The prognostic value of N-ratio in patients with gastric cancer: validation in a large, multicenter series

Eur J Surg Oncol. 2008 Feb;34(2):159-65. doi: 10.1016/j.ejso.2007.04.018. Epub 2007 Jun 13.

Abstract

Aims: The proportion between metastatic and examined lymph nodes (N-ratio) has been proposed as an independent prognostic factor in patients with gastric cancer. In the present work we validated the reliability of N-ratio in a large, multicenter series.

Patients and methods: We retrospectively reviewed the data of 1853 patients who underwent radical resection for gastric carcinoma. Survival of patients with >15 (Group-1, n=1421) and those with < or =15 (Group-2, n=432) lymph nodes examined was separately analyzed in order to evaluate the influence of lymph node dissection on disease staging. N-ratio categories (N-ratio 0, 0%; N-ratio 1, 1-9%; N-ratio 2, 10-25%; N-ratio 3, >25%) were determined by the best cut-off approach.

Results: At multivariate analysis, N-ratio (but not TNM N-category) was retained as an independent prognostic factor both in Group-1 and Group-2 (HR for N-ratio 1, N-ratio 2 and N-ratio 3=1.67, 2.96 and 6.59, and 1.56, 2.68 and 4.28, respectively). After a median follow-up of 45.5 months, the 5-year overall survival rates of TNM N0, N1 and N2 patients were significantly different in Group-1 vs Group-2. This was not the case when adopting the N-ratio classification, suggesting that a low number of excised lymph nodes can lead to patients being understaged using the N-category, but not N-ratio. Moreover, N-ratio identified subsets of patients with significantly different survival rates within TNM N1 and N2 categories in both groups.

Conclusions: N-ratio is a simple and reproducible prognostic tool that can stratify patients with gastric cancer, including those cases with limited lymph node dissection. These data support the rationale to propose the implementation of N-ratio into the current TNM staging system.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Adenocarcinoma / mortality
  • Adenocarcinoma / secondary*
  • Adenocarcinoma / surgery*
  • Aged
  • Aged, 80 and over
  • Analysis of Variance
  • Female
  • Gastrectomy / methods
  • Humans
  • Immunohistochemistry
  • Lymph Node Excision / statistics & numerical data
  • Lymph Nodes / pathology*
  • Lymphatic Metastasis
  • Male
  • Middle Aged
  • Multicenter Studies as Topic
  • Multivariate Analysis
  • Neoplasm Staging / methods*
  • Predictive Value of Tests
  • Probability
  • Prognosis
  • Proportional Hazards Models
  • Retrospective Studies
  • Risk Assessment
  • Sensitivity and Specificity
  • Stomach Neoplasms / mortality
  • Stomach Neoplasms / pathology*
  • Stomach Neoplasms / surgery*
  • Survival Analysis