Correlation between epidermal growth factor receptor tyrosine kinase inhibitor efficacy and circulating tumor cell levels in patients with advanced non-small cell lung cancer

OBJECTIVE: The aim of this study was to investigate the correlation between the efficacy of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) and circulating tumor cell (CTC) levels in patients with advanced non-small cell lung cancer (NSCLC). The efficacy of EGFR-TKIs in reducing CTC counts in patients with advanced NSCLC was studied. PATIENTS AND METHODS: A total of 66 patients with advanced NSCLC were enrolled and divided into two groups (those with high CTC counts and those with low CTC counts) based on the patients’ median CTC counts. All the patients were treated with an EGFR-TKI, and the treatment efficacy and prognoses were compared. RESULTS: The treatment efficacies were 53.3% (16/30) and 27.8% (10/36) for the low CTC group and high CTC group, respectively, and this difference was statistically significant (P<0.05). The median overall survival was 22.8 months (95% confidence interval [CI]: 18.9–26.8 months) for the low CTC group and 18.3 months (95% CI: 2.9–8.2 months) for the high CTC group. The median progression-free survival was 11.5 months (95% CI: 8.1–15 months) and 5.6 months (95% CI: 2.9–8.2 months) for the low and high CTC groups, respectively, and the difference was statistically significant (P<0.05). CONCLUSION: The CTC count can be used as an index for predicting the EGFR-TKI effect on patients with advanced NSCLC. Efficacy and prognosis of EGFR-TKI treatment and CTC count were considered important, and the CTC count could be used to predict the efficacy of EGFR-TKI treatment and prognosis of advanced NSCLC. The change in CTC expression levels can be used as an index for evaluating the prognosis of patients with advanced NSCLC.