Definition: What is Lymphoma?
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Lymphoma is a cancer of the lymphatic system. The lymphatic system's role is to ensure the body's immune system defense, and to protect against external attacks of bacteria or viruses. It consists of the lymph nodes, spleen, tonsils, bone marrow, and thymus.
The lymphatic network allows the creation (via the ganglia) and the circulation (via the lymphatic vessels) of the lymph, a biological fluid composed mainly of lymphocytes. These are white blood cells responsible for fighting infections. An abnormal development of these lymphocytes is the origin of lymphoma.
The Different Types of Lymphoma
There are two main types of lymphoma: Non-Hodgkin's lymphoma (NHL) and Hodgkin disease. What differentiates them is the presence of Reed-Sternberg cells in the case of Hodgkin disease. These are large tumor cells derived from a lymphocyte. This form of lymphoma is much rare than NHL and mainly affects young adults (between 20 and 40 years old).
Non-Hodgkin's lymphoma develops from B cells in 85% of cases, and T lymphocytes in the remaining 15%. There are more than 50 types of NHL. They are classified into two groups:
- aggressive forms: These are forms that evolve very quickly. They affect between 50-60% of patients with lymphoma. They should be taken very seriously and require immediate care. Aggressive forms of lymphoma include Burkitt's lymphoma and mantle cell lymphoma.
- indolent forms: The evolution of these forms is slower and can occur over several years. They represent 40-50% of people affected by this disease. Indolent forms of lymphoma include follicular lymphoma and MALT lymphoma.
Symptoms of Lymphoma
The clinical signs of lymphoma are quite difficult to diagnose because they are not very distinct in the early stages of the disease and are very similar to other pathologies. The first symptom to appear is usually a non-painful increase in the volume of the ganglion (or lymphadenopathy) in the neck, groin, or armpits.
The development of lymphoma is also frequently accompanied by the presence of fever, chills, night sweats, fatigue, and unexplained weight loss.
Depending on the location of the lymphoma and the organ that's affected, the patient may also experience abdominal pain if the lymphatic tissues inside the stomach are affected, or chest pain involving breathing difficulties.
Evolution of Lymphoma
There are four stages in the progression of lymphocytic cancer:
- stage I: only one ganglionic group or one organ is affected
- stage II: the cancer has reached several ganglionic groups but is present on only one side of the diaphragm
- stage III: the lymphoma is now located on both sides of the diaphragm
- stage IV: the cancer has developed beyond the lymphatic system
Causes of Lymphoma
The exact causes of lymphoma are still unknown. That said, researchers were able to pinpoint several factors thay may influence the onset of the disease, such as chronic infections like the Epstein-Barr virus, malaria, HIV, or Helicobacter pylori bacteria. Prolonged immune deficits (Wiskott-Aldrich syndrome, Sjogren's syndrome) also seem to increase the risk of developing lymphoma.
In addition, environmental factors can be taken into account, such as exposure to pesticides or other toxic substances. Chemotherapy and the taking of certain drugs (such as immunosuppressants) must also be taken into consideration.
Treatment of Lymphoma
The treatment of lymphoma depends on which type it is, as well as which stage its at. The survival rate in adults is between 50-80%. B-cell cancers respond better to treatment than T-cell cancers.
In the early stage of the disease, radiotherapy is used to locally destroy cancer cells and prevent them from spreading. High energy X-ray beams are directed at the affected lymph nodes.
Chemotherapy can be used when lymphoma is present in many parts of the body and is at a later stage. It will often be performed in several cycles, via intravenous or oral, and is combined with radiotherapy.
If treatment is not effective, a stem cell transplant can be performed. This involves replacing the cells of the diseased bone marrow with healthy bone marrow cells. This is usually removed from a patient before they start chemotherapy.
