OBJECTIVETo investigate the prognostic significance of metastatic lymph node ratio in patients with colorectal cancer.

METHODSThe clinicopathological data of 303 surgically treated patients with colorectal cancer were retrospectively analyzed. Spearman correlation analysis was used to determine the correlation coefficient. The survival was analyzed using Kaplan-Meier method, and the survival difference was assessed by Log-rank test. Multivariate analysis was performed using Cox proportional hazard regression model in forward stepwise regression. Receiver working characteristic curve was used to compare the accuracy of the metastatic lymph nodes ratio in predicting the death of patients at 5 years postoperatively with that of the number of metastatic lymph nodes.

RESULTSThe MLR was not correlated with the total number of dissected lymph nodes (Spearman correlation coefficient: -0.099, P > 0.05), but the positive rate of metastatic lymph nodes did (correlation coefficient: 0.107, P < 0.05). Kaplan-Meier survival analysis revealed that the MLR significantly influenced the postoperative survival time (Log-rank chi(2) = 42.878, P < 0.01), even in the patients with less than 12 resected lymph nodes. The 5-year survival rates for rN0, rN1, rN2 and rN3 were 90.9%, 68.9%, 54.7% and 39.4%, respectively. There was a significant difference between the different stages (P < 0.01). Cox proportional hazard regression model analysis showed that the metastatic lymph node ratio was an independent prognostic factor. (EXP(B) = 7.809, P < 0.01). There was no significant difference between metastatic lymph node ratio and the number of metastatic lymph nodes in predicting the death of patients at 5 years postoperatively based on the area under the receiver working characteristic curve.

CONCLUSIONThe metastatic lymph node ratio in colorectal cancer patients is not correlated with the total number of dissected lymph nodes. The metastatic lymph node ratio is a major independent prognostic factor for patients with colorectal cancer. The ability of metastatic lymph node ratio in predicting the death of colorectal cancer patients at 5 years postoperatively is the same as that of the number of metastatic lymph nodes.