Lung cancer screening is based on low dose CT scan (LDCT), a highly sensitive but poorly specific tool. Complementary specific approaches are thus strongly needed, among which cell-free DNA (cfDNA) genotyping has been proven highly specific but of low sensitivity (25 to 50% for stage I diseases) due to inconstant tumor shed. Tumor biopsy is thus often required and radial endobronchial ultrasound (rEBUS) bronchoscopy is a minimally invasive approach (\<3% complications) but of limited sensitivity in cases of nodules \< 20 mm. The investigators hypothesized that methylation analysis on cfDNA floating in supernatant derived from rEBUS specimens could improve rEBUS sensitivity