The Prognostic Value Of Lymph Node Ratio In Patients With Esophageal Squamous Cell Carcinoma

Background:The treatment regimen was determined by different stages and the prognosis differed in different stages in patients with esophageal cancers.The TNM stage system released by UICC/AJCC is widely used by clinicians.N represents the lymph node status and lymph node status is one of factors that related to long-term survival in patients with esophageal cancer.Previous studies proved that the 5-year overall survival in esophageal cancer patients without positive lymph node was 50%,compared with 10%in patients with positive lymph nodes.The 6th edition of TNM staging system published by UICC/AJCC was consisted of two N stages:NO without lymph node metastasis and N1 with lymph node metastases.Some studies demonstrated that number of the metastatic lymph nodes played an important part in the prognosis in patients with esophageal cancer.The 7th and 8th version TNM staging systems published by UICC/AJCC updated the N staging criteria.NO was defined as no lymph node metastasis and N1 was 1-2 positive lymph nodes.N2 meant 3-6 positive lymph nodes and N4 7 or more than 7 positive lymph nodes.The update in N staging was the most significant part from 6th to 7th TNM staging system.The estimates of esophageal cancer in China demonstrated that esophageal squamous cell carcinoma accounted for 88.84%esophageal cancer patients.The 7th version UICC/AJCC TNM staging system for esophageal cancer used global data from 4627 patients.However,esophageal squamous cell carcinoma patients only constituted 39.6%of the database(1834 of 4627).Since the publication of the 7th version UICC/AJCC staging system,studies considering the application of this new staging system in Asian esophageal cancer patients showed an overlap in overall survival curves of patients with stages of N2 and N3.A staging system should separate various prognostic conditions of patients with different stages,so that could guide treatment schedule for patients with different stages.Some studies suggested that this staging system was not applicable to Asian esophageal patients.Lymph node ratio(LNR)defines as the ratio of positive lymph nodes with the number of lymph nodes dissected.LNR was proved to predict the prognosis in some other malignancies.Objective:We want to explore the clinical and pathological factors that related to prognosis of patients with esophageal squamous cell carcinoma and to investigate the prognostic value of lymph node ratio in patients with esophageal squamous cell carcinoma.Materials and methods:All newly diagnosed' esophageal squamous cell carcinoma patients who underwent esophagectomy were retrospectively reviewed from January 1,2012 to December 31,2012,in Qilu Hospital,Shandong University.Some clinical and pathological factors were analyzed to explore the factors that affected the prognosis and the effect of LNR in prognosis in patients with esophageal squamous cell carcinoma.The SPSS software package Version 17.0 was used for the statistical analysis.The Chi-square test was used to determine the differences in age,sex,location,tumor length,differentiated degree,pathological stages and the method of operation between high LNR group and low LNR group.The survival curves were constructed with the Kaplan-Meier method and analyzed by Log-rank test.Results:1.A total of 268 patients were included into the present study,225 in LNR<0.2 group and 43 patients in LNR?0.2 group.There was no significant difference between low LNR group and high LNR group with regard to age,sex,location,differentiated degree and the method of operation.There was significant difference between tumor length<3 cm and ?3 cm,and there were much more patients with LNR?0.2 in tumor length?3 cm group(P=0.001).There was significant difference between ?/?and ? stages and there were much more patients with LNR?0.2 in ? stages(P<0.001).2.The 3-year overall survival in patients with pN0,pN1,pN2,pN3 were 67.3%,38.5%,23.1%,and 27.3%,separately.The difference between overall survival of pN0 and pNl was significant(P<0.001).However,the difference between overall survival of pN1 and pN2,pN2 and pN3 was not signficant(P=0.061;P=0.714).3.In the 268 patients cohort,the 3-year overall survival in patients without positive lymph nodes was 67.3%,and the 3-year overall survival in patients with positive lymph nodes was 38.9%in LNR<0.2 group and 20.9%in LNR?0.2 group(P<0.001)?4.Age,tumor length,pathological stages and LNR were the independent prognostic factors for disease free survival.Age?60 years,tumor length<3 cm,?/?stages,LNR<0.2 suggested better disease free survival.Age,tumor length,differentiated degree,pathological stage were the independent prognostic factors for overall survival.Age?60 years,tumor length<3 cm,well and moderately differentiated degree,?/? stages demonstrated better overall survival.LNR was not the independent prognostic factor for overall survival(P=0.055).5.Age,pathological stage and LNR were the independent prognostic factors for disease free survival in patients with positive lymph nodes.Age?60 years,?/? stages and LNR<0.2 suggested better disease free survival.Tumor length,differentiated degree,pathological stage and LNR were the independent prognostic factors for overall survival in patients with positive lymph nodes.Tumor length less than 3 cm,well and moderately differentiated degree,?/? stages and LNR less than 0.2 suggested better overall survival.Conclusion:1.LNR was related to tumor length and pathological stage.There were more patients with LNR?0.2 in patients with tumor length?3 cm and ? stages.2.For patient with esophageal squamous cell carcinoma who underwent esophagectomy,Age,tumor length,differentiated degree and pathological stage were the independent prognostic factors for overall survival.Age?60 years,tumor length<3 cm,well and moderately differentiated degree,?/? stages demonstrated better overall survival.LNR was not the independent prognostic factor for overall survival.3.Tumor length,differentiated degree,pathological stage and LNR were the independent prognostic factor for overall survival in patients with positive lymph nodes.Tumor length less than 3 cm,well and moderately differentiated degree,?/?stages and LNR less than 0.2 suggested better overall survival.4.LNR could predict prognosis in patients with esophageal squamous cell carcinoma.LNR?0.2 predict poor prognosis in patients with esophageal squamous cell carcinoma.