Methotrexate or Thiotepa Combined With R-CHOP and Orelabrutinib in CNSL Patients

Inclusion Criteria: * Fully understand the study and voluntarily sign the informed consent form. * Age: 14-80 years. * Expected survival of more than 3 months, as determined by the investigator. * Pathologically or cytologically confirmed diffuse large B-cell lymphoma (DLBCL) of B-cell origin through pathology or flow cytometry. * Central nervous system (CNS) involvement, confirmed by at least one of the following: 1. Symptoms related to CNS involvement. 2. Abnormal findings on imaging. 3. Pathological evidence (positive cerebrospinal fluid cytology, positive brain lesion biopsy or positive cerebrospinal fluid ctDNA). * Any non-hematologic toxicity related to prior treatments must have resolved to Grade 1 or normal levels (per NCI CTCAE Version 5.0), except for alopecia. * Bone marrow and organ function must meet the following criteria (without blood transfusion, G-CSF administration, or pharmacological correction within 14 days prior to screening): Bone marrow function: 1)Absolute neutrophil count (ANC) ≥ 1.0 × 10⁹/L. 2)Platelet count ≥ 50 × 10⁹/L. 3)Hemoglobin ≥ 60 g/L. * Liver function: 1. Total bilirubin ≤ 1.5 × ULN (≤ 3.0 × ULN if liver metastasis is present). 2. AST and ALT ≤ 2.5 × ULN (≤ 5.0 × ULN if liver metastasis is present). * Coagulation function: International normalized ratio (INR) and activated partial thromboplastin time (aPTT) ≤ 1.5 × ULN. • Renal function: Serum creatinine ≤ 1.5 × ULN or estimated creatinine clearance rate ≥ 30 mL/min (calculated using the Cockcroft-Gault formula): Male: Cr (mL/min) = (140 - age) × weight (kg) / \[72 × serum creatinine (mg/dL)\]. Female: Cr (mL/min) = (140 - age) × weight (kg) / \[85 × serum creatinine (mg/dL)\]. * Women of childbearing potential (WOCBP) and men with reproductive potential must agree to use effective contraception during the study and for 3 months after discontinuing treatment. * Good compliance, with willingness to adhere to visit schedules, dosing regimens, laboratory tests, and other study procedures.- Exclusion Criteria: * Contraindications to any of the drugs included in the treatment regimen. * History of active liver disease, including viral or other hepatitis or liver cirrhosis (Hepatitis B is defined as HBV-DNA exceeding the upper limit of normal; active Hepatitis C is defined as seropositive for HCV antibodies, but patients with HCV-RNA negative results can be included). * Human immunodeficiency virus (HIV) infection. * Congestive heart failure classified as greater than NYHA Class II by the New York Heart Association; history of acute myocardial infarction, unstable angina, stroke, or transient ischemic attack within the past six months. * Congenital long QT syndrome or QTc \> 480 ms (Note: QTc must be calculated using Friederica's formula: QTcF = QT / (RR)\^0.33). * Pregnant or breastfeeding women, or those planning to become pregnant during the study. * History of confirmed neurological or psychiatric disorders, or a history of substance abuse or drug addiction.