Invited Commentary

Abstract

The number of involved lymph nodes in esophageal cancer predicts survival and forms the basis of the Seventh Edition International Cancer Control/American Joint Committee on Cancer (UICC/AJCC) staging system. A growing body of evidence suggests that even in patients with nodal metastases, the number of noninvolved lymph nodes (“negative lymph nodes”) are an important prognostic indicator [1Hsu P.K. Huang C.S. Wang B.Y. Wu Y.C. Chou T.Y. Hsu W.H. The prognostic value of the number of negative lymph nodes in esophageal cancer patients after transthoracic resection.Ann Thorac Surg. 2013; 96: 995-1001Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar, 2Baba Y. Watanabe M. Shigaki H. et al.Negative lymph-node count is associated with survival in patients with resected esophageal squamous cell carcinoma.Surgery. 2013; 153: 234-241Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 3Greenstein A.J. Litle V.R. Swanson S.J. Divino C.M. Packer S. Wisnivesky J.P. Effect of the number of lymph nodes sampled on postoperative survival of lymph node-negative esophageal cancer.Cancer. 2008; 112: 1239-1246Crossref PubMed Scopus (172) Google Scholar]. In this issue of Annals, Wu and colleagues [4Wu S.G. Li F.Y. Zhou J. et al.Prognostic value of different lymph node staging methods in esophageal squamous cell carcinoma after esophagectomy.Ann Thorac Surg. 2015; 99: 284-291Abstract Full Text Full Text PDF Scopus (17) Google Scholar] shed light on the prognostic value of these negative lymph nodes. In their analysis of 603 patients with squamous cell carcinoma who underwent esophagectomy alone, the authors find that patients with uninvolved lymph node counts 14 or greater have improved survival. Uninvolved lymph node counts along with the number of involved lymph nodes were found to provide better prognostic value compared to total lymph node counts or lymph node ratios of involved to total number of lymph nodes. The mechanism by which resecting a greater number of negative lymph node count confers a survival advantage is unknown. One postulated mechanism is that these nodes harbor micrometastatic disease that cannot be detected readily by standard H and E staining techniques. Therefore, the removal of these nodes may reduce the presence of residual disease thereby improving survival. Increased uninvolved nodal counts could also be an indicator of the adequacy of lymphadenectomy, resulting in appropriate pathologic staging and an accurate assessment of survival. Alternatively, as the authors and others have suggested, the presence of a high a number of nodes without disease may be a sign of a vibrant host immune response to the tumor leading to improved survival. These findings challenges us not only to determine the biologic mechanisms of the survival benefit seen, but also to determine the best method of categorizing involved and uninvolved lymph nodes after esophagectomy. Examining the number of involved and uninvolved nodes or total resected and involved nodes or their ratios are all ways of looking at the same phenomenon. This study along with other literature supporting the prognostic utility of uninvolved lymph node counts provide guidance in the design of future larger multiinstitutional studies to determine what the optimal method of evaluating lymph nodes after esophagectomy should be. Prognostic Value of Different Lymph Node Staging Methods in Esophageal Squamous Cell Carcinoma After EsophagectomyThe Annals of Thoracic SurgeryVol. 99Issue 1PreviewThis study aimed to investigate the prognostic value of number of involved lymph nodes, number of removed lymph nodes, ratio of involved to removed nodes (lymph node ratio), and number of negative lymph nodes in esophageal squamous cell carcinoma (ESCC) patients after esophagectomy. Full-Text PDF