ABSTRACT
Objective:
Lymph node metastasis is known to be an important prognostic factor in the gastric cancers. In different staging classifications, the nodal involvement is evaluated in terms of the location and/or number of the metastatic lymph nodes. However, in the Western countries the minimum number of 15 lymph nodes required for an evaluation has been obtained in only 30% of the radical resections performed in the gastric cancer cases; and due to the heterogeneous survival responses in the same stage patients and the phase shifts, use of the metastatic lymph node ratio (N-ratio) rather than of the total number of positive nodes has recently been recommended for the nodal evaluation. In this study, our main objective is to retrospectively analyze the effect of the prognostic parameters to the five-year survival in the gastric cancers, and to particularly investigate the prognostic value of the N-ratio.
Methods:
The clinical records and the pathology and operation reports of the 511 patients who underwent curative surgery with a diagnosis of gastric cancer between January 2002 and December 2009 were analyzed retrospectively. The Kaplan-Meier estimator was used in the calculation of survival. The effects of the existing prognostic factors to the five-year survival were studied in univariate analyses (log-rank test) and in multivariate analyses (Cox regression model). The results were examined in a 95% confidence interval and at a p<0.05 significance level. In the N-ratio classification, the cut-off values of N0 (0%), N1 (1–10%), N2 (11–25%), and N3 (25–100%) were used.
Results:
The general rates of five-year survival were calculated as N0=74.3%, N1=66.3%, N2=59.8%, and N3=30%. When the N-ratio survival rates were compared by log-rank test, a statistically significant difference was observed among the five-year survival rates (p<0.001). The multivariate analysis (Cox regression model) involving all the prognostic factors showed that, in addition to the pT and N stages, the N-ratio was an effective independent prognostic factor in the five-year survival of the gastric cancer patients who underwent a radical resection (p<0.01). In multivariate statistical analyses in which the 6th and 7th AJCC/UICC pathological staging classifications effective to the five-year survival in the univariate analyses, and the N-ratio were involved, the N-ratio was found to be the only independent prognostic factor effecting the survival (p=0.008).
Conclusion:
The N-ratio is an easy, practical, effective and rational prognostic indicator in the gastric cancers with a lymph-node metastasis.
Keywords:
Gastric cancer, lymph node metastasis, metastatic lymph node ratio, prognostic factor
References
1Wang, W., et al., Tumor–ratio–metastasis staging system as an alternative to the 7th edition UICC TNM system in gastric cancer after D2 resection—results of a single-institution study of 1343 Chinese patients. Annals of oncology, 2011. 22(9): p. 2049-2056.
2Marchet, A., et al., The prognostic value of N-ratio in patients with gastric cancer: validation in a large, multicenter series. European Journal of Surgical Oncology (EJSO), 2008. 34(2): p. 159-165.
3Inoue, K., et al., The superiority of ratio-based lymph node staging in gastric carcinoma. Annals of surgical oncology, 2002. 9(1): p. 27-34.
4Hyung, W.J., et al., Prognostic Significance of Metastatic Lymph Node Ratio in T3Gastric Cancer. World journal of surgery, 2002. 26(3): p. 323-329.
5Mihmanlı M, İ.E., Alemdar A, Mihmanlı’nın Mide Kanseri ve Cerrahi Tedavisi. 2 ed. 2006, istanbul Avrupa Tıp Kitapçılık.
6Asoglu, O., et al., Metastatic lymph node ratio is an independent prognostic factor in gastric cancer. Hepatogastroenterology, 2009. 56(91-92): p. 908-13.
7Toker, B., Beş Mide Gastrektomi ve Serisi Şifa 1930: Türk Cerrahi Mecmuası. 165-73.
8Persiani, R., et al., Ratio of metastatic lymph nodes: impact on staging and survival of gastric cancer. European Journal of Surgical Oncology (EJSO), 2008. 34(5): p. 519-524.
9Edge, S.B. and A.J.C.o. Cancer, AJCC cancer staging handbook: from the AJCC cancer staging manual. Vol. 2010. 2010: Springer New York.
10Ding, Y.B., et al., Correlation of tumor-positive ratio and number of perigastric lymph nodes with prognosis of patients with surgically-removed gastric carcinoma. World J Gastroenterol, 2004. 10(2): p. 182-5.
11Crew, K.D. and A.I. Neugut. Epidemiology of upper gastrointestinal malignancies. in Seminars in oncology. 2004. Elsevier.
12Crew, K.D. and A.I. Neugut, Epidemiology of gastric cancer. World J Gastroenterol, 2006. 12(3): p. 354-62.
13Sano, T., et al., Gastric lymphography and detection of sentinel nodes, in Lymphatic Metastasis and Sentinel Lymphonodectomy. 2000, Springer. p. 253-258.
14Larsen, W.J., Essentials of human embryology. 1998: Churchill livingstone.
15Deng, J., et al., The prognostic analysis of lymph node-positive gastric cancer patients following curative resection. J Surg Res, 2010. 161(1): p. 47-53.
16Takagane, A., et al., Evaluation of the ratio of lymph node metastasis as a prognostic factor in patients with gastric cancer. Gastric cancer, 1999. 2(2): p. 122-128.
17Yokota, T., et al., Significant prognostic factors in patients with early gastric cancer. International surgery, 2000. 85(4): p. 286-290.
18Marchet, A., et al., The ratio between metastatic and examined lymph nodes (N ratio) is an independent prognostic factor in gastric cancer regardless of the type of lymphadenectomy: results from an Italian multicentric study in 1853 patients. Annals of surgery, 2007. 245(4): p. 543.
19Nitti, D., et al., Ratio between metastatic and examined lymph nodes is an independent prognostic factor after D2 resection for gastric cancer: analysis of a large European monoinstitutional experience. Annals of surgical oncology, 2003. 10(9): p. 1077-1085.
20Patel, S.H. and D.A. Kooby, Gastric adenocarcinoma surgery and adjuvant therapy. Surg Clin North Am, 2011. 91(5): p. 1039-77.
21Wu, C.W., et al., Comparison of the UICC/AJCC 1992 and 1997 pN categories for gastric cancer patients after surgery. Hepatogastroenterology, 2001. 48(37): p. 279-84.
22Katai, H., et al., Evaluation of the New International Union Against Cancer TNM staging for gastric carcinoma. Cancer: Interdisciplinary International Journal of the American Cancer Society, 2000. 88(8): p. 1796-1800.
23Bando, E., et al., Outcome of ratio of lymph node metastasis in gastric carcinoma. Annals of surgical oncology, 2002. 9(8): p. 775-784.
24Rodriguez Santiago, J.M., et al., Metastatic lymph node ratio as a prognostic factor in gastric cancer. Eur J Surg Oncol, 2005. 31(1): p. 59-66.
25Dinçtürk, C., Tarihçe: Cerrahi Onkoloji Mide Kanseri. Türk Tarih Kurumu Basımevi, Ankara, 1989: p. 9-10.
26Kelley, J.R. and J.M. Duggan, Gastric cancer epidemiology and risk factors. J Clin Epidemiol, 2003. 56(1): p. 1-9.
27Kaminishi, Mide Kanserinin Farklılığı- Patogenez,Tanı ve Tedavi. 1 ed. Mide Kanserinin Endoskopik Tanısı. 2009, istanbul Nobel Tıp Kitabevleri. 185-202.
