7592 Background: Research on the detection of circulating tumor cells (CTCs) in peripheral blood is currently an important field of research. The aim of this study was to evaluate a new method of detecting CTCs in the peripheral blood of small cell lung cancer (SCLC) patients by using the telomerase-specific replication-selective adenovirus OBP-401. Methods: We prospectively enrolled 30 consecutive newly diagnosed SCLC patients who were being started on chemotherapy or chemoradiotherapy as the subjects of this study. We collected peripheral blood specimens from the SCLC patients and detected viable CTCs in them after incubation with a telomerase-specific, replication-selective, oncolytic adenoviral agent carrying the green fluorescent protein (GFP) gene. We also investigated whether the CTC count per 7.5 ml of peripheral venous blood was associated with the outcome of SCLC. Results: CTCs were detected in 96% of the patients (29 of the 30 patients). The group of 22 patients with a CTC count of < 2 before treatment (baseline) had a significantly longer median survival time than the group of 8 patients with a CTC count of ≥ 2 before treatment (14.8 months and 3.9 months, respectively, P = 0.001). The results of a multivariate analysis showed that the baseline CTC count was an independent prognostic factor for survival (hazard ratio = 5.11, P = 0.038). Conclusions: CTCs in the peripheral blood of SCLC patients can be detected by the OBP-401assay, and based on the results of this study the CTC count before treatment appears to be a strong prognostic factor.
Circulating tumor cells as a new predictive and prognostic factor in patients with small cell lung cancer
