Prognostic significance of circulating tumor cells in advanced non-small cell lung cancer patients treated with docetaxel and gemcitabine

To evaluate the association in the change of circulating tumor cell (CTC) levels and clinical outcomes (PFS and OS) in patients with advanced non-small cell lung cancer (NSCLC) treated homogenously with docetaxel and gemcitabine administered every 2 weeks. We prospectively evaluated 37 patients for CTC levels at baseline and after 2 months of chemotherapy (before third cycle). Detection was carried out with the CellSearch system. Nine of the 37 patients (24 %) had a parts per thousand yen2 CTCs at the baseline determination. Median progression-free survival (PFS) was 4.3 months (95 % CI 2.5-8.3) for patients with CTC 0-1 as compared to 9.4 months (95 % CI 1.2-12.2) for those with CTC a parts per thousand yen2 (p = 0.3506). Median overall survival (OS) was 8.1 (95 % CI 2.8-16.3) and 12.2 (95 % CI 1.4-12.2) months for patients with 0-1 CTCs and a parts per thousand yen2 CTCs, respectively (p = 0.7639). Patients with a second CTC quantification were classified as: group 1, CTC = 0-1 at baseline and CTC = 0-1 after second chemotherapy cycle (18 patients); group 2, CTC a parts per thousand yen2 at baseline and CTC = 0-1 after second determination (5 patients). Median PFS was 7.7 and 9.9 months for group 1 and group 2, respectively (p = 0.4467). CTCs a parts per thousand yen2 at baseline were detected only in 24 % of this group of patients with advanced NSCLC and poor performance status. No significant differences in PFS and OS between patients with or without CTCs at baseline were observed.