Yanagawa N, et al. - The clinical impact of tumor spread through air spaces (STAS) in surgically resected lung squamous cell carcinoma (SQCC) was analyzed and validated herein. 19.1% of the cases had STAS, which showed association with recurrence and worse survival in stage I SQCC, but not in stage II and III SQCC. Overall, STAS was suggested to be a useful predictor of recurrence and prognosis in stage I lung SQCC.