A Prospective Clinical Study of the Combination Therapy of Obutinib or Decitabine with Rituximab, Cyclophosphamide, and Prednisone for the Primary Treatment of Elderly Patients with Newly Diagnosed Diffuse Large B-cell Lymphoma

Inclusion Criteria: 1. Individuals aged 65 years or older who are intolerant to chemotherapy, regardless of gender; 2. ECOG 0-1； IPI score ≤ 3 points; 3. Expected survival period of more than 3 months; 4. DLBCL diagnosed by tissue biopsy pathology; 5. No contraindications for chemotherapy (blood and physiological examination results within 7 days), absolute neutrophil count ≥ 1.0 × 10 \^ 9/L, PLT ≥ 75 × 10 \^ 9/L, hemoglobin ≥ 80g/L (excluding patients with lymphoma bone marrow infiltration); 6. According to the RECIST criteria, there must be at least one measurable lesion. For intranodal lesions, it is defined as: long diameter ≥ 1.5cm and short diameter ≥ 1.0cm; For extranodal lesions, the length and diameter should be ≥ 1.0cm; 7. Liver function: TBIL ≤ 1.5 × ULN; ALT or AST ≤ 2.5 × ULN; Non bone invasive patients with alkaline phosphatase ≤ 3 × ULN; 8. Renal function: serum creatinine ≤ 1.5 × ULN; 9. No other serious illnesses that conflict with this plan; 10. Excluding other major illnesses, the heart function is normal; 11. There are no other related treatments including traditional Chinese medicine (anti-tumor effects), immunotherapy, or biologic therapy (except for treatment of bone metastasis and other symptoms); 12. The subjects voluntarily participate in the clinical trial, sign an informed consent form, and cooperate with follow-up; 13. During this treatment period, if other anti-tumor drugs are not used simultaneously, bisphosphonates can be used for bone metastasis treatment and other symptomatic treatments; Exclusion Criteria: 1. Clear patients with neurological or psychiatric disorders, including dementia or seizures, a history of abuse of psychotropic drugs that cannot be quit, or other substantial lesions that may increase central neurotoxicity; 2. Individuals who are currently participating in other clinical trials or have participated in other clinical studies within the first 4 weeks of enrollment (excluding those who have not received treatment); 3. Systemic autoimmune diseases or immunodeficiency; 4. Refusing to collect blood samples; 5. Allergic to any medication in the plan; 6. Pregnant and lactating women; 7. Major diseases that can cause experimental interference and uncontrolled active infections; 8. Primary or secondary central tumors; 9. Chemotherapy contraindications; 10. Within 28 days of using Rituximab/Obutinib/Compound Cyclophosphamide Tablets/Azacitidine; 11. Researchers believe that it is not suitable for inclusion; 12. Known active bacterial, viral, fungal, mycobacterial, parasitic, or other infections (excluding nail bed skin fungal infections) or any major systemic infection requiring intravenous antibiotic treatment or hospitalization within the 4 weeks prior to enrollment (excluding tumor fever); 13. Apply other anti-tumor treatments (such as radiotherapy, chemotherapy, hormone therapy, biotherapy, immunotherapy); 14. Other serious diseases that may restrict the subjects from participating in the test, such as uncontrollable diabetes; Severe heart failure (NYHA grade II or above); Acute coronary syndrome has occurred within the past 6 months; Coronary revascularization such as stent implantation, coronary artery bypass surgery, and other heart and large vessel related surgeries within the past 6 months; Severe arrhythmias include frequent premature ventricular contractions, ventricular tachycardia, rapid atrial fibrillation/flutter, and severe bradycardia. Uncontrolled hypertension: systolic blood pressure\>150mmHg, diastolic blood pressure\>100mmHg. Gastric ulcer (determined by researchers to have a risk of perforation); Active autoimmune diseases (such as systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, Sjogren's syndrome, autoimmune thrombocytopenia, etc.); Severe respiratory diseases (such as obstructive pulmonary disease and history of bronchospasm), etc; 15. Individuals with bloodthirsty cell syndrome; 16. Hepatitis B surface antigen (HBsAg) or hepatitis B core antibody (HBcAb) is positive and the detection of hepatitis B virus (HBV) DNA titer in peripheral blood is not within the normal reference value range; Individuals with positive hepatitis C virus (HCV) antibodies and positive hepatitis C virus (HCV) RNA in peripheral blood; Individuals who are HIV antibody positive; Individuals who test positive for Cytomegalovirus (CMV) DNA; Individuals who test positive for syphilis.