Efficacy and Safety of Apatinib for Recurrent or Metastatic Esophageal Squamous Cell Carcinoma

Inclusion Criteria: 1. Patient age: ≥18 years old 2. An ECOG score of 0-2 3. Pathologically diagnosed with Esophageal Squamous Cell Carcinoma. 4. At least second-line treatment failure regimens without targeted therapy. 5. Measurable lesion. 6. An expected survival of ≥ 3 months. 7. Major organ function had to meet the following criteria: 1)For regular test results: HB(hemoglobin) ≥ 90g / L (14 days without blood transfusion); ANC(absolute neutrophil count) ≥ 1.5 × 109 / L; PLT(platelet) ≥ 80 × 109 / L 2)Biochemical tests results: Bilirubin \<1.5 times the upper limit of normal (ULN) ALT(Alanine aminotransferase) and AST≤2.5 × ULN; liver metastases, if any, the ALT and AST≤5 × ULN; Endogenous creatinine clearance≥50ml/min (Cockcroft-Gault formula) 8. Informing consent. Exclusion Criteria: 1. Previously or presently suffering from other malignancies, except for the cured and stable carcinoma; 2. Pregnant or lactating women; 3. Participation in clinical trials with other drugs in the preceding four weeks. 4. Factors that could have an effect on oral medication (such as inability to swallow, chronic diarrhea and intestinal obstruction). 5. Serious bleeding events within 4weeks (≥3 degree)-CTCAE(Common Terminology Criteria for Adverse Events) 4.0 6. Central nervous system metastasis or a history of central nervous system metastasis. 7. Hypertension and antihypertensive drug treatment that does not normalize blood pressures (systolic blood pressure\> 140 mmHg and diastolic blood pressure \> 90 mm Hg); With unstable angina pectoris; Arrhythmia; Coronary heart disease greater than Class II; Angina pectoris diagnosed with 3 months or myocardial infarction event occurs within 6 months before recruiting. 8. With the open wounds or fractura. 9. A history of organ transplant. 10. Coagulation dysfunction (PT(prothrombin time)\>16 s, APTT(activated partial thromboplastin time)\>43 s, TT(thrombin time)\>21 s, Fbg(Fibrinogen)\<2g/L), a tendency to bleed or receiving thrombolytic or anticoagulant therapy. 11. A history of abuse of psychotropic drugs or mental disorders. 12. Central nervous system disorders. 13. A history of immunodeficiency. 14. Arterial/venous thrombosis events within 12 months before recruiting. 15. Use of CFDA(China Food and Drug Administration) approved anti-gastric modern traditional Chinese medicine preparations and immunomodulatory agents.