B-cell lymphoma is a type of blood cancer that develops in B lymphocytes, white blood cells that normally produce antibodies to fight infection.
B-cell lymphomas are a heterogeneous group of lymphoid neoplasms derived from B lymphocytes at various stages of differentiation.
B-cell lymphoma is the most common category of non-Hodgkin lymphoma (NHL), accounting for approximately 85% of all cases.
Symptoms vary by subtype but often include:
Swollen Lymph Nodes: Painless lumps typically in the neck, armpits, or groin.
B symptoms: Unexplained fever, drenching night sweats, and significant weight loss.
Persistent Fatigue: Often linked to anemia if the cancer affects the bone marrow.
Localized Pain: Abdominal pain or fullness (if the spleen or stomach is involved) or chest pain.
Types: Diffuse Large B-cell Lymphoma (DLBCL) Aggressive fast-growing
Diffuse Large B-cell Lymphoma (DLBCL) is most common type (approx. 30% of cases).
It requires immediate treatment but is often curable.
Burkitt Lymphoma: Very fast-growing; highly aggressive but potentially curable with intensive chemotherapy.
Mantle Cell Lymphoma (MCL): Tends to be aggressive and can be difficult to treat.
Indolent-Slow-growing
Follicular Lymphoma: Second most common; often responds well to treatment but can be hard to cure completely.
Marginal Zone Lymphoma (MZL): Includes MALT lymphoma, often linked to infections like H. pylori.
CLL/SLL: Chronic lymphocytic leukemia and small lymphocytic lymphoma are different forms of the same disease, affecting blood/marrow and lymph nodes, respectively.
Hairy cell leukemia, lymphoplasmacytic lymphoma/Waldenström macroglobulinemia, diffuse large B-cell lymphoma (DLBCL), high-grade B-cell lymphomas (including double-hit and triple-hit lymphomas), Burkitt lymphoma, and unclassifiable B-cell lymphomas with features intermediate between DLBCL and other entities.
Diagnosis of a B-cell lymphoma typically requires a biopsy of a lymph node or affected tissue to identify specific genetic markers (like CD20).
Staging often involves CT, MRI, or PET scans.
Treatment Options:
Chemoimmunotherapy: Combinations like R-CHOP (Rituximab plus chemotherapy) are standard for many types.
Targeted & Immunotherapy: Drugs that target specific proteins or boost the immune system to recognize cancer cells.
CAR T-cell Therapy: Engineering a patient’s own T-cells to attack the lymphoma, often used for relapsed or refractory cases.
Stem Cell Transplant: Used to replace bone marrow after high-dose chemotherapy.
Active Surveillance:for slow-growing types without symptoms.
Each subtype is defined by a combination of morphological features (cell size, growth pattern), immunophenotypic markers (e.g., CD19, CD20, CD22, CD79a, PAX5), and recurrent genetic alterations (e.g., t(14;18) in follicular lymphoma, t(11;14) in mantle cell lymphoma, t(8;14) in Burkitt lymphoma, BRAF V600E in hairy cell leukemia).
Molecular classification, particularly for DLBCL, has become increasingly important.
Gene expression profiling distinguishes germinal center B-cell-like (GCB) and activated B-cell-like (ABC) subtypes, with the ABC subtype associated with chronic B-cell receptor signaling, NF-κB activation, and inferior outcomes.
High-grade B-cell lymphomas with MYC and BCL2 and/or BCL6 rearrangements (double-hit/triple-hit) are recognized as distinct, highly aggressive entities with poor prognosis.
The pathogenesis of B-cell lymphomas is closely linked to the biology of B-cell differentiation, with most subtypes arising from germinal center B cells, which are subject to error-prone processes such as somatic hypermutation and class-switch recombination, leading to characteristic chromosomal translocations and mutations.
Epidemiology, Risk Factors, and Clinical Presentation
B-cell lymphomas account for approximately 85–90% of all non-Hodgkin lymphomas (NHL), with DLBCL and follicular lymphoma being the most common subtypes.
The incidence of B-cell lymphomas varies by subtype, age, sex, and geographic region.
