Metastatic lymph node ratio, 6th or 7th AJCC edition: witch is the best lymph node classification for esophageal cancer? Prognosis factor analysis in 487 patients

BACKGROUND: The esophageal cancer is one of the most common and aggressive worldwide. Recently, the AJCC changed the staging system, considering, among others, the important role of the lymph node metastasis on the prognosis. AIM: To discuss the applicability of different forms of lymph node staging in a western surgical center. METHODS: Four hundred eighty seven patients with esophageal cancer were enrolled. Three staging systems were evaluated, the 6th and the 7th AJCC editions and the Lymph Node Metastatic Ratio. RESULTS: The majority of the cases were squamous cell carcinoma. The mean lymph node sample was eight. Considering the survival, there was no significant difference between the patients when they were classified by the 7th AJCC edition. Analysis of the Lymph Node Metastatic Ratio, just on the group of patients with 0 to 25%, has shown significant difference (p=0,01). The 6th AJCC edition shows the major significant difference between among the classifications evaluated. CONCLUSION: In this specific population, the 7th AJCC edition for esophageal cancer was not able to find differences in survival when just the lymph node analysis was considered.

背景：食管癌是全球范围内最常见且恶性程度较高的肿瘤之一。近期，美国癌症联合委员会（AJCC）更新了食管癌分期系统，其中纳入了淋巴结转移对预后的重要影响等多项考量因素。
目的：探讨不同淋巴结分期方案在西方外科中心的适用性。
方法：本研究共纳入487例食管癌患者，对3种分期方案进行评估，分别为第6版、第7版美国癌症联合委员会（AJCC）分期系统以及淋巴结转移比率（Lymph Node Metastatic Ratio）分期法。
结果：本研究纳入的患者多数为食管鳞状细胞癌，平均送检淋巴结数目为8枚。按第7版AJCC分期系统对患者进行分组后，其总生存期未呈现显著统计学差异。仅针对淋巴结转移比率为0%~25%的患者亚组进行分析时，该指标呈现显著差异（p=0.01）。在本次评估的3种分期方案中，第6版AJCC分期系统的分组差异最为显著。
结论：针对本次研究的特定队列，仅基于淋巴结分析的前提下，第7版AJCC食管癌分期系统无法区分患者的生存差异。