Prognostic value of right upper mediastinal lymphadenectomy in Sweet procedure for esophageal cancer

Esophageal carcinoma (EC) is one of the most frequent malignant tumors in the world. In China, more than 95% of the EC are found to be esophageal squamous cell carcinoma (ESCC) (1). Even though esophagectomy with lymph node dissection (LND) is a main surgical approach for locally-advanced EC, the optimal surgical approach has not well established, especially for the extent of lymphadectomy. In other words, it remains unclear whether the addition of extensive LND improves the survival of EC patients (2). A study involving 4,627 surgically resected EC patients from the Worldwide Esophageal Cancer Collaboration database showed that extensive LND was associated with better survival (3). However, some studies indicated that more extensive LND during operation could not improve the survival of EC patients (4,5). Other studies, comparing extended transthoracic resection with limited transhiatal resection for the mid/distal EC, showed that the 5-year overall survival rate only tended to improvement in the former (6,7). A retrospective study involving 391 patients undergoing McKeown procedure (136 with standard LND and 255 with extended LND) showed that the right upper mediastinal (RUM)-LND was not associated with the 5-year survival rate (8). Therefore, further study on the prognostic role of right upper mediastinal lymph node dissection (RUMLND) is necessary