The purpose of this study is to 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.