Rituximab, Lenalidomide Combined With Methotrexate and Temozolomide For Primary Central Nervous System Lymphoma

Inclusion Criteria: 1. Age between 18 to 70 years old (including 18 and 70) 2. Diagnosed as primary central nervous system lymphoma (limited to the brain, spinal cord, meninges and eyeballs, without involvement of other parts) 3. Having not received anti-tumor therapy before enrollment (except for tumor resection and biopsy and the use of glucocorticoids to reduce central nervous system symptoms) 4. Having at least one measurable lesions 5. World health organization-Eastern Cooperative Oncology Group Performance Status (ECOG) 0-2 ( ECOG 3 due to tumors can be included after being fully assessed by the investigator) 6. Life expectancy no less than 1 month 7. enough main organ function 8. Pregnancy test within 7 days must be negative for women of childbearing period, and appropriate measures should be taken for contraception for women in childbearing period during the study and six months after this study 9. Agreeing to sign the written informed consents Exclusion Criteria: 1. Diagnosed as secondary central nervous system lymphoma 2. Diagnosed as CD20 negative large B cell primary central nervous system lymphoma 3. Active malignant tumor need be treated at the same time 4. Other malignant tumor history 5. Serious surgery and trauma less than two weeks 6. Patients with active tuberculosis 7. Systemic therapy for serious acute/chronic infection 8. Congestive heart failure, uncontrolled coronary heart disease, arrhythmia and heart infarction less than 6 months 9. HIV-positive, AIDS patients and untreated active hepatitis 10. Patients with a history of deep vein thrombosis or pulmonary embolism less than 12 months 11. Patients with a history of mental illness or drug abuse 12. Poor compliance during the trial and/or follow-up phase 13. Allergies or people who are known to be allergic to any active ingredients, excipients, mouse-derived products or heterologous protein contained in this trial 14. Researchers determine unsuited to participate in this trial