Increased microcirculation in subepithelial invasion of lung cancer

Mucosal irregularity and hypervascularity associated with primary lung cancer in large airways are observed by bronchoscopy. The aim of this study was to evaluate microcirculation at subepithelial invasion sites of lung cancer.

Between July 2001 and June 2007, 12 patients who had subepithelial invasion sites of lung cancer in the large airways (aged 52 to 74 years, 12 males) were enrolled into this study. They were 6 patients with adenocarcinoma, 4 patients with squamous cell carcinoma, and 2 patients with small cell carcinoma. We compared 12 control subjects without endobronchial abnormality (aged 51 to 83 years, 9 males and 3 females). The patients underwent conventional bronchoscopy and subsequent high magnification bronchovideoscopy with the conventional imaging and the narrow band imaging (NBI). For evaluating microcirculation of subepithelial invasion, hemoglobin index was calculated.

In high magnification view, aberrant microvessels and/or irregular mucosal thickening were observed at subepithelial invasion sites of lung cancer. Irregularly enlarged microvessels were increased and formed an aberrant microvessel network on the surface of irregular mucosa. The diameter of aberrant microvessels was significantly increased compared to normal microvessels. By switching to NBI, the aberrant microvessels were more clearly visualized. The levels of hemoglobin index were significantly higher in subepithelial invasion sites of lung cancer compared to normal mucosa.

In subepithelial invasion of lung cancer, aberrant microvessels are thought to be characteristic and subepithelial microcirculation may be increased.