Research purpose： To evaluate the efficacy and safety of R-mini-MCOP in first-line treatment of primary treatment of diffuse large B-cell lymphoma (DLBCL) in elderly patients Experimental design： Single-arm, multicenter, prospective study

Inclusion Criteria:

1. Age ≥ 80 years
2. The histopathological diagnosis was diffuse large B-cell lymphoma, and immunohistochemistry was positive for CD20
3. Previously untreated disease
4. Ann Arbor stage I-IV disease
5. According to Lugano2014 criteria, there must be at least one matching evaluable or measurable lesion: lymph node lesion, the length of the measurable lymph node must be greater than 1.5cm; For non-lymph node lesions, the measured extra-nodal lesions should be > 1.0cm in length;
6. ECOG score 0-4(ECOG score 0-2 after pre-treatment and before R-mini-MCOP regimen)
7. Bone marrow function: neutrophil count ≥1.5×109/L, platelet count ≥75×109/L, hemoglobin ≥80g/L (neutrophil count ≥1.0×109/L, platelet count ≥50×109/L, hemoglobin ≥75 g/L in patients with bone marrow involvement);
8. Liver and kidney function: serum creatinine ≤1.5 times the upper limit of normal value; AST and ALT ≤2.5 times the upper limit of normal (≤5 times the upper limit of normal for patients with liver invasion); Total bilirubin ≤1.5 times the upper limit of normal value (≤3 times the upper limit of normal value for patients with liver invasion;
9. Have the swallowing power
10. Life expectancy > 3 months
11. Patients fully understand the study, voluntarily participate and sign an informed consent form (ICF) -

Exclusion Criteria:

1. Previous systemic antitumor therapy (except pre-therapy used before the first cycle of R-CMOP);
2. Metastatic diffuse large B-cell lymphoma；
3. Known central nervous system lymphoma
4. Hypersensitivity to any investigational drug or its ingredients;
5. Uncontrollable systemic diseases (such as advanced infections, uncontrolled hypertension, diabetes, etc.);
6. Hepatitis B and hepatitis C active infection (hepatitis B virus surface antigen positive and hepatitis B virus DNA more than 1x103 copies /mL; More than 1x103 copies /mL of HCV RNA);
7. Human immunodeficiency virus (HIV) infection (HIV antibody positive);
8. Other serious comorbidities, intolerance to this protocol or inappropriate participation in this study (judged by the investigator)
9. Previous or current co-occurrence of other malignancies (other than non-melanoma basal cell carcinoma of the skin that is effectively controlled, breast/cervical carcinoma in situ, and other malignancies that have been effectively controlled without treatment within the past five years);
10. Inability to swallow the drug or any significant removal of the small intestine that may prevent full absorption of the drug;
11. Situations in which other investigators have determined that participation in this study is not appropriate.