Clinical impact of the new IASLC/ATS/ERS lung adenocarcinoma classification for chest surgeons.

In 2011, a new pathological classification of lung adenocarcinoma was proposed by the International Association for the Study of Lung Cancer, the American Thoracic Society and the European Respiratory Society. The new criteria classify adenocarcinomas into eight subtypes according to their histological features. The criteria introduce a new concept of early stage lung cancer, consisting of adenocarcinoma in situ and minimally invasive adenocarcinoma, and categorize invasive adenocarcinomas by the predominant histological pattern. In addition to morphological differences among subtypes, the classification also considers the tumor behavior based on the genetic background within each subtype. We herein review the clinical impact of this new classification for chest surgeons based on the data from several recent validation studies from various institutions.