Spread through air spaces in lung cancer: From controversy to consensus

In 2015, the concept of Spread Through Air Spaces (STAS) was introduced by the World Health Organization (WHO), which is defined as the dissemination of micropapillary clusters, solid nests, and/or individual cancer cells into the airspace of the lung parenchyma beyond the main tumor edge, was introduced by the WHO. In this study, we comprehensively reviewed the evolution and clinical value of STAS in lung cancer. First, to diagnose STAS, it is essential to differentiate it from artifacts, tumor budding, and alveolar macrophages from a pathological perspective. Secondly, STAS is more frequently observed in lung adenocarcinoma; however, it can also be detected in other types of lung cancer. In addition, STAS exhibits characteristic radiological features and driver genes. Studies have found that STAS is more likely to be observed in patients with an EGFR driver gene-negative status and ALK mutations. Lastly, STAS can serve as a prognostic predictor for stage I lung adenocarcinoma. For patients with stage IA lung adenocarcinoma, those with positive STAS are recommended to undergo lobectomy. For patients with stage IB lung adenocarcinoma who have undergone radical resection, STAS can serve as an important reference for adjuvant therapy decisions.