Bendamustine and Rituximab With or Without Orelabrutinib in MCL Treatment

Inclusion Criteria: * Diagnosed with MCL (mantle cell lymphoma) through flow cytometry or histopathology, and has not received prior treatment. * Age \> 18 years of age, both genders are eligible. * Ann Arbor stage II-IV; for stage II subjects, those who require systemic therapy based on the investigator's judgment are eligible. * At least one measurable lesion. * Eastern Cooperative Oncology Group (ECOG) performance status score of 0-2. * Any one of the following high-risk factors is present: MIPI score of 4-11, Ki67 \> 50%, TP53 abnormality, blastic or pleomorphic variation. * Patients who are not suitable candidates for autologous hematopoietic stem cell transplantation. * Laboratory tests (blood routine, liver and kidney function) meet the following requirements: a) Blood routine: White blood cell count ≥3.0×10\^9/L, absolute neutrophil count ≥1.5×10\^9/L, hemoglobin ≥90g/L, platelet count ≥75×10\^9/L. b) Liver function: Transaminases ≤2.5 times the upper limit of normal, bilirubin ≤1.5 times the upper limit of normal. c) Serum creatinine 44-133 mmol/L. * The investigator judges that the subject's life expectancy is greater than 12 weeks from the time of screening. * Willing and able to participate in all required assessments and procedures of the study protocol. Exclusion Criteria: * Patients who have previously received treatment with BTK inhibitors. * Patients with severe complications or serious infections. * Patients with uncontrolled cardiovascular diseases, coagulation disorders, connective tissue diseases, serious infectious diseases, etc. * Patients with active infections requiring systemic treatment, including bacterial, fungal, and viral infections. * HIV-infected individuals. * Patients with mental disorders or those who are known or suspected to be unable to fully comply with the study protocol. * Patients whom the investigator judges to have other conditions that make them unsuitable for participation in this study.