Is lymph node ratio in surgical treatment of esophageal squamous cell carcinoma better than classic TNM system?

Abstract

Introduction: The lymph node ratio (LNR) was defined as the ratio of metastatic lymph node (LNs) compared to the total number of LNs resected. The staging system based on LNR (TNrM), described by some authors, may have better prognostic stratification of patients with esophageal squamous cell carcinoma (ESCC) than the TNM staging system of American Joint Committee on Cancer (AJCC) and is an independent prognostic factor in esophageal cancer patients. The TNM system stratify patients according to the numbers of positive LNs. However, this system does not specify the adequate number of examined LNs for an accurate nodal staging. Methods: Retrospective analysis of a prospective database (n = 85) with esophageal cancer cases submitted to curative intent surgery, between June 2006 and January 2016, in a Upper GI Surgery Unit. We analyzed 66 patients with ESCC according to the inclusion criteria (non-resectional surgery cases were excluded). The LNR and overall survival was analysed. The cut-off point of LNR was established by grouping patients with 10% increment. Results: Our 66 patients with ESCC, had a mean age of 60 years (ranging from 36 to 87 years old), with the majority being male (83.5%). Neoadjuvant treatment was performed in 47 (71.2%) patients, with a complete pathological response rate of 25.5%. In 33 (50%) patients the carcinoma was of the middle third, in 30 (45.5%) it was in the lower third, and in the remaining 3 (4.5%) in the upper third. The median number of resected nodes was 14. When we analysed de LNR (Nr 0 - LNR =0%; Nr 1 - 0% < LNR < = 10%; Nr 2 - 10% < LNR < = 20%; Nr 3 - LNR > 20%) and compared to classic AJCC N categories, there was no benefit in overall survival (p > 0.05 in all subcategories). Conclusion: Unlike the more recent western data, most of esophageal carcinomas in our series were ESCC (71.2%). In contrast to other studies, the LNR/TNrM was not a better prognostic factor than classic TNM system in this study.