Leukemia (British spelling: leukaemia ) is cancer of the blood or bone marrow (which produces blood cells). A person who has leukemia suffers from an abnormal production of blood cells, generally leukocytes (white blood cells).
People sometimes confuse leukemia and lymphoma. Leukemia is a cancer of the blood, lymphoma is cancer of the lymphatic system (lymph glands). The word Leukemia comes from the Greek leukos which means "white" and aima which means "blood".
The DNA of immature blood cells, mainly white cells, becomes damaged in some way. This abnormality causes the blood cells to grow and divide chaotically. Normal blood cells die after a while and are replaced by new cells which are produced in the bone marrow. The abnormal blood cells do not die so easily, and accumulate, occupying more and more space. As more and more space is occupied by these faulty blood cells there is less and less space for the normal cells - and the sufferer becomes ill. Quite simply, the bad cells crowd out the good cells in the blood.
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Fast facts on leukemia
Here are some key points about leukemia. More detail and supporting information is in the main article.
- Leukemia is cancer of the white blood cells. White blood cells help your body fight infection.
- There are about 54,270 new cases of leukemia in the US each year.
- Around 24,450 people die from leukemia per year in the US.
- There are about 20,830 new cases of acute myeloid leukemia (AML) and 10,460 deaths from AML in the US each year, most cases are adults.
- Leukemia is the seventh leading cause of cancer death in the United States.
- Approximately 1.5% of men and women will be diagnosed with leukemia at some point during their lifetime.
- Compared to other cancers, leukemia is relatively rare.
- Although leukemia is among the most common childhood cancers, it most often occurs in older adults.
- Leukemia is slightly more common in men than women.
- People with leukemia have many treatment options, and treatment for leukemia can often control the disease and its symptoms.
In order to better understand what goes on we need to have a look at what the bone marrow does.
Function of the bone marrow
The bone marrow is found in the inside of bones. The marrow in the large bones of adults produces blood cells. Approximately 4% of our total bodyweight consists of bone marrow.
There are two types of bone marrow: 1. Red marrow, made up mainly of myeloid tissue. 2. Yellow marrow, made up mostly of fat cells. Red marrow can be found in the flat bones, such as the breast bone, skull, vertebrae, shoulder blades, hip bone and ribs. Red marrow can also be found at the ends of long bones, such as the humerus and femur.
White blood cells (lymphocytes), red blood cells and platelets are produced in the red marrow. Red blood cells carry oxygen, white blood cells fight diseases. Platelets are essential for blood clotting. Yellow marrow can be found in the inside of the middle section of long bones.
If a person loses a lot of blood the body can convert yellow marrow to red marrow in order to raise blood cell production.
White blood cells, red blood cells and platelets exist in plasma - Blood plasma is the liquid component of blood, in which the blood cells are suspended.
Types of leukemia
Chronic and Acute
Experts divide leukemia into four large groups, each of which can be Acute, which is a rapidly progressing disease that results in the accumulation of immature, useless cells in the marrow and blood, or Chronic, which progresses more slowly and allows more mature, useful cells to be made. In other words, acute leukemia crowds out the good cells more quickly than chronic leukemia.
Lymphocytic and Myelogenous
Leukemias are also subdivided into the type of affected blood cell. If the cancerous transformation occurs in the type of marrow that makes lymphocytes, the disease is called lymphocytic leukemia. A lymphocyte is a kind of white blood cell inside your vertebrae immune system. If the cancerous change occurs in the type of marrow cells that go on to produce red blood cells, other types of white cells, and platelets, the disease is called myelogenous leukemia.
To recap, there are two groups of two groups - four main types of leukemia, as you can see in the illustration below:
Acute Lymphocytic Leukemia (ALL), also known as Acute Lymphoblastic Leukemia - This is the most common type of leukemia among young children, although adults can get it as well, especially those over the age of 65. Survival rates of at least five years range from 85% among children and 50% among adults. The following are all subtypes of this leukemia: precursor B acute lymphoblastic leukemia, precursor T acute lymphoblastic leukemia, Burkitt's leukemia, and acute biphenotypic leukemia.
Chronic Lymphocytic Leukemia (CLL) - This is most common among adults over 55, although younger adults can get it as well. CLL hardly ever affects children. The majority of patients with CLL are men, over 60%. 75% of treated CLL patients survive for over five years. Experts say CLL is incurable. A more aggressive form of CLL is B-cell prolymphocytic leukemia.
Acute Myelogenous Leukemia (AML) - AML is more common among adults than children, and affects males significantly more often than females. Patients are treated with chemotherapy. 40% of treated patients survive for over 5 years. The following are subtypes of AMS - acute promyelocytic leukemia, acute myeloblastic leukemia, and acute megakaryoblastic leukemia.
Researchers from the Memorial Sloan-Kettering Cancer Center reported in the March 2012 issue of NEJM (New England Journal of Medicine that they identified a series of genetic mutations in people with AML. They explained that their findings may help doctors to more accurately predict patient outcomes, as well as choosing therapies they are most likely to respond to.
Chronic Myelogenous Leukemia (CML) - The vast majority of patients are adults. 90% of treated patients survive for over 5 years. Gleevec (imatinib) is commonly used to treat CML, as well as some other drugs. Chronic monocytic leukemia is a subtype of CML.
Symptoms of leukemia
- Blood clotting is poor - As immature white blood cells crowd out blood platelets, which are crucial for blood clotting, the patient may bruise or bleed easily and heal slowly - he may also develop petechiae (a small red to purple spot on the body, caused by a minor hemorrhage).
- Affected immune system - The patient's white blood cells, which are crucial for fighting off infection, may be suppressed or not working properly. The patient may experience frequent infections, or his immune system may attack other good body cells.
- Anemia - As the shortage of good red blood cells grows the patient may suffer from anemia - this may lead to difficult or labored respiration (dyspnea) and pallor (skin has a pale color caused by illness).
- Other symptoms - Patients may also experience nausea, fever, chills, night sweats, flu-like symptoms, and tiredness. If the liver or spleen becomes enlarged the patient may feel full and will eat less, resulting in weight loss. Headache is more common among patients whose cancerous cells have invaded the CNS (central nervous system).
- Precaution - As all these symptoms could be due to other illnesses. A diagnosis of leukemia can only be confirmed after medical tests are carried out.
On the next page we look at what causes leukemia and the available treatment options.