The predictive role of consecutive measurements of serum CEA for treatment efficacy in advanced non-small cell lung cancer patients harboring epidermal growth factor receptor mutations treated with gefitinib or erlotinib.

Abstract

e19029 Background: Patients with non-small cell lung cancers (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations dramatically respond to EGFR tyrosine kinase inhibitors (TKIs) with approximately 70% response rate. Carcinoembryonic antigen (CEA) has been suggested to be associated with tumor recurrence, treatment efficacy and prognosis in some specific tumors. However, the role of CEA in NSCLC with EGFR mutations remains unclear. Therefore, we sought to elucidate whether the determination of serum CEA levels can predict the efficacy of EGFR TKIs in NSCLC harboring EGFR mutations. Methods: Medical records of 326 consecutive patients with advanced NSCLC between January 2007 and November 2012 were reviewed and a total of 104 patients with NSCLC harboring EGFR mutations treated with gefitinib or erlotinib ³2 weeks and with available data of serum CEA were identified for analysis. Results: Female, never smokers, adenocarcinoma histology and cases with pretreatment serum CEA ³ 5 ng/ml presented 63%, 76%, 96% and 68% of 104 eligible cases with mean age of 65.4 ± 13.7 years, respectively. The response rate of EGFR TKIs in patients with pretreatment CEA ³ 5 ng/ml was not significantly different (70% vs 91%, P = 0.339), and it was higher in those with reduction of CEA level after treatment than those without (94% vs 35%, RR=2.7, P <0.001). The average change of pre- and post-treatment CEA in respondents and non-respondents was negative 112 ± 181 ng/ml and positive 368 ± 514 ng/ml, P <0.001, respectively. In details, the pre- and post- treatment CEA levels in respondents were 246 and 71 ng/ml, P < 0.001, respectively, and those in non-respondents were 157 and 268 ng/ml, P= 0.019, respectively. Furthermore, the post-treatment CEA level increased by 14% in non-respondents and decreased by 52% in respondents. Conclusions: Reduction or elevation of post-treatment serum CEA can predict the treatment efficacy in NSCLC patients with EGFR mutations treated with gefitinib or erlotinib. Further studies aiming to investigate the value of serum CEA levels in tumor progression and survival are warranted.