Does lymph node ratio (metastasis/total lymph node count) affect survival and prognosis in gastric cancer?

OBJECTIVES: To investigate the influence of the metastatic lymph node/total lymph node ratio (N-ratio) on survival and prognosis in surgically treated gastric carcinomas. METHODS: A retrospective review of 73 patients who underwent curative resection at the Department of General Surgery, Hitit University Faculty of Medicine, Turkey. Receiver operating characteristic analysis was used to calculate the cut-off value for the N-ratio of the patients. The N-ratio cut-off value was determined to be 0.32. Patients were divided into 2 groups: below 0.32 (Group 1) and 0.32 and above 0.32 (Group 2). RESULTS: Group 2 patients had a total lymph node mean of 25.10±13.64 while Group 1 patients had a total lymph node mean of 18.77±9.36 (p=0.04). In Group 2, the mean of metastatic lymph node was 15.97±10.30 (p<0.001). The mortality rate of Group 1 was 18% while Group 2 was 51.7%, and were statistically significant (p=0.0039). The estimated survival duration of Group 2 was 24.22 months, and Group 1 was 48.01 months (p=0.001). The mean estimated survival time for the entire group was 40.92 months. We differentiated patients from the development of mortality cut-off value in ROC analysis with 65.2% sensitivity and 72% specificity. This ratio was found to be 0.32, which was statistically significant (p=0.003). Ratios greater than 0.32 raised the risk of mortality by 4.8 times, which was statistically significant (p=0.003). CONCLUSION: The N-ratio could be a new metric to evaluate prognosis following curative gastrectomy and improve the existing tumor lymph node metastasis staging system.