The staging of esophageal cancer includes a preoperative clinical staging and a postoperative pathological staging. Clinical staging involves completing various systemic examinations, determining the extent of the tumor, whether there are lymph node metastases, and whether there are distant metastases to organs such as the liver and lungs. This requires thorough assessments, including esophageal endoscopic ultrasound and whole-body examinations like PET-CT, to conduct clinical staging. Postoperative pathological staging, on the other hand, is determined based on the depth of tumor invasion reached during surgery and the status of lymph node metastasis, among other factors.