Dose Adjusted EPOCH-R, to Treat Mature B Cell Malignancies

The subject will need to have a variety of tests, exams, or procedures to find out if s/he can be on the study. The subject will also require placement of a catheter that stays in the vein for safe administration of chemotherapy drugs. During the study... If all of the tests that have been done show that s/he can participate and s/he chooses to participate, treatment cycles will begin. A cycle equals three weeks. The subject will have a minimum of 6 cycles of treatment, possibly 8. The cancer drugs s/he will receive are etoposide, vincristine, doxorubicin, cyclophosphamide, prednisone, and rituximab with each cycle. The amount of the drugs will be determined by the subject's weight at first, and some of the drugs will be adjusted up or down for later cycles. Rituximab will be given on Day 1 prior to continuous infusion drugs. After 4 cycles, the subject will have imaging scans again to see how the cancer responded to treatment. If the cancer responds completely after 4 cycles, s/he will get 2 more cycles (6 cycles total). If the cancer partially responds, s/he will get 4 more cycles (8 total cycles). If the subject has cancer in the Central Nervous System, s/he will receive a drug called methotrexate. If s/he does not have cancer in the CNS, s/he will get methotrexate to try to prevent CNS cancer.