[Prognostic assessment of resected lung cancer based on the new international staging system: analysis by histologic types].

The purpose of this study is to assess the validity of the new international staging system for lung cancer revised in 1997 and to clarify the prognostic value of histologic type. Of 1,042 patients with primary lung cancer who underwent resection from 1982 to 1995, 549 patients with adenocarcinoma (AD) and 363 with squamous cell carcinoma (SQ) were included in this study. Overall deaths including operative deaths were treated as the terminal event. For patients with AD, 5-year survival rates were 83% in T1N0M0, 70% in T2N0M0, 46% in T2N1M0, 45% in T3N0M0, 43% in T1N2M0, 32% in T1N1M0, 27% in T2N2M0, 25% in T3N1M0, and 10% in T3N2M0, respectively. For patients with SQ, 5-year survival rates were 80% in T1N0M0, 78% in T1N1M0, 67% in T1N2M0, 60% in T3N0M0, 56% in T2N0M0, 47% in T2N1M0, 36% in T3N1M0, 26% in T2N2M0, and 10% in T3N2M0, respectively. Survival of T1N2M0 was significantly better than that of T2N2M0 and similar to that of T3N0M0 and T2N1M0 both in AD and SQ. In AD survival was dominantly affected by N factor, while in SQ survival was strongly correlated with T factor. In conclusion, we propose that T1N1M0, T2N1M0, T3N0M0 and T1N2M0 should be classified as stage II and T3N2M0 be included into stage IIIB for AD. The TNM grouping for SQ is same as that for AD except setting T1N1M0 as stage IB and T2N0M0 as stage II.