Carfilzomib, Rituximab, Ifosfamide, Carboplatin, and Etoposide in Treating Patients With Relapsed or Refractory Stage I-IV Diffuse Large B-cell Lymphoma

Inclusion Criteria: * Histological confirmation of relapsed/refractory CD20 positive diffuse large B-cell lymphoma * Ann Arbor stage I to stage IV DLBCL at the time of relapsed/refractory disease to be eligible * Measurable or assessable disease is required; measurable tumor size (at least one node measuring 2.25 cm\^2 in bidimensional measurement) per computed tomography (CT) scan, other radiological study, and/or physical exam * Patients must have received at least 1 prior rituximab-based immunochemotherapy (e.g., R-CHOP, R-EPOCH, etc.) * \>= 2 weeks since major surgery * Patients must not have any significant toxicity associated with prior surgery, radiation therapy, chemotherapy, or immunotherapy, per principal investigator (PI) discretion * Life expectancy \>= 3 months * Karnofsky score (KS) \>= 50 * Serum alanine aminotransferase (ALT)/aspartate aminotransferase (AST) =\< 3.5 times the upper limit of normal within 14 days prior to starting therapy * Absolute neutrophil count (ANC) \>= 1.0 x 10\^9/L within 14 days prior to starting therapy\* * Hemoglobin \>= 8 g/dL (80 g/L) within 14 days prior to randomization (subjects may be receiving red blood cell \[RBC\] transfusions in accordance with institutional guidelines)\* * Platelet count \>= 50 x 10\^9/L (\>= 20 x 10\^9/L if lymphoma involvement in the pretreatment bone marrow is found) within 14 days prior to starting therapy\* * \*Note: If patient has cytopenias due to bone marrow involvement, these requirements are not…