In this study, elderly DLBCL patients will be treated with ZR2 regimen for the first-line treatment. Investigators will compare the complete response rate, survival and incidence of adverse reactions between the RCHOP/RCDOP chemotherapy and the ZR2 regimen. In addition, immune function tests will be performed before treatment and every 2 courses after treatment, including peripheral blood lymphocyte-monocyte ratio, cytokines, immunoglobulins, T and B cells and their quantitative analysis. Patients with ZR2 regimen will undergo gene second-generation sequencing before treatment to compare the gene mutation differences between complete response (CR) and ≤ partial response (PR) in the efficacy of ZR2 regimen, in order to find biomarkers with better efficacy in ZR2 treatment. Moreover, investigators intend to conduct pharmacokinetics/pharmacodynamics (PK/PD) correlation analysis of ZR2 regimen and pharmacoeconomic evaluation of the two regimens.
