Positive esophageal proximal resection margin: an important prognostic factor for esophageal cancer that warrants adjuvant therapy

Esophageal cancer (EC) is the eighth most common malignancy and the fifth leading cause of cancer in males worldwide (1,2). Each year, about 300,000 people died from EC on earth and the half of those patients were Chinese (3). The prognosis of EC patients is much poor with a 5-year overall survival (OS) rate of 15–39.2% (4). Surgical resection has been the standard treatment for localized EC. Some studies have reported that the prognosis of EC is associated with several clinicopathologic characteristics, including pathological stage, lymph node metastases, lymphovascular invasion, and positive esophageal proximal resection margin (ERM+) status (3-5)