What are the diagnostic criteria for B cell lymphoma in newly diagnosed or relapsed cases?

From the Guidelines

The diagnosis of B-cell lymphoma, whether newly diagnosed or relapsing, should be made on the basis of a surgical specimen/excisional lymph node or extranodal tissue biopsy providing enough material for formalin-fixed samples, with minimal immunohistochemistry (CD45, CD20, and CD3) being mandatory. The diagnosis process involves several key steps, including:

• Obtaining a tissue biopsy with adequate material for histopathological examination, which is crucial for accurate diagnosis 1
• Examining the tissue for abnormal B-cell morphology, growth patterns, and immunophenotyping using immunohistochemistry to identify B-cell markers
• Considering the collection of fresh frozen material for molecular characterization, although gene expression profiling remains investigational 1
• Ensuring that the histological report gives the diagnosis according to the current World Health Organization classification, as stated in the guidelines 1
• Noting that the distinction between germinal center-like subtype and activated B-cell-like subtype does not influence treatment choices at the moment, according to the available evidence 1 The goal of these diagnostic steps is to provide a comprehensive understanding of the lymphoma, which is essential for determining the best course of treatment and improving patient outcomes in terms of morbidity, mortality, and quality of life.

From the Research

Diagnosis of B Cell Lymphoma

The diagnosis of B cell lymphoma, whether newly diagnosed or relapsing, involves several criteria and tests.

• The World Health Organization's Classification of Tumours of Haematopoietic and Lymphoid Tissues provides guidelines for the classification and diagnosis of B cell lymphomas 2.
• A practical approach to diagnosis includes intraoperative, microscopic, immunophenotypic, and cytogenetic evaluation to distinguish B cell lymphomas from other hematopoietic or nonhematopoietic tumors 2.
• For diffuse large B-cell lymphoma (DLBCL), a complete metabolic response on PET scan after completion of chemotherapy is associated with superior freedom from progression (FFP) and overall survival (OS) 3.

Relapsing Cases

• Relapses in DLBCL can be suspected by surveillance imaging studies, such as PET scans, or clinically by patient-reported symptoms and physical examination 3.
• The use of PET scans as posttreatment surveillance is not associated with a survival advantage, and lactate dehydrogenase (LDH) is not a sensitive marker for relapse 3, 4.
• A 1.5-fold increase in serum LDH above baseline over a period of 3 months is associated with an increased likelihood of relapse from DLBCL 4.

Newly Diagnosed Cases

• The presence of circulating lymphoma cells (CL) at diagnosis is a prognostic factor for newly diagnosed de novo DLBCL, with CL+ patients having significantly inferior progression-free survival (PFS) and overall survival (OS) compared to CL- patients 5.
• Clinicians should consider checking peripheral blood flow at diagnosis in all newly diagnosed DLBCL patients to assess for CL 5.
• Treatment of newly diagnosed DLBCL with rituximab and CHOP (R-CHOP) has been largely unchanged for the last two decades, but new evidence-based therapeutic strategies are emerging 6.