Prognostic value of circulating tumor cells in non-small cell lung cancer.

Abstract

e20520 Background: Quantitative analysis of circulating tumor cells (CTCs) is increasingly investigated as a novel predictor of prognosis in non-small cell lung cancer (NSCLC). The primary aim of this study was to further investigate the prognostic value of CTCs enumeration in patients with advanced NSCLC. Methods: The medical records of patients with chemotherapy-naïve, advanced NSCLC and at least one available measurement of CTCs were retrospectively reviewed. The presence of CTCs was evaluated using the CellSearch system. A cut-off point of 2 CTCs ( < 2 vs ≥2 ) was used to discriminate between negative and positive samples, respectively. The detection of CTCs was correlated with the clinicopathological features of patients and outcome. Results: Our study population comprised a total of 43 patients (mean age 67.1±9.9 years; male/female ratio: 39/4). Eight out of 43 patients (18.6%) harbored CTCs. No significant associations were found between treatment response and baseline count of circulating tumor cells (CTCs) (p = 0.067). Positive CTC count was associated with the presence of five or more metastatic sites (p = 0.018). Neither PFS nor OS were found to differ significantly between CTC-positive and CTC-negative cases (log-rank p = 0.079 and 0.549, respectively). The presence of five or more metastatic sites and worse PS were recognized as independent predictors of reduced PFS [HR = 2.9, p = 0.042 and HR = 2.7, p = 0.035, respectively], and reduced OS [HR = 7.8, p = 0.003 and HR = 16.9, p < 0.001, respectively]. Conclusions:CTCs were detected in a relatively small percentage of our patient population and their presence was associated with increased metastatic burden. In contrast, we failed to observe any significant associations between baseline CTC count and the prognostic variables evaluated. Our results support the suggested role of CTCs in the metastatic dissemination of cancer and underline the need for more efficient methods of CTCs detection.