Positive Lymph Node Ratio Is an Independent Prognostic Factor in Gastric Cancer After D2 Resection Regardless of the Examined Number of Lymph Nodes

Abstract

The purpose of this study was to clarify the outcome of the ratio between metastatic and examined lymph nodes (N ratio) in gastric cancer patients with < or =15 examined lymph nodes after D2 lymphadenectomy. A retrospective study was performed in 906 patients with gastric cancer who had undergone D2 resection. Patients with < or =15 examined lymph nodes (group 1, n = 729) and those with >15 lymph nodes (group 2, n = 177) were analyzed separately. N ratio categories were identified as follows: N ratio 0, 0%; N ratio 1, 1% to 9%; N ratio 2, 10% to 25%; N ratio 3, >25%. Univariate analysis found that both the tumor, node, metastasis system (N staging system) and N ratio system well classified patients with significantly different prognosis. By multivariate analysis, only the N ratio classification was retained as an independent prognostic factor in both group 1 and 2 compared with the N stage system. Furthermore, when patients were divided into four groups according to the number of lymph nodes examined (1 to 3, 4 to 7, 8 to 11, and 12 to 15), the 5-year survival rates remained similar between groups according to the same N ratio (p > .05). Positive N ratio classification is a better prognostic tool compared with N staging system after D2 resection in patients with gastric cancer. It can prevent stage migration and can be used regardless of the examined number of lymph nodes.

The evaluation of metastatic lymph node ratio staging system in gastric cancer

“…To evaluate the rN staging system, some previous reports excluded patients with fewer than 16 LNs retrieved [16,20,22]; some researchers preferred the patients treated by limited lymphadenectomy, [9,10,18,23]; and some centers evaluated the rN system as an independent prognostic factor in gastric cancer regardless of the type of lymphadenectomy, or in both [15 and B15 LNs examined [17,19,24,25], as we did in our report. All the reports indicated that the rN staging system has superiority in prognosis assessment compared with the traditional AJCC pN system.…”

“…The Cox multivariate analysis showed that rN has a prognostic value independent of the extent of lymphadenectomy. Many previous reports used Cox multivariate examinations, including both pN stage and rN stage, for proving the superiority of the LN ratio system [9,[15][16][17][18][19][20]. The pN and rN systems, two definitions of classifications for staging lymph node status, were highly correlated.…”

“…However, there is much controversy regarding the most appropriate cutoff ratio because the ratios differ among investigators. The following cutoff values have been proposed: 0, 0.20, 0.50 [10,24], 0, 0.30, 0.60 [15,25], 0, 0.10, 0.25 [9,16,20], 0, 0.30, 0.70 [17], 0, 0.015, 0.40 [23], 0, 0.10, 0.25 [19], 0, 0.25, 0.50 [18], and 0, 0.10, 0.40 [22]. The cutoff values showed great variety in different countries, even in different centers in the same country.…”

Mide Kanserli Olgularin Geriye Donuk Incelenmesi

“…Yapılan sağkalım analizlerinde metastatik lenf nodu oranı bağımsız bir faktör olarak sağkalımda etkili bulunmuş ve çalışmaların çoğunda N sınıflamasının bu orana göre yeniden düzenlenmesi önerilmiştir (22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33). Bizim çalışmamızda ise incelenen verilerin sağkalıma etkisini incelemek için gerçekleştirilen Linear Lojistik Regresyon analizinde "evre" ve "metastatik lenf nodunun toplam lenf nodlarına oranı" sağkalıma istatistiksel olarak anlamlı etki yapan faktörler olarak belirlendi (p<0,05).…”

“…Lenf nodu metastazı mide kanserinin prognozuna etkili en önemli faktörlerden biridir (5). Mide kanserinin prognozu genellikle kötüdür.…”