The Stage Classification of Lung Cancer

S classifi cation is an essential part of the approach to patients with cancer, and there are many things we would like to get from a stage classifi cation. The primary purpose of the classifi cation is to consistently describe the anatomic extent of disease, thus providing a common, consistent language. The anatomic extent of the tumor has a major impact on which treatment we choose and what the outcome will be. However, it is important to recognize that the stage classifi cation does not by itself completely defi ne the prognosis (which depends on multiple factors, eg, comorbidities, performance status, treatment given) or serve as a treatment algorithm (which is driven by data from clinical trials and treatment selection criteria). Efforts to develop a comprehensive prognostic index system are under way. Stage classifi cation is founded on the TNM system, which dates back to 1944. Furthermore, the method of staging is classifi ed as clinical stage (denoted by the prefi x c) and pathologic stage (denoted by the prefi x p). Clinical stage is determined using all information available prior to any treatment, and pathologic stage is determined after a resection. The extent of clinical staging can vary from a clinical evaluation alone (history and physical examination) to extensive imaging (CT and PET scans) or invasive staging techniques. It must be emphasized that a surgical staging procedure (eg, mediastinoscopy) is still part of clinical staging because surgical resection as a treatment has not taken place. The current Lung Cancer Stage Classifi cation system is the seventh edition, which took effect in January 2010. This article reviews the defi nitions for the TNM descriptors and the stage grouping in this system. CHEST 2013; 143(5)(Suppl):e191S–e210S