The accurate staging of lung cancer is essential in planning treatment, and it is of crucial prognostic significance. Indeed, in the assessment of lung cancer patients, staging along with obtaining a histologic diagnosis are the two essential factors in treatment planning. In addition, accurate assessment of and documentation of performance status and clear recording of comorbidity are vital.
Lung cancer staging hinges on both noninvasive (CT and CT positron emission tomography),1– minimally invasive (transbronchial needle aspiration with or without endobronchial ultrasound guidance,2– endoscopic ultrasound fine-needle aspiration3– and neck ultrasound fine-needle aspiration),4– as well as sometimes invasive staging (mediastinoscopy, mediastinotomy, and nodal dissection at thoracotomy).5– The current TNM classification for lung cancer is based on the most recent revision of the international staging system published by Mountain6 in 1997. This is based on a relatively small database of 5,319 cases of non-small cell lung cancer (NSCLC). As in previous lung cancer staging publications, the tumor stage (T1–T4) was based on tumor size and proximity to and involvement of vital intrathoracic structures as well as including non–size-based descriptors. Specifically in the case of T2 disease, stage was not only based on size but also based on visceral pleura invasion, hilar atelectasis, and obstructive pneumonitis, and a tumor could be staged as T2, even if < 3 cm, if any of these non–size-based descriptors were present. Nodal status was divided into N0 (no local node involvement), N1 (ipselateral hilar node), N2 (ipselateral mediastinal node), or N3 (contralateral mediastinal node or supraclavicular node) involvement. Using the T and N descriptors, in the absence of metastatic disease, lung cancer has been staged as 1A, 1B, 2A, 2B, 3A, and 3B. This staging system has proved extremely useful in categorizing patients both in terms of treatment and recruitment to studies and in terms of prognosis.