EGFR mutations as a predictive marker of cytotoxic chemotherapy

Epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) are important predictive markers for the response to EGFR-tyrosine kinase inhibitors (EGFR-TKIs). Whether EGFR mutations can also predict the clinical outcomes in NSCLC patients receiving chemotherapy has not yet been established.

We included 217 locally advanced/metastatic NSCLC cases in our study cohort. Each patient had received platinum doublet chemotherapy as a first line treatment, and had been screened for an EGFR mutation.

The subject cohort comprised 80 EGFR wild type and 137 EGFR-mutated lung cancer patients. Gemcitabine-based and taxane-based regimens were administered in 131 (60.4%) and 86 (39.6%) cases, respectively. Among the patients with a wild type EGFR, there was no significant difference in the response rate (RR), disease control rate (DCR), or progression-free survival (PFS) between gemcitabine-based and taxane-based therapies. Among the patients with EGFR mutations, no difference in RR was observed between gemcitabine-based and taxane-based treatments. On the other hand, the DCR and PFS associated with taxane-based therapy were superior when compared with the gemcitabine-based treatments. When we analyzed patients with an EGFR exon 19 deletion, the PFS of the taxane treated cases was better than that of the gemcitabine treated cases (5.3 months vs 3.7 months, P=0.012).

Our current data indicate that lung cancer patients with EGFR-mutations had longer PFS with taxane than gemcitabine when receiving a platinum-based doublet regimen. The predictive meaning of EGFR mutations for cytotoxic chemotherapy should be further investigated.