Maintenance Therapy of Apatinib After Chemoradiotherapy in Metastatic Nasopharyngeal Carcinoma

Inclusion Criteria:

* Male and female patients aged ranging from 18 to 75 years old.
* Naive or recurrent Nasopharyngeal Carcinoma with metastasis after chemotherapy or radiotherapy.
* Eastern Cooperative Oncology Group (ECOG) performance status of 0 - 2.
* Adequate hematologic (neutrophil count\>=1.5×109/L, hemoglobin\>=80g/L, platelets\>=80×109/L), hepatic function (aspartate transaminase (AST) \& alanine transaminase(ALT) =\<upper normal limit(UNL) x2, bilirubin level =\< UNL x 1.5).
* Adequate renal function (creatinine clearance ≥ 60 mL/min).
* Patients have the ability to understand and voluntarily sign the informed consent, and allow adequate follow-up.

Exclusion Criteria:

* Previously, patients did receive the therapy of Apatinib or other VEGFR inhibitor, such as Sorafenib, Sunitinib.
* Difficulties in taking pills (inability to swallow tablets,GI tract resection, chronic bacillary diarrhea and intestinal obstruction).
* Bleeding tendency or coagulation disorders.
* with brain metastases.
* Uncontrolled hypertension (systolic pressure\>150 mmHg , or diastolic pressure\> 90 mmHg).
* Urine protein≥++, or urine protein in 24 hours≥1.0g
* Severe uncured wounds, ulcers or fracture.
* Pregnant or breast-feeding.
* Patients with epilepsy who need to take medicine (such as steroids or anti epilepsy agents).
* Patients have these symptoms, such as neurological diseases, mental illness, serious infection.
* The researcher believe that the Patient is not suitable to participate in the study.