What is the workup for diffuse large B cell lymphoma?

Workup for Diffuse Large B-Cell Lymphoma

The workup for diffuse large B-cell lymphoma requires tissue diagnosis with immunohistochemistry, comprehensive staging with CT imaging and bone marrow biopsy, PET/CT scanning, laboratory assessment including LDH and viral screening, and risk stratification using the International Prognostic Index. 1

Tissue Diagnosis

Obtain an excisional lymph node biopsy or adequate tissue specimen to provide sufficient material for comprehensive pathological evaluation. 1

• Core needle biopsies may be acceptable only in patients requiring emergency treatment where surgical biopsy is not feasible. 1
• Mandatory immunohistochemistry panel must include CD45, CD20, and CD3 to confirm B-cell lineage and CD20 positivity, which is essential for rituximab eligibility. 1
• Fresh frozen tissue collection for molecular characterization is recommended, though gene expression profiling remains investigational and does not currently influence treatment decisions. 1
• The pathology report must provide diagnosis according to current WHO classification. 1

Important caveat: While cell-of-origin classification (germinal center-like versus activated B-cell-like subtypes) has prognostic significance, immunohistochemical determination shows contradictory results and poor reproducibility—do not base routine clinical decisions on these results outside clinical trials. 2

Laboratory Assessment

Complete the following baseline laboratory studies: 1

• Complete blood count
• Comprehensive metabolic panel including lactate dehydrogenase (LDH) and uric acid (critical for IPI calculation and tumor lysis risk assessment)
• HIV, hepatitis B, and hepatitis C screening (mandatory given treatment implications and increased lymphoma aggressiveness with HIV) 1, 3
• Protein electrophoresis (recommended) 1

Imaging Studies

CT scan of chest, abdomen, and pelvis is required as minimum staging imaging. 1

PET/CT scanning is strongly recommended for superior disease delineation and essential for accurate post-treatment response assessment according to revised response criteria. 1, 3

• PET/CT provides better extent-of-disease assessment than CT alone 1
• Post-treatment PET is highly recommended to define complete remission 1
• Do not use routine surveillance PET scans during follow-up—this is not recommended 1

Bone Marrow Evaluation

Perform bone marrow aspirate and biopsy in all patients amenable to curative therapy. 1

• This is required for complete staging according to Ann Arbor classification 1
• Repeat bone marrow assessment at end of treatment only if initially involved 1

CNS Risk Assessment

Consider diagnostic lumbar puncture with CSF analysis in high-risk patients. 1

High-risk features warranting CNS evaluation include: 3

• Multiple extranodal sites (≥2)
• Testicular involvement
• Renal/adrenal involvement
• HIV-positive status
• Elevated LDH with extranodal disease

Functional Assessment

Evaluate performance status and cardiac function before treatment: 1

• Document ECOG or Karnofsky performance status
• Assess left ventricular ejection fraction (LVEF) given planned anthracycline therapy 1
• This is critical for determining treatment intensity and eligibility for dose-intensive approaches

Risk Stratification

Calculate the International Prognostic Index (IPI) and age-adjusted IPI (aa-IPI) using: 1

• Age >60 years
• Elevated LDH
• ECOG performance status ≥2
• Ann Arbor stage III or IV

• 1 extranodal site

Apply Ann Arbor staging system (stages I-IV based on lymph node regions and extranodal involvement). 1

The IPI score directly influences treatment strategy selection and intensity, with higher scores indicating need for more aggressive approaches. 1

Special Considerations

For suspected primary mediastinal large B-cell lymphoma, recognize this as a distinct entity where R-CHOP may not be the definitive treatment and radiotherapy remains controversial. 1

In cases with high tumor burden, assess for tumor lysis syndrome risk and plan prophylaxis with hydration, allopurinol or rasburicase, and electrolyte monitoring before initiating treatment. 3

Common pitfall: Avoid dose reductions of chemotherapy due to hematological toxicity—maintain dose intensity and use prophylactic growth factors instead. 1