Oesophageal adenocarcinoma has a higher risk of lymph node metastasis than squamous cell carcinoma: a propensity score-matched study.

OBJECTIVES: The pattern of lymph node metastasis is a predominant element in tumour biology, which is closely related to optimal therapeutic modality. Controversy remains as to which histopathology type of oesophageal cancer-adenocarcinoma or squamous cell carcinoma (SCC)-is more likely to have lymph node metastasis. Therefore, this study aimed to apply propensity score-matched analysis to draw an objective conclusion for providing initial evidence of the potential need for different therapeutic strategies for these 2 cancer types. METHODS: A retrospective analysis of patients who underwent radical oesophagectomy with lymphadenectomy, but without preoperative treatment for pathologically and immunohistochemically diagnosed oesophageal adenocarcinoma or SCC, was conducted. Data for analysis included age, gender, body mass index, pathologic findings, procedures of oesophagectomy and rate of lymph node metastasis. Propensity score-matched analysis was conducted to eliminate the bias effects of confounding factors. RESULTS: A total of 1204 patients (including 118 with adenocarcinoma and 1086 with SCC) from January 2012 to June 2016 was included for analysis. In the analysis of unmatched patients, those with adenocarcinomas had significantly larger mean numbers of positive lymph nodes (3.8 and 1.5, respectively; P < 0.001) and higher rates of lymph node metastasis (71.2% and 49.0%, respectively; P < 0.001) than those with an SCC. However, other confounding factors such as surgical procedures, tumour location, pT stage and lymphovascular invasion also differed significantly between the adenocarcinoma and SCC cases. In the analysis of 96 matched patients, those confounding factors were well matched, and cases of adenocarcinoma still had a significantly larger mean number of positive lymph node (4.5 and 1.8, respectively; P = 0.003) and higher rate of lymph node metastasis (75.0% and 45.8%, respectively; P = 0.003) than did those with SCC. CONCLUSIONS: Cases of oesophageal adenocarcinoma had a higher risk of lymph node metastasis than did those with SCC in this series, which indicates that different therapeutic modalities should be applied for these 2 different malignant entities.