Spread through air spaces (STAS)



In pathology, the term spread through air spaces (STAS) describes a pattern of invasion seen in lung cancer, where cancer cells are observed spreading into the air spaces in the lung tissue outside of the tumour. This pattern of invasion is commonly seen in a type of lung cancer called adenocarcinoma.

Why is spread through air spaces important?

The presence of STAS has been associated with a higher risk of recurrence and worse overall survival in patients with lung cancer, especially in those with early-stage disease. Recognizing STAS can therefore provide valuable prognostic information and help in risk stratification.

How do pathologists look for spread through air spaces?

Pathologists identify STAS by carefully examining the lung tissue surrounding the tumour under a microscope. They look for tumour cells or clusters of cells within the air spaces separated from the main tumour and not attached to the tumour edge, often located at a distance from the tumour mass itself. These cells can be free-floating or attached to the alveolar walls but are distinguishable from the primary tumour and not explained by other processes such as artefact or lymphovascular invasion.

About this article

Doctors wrote this article to help you read and understand your pathology report. Contact us if you have questions about this article or your pathology report. For a complete introduction to your pathology report, read this article.

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