Serum Carcinoembryonic Antigen as an Index of the Therapeutic Effect of EGFR-TKIs in Patients with Advanced Non-Small Cell Lung Cancer

Purpose For treating advanced non-small cell lung cancer (NSCLC), epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are known to be very effective in nonsmokers, women, Asian and person with EGFR mutations. The efficacy of EGFR-TKI was analyzed based on the radiologic studies and the serum levels of carcinoembryonic antigen (CEA) to evaluate whether serum CEA can be used as a predicative marker of the response to EGFR-TKI therapy. Materials and Methods Forty-one patients with NSCLC treated with gefitinib at Kosin Medical Center from January 2007 to August 2009 were the subjects of this study. We assayed the serum CEA levels before and after gefitinib therapy with concomitant assessments of the tumor response by serial chest X-ray and chest computer tomograms (CT). Results The median age of the patients was 62.6 years (range, 32∼77 years), 29 patients were women, 36 had adenocarcinoma (87.8%) and the baseline serum CEA was equal or above 5 ng/mL in 31 patients (75.6%). These 31 patients were more responsive to the gefitinib therapy (p=0.021). The overall response rate of the patients was 51.2%, the median survival time was 21.9 months and the time to progression was 8.3 months. Among the 21 responding patients, the serum CEA was decreased after 2 months in 17 (80.9%), and among the 14 progressed patients, the serum CEA was increased in 12 (85.7%) (p=0.000). Conclusion The changes of serum CEA at 2 months after gefitinib therapy were closely related to the radiologic changes. The serum CEA could be used as a complimentary tool for monitoring the tumor response to EGFR-TKI in the advanced NSCLC patients.