The relationship between common EGFR, b-raf, k-ras mutations, and prognosis in advanced-stage NSCLC with response to the treatment.

Abstract

e18075 Background: Epidermal growth factor receptor (EGFR) mutations are common in NSCLC and they are predictive in EGFR tyrosine kinase inhibitor treatment. K-ras mutation is associated with poor prognosis in NSCLC, however role of b-raf mutation is not so clear. The aim of the study was to evaluate EGFR (exon 19 deletion, exon 21 L858R point mutation), k-ras and braf mutation rates besides their relationship with survival and response to the treatment. Methods: We evaluated 513 NSCLC patients followed-up between January 2004 and November 2009 according to our registration data, retrospectively. Only 42 advanced stage NSCLC patients had enough tumor tissue material in paraffin blocks for all mutation analysis. These 42 advanced stage NSCLC patients were enrolled to the study. They were evaluated for clinicopathological features, EGFR, k-ras and b-raf mutations, erlotinib treatment, time to progression (TTP) and overall survival (OS). Results: Mutation rates were as 7.14% for EGFR exon 19 deletion; 4.76% for k-ras codon 61 deletion and 2.38% for b-raf V600E mutation. Median folow-up was 26 months (5-83) for all patients. It was 43 months (23-83) for the patients who had erlotinib and 23 months (5-61) for those who did not. Ten (23.8%) patents had erlotinib. Two patients had EGFR exon 19 deletion and one patient had k-ras mutation among these patients. They had neither EGFR exon 21 point mutation nor different mutations together. There was significant survival difference between the patients taking erlotinib and the others (28 + 3 months versus 15 + 4 months, p=0.05). TTP and OS were longer in the patients who had mutations, however the difference was not significant (p=0.119 and p=0.06). Conclusions: This is the first study evaluating EGFR, k-ras and braf mutations in advanced stage NSCLC in our country. Survival of the patients who had erlotinib was longer.