Evaluation of new TNM lung cancer classification.

OBJECTIVE: A new staging system for lung cancer was proposed by the Union Internationale Contre le Cancer in 1997, with Stages I and II subdivided and T3N0M0 assigned as stage IIB. We studied the usefulness of this new classification. METHODS: Subjects were 753 patients with non-small-cell lung cancer undergoing pulmonary resection and follow-up data were retrospectively reviewed. RESULTS: A significant difference was seen between stage IA and IB survival--70.4% vs 52%. No significant difference was seen between survival for T3N0M0, T1N1M0 and T2N1M0--35.3%, 42.3%, and 43.8%--at 5 years. We found, however, that the prognosis for T3N2M0 tumors--6.5% 5-year survival--is too poor to be grouped with other N2 diseases having a better prognosis--23.9% 5-year survival. Significant differences were also seen in the survival of T3N0 or T3N1 patients by organ and diseases involving the rib, diaphragm, or mediastinum may be classified as T4. CONCLUSION: The new staging system predicts patient outcome fairly well and the modification is well grounded. It appears, however, to be appropriate to subdivide T3 tumors by invaded organs and T3N2M0 disease may be better classified as stage IIIB. The classification of pulmonary metastasis appears to require further improvement.