Efficacy and Safety of TC+AVASTIN Versus TC in Patients With Metastatic Nasopharyngeal Carcinoma

Inclusion Criteria: * Patients must meet the following criteria for study entry: * Age ≥ 18 * Eastern Cooperative Oncology Group (ECOG) performance status 0\~1 * Patients with a life expectancy\>12 weeks * Histologically proven NPC diagnosis * Metastatic nasopharyngeal carcinoma with evidence of unsuitable for local treatment(in terms of some relevant therapy for anti-tumor like surgery, radiofrequency ablation, transcatheter arterial chemoembolization(TACE) and radiotherapy(except palliative radiotherapy for metastatic bone pain with appropriate radiation dosage without influence to the hemogram),etc.) * Neoadjuvant or concurrent chemoradiotherapy was allowed, provided that the treatment was completed at least 3 months before the start of study drug treatment -≥1 measurable target based on RECIST criteria * Adequate bone marrow, hepatic and renal function, defined as follows within 1 weeks prior to randomization * Patients must sign study specific informed consent prior to registration * Patient must have recovered (be \>28 days post-surgery) from the effects of surgery, postoperative infection, and other complications before initial treatment with bevacizumab * Systolic blood pressure ≤ 160 mmHg and diastolic pressure ≤ 90 mmHg within 7 days prior to randomization. Exclusion Criteria: * Prior systemic treatment for metastatic nasopharyngeal carcinoma * Preparing for receiving local treatment for metastatic nasopharyngeal carcinoma (excluding palliative irradiation to release skeletal pain) * Prior treatment with bevacizumab or other agents specifically targeting VEGF * Patients with hemorrhage tendency including acute hemorrhage of digestive tract, nasal bleeding （not including nasal epistaxis), continuous hemorrhagic disease or Coagulation function disorder disease. Patients are using known NSAIDS to inhibit platelets. * Patients with gross hemoptysis or hematemesis (defined as bright red blood of 1 teaspoon or more or frank clots within minimal or no phlegm per coughing episode) within 4 weeks prior to registration; patients with incidental blood mixed with phlegm are not excluded * Patients receiving other experimental therapeutic cancer treatment * Severe, active co-morbidity, defined as follows: i.--Unstable angina and/or congestive heart failure or vascular (e.g. aortic aneurysm requiring surgical repair or peripheral thrombosis) disease requiring hospitalization within the last 12 months, or other cardiac compromise (e.g. an inadequately controlled cardiac arrhythmia) that in the judgment of the investigator will preclude the safe administration of a study drug; Patient must not show sign of recent myocardial infarction or ischemia by the findings of S-T elevations of ≥ 2mm on an EKG ii.--History of arterial thromboembolic events, venous thromboembolism \>NCI CTCAE Grade 3, transient ischemic attack (TIA), cerebral vascular accident (CVA), transmural myocardial infarction (MI), or hypertensive crisis or hypertensive encephalopathy iii.--History of ongoing bleeding diathesis, hemorrhagic disorder, or coagulopathy iv.--Chronic Obstructive Pulmonary Disease exacerbation or other respiratory illness requiring hospitalization or precluding study therapy within 30 days prior to registration v.--History of abdominal fistula, gastrointestinal perforation, intra-abdominal abscess, or active GI bleeding within the last 6 months prior to registration; vi.--Esophageal varices, non-healing ulcer, non-healing wound, or bone fracture within the last 6 months prior to registration vii.--Active, untreated infection and/or acute bacterial or fungal infection uiring intravenous antibiotics at the time of registration viii.--Acquired Immune Deficiency Syndrome (AIDS) based upon current CDC definition; ix. Hepatic insufficiency resulting in clinical jaundice and/or coagulation defects x. - Minor surgical procedure including placement of a vascular access device, within 2 days of the first study treatment * Patients currently (within 10 days of study enrollment) taking warfarin, heparin, daily treatment with aspirin (\> 325 mg/day), or nonsteroidal anti-inflammatory medications known to inhibit platelet function; treatment with dipyramidole, ticlopidine, clopidogrel, or cilostazol * Pregnancy or women of childbearing potential and men who are sexually active and not willing/able to use medically acceptable forms of contraception; * Prior allergic reaction to the study drug(s) involved in this protocol * Contraindication to Bevacizumab * Patients has another cancer history （not NPC）within 5 years before randomization.