Impact of the anatomical location and the number of metastatic lymph nodes on gastric cancer patient´s survival.

Abstract

The most serious problem in surgical treatment of gastric cancer includes the area of resection and the extent of lymphadenectomy. The extent of gastric resection is determined by the extent of tumor affection. The aim of radical surgical intervention is to achieve microscopically clear resection line, since R0 resection is the main criterion for the patient´s prognosis. Curative surgical resection for gastric cancer includes the lymph nodes dissection. In the treatment of gastric cancer, there are two views on the importance of lymphadenectomy. The Far East considers that operation improves the survival and the Europe considers that surgery is not curative, but it determines the staging and prognosis. There is also a difference in staging systems. The one from East is importance based on the anatomical location of affected lymph nodes, the second from Europe is based on the number of positive lymph nodes. This work is a retrospective observational study. In the study cohort, comparing the survival of patients according to different classification systems, depending on the N-stage of disease, 119 patients with gastric adenocarcinoma in clinical stage I to III, i.e. without metastasis, who underwent a radical surgical resection with D2 lymphadenectomy, were enrolled. For the evaluation of the survival versus the time after operation, we used Kaplan‒Meier method. To evaluate the correlation between the survival rate and the explanatory variables, Cox regression and Kendall correlation coefficient were used. The median survival, according to different classification systems, depending on the N-stage of the disease, was significantly correlated with the survival for the 6th and 7th editions of TNM classification system for the Japanese classification system, for N-ratio classification system).The new finding was differentiation of patients in groups N1 vs N2 under the 6th TNM classification (HR=0.910249), also a little differentiation in groups N1 vs N2 according to the classification of N-ratio (HR=0.8750926) and equally a poor differentiation in the survival in groups N2 vs N3 according to the 7th TNM classification (HR=0.881797).The strongest correlation reached the Japanese classification system, but not significantly different from the 6th TNM classification system. In the 7th edition of TNM classification system, we then found the weakest correlation with the survival time, but not significantly different from the previous two. Our retrospective study confirmed the strongest correlation between the patient´s prognosis and the anatomic localization of the affected lymph nodes. This correlation was not statistically significant compared to the correlation between patient´s prognosis and the number of positive lymph nodes. It leads us to the conclusion that both classification systems are comparable and the difference is statistically insignificant (Tab. 4, Fig. 8, Ref. 16).