Revisions in stage grouping of the TNM subsets (T= primary tumor, N= regional lymph
nodes, M= distant metastasis) in the International System for Staging Lung Cancer have
been adopted by the American Joint Committee on Cancer and the Union Internationale
Contre le Cancer. These revisions were made to provide greater specificity for identifying
patient groups with similar prognoses and treatment options with the least disruption of the
present classification: T1N0M0, stage IA; T2N0M0, stage IB; T1N1M0, stage IIA; T2N1M0 …