<p>Spread Through Air Spaces (STAS) in Lung Cancer: A Multiple-Perspective and Update Review</p>

Abstract

Background: Spread through air spaces (STAS) is a spreading phenomenon of lung cancers, which is defined as tumor cells within air spaces in the lung parenchyma beyond the edge of the main tumor. To date, several articles have reviewed the studies concerning the significance of STAS; however, most articles focused on the prognosis without summarizing the significance of STAS on other aspects. In this review, we comprehensively summarized the current literature related to STAS, so as to explore the clinical significance of STAS from multiple perspectives. Main Body: This section provided a comprehensive overview of the significance of STAS from multiple perspectives and summarized current controversies and challenges in the diagnosis and clinical application. Conclusion: STAS is a conspicuous spreading phenomenon of lung cancers indicating worse prognosis; nevertheless, the treatment strategy for patients with STAS remains to be discussed. Further studies are needed to elaborate whether a STAS-positive patient who underwent limited resection needs a second operation or postoperative adjuvant treatment. Meanwhile, the internal mechanism of STAS formation is largely undiscovered. Whether the capability of detachment-migration-reattachment in STAS tumor cells is achieved at the time of primary tumorigenesis or in the progress of tumor development needs to be studied, and the related signal pathways or genetic alterations need to be explored. With this information, it may be possible to improve the prognosis of patients with STAS-positive lung cancers.

Peritumoral radiomics features on preoperative thin-slice CT images can predict the spread through air spaces of lung adenocarcinoma

“…Fourth, our prediction model was solely based on imaging features because our main hypothesis was that the imaging features could reflect the information of the existence of STAS. However, clinical factors such as age, gender, and serum carcinoembryonic antigen are also reported to be predictors of STAS, and the addition of these factors may lead to a more predictive model 27 . Lastly, there is room to further reduce data sampling bias by applying sophisticated methods to building a prediction model, such as nested cross validation; however, we needed to leave a test cohort aside in advance for the following survival outcome analysis.…”

A case of haemoptysis and bilateral areas of lung consolidation sparing the right lower lobe

“…According to some authors, STAS is not a pattern of invasion but just an artefact associated with lung resection and specimen preparation (tumour cells displaced by the knife along the plane of sectioning) [ 39 , 40 ]. Furthermore, from a biological perspective, the cells can't live on air [ 41 , 42 ]. However, STAS has been observed without cutting through the main tumour [ 43 ], and, with the help of three-dimensional reconstruction, it has been found that detached tumour islands, after migration through air spaces, reattach in close apposition to alveolar vessels, which is a potential mechanism for cell survival [ 44 , 45 ].…”

The Diameter of Bronchial Resection Margin is Associated With Postoperative Lung Metastasis and Long-term Survival

“…Tumor spread through air spaces (STAS) was reported as a novel poor prognostic factor in the latest World Health Organization (WHO) classi cation (2). In recent studies, STAS in patients with lung cancer was shown to be associated with high recurrence rates and poor survival after surgical resection (3,4). We consider that the size of DBRM may affects STAS, which in turn affects the prognosis.…”