Lymphoma is a cancer that affects the lymphatic system. There are two main types of lymphoma: Hodgkin's lymphoma (or Hodgkin's disease, named after Dr. Thomas Hodgkin) and Non-Hodgkin's lymphoma. Both Hodgkin's and Non-Hodgkin's lymphoma derived from white blood cells called lymphocytes – which are part of the body's immune system – but they have different behaviors and responses to treatment.
Hodgkin's lymphoma is a relatively rare disease. While the median age at diagnosis is 38, older patients can develop the disease, requiring specialized attention. Since Hodgkin's lymphoma commonly afflicts younger women, it is important to take the appropriate steps to preserve fertility in younger patients, whenever possible.
In general, Hodgkin's is more common in men. It can occur in both children and adults, but is rare in children younger than five years old. It is most common in either early adulthood (in the 20s), or after age 55. Hodgkin's disease is most common in the United States, Canada, and northern Europe, and is least common in Asian countries.
Hodgkin's lymphoma is characterized by the presence of a specific type of abnormal cells called Reed-Sternberg cells, that are larger than normal lymphocytes and not found in Non-Hodgkin's lymphomas.
Almost all cases of Hodgkin's lymphoma are derived from so-called B lymphocytes (B cells), which mature into antibody-producing plasma cells and protect against infection The most common type of Hodgkin's disease is known as Classical Hodgkin's disease (HD) and accounts for about 95 percent of Hodgkin's disease cases in developed countries. Nodular lymphocyte predominant Hodgkin's disease (NLPHD), accounts for about 5 percent of Hodgkin's disease. Hodgkin's disease can start almost anywhere in the body but is most likely to occur in the lymph nodes, spleen, bone marrow, thymus, and digestive tract.
Hodgkin's disease has a relatively high survival rate. Those rates are improving due to advances in treatment.
The exact cause of Hodgkin disease is not known and it is not possible to prevent the disease at present. Having had the Epstein-Barr virus (EBV), which causes infectious mononucleosis, raises the risk of developing Hodgkin's lymphoma, albeit slightly. Being infected with Human Immunodeficiency virus (HIV), the virus that causes AIDS, also raises the risk, again, only slightly. The risk seems to be greater in people with a higher socioeconomic background. Siblings of people with this disease have a higher risk, but the family link is evident in only around 5 percent of all cases.
There are no widely recommended screening tests for Hodgkin's disease and symptoms may not appear early in the disease. When symptoms do appear, the most common is painless enlargement of lymph nodes, particularly in the neck, arm pit, or the groin. Other symptoms can include persistent fever, heavy night sweats, fatigue, unexplained weight loss and loss of appetite, and severe itching. Sometimes Hodgkin's disease affects lymph nodes inside the chest. When those nodes swell, the pressure on the windpipe (trachea) may cause coughing or difficulty breathing.
These symptoms are more often a sign of infection (or even another cancer), rather than Hodgkin's disease, but it is important to have such lumps checked by your doctor.
Chemotherapy and/or radiation, or a combination, are the primary methods of treating Hodgkin's disease. Surgery is not normally a suitable treatment.
CLL starts in B lymphocytes in bone marrow. These bone-marrow cells mature somewhat more than in ALL, but not completely. They can perform some of the functions of white blood cells but are less effective, and gradually crowd out the fully formed white cells.
About one third of all leukemia cases are CLL. The disease mainly affects older adults, and the average age of diagnosis is 72. There are two types of CLL. One grows slowly and rarely needs to be treated. The other type grows faster and is a more serious disease.
As with ALL, there are few known risk factors. There seems to be some genetic component to CLL, as there is a greater likelihood of contracting the disease if a first-degree family member has it. CLL has the same symptoms and diagnostic methods as ALL. As with ALL, CLL is treated with chemotherapy. In addition, monoclonal antibodies may be used in some cases.
Acute myeloid leukemia starts in myeloid blood cells in bone marrow that would normally develop into white blood cells, red blood cells, or platelets. AML is really a group of related diseases with certain common characteristics. The different types of AML are caused by abnormalities in various chromosomes and are defined by which chromosome is abnormal.
AML is generally a disease of older people and is uncommon in people under 40. Most patients have no known risk factors. Smoking is the only proven lifestyle-related risk factor for AML. Exposure to benzene, certain chemotherapy drugs, radiation, and certain congenital conditions are also known causes.
The symptoms of AML are similar to those of ALL and diagnosis and treatment are the same.
CML starts in the blood-forming cells of the bone marrow and moves into the blood. The disease tends to build up over time and can eventually invade other parts of the body, often the spleen. CML can also develop into an acute leukemia.
CML normally affects adults and accounts for about 10% to 15% of all leukemias. As with other forms of leukemia, there are few, if any, risk factors aside from exposure to high-dose radiation. Symptoms are vague, similar to those described above, and can take years to develop.
Treatment for CML has advanced tremendously with the advent of a class of drugs known as tyrosine kinase inhibitors (TKIs), first introduced in 2001. Though it is too soon for scientific studies to show proven results, anecdotal evidence suggests a very good survival rate for at least five years. These drugs have become the standard treatment, although occasionally, chemotherapy and radiation might still be used.