Validity and controversies in the new postoperative pathologic TNM classification based on the results of surgical treatment of non-small cell lung cancer

In 1997, the latest revision of the International System for Staging Lung Cancer was published. To validate the new pathologic TNM classification for non-small cell lung cancer (NSCLC), we analyzed the survival data of 455 patients who underwent pulmonary resection and pathologic staging at our institution from January 1980 through December 1999. The overall 5-year survival rate was 51.0%. Using the revised new stage classification, the survival rate for each stage was as follows; IA: 74.2%, IB: 66.4%, IIA: 56.0%, IIB: 51.8%, IIIA: 21.0%, IIIB: 16.0%, and IV: 0%. The current TNM classification well reflected the long-term prognostic hierarchy. There were significant differences in survival rates between patients with stage IA and IB, and between patients with stage IIB and IIIA. However, there was no significant difference between patients with stage IIA and IIB. No significant difference in survival was observed among patients with stage IIIA, stage IIIB, and stage IV. Five-year survival rate of 48.3% in the T3N0M0 category was significantly better than that of 21.0% found in the new stage IIIA. The survival of patients with intrapulmonary metastases in the same lobe (pm1) was not significantly better than that found in the stage IV. The TNM staging system accurately reflects the prognosis in NSCLC, but some stage definitions can be discussed.