AI-Driven Treatment Strategy vs Pola-R-CHP in Untreated LBCL

Inclusion Criteria: * Age 18-75 years with comprehensive geriatric assessment stratified as fit * Previously untreated participants with CD20-positive LBCL (without central nervous system involvement) * ECOG Performance Status of 0, 1, or 2 * After 1 cycle of Pola-R-CHP, classified as intermediate-risk or high-risk by AI-based multimodal stratification * Life expectancy ≥ 3 months * 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) * 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: * Prior solid organ transplantation or SCT * Significant or extensive history of cardiovascular disease such as New York Heart Association Class III or IV cardiac disease or Objective Assessment Class C or D, myocardial infarction within the last 6 months prior to the start of Cycle 1, unstable arrhythmias, or unstable angina * History or presence of an abnormal ECG that is clinically significant in the investigator's opinion * Any of the following abnormal laboratory values (unless any of these abnormalities are due to underlying lymphoma): * Absolute neutrophil count \<1.0 × 10⁹/L. * Platelet count \<75 × 10⁹/L * Serum AST and ALT ≥ 2.5 x ULN * Total bilirubin ≥ 1.5 x ULN * Serum creatinine clearance \< 30 mL/min (using Cockcroft-Gault formula) * Any active infection within 7 days prior to Cycle 1 Day 1 that would impact participant safety * Positive test results for chronic hepatitis B infection (defined as positive hepatitis B surface antigen \[HBsAg\] serology)：Participants with occult or prior hepatitis B infection (defined as positive total hepatitis B core antibody and negative HbsAg) may be included if hepatitis B virus (HBV) DNA is undetectable at the time of screening. Such participants must be willing to undergo HBV DNA testing every month and appropriate antiviral therapy as indicated * Positive test results for hepatitis C (hepatitis C virus \[HCV\] antibody serology testing)：Participants positive for HCV antibody are eligible only if PCR is negative for HCV RNA * Participants with a history of progressive multifocal leukoencephalopathy * Pregnancy or breastfeeding, or intention of becoming pregnant during the study or within 12 months after final dose of treatment * Participants with uncontrolled coagulation disorders, connective tissue diseases, severe infectious diseases * Other concurrent and uncontrolled medical conditions that, in the opinion of the investigator, would affect the patient's participation in the study