Lymphoma is a group of cancers originating in lymphocytes, the infection-fighting white blood cells. Lymphocytes are part of the lymphatic system, which maintains fluid balance and protects the body from disease. When a lymphocyte multiplies uncontrollably, it forms a cancerous mass that disrupts immune function. Lymphoma is broadly categorized into two major groups, which are further divided into numerous subtypes, each having unique behaviors and treatment approaches.
The Primary Distinction Between Lymphoma Types
The fundamental division of lymphoma relies on a microscopic examination of the cancerous tissue, separating the disease into Hodgkin Lymphoma (HL) and Non-Hodgkin Lymphoma (NHL). This distinction is based on the presence or absence of a specific abnormal cell, known as the Reed-Sternberg cell.
If a biopsy sample contains these large, multinucleated cells, the diagnosis is Hodgkin Lymphoma. These cells are an abnormal type of B-lymphocyte. If these characteristic cells are not found, the diagnosis is Non-Hodgkin Lymphoma. NHL is significantly more common, accounting for about 85% of all cases. HL, though less prevalent, typically spreads in a more predictable pattern. This pathological separation is important because the management and prognosis for HL and NHL differ considerably.
Cellular Origins of Non-Hodgkin Lymphoma
Non-Hodgkin Lymphoma is categorized by the type of lymphocyte from which it originates: B-cells or T-cells. The cancer is named for the cell line that became malignant. The vast majority of NHL cases, about 90%, arise from B-lymphocytes, resulting in B-cell lymphomas.
B-cells produce antibodies that neutralize foreign invaders, while T-cells are the immune system’s direct attackers, destroying infected or cancerous cells. The remaining 10% of NHL cases are T-cell lymphomas. The cellular origin influences the disease’s behavior and responsiveness to specific therapies. For example, many B-cell lymphomas express the CD20 protein, allowing for targeted antibody treatments that are ineffective against T-cell lymphomas. Identifying the precise cellular lineage is paramount for determining the most effective therapeutic strategy.
Aggressive Non-Hodgkin Lymphomas
Non-Hodgkin Lymphomas are categorized by their growth tempo into aggressive and indolent types. Aggressive lymphomas are characterized by rapid cell division and proliferation, leading to swiftly worsening symptoms and disease progression. These types require immediate, intensive treatment because they can quickly become life-threatening.
Diffuse Large B-Cell Lymphoma (DLBCL) is the most common aggressive subtype, representing 30% to 40% of adult NHL cases. DLBCL is defined by the large size of the malignant B-cells and their diffuse growth pattern. Although fast-growing, DLBCL is potentially curable, with intensive chemoimmunotherapy regimens leading to long-term remission in a significant proportion of patients.
Burkitt’s Lymphoma represents an extreme example of aggressive growth, possessing one of the fastest doubling times of any human tumor. This rapid proliferation is often linked to a genetic change involving the MYC gene. The urgency of this disease requires high-intensity chemotherapy protocols to achieve a cure, which is successful for a high percentage of children and adults.
Indolent Non-Hodgkin Lymphomas
Indolent, or slow-growing, lymphomas follow a protracted clinical course, sometimes taking years to cause noticeable symptoms or health problems. Follicular Lymphoma (FL) is the most prevalent indolent subtype, characterized by a nodular growth pattern. Marginal Zone Lymphoma (MZL) is another common indolent form.
For many asymptomatic patients with low tumor burden, oncologists often recommend “watchful waiting” or active surveillance. This approach is counterintuitive to treating cancer immediately, but studies show that starting treatment before symptoms appear does not extend the patient’s overall survival time. Instead, it only exposes them to unnecessary side effects from therapy.
Treatment is typically initiated when a patient develops specific symptoms, such as fever or night sweats, experiences compromise to organ function, or shows evidence of rapid progression or transformation to a more aggressive lymphoma type. While indolent lymphomas are generally not curable with standard therapy, they are often manageable over many decades, effectively treating the disease as a chronic condition.