In Europe and North America, DLBCL represents about 30–40% of NHL cases, with a median age at diagnosis in the mid-60s and approximately 30% of patients older than 75 years.
Follicular lymphoma and marginal zone lymphoma increase in incidence from age 30 to 70, with no marked male predominance.
Burkitt lymphoma, though rare in the United States, is one of the most common childhood lymphomas and exhibits a bimodal age distribution.
Risk factors for B-cell lymphomas are multifactorial, including genetic susceptibility, immune dysregulation, chronic inflammation, infection, and environmental exposures.
Severe immunosuppression (e.g., HIV infection, organ transplantation, immunosuppressive therapy for autoimmune diseases) is strongly associated with aggressive subtypes such as DLBCL and Burkitt lymphoma.
Chronic infections, such as Helicobacter pylori (gastric MALT lymphoma), hepatitis C virus (splenic marginal zone lymphoma, DLBCL), and Epstein-Barr virus (Burkitt lymphoma, EBV-positive DLBCL), are causally linked to specific subtypes.
Lifestyle factors such as obesity (DLBCL) and cigarette smoking (follicular lymphoma) also contribute to risk.
The most common clinical presentation is painless lymphadenopathy, which may be localized or generalized.
Constitutional “B symptoms” include fever, night sweats, weight loss and are present in a subset of patients, particularly in aggressive subtypes.
Extranodal involvement is frequent, especially in DLBCL, where 30–40% of cases are primary extranodal, affecting sites such as the gastrointestinal tract, skin, CNS, bone marrow, or mediastinum.
Specific subtypes have characteristic presentations, such as mediastinal masses in primary mediastinal large B-cell lymphoma and neurologic symptoms in primary CNS DLBCL.
Diagnosis:
The diagnosis of B-cell lymphoma requires an excisional biopsy of an involved lymph node or extranodal mass, with core-needle biopsy acceptable only when excisional biopsy is not feasible.
Fine-needle aspiration is generally inadequate.
Histopathological examination, immunohistochemistry, flow cytometry, and molecular studies (e.g., FISH, NGS) are essential for accurate classification.
Immunophenotyping confirms B-cell lineage (CD19, CD20, CD22, CD79a), and additional markers and genetic features are used for subclassification (CD10, BCL6, IRF4/MUM1 for DLBCL cell-of-origin; MYC, BCL2, BCL6 rearrangements for high-grade lymphomas).
Staging is performed using the Lugano classification, a modification of the Ann Arbor system, as recommended by the American Society of Clinical Oncology and other international societies.
PET-CT is the gold standard for staging FDG-avid lymphomas (e.g., DLBCL, follicular lymphoma), offering superior sensitivity and specificity compared to CT alone and often resulting in upstaging or downstaging in 10–30% of cases.
Bone marrow biopsy is no longer routinely required for staging in most FDG-avid B-cell lymphomas if PET-CT is performed, except in indolent lymphomas or when PET-CT findings are equivocal.
Prognostic assessment integrates clinical, laboratory, and molecular features.
The International Prognostic Index (IPI) is the cornerstone for aggressive B-cell lymphomas, incorporating age >60 years, stage III/IV, elevated LDH, ECOG performance status ≥2, and ≥2 extranodal sites.
For indolent lymphomas, the Follicular Lymphoma International Prognostic Index (FLIPI) and Mantle Cell Lymphoma International Prognostic Index (MIPI) are used.
Molecular features, such as cell-of-origin in DLBCL (GCB vs. ABC), MYC/BCL2/BCL6 rearrangements, double expression of MYC and BCL2, high Ki-67, TP53 mutations, and CDKN2A deletions, are associated with prognosis and may guide therapy.
The standard first-line therapy for most patients with newly diagnosed DLBCL is R-CHOP (rituximab 375 mg/m² IV day 1, cyclophosphamide 750 mg/m² IV day 1, doxorubicin 50 mg/m² IV day 1, vincristine 1.4 mg/m² [max 2 mg] IV day 1, prednisone 100 mg orally days 1–5, every 21 days for 6 cycles).
Attempts to improve outcomes by intensifying chemotherapy, shortening intervals, or adding novel agents to R-CHOP have not shown meaningful improvements, and R-CHOP remains the standard of care.
