Evaluation of Prognostic Values according to the New TNM Classification in Gastric Cancer

Abstract

Purpose: In 2010, the new UICC/AJCC TNM classification for gastric cancer was declared. The new classification for gastric cancer has several changes from the 6th classification. We evaluated the prognostic values and differences according to the new UICC/AJCC TNM classification. Methods: From 2000 to 2004, 1,196 patients who underwent curative resection with D1＋β or more lymph node dissection and with 15 or more lymph nodes retrieved were studied retrospectively. We analyzed clinical characteristics and survival outcomes retrospectively from medical records. Results: According to UICC/AJCC 7th TNM classification, the 5-year survival rate (5YSR) of each group for depth of invasion and node metastasis were significantly different. The 5YSR of stage Ⅱ in 6th classification was 82.4% and the 5YSR of stage Ⅱa and Ⅱb in 7th classification were 92.2% and 82.9%. The 5YSR of stage Ⅲa and Ⅲb in 6th classification were 56.3% and 33.0%. The 5YSR of stage Ⅲa, Ⅲb and Ⅲc in 7th classification were 72.7%, 48.4% and 26.1%. In our Cox regression multivariate analysis, N stage of the 6th UICC/AJCC TNM classification was the main independent prognostic factor. Conclusion: N stage of the 6th UICC/AJCC TNM classification is a more reliable prognostic factor than N stage of the 7th UICC/AJCC TNM classification. Further study should be performed to confirm the appropriateness of N stage TNM classification for gastric cancer.