Efficacy and Safety of Polatuzumab Vedotin, Rituximab Combined With Reduced-dose Cyclophosphamide, Doxorubicin and Prednisone Regimen in the Treatment of Elderly Patients With Diffuse Large B-cell Lymphoma: A Multicenter, Single-arm, Prospective Study

Prior treatment

• Prior anti-tumor therapy directed at DLBCL.
• Currently participating in another interventional clinical study, or receiving other anti-tumor drug therapy that may affect the efficacy assessment of this study.
• Patients eligible for transplantation.

Other illness

• Concurrent other active malignancy, or a prior malignancy that in the investigator's judgment may affect the efficacy and safety evaluation of this study.
• Uncontrolled active infection.
• Severe cardiac, pulmonary, hepatic, renal or other major organ dysfunction that in the investigator's judgment precludes tolerance of the study treatment.
• Other conditions considered unsuitable for enrollment by the investigator.

Other

• Bone marrow involvement or involvement of immune-privileged sites.

• Histologically confirmed diagnosis of diffuse large B-cell lymphoma (DLBCL).
• Age \>= 75 years; or age \>= 65 years with a G8 screening score \<= 14.
• Assessed as "frail / poor tolerance" by geriatric assessment during screening, defined as meeting any one of the following: (a) G8 score \<= 14; (b) IADL score \<= 7; (c) \>= 5 cumulative Grade 2 comorbidities on CIRS-G; (d) \>= 1 system with a Grade 3-4 comorbidity on CIRS-G.
• No prior systemic anti-tumor therapy for DLBCL, including chemotherapy, immunotherapy, targeted therapy or radiotherapy.
• Adequate major organ function, defined as: (a) Hematologic: absolute neutrophil count (ANC) \>= 1.0 x 10\^9/L, platelets (PLT) \>= 75 x 10\^9/L; (b) Hepatic: AST and ALT \<= 3 x upper limit of normal (ULN), total bilirubin \<= 1.5 x ULN; (c) Renal: creatinine clearance (Ccr) \>= 30 mL/min; (d) Cardiac: left ventricular ejection fraction (LVEF) within the institutional normal range by echocardiography, or LVEF \>= 50%.
• Expected survival \>= 3 months.
• The patient or their legal representative voluntarily participates in the study and signs the written informed consent form.