Non-Hodgkin’s lymphoma (NHL) is a cancer that begins in the lymphatic system, a part of the immune system. Understanding the different types of NHL is crucial because treatment strategies vary depending on the specific type. Doctors need to pinpoint the exact type of lymphoma to tailor the most effective treatment plan. The classification depends on the type of lymphocyte affected (B cells or T cells), the maturity of the cells when they become cancerous, and various other factors.
B-Cell vs. T-Cell Lymphomas: Key Differences
The lymphatic system primarily comprises lymphocytes, a type of white blood cell essential for fighting infections. There are two main types of lymphocytes: B cells and T cells.
- B Lymphocytes (B Cells): B cells defend the body against germs (bacteria or viruses) by producing antibodies. Antibodies attach to germs, marking them for destruction by other immune system components.
- T Lymphocytes (T Cells): T cells come in several varieties. Some T cells directly destroy germs or abnormal cells. Others regulate the activity of other immune system cells, either boosting or slowing down their responses.
Lymphoma can originate in either B cells or T cells. However, B-cell lymphomas are more prevalent.
Indolent vs. Aggressive Lymphomas: Growth Rate Matters
NHL types can also be categorized by their growth and spread rate:
- Indolent Lymphomas: These lymphomas grow and spread slowly. Some might not require immediate treatment but are instead closely monitored. Follicular lymphoma is the most common indolent lymphoma in the United States.
- Aggressive Lymphomas: These lymphomas grow and spread rapidly, necessitating immediate treatment. Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive lymphoma in the United States.
Some lymphomas, such as mantle cell lymphoma, don’t fit neatly into these categories.
Regardless of their growth rate, all non-Hodgkin lymphomas can spread to other parts of the lymphatic system if left untreated. Eventually, they may spread to other areas of the body, including the liver, brain, or bone marrow.
Classifying NHL Types: The WHO System
Classifying the many types of NHL can be complex. The most current classification system is the World Health Organization (WHO) classification. The WHO system categorizes lymphomas based on:
- The type of lymphocyte (B-cell, T-cell, or other) where the lymphoma originates.
- The appearance of the lymphoma cells under a microscope.
- The chromosomal characteristics of the lymphoma cells.
- The presence of specific proteins on the cancer cell surfaces.
Understanding the WHO classification is vital for diagnosis and treatment planning, as it provides a standardized way to categorize and understand the various subtypes of non-Hodgkin’s lymphoma. This classification ensures that patients receive the most appropriate and effective care based on the specific characteristics of their disease.
