Baseline and post-surgery endothelial progenitor cell levels in patients with early-stage non-small-cell lung carcinoma: impact on cancer recurrence and survival

OBJECTIVES: Endothelial progenitor cells (EPCs) are believed to play a role in promoting abnormal vascularization in neoplastic sites. We measured the number of circulating EPCs in treatment-naive patients with early non-small-cell lung cancer (NSCLC) and healthy controls. The prospective influence of baseline and post-surgery EPC levels on cancer recurrence and survival was investigated. METHODS: Circulating EPCs were quantified by FACS analysis in 34 patients with Stage I–II NSCLC and 68 healthy age- and sex-matched controls. Measurement of EPCs was repeated 48 h after thoracic surgery and at the hospital discharge. Cancer recurrence and survival was evaluated after 446 ± 106 days of follow-up (range 182–580 days). RESULTS: The base 10 logarithmic [log] number of circulating EPCs was comparable between patients with NSCLC and controls [mean ± standard deviation (SD): 2.3 ± 0.32 vs 2.3 ± 0.26 n/ml, P= 0.776]. In regression analysis, smoking status [standardized coefficient beta (β)=−0.26, 95% confidence interval (CI) for B −0.29/−0.03, P= 0.014] and systolic blood pressure [β= −0.23, 95% CI for B −0.011/−0.001, P= 0.018] were independent predictors of the number of EPCs, irrespective of the NSCLC status. The mean number of EPCs did not change after surgical treatment. However, a post-surgery EPC increase was observed in 44% patients. Patients with a 48 h post-surgery EPC increase had a higher rate of cancer recurrence/death than patients with either stable or decreased post-surgery EPC levels [hazard ratio (HR) 4.4, 95% CI 1.1–17.3; P= 0.032], irrespective of confounders. CONCLUSIONS: Circulating EPC levels are comparable between patients with early-stage NSCLC and healthy controls. Overall, surgical cancer resection was not associated with a significant early EPC change. However, an early post-surgery EPC increase is able to predict an increased risk of cancer recurrence and death.