The implications of the 9th lung cancer TNM classification on the thoracic interventional radiologist: A pictorial review.

Lung cancer (LC) remains the leading cause of cancer mortality worldwide. An accurate staging is pivotal for the development of successful treatment approaches and improvement of patient outcomes. Traditionally, LC staging has depended on the TNM staging system, and the International Association for the Study of Lung Cancer (IASLC) has recently recommended modifications. The updated classification for the ninth edition of the TNM staging system (TNM-9), slated to take effect in January 2025, is derived from an exhaustive analysis of a newly established large international database of LC cases compiled by the IASLC. The main changes in TNM-9 include the following: (1) The N2 category is split into single-station (N2a) and multiple-station (N2b) subcategories, and (2) the multiple extrathoracic metastatic category (M1c) is split into single-organ system (M1c1) and multiple-organ systems (M1c2) subcategories. With these changes in mind, adjustments have been made to the established stage groups. Understanding the changes introduced in TNM-9 enables interventional thoracic radiologists to refine the percutaneous procedures necessary for a more accurate initial staging of LC patients and, subsequently, for an optimized customized treatment.