A Phase II Single Arm Study of the Use of CODOX-M/IVAC With Rituximab (R-CODOX-M/IVAC) in the Treatment of Patients With Diffuse Large B-Cell Lymphoma (International Prognostic Index High or High-Intermediate Risk)

RATIONALE: Drugs used in chemotherapy work in different ways to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Monoclonal antibodies, such as rituximab, can block cancer cell growth in different ways. Some block the ability of cancer cells to grow and spread. Others find cancer cells and help kill them or carry cell-killing substances to them. Giving more than one drug (combination chemotherapy) together with rituximab may kill more cancer cells.

PURPOSE: This phase II trial is studying how well giving combination chemotherapy together with rituximab works in treating patients with diffuse large B-cell non-Hodgkin lymphoma.