(A) Circulating endothelial progenitor cell (CEP) kinetics during the first cycle of chemotherapy in patients with non‐small‐cell lung cancer. A significant decrease was seen at day 8 (n = 37) and before the second cycle of chemotherapy (n = 38). (B) Number of CEPs (cells/μL) in patients treated with the platinum doublet regimen (n = 32, P < 0.0001 and n = 33, P = 0.0276). Number of CEPs (cells/μL) in patients treated with cytotoxic monotherapy. (C) Number of CEPs (cells/μL) in patients treated with regimens not containing PAC (cisplatin, doxorubicin, cyclophosphamide) (n = 34, P < 0.0001 and n = 35, P = 0.0131). (D) Number of CEPs (cells/μL) in patients with adenocarcinoma and non‐adenocarcinoma patients (P < 0.0001 and P = 0.0466, respectively). (E) Number of CEPs (cells/μL) in patients with partial response (PR) and stable disease (SD) + progressive disease (PD) patients (P = 0.0264). *P < 0.05, Wilcoxon test, paired t‐test, or t‐test.