The most appropriate category of metastatic lymph nodes to evaluate overall survival of gastric cancer following curative resection

Abstract

The purpose of this study was to provide a nodal grouping category based on metastatic lymph nodes to evaluate overall survival in gastric cancer patients following curative resection (R0). We reviewed data of 308 gastric cancer patients following curative resection to evaluate significantly survival differences in different categories of the number of metastatic lymph nodes. In 308 evaluable patients, 5-year survival rate (YSR) was 52.9% (median follow-up, 84 months; range, 6-144 months). A total of 6309 lymph nodes were harvested and examined from all 308 patients, and the average number of lymph nodes harvested for per patient was 20.5 (range, 15-49). The average number of metastatic lymph nodes was 5.4 (range, 0-37) per patient. The initial metastatic node cutoffs were designed as 0, 1-4, 5-8, 9-11, 12-16, and >or=17. According to this new category of the number of metastatic lymph nodes, the 5-YSR of various patient groups were 85.7%, 62.8%, 34.3%, 0%, 0%, and 3.4%, respectively. However, we found that there were not significant prognostic differences between patients with 9 metastatic lymph nodes and patients with more than 9 metastatic lymph nodes (P > 0.05). So we redesigned the later cutoffs of number of metastatic lymph nodes. They were as follows: 0, 1-4, 5-8, and >or=9 of metastatic lymph nodes. We demonstrated this new category of the number of metastatic lymph nodes was more appropriate to evaluate overall survival of gastric cancer patients following curative resection than anyone of the current metastatic lymph nodal stagings (such as N stag in UICC, location of metastatic lymph nodes in JCGC, or ratio of metastatic lymph nodes) by using the case-control matched fashion. Our new category of the number of metastatic lymph nodes was an important prognostic factor of gastric cancer patients following curative resection. There were significant overall survival differences in gastric cancer patient groups with various numbers of metastatic lymph nodes following curative resection.