Peripheral arterial rather than venous blood is a better source of circulating tumor cells in early lung cancer

Abstract Background Circulating tumor cells (CTCs) play a crucial role in the early diagnosis and prognosis of lung cancer. Identification of a more suitable sample source could be a breakthrough towards enhancing CTC detectability in early‐stage lung cancer. We investigated the differences in detectable CTCs between peripheral arterial and venous blood in early‐ and mid‐stage lung cancer patients undergoing surgery and analyzed the association between clinicopathological factors and detectable CTCs in peripheral arterial and venous blood. Methods Peripheral arterial and venous blood was collected in 5‐mL samples from 56 patients with surgically resected and pathologically clear at early‐ or mid‐stage lung cancer. Blood specimens were enriched for CTCs based on isolation by size of epithelial tumor cells. The CTCs were identified using Swiss Giemsa staining and immunohistochemistry for CD45/CD31. Results In stage I lung cancer, CTC‐positive rate was significantly higher in peripheral arterial than in venous blood (45.45% vs. 17.39%). There was no significant difference in the number of detectable CTCs between peripheral arterial and venous blood. A low degree of differentiation was associated with a high positive rate of CTCs in peripheral venous blood. The number of circulating tumor microemboli was significantly higher in patients with tumor size >3 cm compared with ≤3 cm. Conclusion CTC levels in peripheral arterial and venous blood differed little in lung cancer patients.Compared to peripheral venous blood, peripheral arterial blood had a higher CTC positivity rate in early‐stage lung cancer.This study was favorable for early detection and monitoring of lung cancer.