The impact of spread through air spaces on intrapulmonary metastasis in lung cancer: a retrospective study of multiple primary lung adenocarcinomas with confirmed common origin based on histological classification alone and combined histological-molecular classification

STAS is associated with IPM and may serve as a supportive diagnostic marker when distinguishing IPM from MPLA. In resource-limited settings where molecular testing is not always available, STAS may offer a practical, cost-effective histologic adjunct to guide clinical decision-making.