[Correlation between the efficacy of epidermal growth factor receptor tyrosine kinase inhibitors and EGFR mutations in advanced squamous cell lung cancer].

OBJECTIVE

To investigate the frequency of epidermal growth factor receptor (EGFR) mutations and their correlation with the efficacy of tyrosine kinase inhibitors (EGFR-TKI) in advanced squamous cell lung cancer.

METHODS

This retrospective study enrolled 79 patients with advanced squamous cell lung cancer who received EGFR-TKI at Department of Thoracic Medical Oncology in Peking University Cancer Hospital from June 2004 to June 2011. Among them, 67 patients had tissue and/or plasma EGFR exon 19 and 21 mutation detection in order to make an analysis on the relationship between EGFR mutation and the TKI's effect.

RESULTS

The disease control rate (DCR) was 56% in all the patients. The median progression free survival (mPFS) and median overall survival (mOS) was 3.7 months (95%CI: 2.0 - 5.0) and 11.5 months (95%CI: 6.6 - 14.2), respectively. Of the 67 patients who received EGFR mutation detection, there were 31 patients harboring EGFR-mutation, for whom the DCR was 71% (22/31), and mPFS and mOS was 6.3 months (95%CI: 2.2 - 10.0) and 13.5 months (95%CI: 7.3 - 18.6) respectively. 36 patients' EGFR status were wild type, for whom the DCR was 44% (16/36), mPFS and mOS was 2.2 months (95%CI: 1.1 - 4.0) and 6.4 months (95%CI: 4.0 - 12.0). There were 17 patients who received erlotinib and 7 patients who received gefitinib as second or more line treatment. mPFS and mOS were 7.9 months and 15.8 months in the erlotinib group, respectively; and the mPFS and mOS were both 6.3 months in gefitinib group; the difference between the 2 groups did not reach statistical significance. Cox-regression analysis showed that EGFR mutation was significantly correlated with PFS and OS (P < 0.05, respectively). EGFR mutation was significantly correlated with DCR by Chi-square test, P < 0.05.

CONCLUSIONS

EGFR mutation was a predictor for advanced squamous cell lung cancer to EGFR-TKI. However, the effect was inferior in advanced squamous cell lung cancer as compared to lung adenocarcinoma. Erlotinib tended to be superior to gefitinib.