Study of Anlotinib as the Maintenance Therapy for Extensive-stage Small Cell Lung Cancer

Inclusion Criteria: * Histologic or cytologic diagnosis of small cell lung caner * Advanced small cell lung cancer who had no prior cisplatin-based chemotherapy or radiotherapy,at least one measurable lesion (by RECIST1.1) * Males or females between 18 Years to 75 Years. * Performance status of 0～2 on the ECOG criteria. * Main organs function is normal * Expected survival is above three months. * with asymptomatic brain metastases. * At least one measurable lung tumor lesion (according to RECIST criteria, the application of conventional technology, diameter length of the lesion \>= 20mm or spiral CT \>=10mm). * Adequate hematologic (Leukocyte count \>= 4.0×109/L, neutrophil count\>=2.0×109/L, hemoglobin\>=95g/L, platelets\>=100×109/L), hepatic function (aspartate transaminase (AST) \& alanine transaminase(ALT) =\<upper normal limit(UNL) x1.5, bilirubin level =\< UNL x 1.5). * Patient can take oral medicine. * Patients have the ability to understand and voluntarily sign the informed consent, and allow adequate follow-up. Exclusion Criteria: * History of cardiovascular disease: congestive heart failure (CHF) \> New York Heart Association (NYHA) II, active coronary artery disease(patients with myocardial infarction six months ago can be recruited), arrhythmias need to be treated (allow taking beta blockers or digoxin). * Serious clinical infection (\> NCI-CTCAE version 4.0 ,infection standard II). * Patients with epilepsy who need to take medicine (such as steroids or anti epilepsy agents). * The patients had accepted allogeneic organ transplantation. * Bleeding tendency or coagulation disorders. * patients who need renal dialysis. * suffered from other tumor within 5 years( Except: cervical carcinoma in situ, cured basal cell carcinoma, cured bladder epithelial tumor). * uncontrolled hypertension (systolic pressure\>150 mmHg , or diastolic pressure\> 90 mmHg). * thrombosis or embolism(cerebrovascular accidents including transient ischemic attack within the last 6 months). * pulmonary hemorrhage \>CTCAE grade 2 within 4 weeks before first use of drugs. * Other organ hemorrhage \>CTCAE grade 3 within 4 weeks before first use of drugs. * severe uncured wounds, ulcers or fracture. * uncured dehydration. * Drugs abuse and medical, psychological or social conditions may interfere with the patient's participation in research or the results of the evaluation effect. * Patients are allergic to drugs used in research. * Factors influencing the safety and compliance of patients. * Inability to comply with protocol or study procedures. * Pregnant or breast-feeding. * The researcher believe that the Patient is not suitable to participate in the study.