| Background:The "2022 National Cancer Report" issued by the National Cancer Center after analyzing the data of cancer patients recorded at 487 cancer monitoring points in China pointed out that,in 2016,there were about 253,000 new cases of esophageal cancer in China,and the incidence rate ranked sixth among all malignant tumors.The death toll of esophageal cancer was about194,000,and the mortality rate ranked fifth among all malignant tumors.Although the incidence of esophageal cancer in China is gradually declining with the progress of society and economic development,it is still far higher than the global average.The overall 5-year survival rate of patients is still only 30%.Esophageal cancer has a serious impact on the physical and mental health of the patients and brings a heavy burden to the national medical expenditure.The diagnosis and treatment of esophageal cancer has long been a very important medical and social problem.Lymph node metastasis is the most common and important metastasis mode of esophageal cancer,and mediastinum is the most serious site of lymph node metastasis of esophageal cancer.Mediastinal lymph node metastasis greatly affects the clinical treatment plan and is one of the decisive factors for the prognosis of the disease.It is of great clinical significance to master the regularity of mediastinal lymph node metastasis and to carry out accurate early detection.At present,the imaging techniques that can be used to detect lymph node metastasis in esophageal cancer include computed tomography(CT),endoscopic ultrasonography(EUS),body surface ultrasonography(US),magnetic resonance imaging(MRI)and positron emission tomography(PET).Among them,contrast-enhanced CT is the most widely used,it can clearly detect enlarged lymph nodes and judge the nature of lymph nodes according to the size,density and other information,but the diagnostic evaluation indicators given by existing studies fluctuate greatly.EUS is a relatively new fusion technology which has the advantages of close detection and high resolution.It can provide information such as lymph node size,echo,boundary,morphology,and blood flow.In recent years,it has also been gradually used for the detection of lymph node metastasis in esophageal cancer.However,the clinical application has not been popularized,and the diagnostic value needs to be further confirmed.US is mainly used for the detection of cervical lymph node metastasis of esophageal cancer,and has been clearly written into the guidelines for esophageal cancer.MRI and PET are often not the first choice for the detection of lymph node metastasis of esophageal cancer for various reasons.The purpose of this study was to identify the key detection sites of metastatic lymph nodes by analyzing the regularity of mediastinal lymph node metastasis of esophageal cancer,and to analyze the diagnostic value of contrast-enhanced chest CT and EUS in lymph node metastasis of esophageal cancer.Objective:1.To study the regularity of mediastinal lymph node metastasis of esophageal cancer,and to analyze the related factors affecting mediastinal lymph node metastasis of esophageal cancer.2.To study the diagnostic value of contrast-enhanced chest CT in mediastinal lymph node metastasis of esophageal cancer,and to analyze the related factors affecting its diagnostic accuracy.3.To study the diagnostic value of EUS for lymph node metastasis of esophageal cancer,and to analyze the related factors affecting its diagnostic accuracy.Methods:1.A retrospective case-control study was conducted on 463 patients with esophageal cancer treated in the First Affiliated Hospital of Army Medical University from July 2016 to June 2021.Postoperative pathological results were used as the gold standard for the diagnosis of mediastinal lymph node metastasis.According to the pathological results,the cases were divided into mediastinal lymph node metastasis group and non-metastasis group.The regularity of mediastinal lymph node metastasis of esophageal cancer was analyzed.Univariate chi-square test and multivariate logistic regression analysis were used to evaluate the relationship between tumor location,tumor diameter,pathological type,depth of invasion,degree of differentiation,vascular invasion,neural invasion and mediastinal lymph node metastasis of esophageal cancer.According to whether the mediastinal lymph node metastasis was correctly diagnosed by preoperative contrast-enhanced chest CT,the cases were divided into CT correct diagnosis group and CT misdiagnosed group.The diagnostic value of contrast-enhanced chest CT was evaluated by calculating sensitivity,specificity,Kappa value,and other indicators.Univariate chi-square test and multivariate