Background: We examined the prognostic value of metastatic lymph node ratio (the ratio of the number of metastatic lymph nodes to the number of lymph nodes removed) after curative resection.
Patients and methods: The results of surgery on 758 patients were assessed by uni-and multi-variate analysis by classifying the metastatic lymph node ratio into 4 categories: 0, <0.1, >0.1 <0.2, >0.2. Furthermore, the rationality and prognostic significance of the lymph node ratio classification as a nodal staging system was compared with the UICC/TNM classification.
Results: Univariate analysis showed that operative method, location of tumor, macroscopic appearance, tumor diameter, depth of invasion, metastatic lymph node ratio, lymphatic invasion and venous invasion significantly affected prognosis. A Cox proportional regression hazard model revealed that macroscopic appearance, tumor diameter, depth of invasion and metastatic lymph node ratio independently influenced prognosis. Among patients with pN2 by the UICC/TNM classification, survival in those with a metastatic lymph node ratio less than 0.1 was significantly better than in those with a higher metastatic lymph node ratio.
Conclusions: The metastatic lymph node ratio is an independent prognostic factor. Extended lymphadenectomy could increase survival of patients with pN2 gastric cancer by decreasing the metastatic lymph node ratio below 0.1.