BACKGROUND AND OBJECTIVES: To determine the prognostic value of the ratio of metastatic lymph nodes (RML) for gastric cancer and compare it to the prognostic value of the number-based pN classification. METHODS: The survival of 513 patients who underwent curative resection between 2000 and 2005 was retrieved. The prognostic value of two factors for nodal status: RML classification (RML0, 0%; RML1, < or =30%; RML2, < or =50%; RML3, >50%) and pN classification (6th TNM system), was analyzed. RESULTS: Both RML and pN classifications were independent prognostic factors when considered separately in multivariate analysis (P-values < 0.05). Moreover, the proportion of explained variation (PEV) analysis showed that each classification had more prognostic value than other prognostic factors in two models respectively (P-values < 0.05). The D-measure for prognostic separation was 1.563 versus 1.383 for RML versus pN. Bootstrap results for the difference of D-measures did not show a significant difference between RML and pN in terms of prognostic power (95% CI, -0.102 to 0.175). CONCLUSIONS: RML is an independent prognostic factor for gastric cancer. However, no significant evidence is found to support the hypothesis that RML classification carries more prognostic value than pN classification.
BACKGROUND AND OBJECTIVES: To determine the prognostic value of the ratio of metastatic lymph nodes (RML) for gastric cancer and compare it to the prognostic value of the number-based pN classification. METHODS: The survival of 513 patients who underwent curative resection between 2000 and 2005 was retrieved. The prognostic value of two factors for nodal status: RML classification (RML0, 0%; RML1, < or =30%; RML2, < or =50%; RML3, >50%) and pN classification (6th TNM system), was analyzed. RESULTS: Both RML and pN classifications were independent prognostic factors when considered separately in multivariate analysis (P-values < 0.05). Moreover, the proportion of explained variation (PEV) analysis showed that each classification had more prognostic value than other prognostic factors in two models respectively (P-values < 0.05). The D-measure for prognostic separation was 1.563 versus 1.383 for RML versus pN. Bootstrap results for the difference of D-measures did not show a significant difference between RML and pN in terms of prognostic power (95% CI, -0.102 to 0.175). CONCLUSIONS: RML is an independent prognostic factor for gastric cancer. However, no significant evidence is found to support the hypothesis that RML classification carries more prognostic value than pN classification.