A novel lymph node staging system for gastric cancer including modified Union for cancer Control/American Joint Committee on cancer and Japanese Gastric Cancer Association criteria

12 Background: The aim this study was to clarify what the most informative pathologic lymph node staging system in gastric cancer is, by using time-dependent receiver operating characteristic (ROC) analysis with Harrell’s concordance (c) index. Methods: This study enrolled 2747 primary gastric cancer patients, without prior chemotherapy, who underwent R0 or R1 macroscopically curative resection. We calculated concordance indices of different 3 nodal staging systems (anatomical level based on JPN 13th edition vs. numbers of metastatic nodes based upon TNM 7th edition vs. ratio of metastatic nodes; derived from Yu’s definition {Yu et al. Br J Surg;1997,N0:0, N1;0-0.1, N2;0.1-0.25, N3;0.25-}) for survival. Results: (Anatomical level) Harrell’s c-index was 0.754 with 5-year survival rate of N0; 93%, N1; 73%, N2; 51%, N3; 19%. C-index without node-negative patients was 0.628. (Numbers of positive nodes) C-index was 0.767 with 5-year survival rate of N0; 93%, N1; 81%, N2; 68%, N3; 37%. C-index without node-negative patients was 0.669. (Ratio of nodal involvement) C-index was 0.770 with 5-year survival rate of N0; 93%, N1; 80%, N2; 63%, N3; 29%. C-index without node-negative patients was 0.691, which is significantly larger than those in anatomical level or numbers of positive nodes (p<0.001, p=0.014, respectively). (Comparison of Staging System) If combined pT category with ratio grading system without pStage IA, new staging system is the significantly most informative (c-index; 0.760) than JPN 13th (c-index; 0.735) or TNM 7th (c-index; 0.742) (p=0.009, p=0.023, respectively). Conclusions: Lymph node staging system based on the conception of ratio of metastatic nodes is the most informative staging system than those with anatomical location or numbers of metastatic nodes. These results suggested that in gastric cancer pathologic staging system in next TNM classification should include the ratio of metastatic nodes.

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A novel simplified approach to incorporating lymph node ratio into gastric cancer staging.

Journal of Clinical Oncology ◽

10.1200/jco.2013.31.4_suppl.24 ◽

2013 ◽

Vol 31 (4_suppl) ◽

pp. 24-24

Author(s):

Sarah B. Fisher ◽

Malcolm Hart Squires ◽

Sameer H. Patel ◽

David A. Kooby ◽

Kenneth Cardona ◽

...

Keyword(s):

Gastric Cancer ◽

Lymph Node ◽

Lymph Node Ratio ◽

Staging System ◽

Cancer Staging ◽

Lymph Node Staging ◽

Cox Regression Analysis ◽

Simplified Approach ◽

Staging Systems ◽

Node Ratio

24 Background: Previous investigators have reported on the value of lymph node ratio (LNR, defined as the number of positive nodes divided by the total number of nodes assessed) in gastric adenocarcinoma (GAC) staging. Given the complexity of previously proposed staging systems, it has not gained widespread acceptance. The aim of our study was to offer a novel simplified approach to incorporating LNR into gastric cancer staging. Methods: 131 patients who underwent curative intent resection with lymphadenectomy for GAC between 1/00-6/11 were identified. Clinicopathologic factors were assessed. Primary outcome was overall survival (OS). Results: Median age was 64 yrs, 51% were male. Median tumor size was 3.5 cm, 67% were poorly differentiated, 20% had perineural invasion, 31% had lymphovascular invasion, and 6% had a positive margin. Locoregional nodal metastases were present in 59% (n=77, N0: 41%, N1: 18%, N2: 22%, N3a: 14%, N3b: 5%). Median number of lymph nodes (LN) assessed was 15.5. Mean FU was 27.3 mos, median OS was 29.3 mos. Median LNR was 0.4 (.04-1). Patients with LNR ≥0.4 had decreased OS as compared to patients with LNR <0.4 (15.1 vs 41.5 mos, p<0.0001); the survival of patients with LNR <0.4 was similar to that of node negative pts (48 mos, p=0.882). On Cox regression analysis, LNR ≥0.4 was more strongly associated with decreased OS (HR 3.09, 95%CI: 1.81-5.26; p<0.0001) compared to the AJCC 7th edition N stage (HR 1.36, 95%CI: 1.11-1.68; p=0.004). In the subset of patients who were inadequately staged and had <16 nodes examined, a LNR ≥0.4 was associated with reduced survival compared to a LNR <0.4 (17.3 vs 41.5 mos, p=.04). Conclusions: Compared to the current lymph node staging system, a lymph node ratio using 0.4 as the cutoff may more accurately predict survival outcomes. It seems to be particularly useful in patients who have inadequate nodal assessment. This simplified approach to lymph node ratio may be a more valuable staging tool than the current AJCC nodal staging system for gastric cancer and needs to be validated.

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