The TNM classification of lung cancer-a historic perspective.

Developed by Pierre F. Denoix in the mid-20th century as a clinical classification of anatomic tumour extent, the tumour, node, and metastasis (TNM) classification was adopted by the Union for International Cancer Control (UICC) and the American Joint Committee on Cancer (AJCC). The first lung cancer classification was published as a brochure in 1966 by the UICC, and 2 years later, the UICC published the first edition of the TNM Classification of Malignant Tumours, which was followed 9 years later by the first edition of the AJCC Manual for Staging of Cancer. The 2^nd to 6^th editions of the lung cancer classification were based on a North American database managed by Clifton F. Mountain, who also introduced the pathologic classification for tumours undergoing resection. Most descriptors used today originated in the second edition of the classification. To address the limitation of the North American database being restricted to a single geographic region, Peter Goldstraw proposed the creation of a larger, international database within the International Association for the Study of Lung Cancer (IASLC). The IASLC Staging Project, developed by the members of the IASLC Staging and Prognostic Factors Committee (SPFC) and the statisticians of Cancer Research and Biostatistics (CRAB), has already compiled three databases, which informed the analyses for the 7^th, the 8^th, and the 9^th editions of the lung cancer TNM classification. This classification has stood the test of time and will remain valuable as long as the anatomic extent of lung cancer continues to play a role in therapy and research.