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

Marchet, A.; Mocellin, S.; Ambrosi, A.; de Manzoni, G.; Di Leo, A.; Marrelli, D.; Roviello, F.; Morgagni, P.; Saragoni, L.; Natalini, G.; De Santis, F.; Baiocchi, L.; Coniglio, A.; Nitti, D.; on behalf of the Italian Research Group for Gastric Cancer Study (GIRCG),

doi:10.1016/j.ejso.2007.04.018

« Previous Next »European Journal of Surgical Oncology
Volume 34, Issue 2 , Pages 159-165, February 2008

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

A. Marchet
- Clinica Chirurgica II, University of Padova, Padova, Italy
S. Mocellin
- Clinica Chirurgica II, University of Padova, Padova, Italy
A. Ambrosi
- Clinica Chirurgica II, University of Padova, Padova, Italy
- Statistics Center for Biomedical Sciences, San Raffaele University, Milan, Italy
G. de Manzoni
- First Division of General Surgery, University of Verona, Verona, Italy
A. Di Leo
- First Division of General Surgery, University of Verona, Verona, Italy
D. Marrelli
- Surgical Oncology Unit, University of Siena, Siena, Italy
F. Roviello
- Surgical Oncology Unit, University of Siena, Siena, Italy
P. Morgagni
- Department of General Surgery, Morgagni-Pierantoni Hospital, Forlì, Italy
L. Saragoni
- Department of General Surgery, Morgagni-Pierantoni Hospital, Forlì, Italy
G. Natalini
- General Surgery Unit, General Hospital of Perugia, Perugia, Italy
F. De Santis
- Department of Surgery, Todi-Marsciano General Hospital, Todi, Italy
L. Baiocchi
- Institute of Clinica Chirurgica, University of Brescia, Brescia, Italy
A. Coniglio
- Institute of Clinica Chirurgica, University of Brescia, Brescia, Italy
D. Nitti
- Clinica Chirurgica II, University of Padova, Padova, Italy
- Corresponding author. Address: Clinica Chirurgica II, Dipartimento di Scienze Oncologiche e Chirurgiche, Università di Padova, Via Giustiniani 2, 35128 Padova, Italy. Tel.: +39 049 8212055; fax: +39 049 651891.
on behalf of the Italian Research Group for Gastric Cancer Study (GIRCG)

Accepted 28 April 2007.

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 ≤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 45.5months, 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.

Keywords: Gastric cancer, Prognosis, TNM staging system, N-ratio