Lung cancer is a leading cause of cancer-associated mortality worldwide. By conventional morphology it is divided into small cell neuroendocrine (SCLC) and non-small cell lung cancer (NSCLC), with NSCLC further subdivided into adenocarcinoma (ADC), squamous (SQC) and large cell carcinoma (LCLC). Even this very basic classification scheme has been shown to be valuable for treatment decisions in regard of safety and efficacy.
This rather descriptive taxonomy of LC has been both strengthened and challenged by the recognition of numerous somatic genetic alterations in the last decade. Whereas the histotype and genotype of ADCs and SQCs show considerable concordance, there is substantial transcriptional similarity between the morphologically separate entities of SCLC and large cell neuroendocrine carcinoma. Moreover LCLCs in most cases group with either ADC or SQC on a molecular level, challenging the conventional classification scheme.
The treatment of lung cancer has been subject to major changes in the recent past due to the discovery of drugable molecular alterations and the introduction of immune checkpoint therapy. Thus thoracic oncology has become one of the most rapidly developing oncological disciplines.
For thoracic pathology this implies constantly new challenges regarding the diagnosis of lung cancer and especially the implementation of biomarker into the daily practice. For patients in advanced stages of lung cancer the molecular analysis of EGFR, ALK, ROS1 and the immunohistochemical detection of PD-L1 are routine requirements.