Fig. 1.

Comparison of the 8th and 9th Editions of the TNM Staging System for Lung Cancer, with Highlighted Changes. This table illustrates the modifications introduced in the 9th edition, including the subdivision of the N2 category into N2a (single station) and N2b (multiple stations). Orange cells indicate unchanged staging, green cells represent downstaging (stage lowered in TNM 9), and red cells highlight upstaging (stage increased in TNM 9). Notably, T1N1 has been downstaged from stage IIB to IIA, T1N2a from stage IIIA to IIB, and T3N2a from stage IIIB to IIIA, reflecting a reclassification that places these tumors in lower prognostic categories. Conversely, T2N2b has been upstaged from stage IIIA to IIIB