OBJECTIVETo study the pattern of lymph node metastasis of thoracic esophageal squamous cell carcinoma (ESCC) after esophagectomy and its impact on the clinical target volume (CTV) delineation in radiotherapy fpr thoracic ESCC.

METHODSThe pattern of lymph node metastasis was retrospectively analyzed in 1077 patients with primary thoracic ESCC. All patients received esophagectomy with two- or three-field lymphadenectomy. The clinicopathologic factors related to lymph node metastasis were then analyzed using logistic regression analysis.

RESULTSThe rates of cervical, upper mediastinal, middle mediastinal, lower mediastinal and abdominal cavity lymph node metastasis were 16.7%, 33.3%, 11.1%, 5.6% and 5.6%, respectively. The rates of those node metastasis in the middle thoracic ESCC were 4.0%, 3.8%, 28.5%, 7.1% and 17.1%, respectively, and the rates of those node metastasis in the lower thoracic ESCC were 1.5%, 3.0%, 22.7%, 37.0% and 33.2%, respectively. The depth of tumor invasion, histologic differentiation and the length of tumor were showed to be statistically most significant risk factors of lymph node metastasis of ESCC (P < 0.001).

CONCLUSIONThe depth of tumor invasion, histologic differentiation, and length of tumor were closely correlated with lymph node metastasis of ESCC. All these factors and tumor location should be considered comprehensively when designing the target volume for radiotherapy.