Abstract
BACKGROUND: The role of upper mediastinal lymphadenectomy for distal esophageal or gastroesophageal junction (GEJ) adenocarcinomas remains a matter of debate. This systematic review aims to provide a comprehensive overview of evidence on the incidence of nodal metastases in the upper mediastinum following transthoracic esophagectomy for distal esophageal or GEJ adenocarcinoma. METHODS: A literature search was performed using Medline, Embase and Cochrane databases up to November 2020 to include studies on patients who underwent transthoracic esophagectomy with upper mediastinal lymphadenectomy for distal esophageal and/or GEJ adenocarcinoma. The primary endpoint was the incidence of metastatic nodes in the upper mediastinum based on pathological examination. Secondary endpoints were the definition of upper mediastinal lymphadenectomy, recurrent laryngeal nerve (RLN) palsy rate and survival. RESULTS: A total of 17 studies were included and the sample sizes ranged from 10-634 patients. Overall, the median incidence of upper mediastinal lymph node metastases was 10.0% (IQR 4.7-16.7). The incidences of upper mediastinal lymph node metastases were 8.3% in the 7 studies that included patients undergoing primary resection (IQR 2.0-16.6), 4,4% in the 1 study that provided neoadjuvant therapy to the full cohort, and 10.6% in the 9 studies that included patients undergoing esophagectomy either with or without neoadjuvant therapy (IQR 8.9-15.8%). Data on survival and RLN palsy rates were scarce and inconclusive. CONCLUSIONS: The incidence of upper mediastinal lymph node metastases in distal esophageal adenocarcinoma is up to 10%. Morbidity should be weighed against potential impact on survival.