What is Lymphoma?
Lymphoma is a cancer that originates from lymphocytes (a type of white blood cell) and primarily affects the lymphatic system, including lymph nodes and other lymphoid tissues. It is broadly classified into two main types: Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL), with NHL accounting for approximately 80-85% of all lymphoma cases in the United States 1, 2.
Main Types of Lymphoma
Hodgkin Lymphoma (HL)
- Characterized by the presence of Reed-Sternberg cells in an inflammatory background 1
- Two main subtypes:
- Classical Hodgkin Lymphoma (CHL) - most common in Western countries
- Nodular Lymphocyte-Predominant Hodgkin Lymphoma (NLPHL) - characterized by "popcorn cells" instead of Reed-Sternberg cells 1
- Typically presents with painless lymphadenopathy
- Higher cure rates (80% or more) compared to many NHL subtypes 1
Non-Hodgkin Lymphoma (NHL)
- Heterogeneous group with over 90 subtypes 3
- Cell origin breakdown:
- B-cell origin: 80-85% of cases
- T-cell origin: 15-20% of cases
- NK-cell origin: Rare 1
- Most common B-cell NHL subtypes:
- Diffuse Large B-Cell Lymphoma (DLBCL): 31% of NHL cases
- Follicular Lymphoma (FL): 22% of NHL cases
- Small Lymphocytic Lymphoma/Chronic Lymphocytic Leukemia (SLL/CLL): 6%
- Mantle Cell Lymphoma (MCL): 6%
- MALT Lymphoma: 5% 1
Diagnosis
Diagnosis of lymphoma requires:
- Tissue biopsy: Open lymph node biopsy is preferred for accurate diagnosis 3
- Pathological evaluation:
- Staging: The Lugano classification system incorporates:
- PET/CT imaging to determine disease extent
- Presence of systemic symptoms (B symptoms: fever, night sweats, weight loss) 3
Classification Systems
Lymphoma classification has evolved over time:
- Working Formulation (1982): Based on morphology and clinical behavior
- REAL Classification (1994): Incorporated cell of origin, morphology, immunophenotype, genetic features, and clinical aspects 1
- WHO Classification (2001, updated 2008,2017,2022): Current standard that builds on REAL principles, classifying lymphomas by cell of origin, maturity, and other biological features 1
Clinical Presentation
Common presentations include:
- Painless lymphadenopathy (most common)
- B symptoms (fever, night sweats, unexplained weight loss) in advanced disease
- Organ-specific symptoms based on site of involvement
- Splenomegaly and abdominal lymphadenopathy 1, 3
Treatment Approaches
Treatment varies by lymphoma type, stage, and patient factors:
Hodgkin Lymphoma
- Combined modality therapy with chemotherapy regimens like ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine) 1, 3
- PET/CT for response assessment using the Deauville 5-point scale 1
Non-Hodgkin Lymphoma
- B-cell NHL: Often treated with CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) plus rituximab (R-CHOP) 3
- Indolent lymphomas: May use "watch and wait" approach for asymptomatic patients
- Aggressive lymphomas: Require immediate treatment with combination chemotherapy 1
- Relapsed/refractory disease: Novel approaches including CAR-T cell therapy targeting CD19 4
Prognosis
Prognosis varies widely depending on:
- Lymphoma subtype
- Stage at diagnosis
- Patient factors (age, comorbidities)
- Response to initial therapy
For example, follicular lymphoma generally has a favorable prognosis with 5-year survival rates >80%, while some aggressive NHLs have poorer outcomes without prompt treatment 2.
Important Considerations
- Long-term follow-up is essential due to potential late treatment effects including secondary malignancies
- Patients with lymphoma should receive appropriate vaccinations due to immunosuppression 3
- Risk factors include tobacco use, obesity, genetic predisposition, and certain infections 3
Lymphoma represents a diverse group of diseases with distinct biological behaviors requiring specific diagnostic approaches and treatment strategies tailored to the exact lymphoma subtype.