A 65-year-old man presents with abdominal pain that has been increasing over the past 3 months. He is less active than before but is able to mow the lawn and tend to his garden. Positron emission tomography (PET)/computed tomography (CT) scan shows adenopathy in the cervical and axillary regions as well as an 8-cm mass in the retroperitoneum. Excisional lymph node biopsy demonstrates diffuse large B-cell lymphoma (DLBCL). His complete blood count (CBC) is within normal limits. His lactate dehydrogenase (LDH) ratio is slightly elevated, but less than two-fold the upper limit of normal. Bone marrow biopsy shows no evidence of lymphoma. His National Comprehensive Cancer Network International Prognostic Index (NCCN-IPI) score is 4 (high/intermediate risk), which predicts a 56% survival at 5 years.