[The ninth edition of TNM staging for lung cancer: precise staging for precise diagnosis and treatment].

The ninth edition of TNM staging for lung cancer has been announced at the 2023 World Lung Cancer Congress and implemented from January 1, 2024. The focus of the ninth TNM staging change is dividing N2 into N2a and N2b, as well as M1c into M1c1 and M1c2. Although the T staging has not changed, it has played an important role in verifying the eighth edition of the T staging. The subdivision of stage N2 has led some patients with ⅢA of the eighth edition to experience ascending or descending stages, which will more accurately help to assess the condition and prognosis of patients with mediastinal lymph node metastasis, as well as the design of related clinical studies. Modifying the M1c staging will help define oligometastasis and explore new treatment models in the future. The ninth edition of the TNM staging system provides a more detailed division of different tumor loads, but there is no clear explanation for the staging of lung cancer after neoadjuvant therapy. Further data analysis is needed, and it is expected to be answered in the tenth edition of TNM staging.

[Introduction to the 9th edition of TNM classification for lung cancer].

Lung cancer is the second commonly diagnosed cancer and remained the leading cause of cancer-related death, with an estimated 1.8 million deaths in 2020. The identification of driver gene mutation and administration of corresponding tyrosine kinase inhibitor have improved overall survival and quality of life in advanced lung cancer patients. Check point inhibitor has revolutionized treatment strategy of driver gene negative advanced NSCLC patients. TNM staging system is the most widely used classification method, providing an international common language during academic communication and important tool for predicting prognosis and subsequent treatment decision making. Accumulating knowledge about prognostic factors in lung cancer promotes the update of TNM classification. In the World Conference on Lung Cancer (WCLC) held in Singapore, September, 2023, International Association for Study of Lung Cancer (IASLC) released the forthcoming 9th edition of TNM classification for lung cancer, which is supposed to be adopted at January, 2024. The manuscript discussed the history, data resource and limitation of the TNM staging system.