Ajcc 6(Th) And 7(Th) Tnm Staging Systems Comparison In Locally Advanced Gastric Cancer

Objective To compare the role of AJCC 6th and 7th TNM staging systems in predicting the long term survival of locally advanced gastric cancer patients after curative surgery. Methods All patients who met the following criteria were included for analyses: treated between January 2002 and December 2004, primary gastric or gastroesophageal cancer, underwent curative gastrectomy ( UICC R0 ) and at least more than D1 lymphadenectomy, pathologically staged as T3-4N0-1 M0, or any T, N2-3M0. Overall survival (OS), disease-free survival ( DFS), locoregional recurrence-free survival (LRFS) and distant metastasis-free survival (DMFS) were calculated and compared according to N and TNM stage of the two TNM staging systems (T stage were not analyzed due to its extremely unbalanced distribution). The N and TNM stage and other significant variables in univariate analyses were evaluated further for both OS and DFS by Cox regression. Results The median follow-up time was 61 months. The follow-up rate was 92. 3％.Among the 297 enrolled patients, 56. 9％ of the patients had a stage migration between the two staging systems. According to 6th, no difference in DMFS was detected between different N and TNM stages (x2 =6. 65, P =0. 084 ; x2 =6. 61, P =0. 108 ). When using 7th, statistically significant difference was found in DMFS between different N stages ( x2 =9. 035,P =0. 029), and TNM stage also tended to have an influence on DMFS ( x2 =7.27,P =0. 064). The N and TNM stage had similar significant influence on OS, DFS and LRFS based on both staging systems ( x2 =9. 23 - 19. 00,P =0. 000 -0. 026 and x2 =11.67 - 19. 11 ,P =0. 000 -0. 009). In Cox regression, TNM stage was an independent prognostic variable for both OS and DFS based on these two staging systems (x2=9.05 -25.51, P=0.000 -0.003 ), but the 7thappeared to be a better predictor than the 6 th ( OS : RR =1.6 1 8 vs 1.4 9 6 ; DFS : RR =1.5 9 4 vs 1. 5 6 4 ).Conclusions The N and TNM stage in 7th TNM staging system are more predictive for DMFS than in 6th TNM staging system for locally advanced gastric cancer patients. The 7th TNM staging system provides a better prognostic estimation of both OS and DFS.