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

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.