Lymph-node mapping in lung cancer staging: accuracy and limits of the current approaches

Lung cancer is among the most important causes of death worldwide. The presence of tumor metastasis in the mediastinum is one of the most relevant elements in determining the optimal treatment strategy in lung cancer. Lymph node "maps" are used to describe the location of nodal metastases, the latest was proposed by the International Association for the Study of Lung Cancer (IASLC) in 2009. Here we present and analyze a recent paper by El-Sherief and collaborators aimed to verify if and how lung cancer specialists really apply the IALSC lymph node map when classifying thoracic lymph nodes documented on CT scans during lung cancer staging. In addition, we discuss the critical issues related to a correct N staging of lung cancer, mainly focusing on the limits of the present approaches and on how the increasing knowledge on the molecular basis on lung carcinogenesis can be exploited to properly dissect ambiguous and doubtful cases.