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. Oblimersen sodium may help chemotherapy work better by making cancer cells more sensitive to the drugs. Giving oblimersen sodium together with combination chemotherapy may kill more cancer cells. PURPOSE: This clinical trial is studying the side effects of giving oblimersen sodium together with combination chemotherapy and to see how well it works in treating patients with newly diagnosed stage I, stage II, stage III, or stage IV diffuse large B-cell lymphoma