A Proposal of New Staging System Based on Survival Rates in Gastric Cancer Patients

Hyung, Woo Jin; Cheong, Jae Ho; Chen, Jian; Kim, Junuk; Choi, Seung Ho; Noh, Sung Hoon

Abstract

PURPOSE
This study was carried out to propose a new staging system to improve the current UICC/AJCC staging system. METHODS: A total of 4217 patients who had undergone gastrectomy for gastric cancer from 1987 to 1997 were retrospectively reviewed. Among them, 4040 patients with either early gastric cancer (EGC, n=1202) or advanced gastric cancer (AGC, n=2838) can be appropriately staged by the 6th UICC/AJCC system. Survival rates of EGC were analyzed according to the number of lymph node metastasis while those of AGC patients were analyzed according to the TNM classifications. RESULTS: The 5-year survival rate (5-YSR) of EGC patients according to the 6th UICC/AJCC was 94.6% for stage Ia, 92.9% for stage Ib, and 40.9% for stage II or IV. The 5-YSR according to the number of lymph node metastases in EGC patients was 94.6% for EGC patients with node negative, 95.1% for those with 1 or 2 positive nodes, and 73.4% for those with 3 or more positive nodes. The 95% confidence intervals of mean survival duration were narrower when patients were grouped with a reference number of metastatic lymph nodes as 3 than when patients were grouped according to the 6th UICC/AJCC staging system. The 5-YSR according to TNM classifications in AGC patients wss 89.8% for T2N0M0, 71.5% for T2N1M0, 74.9% for T3N0M0, 55.2% for T2N2M0, 58.6% for T3N1M0, 44.4% for T4N0M0, 35.1% for T3N2M0, 32.3% for T4N1M0, 9.4% for T4N2M0, 14.1% for TanyN3M0, and 7.6% for TanyNanyM1. The survival of T4N1M0 was rather similar to that of T3N2M0 (P=0.9225) than other TNM classifications in stage IV (P<0.0001). CONCLUSION: With these results we may propose following new staging proposal. For EGC patients, the following division of N1 into two groups is recommanded: 1 or 2 positive lymph nodes as N1a and 3 or more positive nodes as N1b is recommended. With the new nodal classification in EGC, the staging recommendation for EGC patients is I for T1N0M0 and T1N1aM0, and II for T1N1bM0. For AGC patients, the following redistribution of TNM classification is recommanded for a new staging system, regarding T2N0M0 as stage I and T4N1M0 as stage IIIb. In this new staging system, we can reduce the 6 stage groups into 5.