Re-evaluating the prognostic validity of the negative to positive lymph node ratio in node-positive gastric cancer patients

Abstract

Lymph node status is one of the most important clinical outcome determinants in gastric cancer patients. Categorization based on the metastatic node count alone, however, would presumably be influenced by the extent of lymphadenectomy and the stage migration phenomenon. We statistically analyzed relevant clinicopathologic data of 351 gastric cancer patients with node metastasis who had undergone R0 surgery to compare the reliability of the negative to positive lymph nodes ratio to those of other classifications of lymph node metastasis for predicting outcomes. Survival analyses demonstrated the negative to positive lymph nodes ratio to be an independent predictor of overall survival in the 351 gastric cancer patients (hazard ratio=0.414; P<.001) and revealed significant superiority (P<.001) for evaluating overall survival based on direct comparison with other categories of lymph node metastasis applying case-control matching. In addition, the negative to positive lymph nodes ratio was found to correlate significantly with the number of negative lymph nodes (P<.001), pN stage (P<.001), and the positive to dissected lymph nodes ratio (P<.001) by multinomial logistic regression analysis. Finally, the interplay effect analyses revealed the negative to positive lymph nodes ratio to yield information similar to that provided by the positive to dissected lymph nodes ratio (R2=1.000), while providing more information on both the number of dissected lymph nodes and the number of negative lymph nodes than the positive to dissected lymph nodes ratio. The negative to positive lymph nodes ratio, which reflects comprehensive information on dissected, positive, and negative node counts, appears to be a useful alternative for predicting the outcomes of node-positive gastric cancer patients.