Prognostic evaluation based on a new TNM staging system proposed by the International Association for the Study of Lung Cancer for resected non–small cell lung cancers

Abstract

The TNM classification has been widely used as a guide for estimating prognosis and is the basis for treatment decisions on various solid tumors. The International Association for the Study of Lung Cancer Staging Committee has proposed a new staging system for the next revision scheduled in 2009. However, its validity has not been established fully. Here we assessed its utilities and drawbacks. We reviewed 1556 consecutive patients with non-small cell lung cancers who underwent pulmonary resection in our institution and reviewed their survival characteristics based on the 2009 system compared with the current (1997) system. The numbers of patients with stage IIA disease increased remarkably when using the 2009 system because of the reclassification of stages IB and IIB. Although the 5-year survival rates of the patients with stage IB and IIA disease in the 1997 system showed no difference with the 2009 system, the survival rates of patients with stage IB disease was 68.0%, which is better than that of patients with stage IIA disease (57.6%). The patient survival curves showed stepwise deterioration as the numbers increased, except for patient with stage IV disease. Our study supported the proposal for this new staging system. Compared with the 1997 system, the 2009 system appears to be superior in separating stage IB and IIA disease and provides an even distribution among the stage groupings, although it is slightly complicated. The survival characteristics of 1556 resected cases in this single Japanese institution validated the proposed 2009 system.