Lymph Node Ratio Versus TNM System As Prognostic Factor in Colorectal Cancer Staging. a Single Center Experience.

Francesco Moccia,Ferrante Ilaria,Manto Ottavia,D’Amico Rosa,Vincenzo Napolitano,Alfredo Allaria,Landino Fei,Salvatore Tolone,Edoardo Cesaro,Ludovico Docimo

doi:10.1515/med-2019-0058

Francesco Moccia, Ferrante Ilaria + Show 8 more

Open Access

https://doi.org/10.1515/med-2019-0058

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Abstract

ObjectiveThis study aims to establish the actual validity of the lymph node ratio (LNR) as a prognostic factor for colorectal cancer patients, and to verify differences of survival and disease-free interval.MethodsPatients referred with colorectal cancer who underwent potentially curative surgery between January 1997 and December 2011 were included. Lymph node ratio, TNM staging and survival were extracted from surgical, histological and follow-up records.ResultsTwo hundred eigthy six patients with different stages of colorectal cancer underwent surgery, with comparison of survival prediction based on lymph node ratio and TNM staging. The overall survival rate was 78.3%, the recurrence rate was 11.9% and the mortality rate was estimated as 21.7%. Univariate analysis in relation to survival was significant for the following variables: serum level of CEA, CA 19.9 value, degree of histological differentiation, and tumor growth. There weren’t any statistically significant differences for the LNR (LNR </ ≥0.16: p = 0.116). The TNM system was effective both in discriminating between survival stages (Stage II vs. Stage III: p = 0.05) and in differentiating sub-groups (p = 0.05).ConclusionsLNR alone could not be considered a better prognostic factor than the TNM system. However, future studies are needed in a larger number of patients with a standardized surgical, pathological and medical protocol.

Highlights

Colorectal Cancer (CRC) is one of the most common cancers in Western countries and it is a frequent cause of death [1]
With regard to patients with stage II and III (Dukes’s stage B and C), the lymph node ratio (LNR) was calculated by dividing the number of metastatic lymph nodes by the total number of excised lymph nodes (LNs + / total LNs); by doing so, we evaluated the population with positive lymph nodes, in reference to the critical value or threshold value of the LNR calculated using statistical methods (
The present study shows that an LNR >0.16 wasn’t an independent risk factor in predicting overall survival and disease-free interval, whereas the seventh TNM System edition seemed to be the most effective prognostic tool to predict disease-free interval and overall survival in CRC patients, even in differentiating sub-groups

Summary

Introduction

Colorectal Cancer (CRC) is one of the most common cancers in Western countries and it is a frequent cause of death [1]. Among the parameters of the TNM system [2], there is a prevalence of lymph node status; the presence of metastasis in one or more lymph nodes determines the passage from one lower stage of disease to a higher stage, directly impacting on overall survival of patients. Many researchers believe that patients suffering from CRC treated with radical surgery and with extensive lymphadenectomy have a better survival and greater disease-free interval [3,4]. Le Voyer et al showed that an increased number of lymph nodes harvested is related to an increase of survival, both for patients with negative lymph nodes than for those with positive lymph nodes [5]. This is a bio-statistical model used to explain migration between stages with different prognoses, caused by inadequate lymph node sampling responsible for an erroneous sub-staging

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