ABSTRACT
INTRODUCTION Clinical TNM staging comprises accurate assessment of the extent of the primary tumor (T), the spread to locoregional lymph nodes (N), and the presence or absence of distant metastases (M), and is based on evidence acquired before treatment. The clinical TNM stage (or cTNM) is essential to select and evaluate treatment. Patients with distant metastasis (advanced stage), or stage IV, will be treated with cytotoxic and/or targeted agents. Patients with metastatic mediastinal lymph nodes, or stage III, will usually have a combined modality therapy including a systemic (chemotherapy) and locoregional (surgery and/or radiotherapy) component. Patients without metastatic lymph nodes or with hilar metastatic lymph nodes only (early stages I and II) are-also depending on their cardiopulmonary and general medical condition-candidates for upfront surgical resection often followed by postoperative chemotherapy. As such, the TNM stage determines the choice of treatment, and is also the most important prognostic factor in non-small cell lung cancer (NSCLC) to date. Staging nowadays is a truly multidisciplinary process-involving physical examination, imaging techniques, endoscopic techniques, and surgical techniques-to determine the most accurate clinical TNM stage.
