The effectiveness of the new (7th) UICC N classification in the prognosis evaluation of gastric cancer patients: a comparative study between the 5th/6th and 7th UICC N classification

Abstract

Background The most important prognostic factor after curative surgery for gastric carcinoma is the presence of lymph node metastases. According to the 7th edition of the UICC TNM staging system for gastric cancer, N classification was categorized as N0 (no regional lymph node metastasis), N1 (1-2 regional lymph node metastases), N2 (3-6 regional lymph node metastases), and N3 (7 or more regional lymph node metastases). The purpose of this study was to evaluate the rationality of the new UICC/AJCC N classification in comparison with the 6th UICC classification. Methods From August 2002 to July 2006, 295 patients with gastric cancer underwent curative resection with D2 lymph node dissection by a single surgeon. We analyzed retrospectively the significant prognostic factors and identified the suitability of the 7th UICC N staging system. Results According to the 7th UICC N classification, the 5-year cumulative survival rates (5-YSR) of N0, N1, N2, N3a, and N3b were 89.7, 73.6, 54.9, 23.1, and 5.4%, respectively (P \ 0.0001). Using univariate analysis, the N classification of the 7th and 6th UICC/AJCC TNM staging system, T classification of the 7th UICC TNM staging system, size and location of tumor, and histology were associated with the overall survival of gastric cancer after curative surgery. However, Cox regression multivariate analysis showed the 7th UICC N classification was an independent prognostic factor instead of the 6th UICC N classification (P \ 0.0001). ConclusionThe 7th UICC classification for lymph node metastasis is thought to be a more reliable prognostic factor for gastric cancer than the 6th classification.

Gastric Cancer: Clinical Aspects, Epidemiology and Molecular Background

“…Another study from Korea showed similar results for the new TNM system, proving a more detailed prognostic assessment, especially between T2 and T3 and N1 and N2 tumors [2]. The advantage of the new (7th) edition was mainly confirmed for the prognostic value of accurate lymph node assessment [3].…”

“…Another study from Korea showed similar results for the new TNM system, proving a more detailed prognostic assessment, especially between T2 and T3 and N1 and N2 tumors [2]. The advantage of the new (7th) edition was mainly confirmed for the prognostic value of accurate lymph node assessment [3].Concerning the classification of early gastric cancer (GC) in the new system, a study from Italy confirmed the usefulness of the new classification for metastatic lymph nodes as a prognostic tool in case of early GC. …”

Validity and Necessity of Sub-classification of N3 in the 7thUICC TNM Stage of Gastric Cancer

“…It seems that there should be a compensation for this problem. There was a significant difference in the 5-year survival rate between the 7 th N3a and N3b (Ichikura et al, 1999;Chae et al, 2011). As several data indicated there was a significant difference in survivals between N2 and N3 in the 6 th N classification (Ichikura et al, 1999;).…”

“…The revision of the pN classification for the 7 th TNM classification will be more conspicuous and needs to be fully discussed Chae et al, 2011;Jung et al, 2011). An ideal lymph node staging system for gastric cancer has been controversial and has changed whenever a revision in the TNM classification has been made (Klein et al, 2001;Yamashita et al, 2008;Jung et al, 2011).…”

“…Therefore, T1-T2N3M0 gastric cancer has a lower incidence in China, as did our specimen. Because of the narrow definition, T3 gastric cancer also has a lower incidence (Chae et al, 2011;Qiu et al, 2011;Wang et al, 2011). So a multi-center observational study is necessary in exploration of N3 sub-stage in these patients.…”