A Study Comparing the Efficacy and Safety Between I-CHOP and R-CHOP in Untreated CD20-Positive Diffuse Large B-cell Lymphoma Patients

Inclusion Criteria: * Untreated CD20-positive DLBCL confirmed by histopathology or cytology. * 18 years to 75 years; Male or female patients. * International Prognostic Index (IPI) score of 0 to 2. * Signed an informed consent. * At least one measurable lesions: for nodal tumor mass, more than 1.5 cm in the long axis and more than 1.0 cm in the short axis; for extranodal tumor mass, more than 1.0 cm in the long axis. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2. * More than 6 months life expectancy. Exclusion Criteria: * Participation in another interventional clinical trial in the past 3 months. * Known allergic reactions against monoclonal antibody or rituximab. * Contraindication to any component of CHOP regimen. * Previous treatment for DLBCL, including chemotherapy, immunotherapy, partial radiotherapy for lymphoma, or surgical treatment (excluding tumor mass biopsies and surgical resection for non-lymphoma lesions), or prior use of any monoclonal antibody within 3 month. * History of cytotoxic drugs treatment or anti-CD20 monoclonal antibody treatment for other disease (e.g., rheumatoid arthritis). * Primary central nervous system (CNS) lymphoma, secondary CNS involvement, primary testicular lymphoma.