Tumor-Specific Clonotype, Metabolic Profile, and PET/CT in Predicting Chemotherapy Response in Patients With Relapsed or Refractory Diffuse Large B-cell Lymphoma

PRIMARY OBJECTIVES: I. To evaluate the ability of blood based detection of a tumor-specific clonotype and metabolic profiling and functional imaging to predict response to standard immunochemotherapy. SECONDARY OBJECTIVES: I. To evaluate the optimal time points to create the diffuse large B-cell lymphoma (DLBCL) response prediction model. TERTIARY OBJECTIVES: I. To evaluate the prognostic value of clinical factors, cell of origin subtype, and circulating immune cell subsets for response to therapy. II. To evaluate for novel genomic aberrations or signatures which correlate with therapeutic failure. III. To evaluate the ability of additional positron emission tomography (PET)/computed tomography (CT) imaging interpretation techniques to correlate with clinical outcomes. IV. To evaluate the correlation of blood-based detection of clonotype with fludeoxyglucose F-18 (FDG) PET/CT disease assessment. V. To evaluate the utility of alternative methods of minimal residual disease detection. VI. To evaluate measurement of circulating metabolic profiling with imaging results and clinical outcomes. OUTLINE: Patients receive standard salvage chemotherapy as determined by the treating physician. Patients undergo FDG PET/CT scans at baseline (between days -21 to 0), on day 4 after completion of first high-dose chemotherapy, on day 21 after completion of the first course of chemotherapy, and on day 42 after the end of the second course of chemotherapy. Blood samples are also collected for tumor-specific clonotype and metabolic profile at baseline (days -5 to 0) and on days 4, 8, 21, and 42.