Leukemia: What you need to know
In the United States, 62,130 people are expected to receive a diagnosis of leukemia in 2017, and around 24,500 deaths will likely be due to this disease.
Acute leukemia develops quickly and worsens rapidly, but chronic leukemia gets worse over time.
Here are some key points about leukemia. More detail is in the main article.
- About 62,130 new cases of leukemia are expected to be diagnosed in the United States in 2017.
- Leukemia is one of the most common childhood cancers, but it most often occurs in older adults.
- Leukemia can be fatal, but there are ways of treating and controlling the disease and its symptoms.
Leukemia happens when the DNA of immature blood cells, mainly white cells, becomes damaged in some way.
This causes the blood cells to grow and divide continuously, so that there are too many.
Healthy 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 when they should. They accumulate, occupying more space.
As more cancer cells are produced, they stop the healthy white blood cells from growing and functioning normally, by crowding out space in the blood.
Essentially, the bad cells crowd out the good cells in the blood.
Some factors increase the risk of developing leukemia.
The following are either known or suspected factors:
- artificial ionizing radiation
- viruses, such as the human T-lymphotropic virus (HTLV-1) and HIV
- benzene and some petrochemicals
- alkylating chemotherapy agents used in previous cancers
- hair dyes
Genetic predisposition: Some people appear to have a higher risk of developing leukemia because of a fault in one or several genes.
Down syndrome: People with Down syndrome appear to have a higher risk, possibly due to certain chromosomal changes.
It has been suggested that exposure to electromagnetic energy might be linked to leukemia, but there is not enough evidence to confirm this.
There are various types of leukemia, and they affect people differently. Treatment options will depend on the type of leukemia and the person's age and overall state of health.
Progress in medicine means that treatment can now aim for complete remission, where the cancer goes away completely for at least 5 years after treatment.
In 1975, the chances of surviving for 5 years or more after receiving a diagnosis of leukemia were 33.1 percent. By 2009, this figure had risen to 62.9 percent.
The main type of treatment is chemotherapy. This will be tailored to the type of cancer a patient has.
If treatment starts early, the chance of remission is higher.
Types of treatment include:
- targeted therapy
- interferon therapy
- radiation therapy
- stem cell transplantation
Chemotherapy can affect the whole body, but targeted therapy is aimed at a specific part of the cancer cell.
Some types of chronic leukemia do not need treatment in the early stages, but monitoring is essential. The oncologist may suggest watchful waiting with frequent doctor's visits.
For a type of leukemia known as chronic myeloid leukemia (CML), a bone marrow transplant may be effective. Younger patients are more likely to undergo transplantation successfully.
Signs and symptoms of leukemia vary.
They may include:
- being tired all the time
- weight loss
- having fevers or chills
- getting frequent infections
There is more information on symptoms later in this article.
Leukemia can be divided into four main groups. These groups distinguish acute, chronic, lymphocytic, and myelogenous leukemia.
Chronic and acute leukemia
During its lifespan, a white blood cell goes through several stages.
In acute leukemia immature, useless cells develop rapidly and collect in the marrow and blood. They are squeezed out of the bone marrow too early and are not functional.
Chronic leukemia progresses more slowly. It 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 leukemia
Leukemias are also classified according to the type of blood cell they affect.
Lymphocytic leukemia occurs if the cancerous changes affect the type of bone marrow that makes lymphocytes. A lymphocyte is a kind of white blood cell that plays a role in the immune system.
Myelogenous leukemia happens when the changes affect the type of marrow cells that go on to produce red blood cells, other types of white cells, and platelets.
Acute lymphocytic leukemia (ALL)
Also known as acute lymphoblastic leukemia, this is the most common type of leukemia among young children. It can also affect adults, especially after the age of 65 years. Among children, the 5-year survival rate is higher than 85 percent.
The subtypes of ALL are:
- precursor B acute lymphoblastic leukemia
- precursor T acute lymphoblastic leukemia
- Burkitt's leukemia
- acute biphenotypic leukemia
Chronic lymphocytic leukemia (CLL)
This is most common among adults over 55 years, but younger adults can also have it. It is the most common type of leukemia in adults, and it rarely affects children. It is more common in men than in women.
A person with CLL has an 82 percent of surviving 5 years after diagnosis.
Acute myelogenous leukemia (AML)
AML is more common in adults than in children. It affects men more often than women.
It develops quickly, and symptoms include fever, difficulty breathing, and pain in the joints. Environmental factors can trigger it.
Chemotherapy is the main treatment. Sometimes, a bone marrow transplant may be recommended.
Chronic myelogenous leukemia (CML)
CML mostly affects adults. According to the National Cancer Institute, the 5-year survival rate is 65.1 percent.
However, many people with CML have a gene mutation that responds to targeted cancer therapy, called Gleevec, or imatinib. For those people whose cancer is susceptible to Gleevec, the 5-year survival rate can be up to 90 percent.
Signs and symptoms of leukemia include the following:
Poor blood clotting: Immature white blood cells crowd out platelets, which are crucial for blood clotting. This can cause a person to bruise or bleed easily and heal slowly. They may also develop petechiae, small red to purple spots on the body, indicating a minor hemorrhage.
Frequent infections: The white blood cells are crucial for fighting off infection. If these are suppressed or not working properly, frequent infections can result. The immune system may attack other good body cells.
Anemia: As the shortage of good red blood cells grows, anemia can result. This can involve difficult or labored breathing and pale skin.
Other symptoms: There may be nausea, fever, chills, night sweats, flu-like symptoms, weight loss, bone pain, and tiredness. If the liver or spleen becomes enlarged the person may feel full and will eat less, resulting in weight loss.
These can all be symptoms of other illnesses. Tests are needed to confirm a diagnosis of leukemia.
A doctor will carry out a physical examination and ask about personal and family medical history. They will check for signs of anemia and feel for an enlarged liver or spleen.
They will also take a blood sample for assessment in the laboratory.
If the doctor suspects leukemia, they may suggest a bone marrow test. Bone marrow is taken, usually from the hip, using a long, fine needle. This can help to show which kind of leukemia, if any, is present.
The outlook for people with leukemia depends on the type.
All patients who experience remission will need to undergo regular monitoring, including blood tests and possible bone marrow tests, to ensure the cancer has not returned.
If the leukemia does not return, the doctor may decide, over time, to reduce the frequency of the tests.