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.

Esophageal carcinoma is a prevalent and aggressive malignant disease with poor prognosis in China. Complete surgical resection with systemic lymph node dissection remains the most effective treatment method for this malignancy. Although tree-field lymph node dissection was reported to be effective in improving long-term survival in Japan,there is no enough evidences yet to demonstrate that three field lymph node dissection is superior to two field lymph node dissection in reducing postoperative recurrence and improving long-term survival. In this study, the dissection of lymph node adjacent to the right recurrent laryngeal nerve would be performed and examined routinely by intraoperative frozen-section. If the lymph node is positive, three field lymph node dissection(Cervical-thoracic-upper abdominal lymphadenectomy) will be performed, if negative, the patients will be randomly assigned either to three-field lymphadenectomy group or two-field lymphadenectomy group. The purpose of this large scale multi-center trial is to compare the lymph node dissection results and prognosis in thoracic esophageal carcinoma without cervical lymph node involvement treated by three-field lymphadenectomy or two-field lymphadenectomy and clarify whether the lymph node along the right recurrent laryngeal nerve could be taken as sentinel lymph node indicating neck lymph node metastasis and necessity of three-field lymphadenectomy.

Inclusion Criteria:

1. Patients with histologically confirmed squamous cell esophageal cancer, without any previous anti-tumor therapy;
2. Preoperative clinical TNM stage：cT1b-3N0-1M0;
3. Adequate cardiopulmonary, liver, brain and kidney functions for esophagectomy either via right thoracotomy or VATS;
4. No evidence of suspicious neck lymph node metastasis (LN short diameter < 0.8cm or LN short/long diameter <0.65 by cervical CT and/or ultrasound);
5. Willing to participate the clinical trial and sign the informed consent before being enrolled into clinical trail

Exclusion Criteria:

1. Previous use of anti-cancer therapy;
2. Preoperative clinical TNM stage: N2-3 or M1;
3. Inadequate cardiopulmonary,liver, brain and kidney function for surgery;
4. Previous malignancy history.
5. Suspicious neck lymph node metastasis (LN short diameter ≧0.8cm or LN short/long diameter ≧0.65 by cervical CT and/or ultrasound);
6. Unwilling to participate the clinical trial and refuse to sign informed consent.