Lymphoma is a cancer that originates in lymphocytes, specialized white blood cells that form a vital part of the body’s immune system. These cells are normally responsible for fighting infections and are found throughout the body, primarily in the lymph nodes, spleen, bone marrow, and thymus. When a lymphocyte undergoes a malignant change and begins to multiply uncontrollably, it forms a mass of cancerous cells, leading to lymphoma. Lymphoma is not a single entity, but a collective term for a diverse group of cancers affecting the lymphatic system.
The Primary Division of Lymphoma
The primary way doctors classify lymphoma is by separating it into two major categories: Hodgkin Lymphoma (HL) and Non-Hodgkin Lymphoma (NHL). This division is based on the microscopic appearance of the cancerous cells and the presence or absence of a specific abnormal cell type known as the Reed-Sternberg cell.
Hodgkin Lymphoma is defined by the presence of these large, often multinucleated Reed-Sternberg cells, which are typically derived from B-lymphocytes. HL is the less common type, accounting for approximately 10% of all lymphoma cases diagnosed annually. It is frequently considered highly treatable and often curable, especially when detected early.
The majority of diagnoses, about 90% of cases, fall into Non-Hodgkin Lymphoma (NHL), characterized by the absence of Reed-Sternberg cells. NHL is a far more heterogeneous group of diseases with varied behaviors and prognoses. While HL tends to spread in an organized manner, NHL can appear in virtually any organ or tissue throughout the body.
Understanding Non-Hodgkin Lymphoma Subtypes
Non-Hodgkin Lymphoma requires a granular classification system based on the specific type of lymphocyte involved and the speed at which the cancer cells grow. NHL is categorized by its cell of origin: B-cell or T-cell. B-cell lymphomas make up 85% to 90% of all NHL diagnoses, while T-cell lymphomas comprise the remaining 10% to 15% of cases.
The growth rate divides lymphomas into two clinical groups: indolent and aggressive. Indolent lymphomas are slow-growing and may not require immediate, intensive treatment. Follicular Lymphoma, the second most common NHL subtype, is typically indolent and often managed initially with “watchful waiting.”
Aggressive lymphomas are fast-growing and require prompt, intensive therapy. Diffuse Large B-cell Lymphoma (DLBCL) is the most common form of NHL globally, representing about 30% of all cases, and is classified as an aggressive B-cell lymphoma. DLBCL often responds well to modern treatment regimens, achieving a high rate of cure.
Rare and highly aggressive types include Burkitt Lymphoma, which is one of the fastest-growing human cancers and necessitates immediate, intensive chemotherapy. The specific subtype, including its cell lineage and growth rate, determines the most effective course of action for each patient.
How Lymphoma Types Determine Treatment
The precise classification of a patient’s lymphoma is the fundamental factor that directly dictates the appropriate treatment strategy and expected outcome. Treatment goals differ substantially between the major categories and their subtypes, ranging from curative intent to long-term disease management. Hodgkin Lymphoma’s high curability often involves a combination of multi-agent chemotherapy, such as the ABVD regimen, frequently supplemented by radiation therapy directed at the affected lymph node areas.
The treatment approach for Non-Hodgkin Lymphoma is far more varied, reflecting the heterogeneity of its many subtypes. For indolent types like Follicular Lymphoma, the slow pace of the disease means some patients may undergo “watchful waiting.” Treatment is deferred until the disease shows signs of progression or causes symptoms, avoiding unnecessary exposure to therapy side effects for a cancer that may remain stable for years.
In contrast, aggressive NHL subtypes, such as DLBCL, require immediate and intensive multi-agent chemotherapy, typically combined with immunotherapy. The addition of monoclonal antibodies, a form of targeted therapy, has greatly improved outcomes for many B-cell lymphomas. This targeted approach, often combined with chemotherapy in a regimen like R-CHOP, informs treatment selection.
Beyond traditional chemotherapy and radiation, a patient’s specific lymphoma type may also qualify them for advanced therapies like CAR T-cell therapy or a stem cell transplant. These are often used for cases that have returned or have been difficult to treat. The specific genetic markers and cell lineage identified during diagnosis ultimately determine which tools will be employed to maximize the chances of a favorable outcome.