Circulating tumor cells as a predictive marker for chemotherapy and prognostic marker in patients with metastatic non-small cell lung cancer.

Abstract

e21020 Background: Circulating tumor cells (CTCs) are extremely rare in healthy subjects and patients with nonmalignant diseases but present in various metastatic carcinomas. The number of CTCs before treatment has been reported to be prognostic factor for metastatic breast cancer. We investigated the relationship of the number of CTCs with overall survival, progression free survival, and response rate in patients with metastatic non-small cell lung cancer (NSCLC). Methods: We prospectively evaluated CTCs in 7.5-mL samples of peripheral blood sampled from patients with previously untreated metastatic NSCLC. A semiautomated system was used to capture CTCs with an antibody against epithelial cell adhesion molecule. From May 2008 through August 2010, 33 patients (23 men and 10 women; median age, 64 years; range, 46 to 74 years) were enrolled. All patients received chemotherapy of the combination of gemcitabine and carboplatin. Results: CTCs were detected in 36.4% of patients. Patients with positive CTCs were trend toward to longer survival (23 months) and progression free survival (5 months) than patients with negative CTCs (7 months, 2.5 months), although there were not statistically significant differences. The stable disease rate to chemotherapy was significantly lower in patients with positive CTCs (18%) than in patients with negative CTCs (75%; p = 0.002). Conclusions: CTCs could be a useful predictive marker for chemotherapy and might be prognostic marker in patients with metastatic NSCLC.