New Metastatic Lymph Node Ratio System Reduces Stage Migration in Patients Undergoing D1 Lymphadenectomy for Gastric Adenocarcinoma
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The American Joint Committee on Cancer (AJCC)/International Union Against Cancer (UICC) staging system for gastric cancer incorporates the absolute number of metastatic lymph nodes (N status) and is optimally used when ≥15 nodes are examined. The ratio of metastatic to examined nodes (N ratio) is an effective prognostic tool, but has not been examined in Western patients undergoing primarily D1 lymphadenectomy.
Two hundred and fifty seven patients with gastric adenocarcinoma who underwent gastric resection between 1995 and 2005 at our institution were examined. Novel N ratio intervals were determined using the best cutoff approach (Nr0: N ratio = 0 and ≥15 nodes examined; Nr1: 0 ≤ N ratio ≤ 0.3; Nr2: 0.3 < N ratio ≤ 0.7; and Nr3: N ratio > 0.7). Overall survival was examined according to N status and N ratio.
83% of patients underwent D1 lymphadenectomy with a median of 14 lymph nodes examined. Overall survival stratified by N status was significantly different in patients with <15 nodes examined compared with those with ≥15 nodes examined. When we stratified by N ratio intervals, there was no significant difference in overall survival in patients with <15 versus ≥ 15 nodes examined. On multivariate analysis, N ratio but not N status was retained as an independent prognostic factor.
The use of N status for staging patients undergoing primarily D1 lymphadenectomy results in significant stage migration due to varying numbers of nodes examined. Use of N ratio reduces stage migration and may be a more reliable method of staging these patients.
The authors would like to thank Carol Venuti of the Massachusetts General Hospital Cancer Data Registry. Dr. Maduekwe was supported by the Scholars in Clinical Science Program at Harvard Medical School under National Institutes of Health grant no. 1 KL2 RR025757-0 1, Harvard Clinical and Translational Science Center (KL1).
- 3.World Health Organization. Fact Sheet No 297, Cancer. 2-1-2009. http://www.who.int/mediacentre/factsheets/fs297/en/index.html. Accessed 19 Jan 2010.
- 5.Greene FL, Page DL, Fleming ID et al. AJCC cancer staging manual. 6th ed. New York: Springer; 2002.Google Scholar
- 11.Marchet A, Mocellin S, Ambrosi 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. Ann Surg. 2007;245:543–552.CrossRefPubMedGoogle Scholar
- 17.Persiani R, Rausei S, Antonacci V, et al. Metastatic lymph node ratio: a new staging system for gastric cancer. World J Surg. 2009.Google Scholar
- 22.Japanese Research Society for Gastric Cancer: the general rules for the gastric cancer study in surgery. Jpn J Surg. 1973;3:61.Google Scholar
- 25.Kaplan E, Meier P. Nonparametric estimation from incomplete observations. J Am Stat Assoc. 1958;457–81.Google Scholar
- 27.Cox D. Regression models and life-tables. J R Stat Soc. 1972;34:187–220.Google Scholar