logistic regression analysis were used to evaluate the relationship between CT equipment model,tumor location,tumor diameter,pathological type,depth of invasion,degree of differentiation,vascular invasion,neural invasion and the diagnostic accuracy of contrast-enhanced chest CT.2.The studies in Pub Med,Embase and Cochrane Library databases from January 1,2000 to October 1,2022 were comprehensively searched and screened.The quality of the included studys was assessed using the QUADAS-2 tool.The Stata14.0 software was used to analyze the data using the bivariate mixed effect model to evaluate the diagnostic value of EUS for lymph node metastasis of esophageal cancer.The source of heterogeneity among studies and the factors affecting the diagnostic accuracy of EUS were analyzed.Results:1.Mediastinal lymph node metastasis of esophageal cancer.Among 463 patients with esophageal cancer,108 patients of mediastinal lymph node metastasis were diagnosed by postoperative pathology,and the metastasis rate was 23.3 %(108/463).A total of 3470 mediastinal lymph nodes were dissected by surgery,of which 211 were diagnosed as malignant lymph nodes by postoperative pathology,with a metastatic degree of 6.1%(211/3470).The location of mediastinal lymph node metastasis was ranked as follows: 8station(37.0%,78/211),7 station(26.5%,56/211),2 station(21.3%,45/211),4 station(8.1%,17/211),15 station(3.8%,8/211)and 9 station(3.3%,7/211).2.Analysis of influencing factors of mediastinal lymph node metastasis in esophageal cancer.Univariate analysis showed that tumor diameter,depth of invasion,degree of differentiation,and vascular invasion were related factors affecting the mediastinal lymph node metastasis of esophageal cancer(χ~2=8.169,11.754,6.297,21.155,P<0.05).Multivariate analysis showed that depth of invasion(odds ratio=3.799,95% confidence interval was1.589~9.086,P=0.003)and vascular invasion(odds ratio=3.565,95% confidence interval was1.943~6.544,P=0.000)were related factors affecting the mediastinal lymph node metastasis of esophageal cancer.3.Diagnostic value of contrast-enhanced chest CT in mediastinal lymph node metastasis of esophageal cancer.The sensitivity,positive predictive value,specificity,negative predictive value,accuracy,Youden index and Kappa value were 32.4%、38.9%、84.5%、80.4%、72.4%、0.169 and 0.180(P=0.000),respectively.4.Analysis of related factors influencing accuracy of contrast-enhanced chest CT in diagnosing mediastinal lymph node metastasis of esophageal cancer.Univariate analysis showed that tumor diameter and depth of invasion were related factors affecting the diagnostic accuracy of contrast-enhanced chest CT(χ~2=7.653,6.068,P<0.05).Multivariate analysis showed that tumor diameter was an related factors affecting the diagnostic accuracy of contrast-enhanced chest CT(odds ratio=0.488,95% confidence interval was 0.291~0.817,P=0.006).5.Diagnostic value of EUS for lymph node metastasis of esophageal cancer.Meta-analysis included 12 studies,including 1244 patients with esophageal cancer.The pooled sensitivity,positive likelihood ratio,specificity,negative likelihood ratio,diagnostic score and diagnostic odds ratio of EUS in diagnosing lymph node metastasis of esophageal cancer were 0.64(95% confidence interval was 0.51~0.76),3.33(95% confidence interval was 2.27~4.87),0.81(95% confidence interval was 0.70~0.88),0.44(95% confidence interval was 0.33~0.59),2.02(95% confidence interval was 1.53~2.50)and 7.52(95%confidence interval was 4.64~12.18),respectively.The area under curve of summary receiver operating characteristic was 0.79(95% confidence interval was 0.75~0.83).Threshold effect was part of the source of heterogeneity among studies.No significant publication bias was observed.Conclusion:1.The mediastinal lymph node metastasis rate of esophageal cancer is high,and paraesophageal,subtracheal carina and pararecurrent laryngeal nerve lymph nodes are common metastatic sites.For advanced esophageal cancer or esophageal cancer with vascular invasion,the risk of mediastinal lymph node metastasis may increase.2.The diagnostic value of contrast-enhanced chest CT for mediastinal lymph node metastasis of esophageal cancer is limited.For esophageal cancer with tumor diameter ≥ 2.1cm,the diagnostic accuracy of contrast-enhanced chest CT may be reduced.3.EUS can be used to detect lymph node metastasis of esophageal cancer.In terms of the diagnostic value of lymph node metastasis in esophageal cancer,contrast-enhanced CT has better specificity and EUS has better sensitivity.The combination of the two techniques can further improve the detection rate of lymph node metastasis in esophageal cancer. |
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