Isaka T, et al. - The purpose of this work was to determine the tumor progression through airspaces, with the aid of airway secretion cytology from resected lung cancer specimens. The findings exhibited that spread through airspaces (STAS) could be identified in the airway secretion cytology. STAS appeared to be common in papillary or micropapillary adenocarcinoma. It could spread as far as the segmental or lobar bronchus at the time of surgery.