Two-field Versus Three-field Lymphadenectomy in Thoracic Esophageal Carcinoma Without Cervical Lymph Node Involvement

The purpose of this study is to compare the lymph node dissection results and prognosis in thoracic esophageal carcinoma patients without cervical lymph node involvement by preoperative CT and/or ultrasound treated by two-field lymphadenectomy or three-field lymphadenectomy.Another purpose of this study is to clarify whether the lymph node along the right recurrent laryngeal nerve can be taken as the sentinel lymph node which is able to indicate neck lymph node metastasis and necessity for three-field lymphadenectomy.