For primary mediastinal large B-cell lymphoma and high-grade B-cell lymphomas with MYC and BCL2 and/or BCL6 rearrangements, dose-adjusted EPOCH-R (etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, rituximab) is preferred.
For follicular lymphoma, first-line therapy is risk-adapted.
Observation is appropriate for low tumor burden, asymptomatic patients.
When treatment is indicated, rituximab plus bendamustine or rituximab plus CHOP are commonly used.
For relapsed/refractory DLBCL, approximately 30–40% of patients will relapse or have refractory disease after first-line R-CHOP.
For patients relapsing more than 12 months after initial therapy and eligible for autologous stem cell transplantation (ASCT), salvage chemotherapy (e.g., R-DHAP, R-ICE, R-GDP) followed by high-dose chemotherapy and ASCT is standard.
For primary refractory disease or early relapse (≤12 months), anti-CD19 CAR T-cell therapy is preferred for transplant-eligible patients, based on randomized trials showing superior event-free survival compared to salvage chemotherapy and ASCT.
For transplant-ineligible or CAR T-cell-ineligible patients, polatuzumab vedotin (1.8 mg/kg IV day 1) plus bendamustine (90 mg/m² IV days 1 and 2) and rituximab (375 mg/m² IV day 1) every 21 days for 6 cycles has demonstrated improved complete remission rates and overall survival compared to bendamustine-rituximab alone.
Tafasitamab (12 mg/kg IV days 1, 8, 15, 22 for cycles 1–3, then days 1 and 15 for cycles 4–12) plus lenalidomide (25 mg orally days 1–21 of each 28-day cycle for up to 12 cycles) is approved for relapsed/refractory DLBCL in patients not eligible for ASCT.
Loncastuximab tesirine (0.15 mg/kg IV every 3 weeks for 2 cycles, then 0.075 mg/kg every 3 weeks) is approved for heavily pretreated and high-risk DLBCL.
The following table from Tilly et al in The New England Journal of Medicine summarizes the efficacy of polatuzumab vedotin plus R-CHP compared to R-CHOP in previously untreated DLBCL, providing quantitative data on progression-free survival, overall survival, and response rates.
CAR T-cell therapy (axicabtagene ciloleucel, lisocabtagene maraleucel, tisagenlecleucel) is FDA approved for relapsed/refractory DLBCL after at least two prior lines of therapy, with complete response rates of 40–60% and median progression-free survival of 11–12.5 months.
CAR T-cell therapy is associated with higher rates of severe cytokine release syndrome (CRS) and neurotoxicity (ICANS), requiring administration in specialized centers.
Bispecific antibodies (BsAbs) such as glofitamab, epcoritamab, and mosunetuzumab are now FDA approved for relapsed/refractory DLBCL and follicular lymphoma after two or more prior lines of therapy, offering off-the-shelf availability, outpatient administration, and a more favorable safety profile, with lower rates of severe CRS and neurotoxicity.
Meta-analyses demonstrate that CAR T-cell therapy achieves higher complete response rates and longer progression-free survival compared to BsAbs in both DLBCL and follicular lymphoma.
In third- or later-line DLBCL, pooled complete response rates are 51% for CAR T-cell therapy versus 36% for BsAbs, with 1-year progression-free survival rates of 44% and 32%, respectively.
In follicular lymphoma, CAR T-cell therapy achieves complete response rates of 82–94% and median progression-free survival of 15 months, compared to 65–67% and 9 months for BsAbs.
However, BsAbs are more accessible and have a lower incidence of severe adverse events, making them suitable for patients ineligible for CAR T-cell therapy or requiring rapid disease control.
Complications, Supportive Care, and Survivorship
B-cell lymphomas and their treatments are associated with a broad spectrum of complications, including immune dysfunction, infection, cytopenias, neuropathy, cardiotoxicity, and secondary malignancies.
Disease-related immune compromise, particularly in CLL and indolent lymphomas, leads to increased risk of bacterial, viral, and fungal infections, accounting for up to 50% of deaths in CLL.
Autoimmune phenomena such as hemolytic anemia and immune thrombocytopenia are also common, especially in CLL.