SBRT Combined With Thymalfasin for Metastatic Esophageal Cancer

Inclusion Criteria: 1. Patients with histologically confirmed esophageal cancer which is persistent and metastatic or recurrent and metastatic; 2. Patients must have at least 2 distinct measurable metastatic sites at least 1 cm of larger in their largest diameter; 3. Age ≥18 years; 4. Metastatic disease measurable on a CT/MRI scan. The primary tumor is not considered measurable disease. Metastatic lesions within a prior radiation field are acceptable as long as disease has progressed in the radiation field by RECIST criteria. The same imaging modality performed at baseline (CT or MRI) will be repeated at subsequent imaging. 5. ECOG performance status: 0-1; 6. Life expectancy ≥ 3 months. 7. Patients have adequate baseline organ and marrow function as defined by an absolute neutrophil count greater than 1500 cells per μL, platelet concentration of greater than 50 000 per μL, total bilirubin less than 1•5 times the upper limit of normal (ULN), aspartate aminotransferase and alanine aminotransferase less than 2•5 times the ULN, and serum creatinine less than 1•5 times the ULN; 8. Signed consent forms voluntarily; Exclusion Criteria: 1. Patients undergoing therapy with other investigational agents. 2. Women who are pregnant or breastfeeding; 3. Patients with known brain metastases can be included in this clinical trial but brain lesions are not eligible as target or non target lesion; 4. Anticipated patient survival under 3 months; 5. Active severe infection or known chronic infection with HIV, hepatitis B virus, or hepatitis C virus; 6. Cardiovascular disease problems including unstable angina, therapy for life-threatening ventricular arrhythmia, myocardial infarction, stroke or congestive heart failure within the last 6 months; 7. The subject has had another active malignancy within the past five years except for cervical cancer in site, in situ carcinoma of the bladder or non-melanoma carcinoma of the skin; 8. Clinically significant and uncontrolled major medical conditions including but not limited to: active uncontrolled infection, symptomatic congestive heart failure, Unstable angina pectoris or cardiac arrhythmia, psychiatric illness/ social situation that would limit compliance with study requirements; any medical condition, which in the opinion of the study investigator places the subject at an unacceptably high risk for toxicities; 9. Patients with any other concurrent disease which, in the judgment of the investigator, would make the patient inappropriate for participation in the study.