were carried out to assess the effectiveness of gefitinib treatment according to activated mutations located in exons 19 (Del 19) and 21 (L858R).

Results: Out of 127 treated patients, 83 (53 female, 25 male) had EGFR mutations in exon 19, and 44 (31 female, 11 male) had EGFR mutations in exon 21. In both groups, most patients were in stage IV and their median age was 65 years. No statistically significant difference was observed in the representation of smokers at the chosen significance level α=0.05 (P=0.893). A statistically significant difference was found in the representation of patients with adenocarcinomas (P=0.016). In the group of patients with mutation located in exon 19, 94% were adenocarcinomas; in the group with mutation in exon 21, 82% were adenocarcinomas. Between these two groups, there was no statistically significant difference according to performance status (P=0.887); no statistically significant difference according to disease control (CR+PR+SD) (P=0.148); but there was a statistically significant difference according the response to the treatment (CR+CP) (P=0.048). There was no statistically significant difference (P=0.452) in overall survival. In the group of patients with mutation located in exon 19, the overall survival was 22.7 months (95% CI: 16.1-29.4); in the group with mutation in exon 21, overall survival was 16.1 months (95% CI: 11.6-20.5), with70% patients still alive in both groups. There was no statistically significant difference (P=0.301) in progression free survival; in the group of patients with mutation in exon 19 it was 10.6 months (95% CI: 8.8-12.4) and in the group with mutation in exon 21 it was 9.4 months (95% CI: 7.3-11.4).

Conclusions: In both groups progression-free survival (PFS) and median overall survival (OS) were satisfactory without statistically significant differences between the two groups; however, a better trend was observed in the group of patients with mutations in exon 19.

Keywords: Non-small cell lung cancer (NSCLC); epidermal growth factor receptor (EGFR) mutations; gefitinib