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.
This phase II trial studies how well bendamustine hydrochloride, obinutuzumab, and dexamethasone work in treating older patients with diffuse large B-cell lymphoma. Drugs used in chemotherapy, such as bendamustine hydrochloride and dexamethasone, work in different ways to stop the growth of cancer cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Monoclonal antibodies, such as obinutuzumab, may find cancer cells and help kill them. Giving bendamustine hydrochloride, obinutuzumab, and dexamethasone may kill more cancer cells.