Paradigm shifts in lung cancer as defined in the new IASLC/ATS/ERS lung adenocarcinoma classification

Abstract

The new international multidisciplinary lung adenocarcinoma classification is sponsored by the European Respiratory Society (ERS), as well as the International Association for the Study of Lung Cancer (IASLC) and the American Thoracic Society (ATS) [1]. This classification is now published in the Journal of Thoracic Oncology , the official journal of the IASLC. Under the scientific oversight of the ATS and ERS, the classification project involved a systematic review to provide an evidence-based foundation with specific recommendations. For decades, the field of lung cancer has been relatively static with few major advances. However, in the past 5–6 yrs this has changed to a rapidly evolving field. At the heart of this change is the impact of the molecular discovery that the activating mutations in the epidermal growth factor receptor ( EGFR ) are a marker for response and improved progression-free survival with tyrosine kinase inhibitor (TKI) therapy compared to conventional chemotherapy in advanced lung adenocarcinoma patients [2–5]. In this editorial, we summarise a series of major paradigm shifts that are outlined in this classification that will result in major changes in the approach to diagnosis of lung cancer compared to those outlined in previous World Health Organization (WHO) classifications. While this classification is primarily focused on lung adenocarcinoma, many of the recommendations will impact on how all histologic types of lung cancer are diagnosed in the future. This classification is divided into two major components: classification based on resection specimens (table 1) and on small biopsies and cytology (table 2). View this table: Table 1– 2011 International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification of lung adenocarcinoma in resection specimens View this table: Table 2– Proposed International Association for the Study of Lung Cancer (IASLC)/American Thoracic Society (ATS)/European Respiratory Society (ERS) classification for small biopsies/cytology Historically, tumour classification has been primarily been performed by the WHO with panels primarily consisting of pathologists [6–9]. Due to the many major advances that have occurred at each level (pathology, molecular biology, radiology, respiratory medicine, oncology and surgery) this current …