Clinical Characteristics And Surgical Strategies Of Siewert ? Type Adenocarcinoma Of Esophagogastric Junction

ObjectiveThis study based on Tianjin Medical University Cancer Hospital retrospective analyses 368 patients of Siewert ? esophagogastric adenocarcinoma and investigates the lymph node metastasis and prognosis of Siewert ? esophagogastric adenocarcinoma and three approaches that Chinese thoracic surgeons prefer to treat this cancer and provide evidences for surgical strategies for Siewert ? AEG.Methods1.General information A total of 368 cases of patients with adenocarcinoma of esophagogastric junction after radical resection were collected in June 2010 to November 2015 among which 209 were Left transthoracic approach,112 were Left thoracoabdominal approach and 47 were Ivor-Lewis.Record preoperative data(gender,age),intraoperative data(operation,tumor size,lymph nodes cleaning,etc.)and postoperative data(with and without vascular tumors,T stages,differentiation,lymph node metastasis,etc.).2.Follow-up Outpatient or telephone follow-up were conducted until November2018.Among the 368 patients,309 patients were followed up and the follow-up rate was 84.0%.The follow-up time was 1-103 months and the median follow-up time was 38 months.3.Statistical methods(1)SPSS 25.0 statistical software was used for statistical analysis.(2)Calculate sample overall rate of lymph node metastasis(cases of lymph node metastasis/all cases),abdominal lymph node metastasis rate(cases of abdominal lymph node metastasis/all cases),thoracic lymph node metastasis rate(cases of thoracic lymph node metastasis/all cases),upper and lower mediastinal lymph node metastasis rate(cases of upper and lower mediastinal lymph node metastasis/all cases),frequency of dissection for each lymph node groups(cases of cleaning the group/all case),and calculate lymph node metastasis rate of the group whose dissection rate>10%(cases of lymph node metastasis in the group/cases of lymph node dissection in this group).(3)The measurement data with normal distribution were expressed by`x±S and the independent sample t test was used for comparison between groups.The measurement data with skewed distribution were expressed by the median(minimum,maximum).(4)Comparison between two independent samples:T test of independent samples was used for comparison among normal distribution data sets.Rank-sum test was used to compare two independent sample groups with non-normal distribution.Chi-square test or Fisher exact probability method was used to compare the counting data sets.(5)Propensity Score Matching was used to balance the baseline index.PSM(nearest neighbor matching method)with a ratio of 1:3 was performed,in which the caliper value was 0.2(6)Comparison of three independent samples:Univariate anova was used for comparison among the normal distribution measurement groups,and Bonfereoni method was used for pairwise comparison of the data with statistically significant differences.The Kruskal Wallis H test was used for the comparison among the non-normal distribution measurement data sets,and then pairwise comparison was made through the Bonferroni correction.The chi-square test or Fisher's exact probability method was used to compare the counting data sets,and pairwise comparison was made afterwards.(7)P<0.05 was considered statistically significant.Results1.The lymph node metastasis rate was 65.6%in 368 patients,mainly at abdominal lymph node(65.5%).The stations respectively are No.7Left gastric artery(52.0%),No.1Left paracardial(34.2%),No.2Right paracardial(33.9%),No.3 Lesser curvature(28.9%),No.11Splenicartery(27.1%),No.9Celiac artery(19.8%),No.4Greater curvature(28.9%),and No.8 Common hepatic artery(11.1%)from high to low.The thoracic metastasis rate was lower(12.8%),mainly in the lower mediastinum(12.2%),followed by No.E8Lo Lower paraoesophageal(15.3%),No.E8M Middle paraoesophageal(11.8%),No.E9L Left inferior pulmonary ligamental(4.7%)and No.E7 Subcarinal(3.4%).2.Univariate analysis indicates that Histopathological grade,presence of thoracic lymph node metastasis,numbers of lymph node metastasis,T stages,tumor diameter and length of esophageal invasion are relevant with prognosis(c~2=9.320,26.582,46.057,18.769,22.460,9.158,P<0.05).Cox multivariate regression analysis indicates that presence of thoracic lymph node metastasis,numbers of lymph node metastasis and T stages are independent risk factors for the prognosis(OR=1.699,1.271,1.422,P<0.05)3.The single factor analysis indicates that the tumor diameter,the number of thoracic lymph node dissection and length of esophageal invasion(c~2=5.129,13.605,43.140,P<0.05)were related to the occurrence of thoracic lymph node metastasis.Logistics multi-factor regression analysis indicates that numbers of lymph node dissection and length of esophageal invasion are independent risk factors for thoracic lymph node metastasis(OR=6.321,1.097,P<0.05)4.The prognosis of patients whose thoracic lymph nodes are positive are worse.37 patients in the experimental group and 55 patients in the control group were obtained,after PSM.The survival curves for 92 patients after PSM indicates the3-year overall survival rate of patients without thoracic lymph node metastasis was34.1%,and that of patients with thoracic lymph node metastasis was 24.6%,with statistically significant difference(p=0.043).6.The advantage of lymph node cleaning for Ivor-Lewis is on left paracardial,right paracardial,common hepatic artery,middle paraoesophageal and lower paraoesophageal.And Ivor-Lewis also have advantage on amount of numbers and groups on lymph node cleaning from all/thoracic/abdominal.ConclusionThe lymph node metastasis of Siewert ? type of gastroesophageal adenocarcinoma is mainly in the abdominal cavity,followed by the chest cavity,and mainly concentrated in the lymph nodes near the stomach of the cardia and the middle and lower esophagus of the chest.Thoracic lymph node metastasis,number of lymph node metastasis and T staging were independent risk factors for prognosis.Esophageal invasion distance(?2cm)and thoracic lymph node dissection number(?4)were independent risk factors for thoracic lymph node metastasis.Thoracic lymph node metastasis is a sign of poor prognosis of type ? AEG.Ivor-Lewis has obvious advantages in thoracic and abdominal lymph node dissection.There was no difference in survival among the three methods,which required further prospective study.