Differential efficacy of docetaxel according to non-small cell lung cancer histology and the therapeutic effect of epidermal growth factor receptor tyrosine kinase inhibitors

The active mutation of epidermal growth factor receptor (EGER) and clinical characteristics are significant biomarkers for chemotherapy selection in non-small cell lung cancer (NSCLC). Although docetaxel is a key agent in second-line therapy for NSCLC, predictive biomarkers for assessing its efficacy have yet to be determined. To assess the clinical efficacy of docetaxel in second-line therapy for NSCLC according to NSCLC histology and the therapeutic effect of EGFR-tyrosine kinase inhibitors (EGFR-TKIs), we retrospectively reviewed 454 NSCLC patients treated with docetaxel between April 2002 and April 2009. In total, 239 patients with advanced NSCLC treated with docetaxel as second-line therapy following failure of platinum-based chemotherapy were analyzed in this study. A total of 59 (25%) patients had squamous cell carcinoma. The overall response rate and median progression-free survival time in the squamous cell group were significantly inferior to those in the non-squamous cell group (p=0.031 and p=0.005, respectively). Following the failure of docetaxel, 91 non-squamous patients were treated with EGFR-TKIs. The patients that achieved clinical benefit from EGFR-TKIs (n=32) demonstrated a significantly better response rate and longer progression-free survival compared to the other group (p<0.001 and p=0.027, respectively). In the univariate and multivariate analysis, the favorable therapeutic effect of EGFR-TKIs had an independent effect on progression-free survival (HR 1.484, p=0.0464). In conclusion, this retrospective study suggests that non-squamous histology and favorable therapeutic effect from EGFR-TKIs are useful markers for predicting the efficacy of docetaxel in second-line therapy for NSCLC.