Bendamustine, Obinutuzumab, and Dexamethasone in Older Patients With Diffuse Large B-cell Lymphoma

PRIMARY OBJECTIVES: I. Assess the overall response rate (ORR; complete responders \[CR\] + partial responders \[PR\]) using the Cheson et al parameters of this novel combination regimen. SECONDARY OBJECTIVES: I. Assess the feasibility of incorporating prospective geriatric assessments in patients \>= 70 years of age diagnosed with diffuse large B-cell lymphoma (DLBCL) and treated in a multi-center setting. II. Quality of life (QOL) based on Functional Assessment of Cancer Therapy-Lung (FACT-L) scale on all enrolled patients. III. Progression-free survival (PFS) at 2 and 3 years. IV. Overall survival (OS) at 2 and 3 years. OUTLINE: Patients receive bendamustine hydrochloride intravenously (IV) over 30 minutes on days 1 and 2, obinutuzumab IV over 4 hours on days 1 or 2, 8, and 15 (on both days 1 and 2 in course 1 only), dexamethasone orally (PO) daily on days 1-5. Treatment repeats every 21 days for up to 6 courses in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up every 6 months for 40 months.