Improve the Treatment of Thoracic Esophageal Cancer

The purpose of this study is 1. To compare the effects of the two types of thoracic esophageal cancer lymphadenectomy on the staging and prognosis of resectable esophageal cancer, which defined by the International Association of esophageal disease(ISDE) - standard mediastinal lymphadenectomy,total mediastinal lymphadenectomy and three field lymphadenectomy,and to find out reasonable range of lymphadenectomy. 2. To compare the effects of Chemotherapy Group (Docetaxel + Nedaplatin) with Control Group on the prognosis of resectable thoracic esophageal cancer,and to explore the indications of adjuvant chemotherapy.