Evaluation of the 7th edition of the TNM classification for lung cancer at a single institution

Abstract

To assess the utilities and drawbacks of the 7th edition of the TNM classification for lung cancer. Subjects included 1,469 patients who underwent pulmonary resection for primary non-small cell lung cancer. Survival characteristics were compared using the 6th and 7th editions of the staging system. According to the 6th and 7th editions, respectively, the 5-year survival rates based on stages were as follows: pStage IA (81.0, 81.0 %), pStage IB (70.6, 72.0 %), pStage IIA (61.3, 59.7 %), pStage IIB (56.6, 47.2 %), pStage IIIA (43.4, 37.6 %), pStage IIIB (8.9, 14.9 %), and pStage IV (14.0, 8.0 %). According to the 6th edition, there was no significant difference between pStages IB and IIA (P = 0.268), or between pStages IIA and IIB (P = 0.622), or between pStages IIIB and IV (P = 0.737). According to the 7th edition, there were significant differences between each adjacent stage group, except between pStages IIIB and IV (P = 0.424). According to the 7th edition staging system, 5-year survival rates by T classification were as follows: pT1a, 81.6 %; pT1b, 75.9 %; pT2a, 60.1 %; pT2b, 44.7 %; pT3, 24.4 %; and pT4, 13.2 %; with significant differences between each adjacent pT classification. The 5-year survival rates by M classification were as follows: M0, 57.2 %, M1a, 9.1 %, M1b, 0 %, with a significant difference between M0 and M1a, but there was no significant difference between M1a and M1b. The UICC 7th edition staging system is considered valid for non-small cell lung cancer patients and appears to be superior in defining different prognostic groups than the 6th edition.