Prognostic Significance of Ratio of Metastatic Lymph Nodes in Colorectal Cancer Patients Treated with Curative Resection

Abstract

INTRODUCTION: Metastatic lymph node ratio (mLNR) has been shown to be an important prognostic factor in some solid tumours. The aim of this study was to investigate the prognostic value of mLNR in patients with colorectal carcinoma (CRC). METHODS: The records of 246 CRC patients who had not distant metastasis and treated with curative surgery were retrospectively evaluated between January 2008 and April 2014. The effects of age, gender, the number of total lymph nodes removed, the number of metastatic lymph nodes, pathological T stage, TNM staging, mLNR and lymphovascular invasion on disease free survival and overall survival were analyzed with univariate and multivariate Cox-regression tests. Survival curves were calculated using Kaplan-Meier method and survival differences were assessed by log-rank test. Optimal cut-off value for mLNR is determined with ROC analysis. RESULTS: Median age was 61 (23-86) and median follow-up period was 38 (11-78) months. Optimal cut-off value for mLNR was found as 0,08 in ROC analysis. In the multivariate analysis, the number of total lymph nodes removed (p<0.007) and mLNR (HR, 2.1; 95% CI, 1.2-4.2; p<0.003) were found to be independent risk factors on disease-free survival. For overall survival, mLNR only was the independent risk factor on overall survival (HR,7.5; 95% CI, 2.6-21.2; p<0.0001). DISCUSSION AND CONCLUSION: mLNR value more than 0,08 was found to be an independent risk factor on both overall survival and disease-free survival in patients with non-metastatic CRC. Larger prospective studies are needed to support the significance of mLNR for TNM classification of CRC.

Keywords

• colorectal cancer
• metastatic lymph node ratio
• prognostic factors