The eligibility criteria for this study were as follows: patients had undergone radical esophagectomy with 3-field lymph node dissection and were pathologically confirmed with stage II ⁄ III thoracic ESCC; Liver and kidney function and results of blood tests were normal. Heart and lung function were not obviously damaged, and patients were supposed to be able to tolerate chemotherapy; Eastern Cooperative Oncology Group performance status <2. The exclusion criteria were as follows: patients with preoperative chemotherapy or preoperative radiotherapy; with a type of esophageal cancer other than squamous cell carcinoma (SCC) or with cancer at other site; with a history of cancer at any other site; and those lost to follow-up.
According to the type of postoperative adjuvant treatments, patients were classified into three groups: surgery alone (Group S), adjuvant chemotherapy alone (Group CT) and postoperative concurrent chemoradiotherapy (Group CRT). This study was approved by the Institutional Review Board and performed at the 1st Affiliated Hospital of Wenzhou Medical University. The informed consents from all the patients were obtained.