AI-Driven Treatment Strategy vs ZR2 in Older Treatment-naive Patients With LBCL

Inclusion Criteria: Patients must satisfy all of the following criteria to be enrolled in the study: * Histologically-confirmed large B-cell lymphoma (without central nervous system involvement) * Aged ≥ 70 years old with comprehensive geriatric assessment stratified as unfit or frail, or those who decline immunochemotherapy. * After 1 cycle of ZR2, classified as intermediate-risk or high-risk by AI-based multimodal stratification * Eastern Cooperative Oncology Group Performance Status 0-2 * At least 1 measurable site of disease (defined as lymph nodes with the long diameters longer than 1.5cm, or extra-nodal sites with the long diameters longer than 1.0cm; meanwhile, any lesion site with at least 2 measurable vertical diameters) * Life expectancy of at least 3 months determined by researchers * The patient or his or her legal representative must provide written informed consent prior to any special examination or procedure for the research. * Anti-lymphoma drugs have not been used before (except glucocorticoids) Exclusion Criteria: Presence of any of the following criteria will exclude a patient from enrollment: * Uncontrolled blood clotting disorders, connective tissue diseases, serious infectious diseases and other diseases * Laboratory measures meet the following criteria at screening (unless caused by lymphoma): Neutrophils\<1.0×10\^9/L Platelets\<75×10\^9/L ALT or AST is 2.5 times higher than the upper limits of normal (ULN), serum bilirubin are 1.5 times higher than the ULN. eGFR is lower than 30ml/min/1.73m\^2 (according to Cockcroft-Gault Equation or MDRD Equation). * uncontrollable or significant cardiovascular diseases, including but not limited to: Left ventricular ejection fraction\<50% Cardiomyopathy, such as dilated cardiomyopathy, hypertrophic cardiomyopathy, restrictive cardiomyopathy QTc prolongation with clinical significance, QTc interval\>470ms (females) or 480ms (males), type 2 second-degree atrioventricular block or third-degree atrioventricular block * Patients with HbsAg positive are required to have HBV DNA\<1.0×10\^3 IU/ml before entering the group. In addition, if the patient is HBsAg negative but HBcAb positive (regardless of HBsAb status), HBV DNA test is also required, and HBV DNA\<1.0×10\^3 IU/ml is required before entering the group * Patients with psychiatric disorders or patients who are known or suspected to be unable to fully comply with the study protocol * HIV-infected patients * History of stroke or intracranial hemorrhage within 6 months prior to start of therapy * Other medical conditions determined by the researchers that may affect the study