Induction therapy (VcR-CVAD): Patients receive VcR-CVAD comprising bortezomib 1.3 mg/m2 IV over 3-5 seconds on days 1 and 4; rituximab 375 mg/m2 IV over 3-4 hours on day 1; doxorubicin hydrochloride 25 mg/m2/d IV over 48 hours on days 1 and 2; cyclophosphamide 300 mg/m2 IV over 3 hours every 12 hours on days 1-3; vincristine 1 mg IV over 3-5 seconds on day 3; and dexamethasone 40 mg IV or orally once daily on days 1-4. Patients also receive filgrastim (G-CSF) subcutaneously (SC) or IV once daily beginning on day 5 or 6 and continuing until blood counts recover OR pegfilgrastim SC on day 5 or 6. Treatment repeats every 21 days for up to 6 courses in the absence of disease progression or unacceptable toxicity.