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What is Leukemia?
Posted by AdminWhat is Leukemia?
Over 35,000 people will be diagnosed with some form of leukemia this year with CLL affecting 25 percent of all patients over the age of 50, making it the most common form of this disease.
But what is leukemia, and are you at risk? Dr. Neil Shah, assistant professor of the division of hematology and oncology and the University of California, San Francisco and Dr. Brian Drunker, director of the leukemia center at Oregon Health Sciences University, answer some common questions about this disease.
What is leukemia?
Leukemia is defined as the overproduction of white blood cells. It's a blood disorder caused by an abnormality in the cells in the bone marrow. These cells do not develop normally, so they accumulate in an immature stage, and they don't serve any useful function.
What are the types of leukemia?
The types of leukemia are categorized by how quickly the disease develops. A chronic form of leukemia develops slowly. Acute leukemia, on the other hand, quickly worsens and is a more aggressive form of the disease. But leukemia is also grouped by the types of white blood cells that are affected. The disease can arise in the myeloid cells or the lymphoid cells. So, there are four categories of leukemia: chronic myeloid leukemia (CML), chronic lymphocytic leukemia (CLL), acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL).
How common is each type of leukemia?
Each form of leukemia occurs at different rates in the population. CLL, the most common form, strikes about 10,000 people a year, while AML will be diagnosed in 8,000 people a year. Less common is CML, which will affect about 5,000 people a year, and ALL will be diagnosed in about 4,000 people this year.
However, leukemia can also affect children. The most common form of leukemia in children is ALL, which will be diagnosed in about 2,000 children this year.
Who is most at risk for developing leukemia?
For most cases of leukemia, the average age of onset is between the ages of 50 to 60. In children, leukemia is seen more often in younger children, generally between the ages of 2 and 4.
What causes leukemia?
The cause of leukemia is not completely understood, but we know that there are some risk factors for the development of leukemia, such as exposure to certain chemicals, such as chemotherapy or radiation. The vast majority of patients, however, don't have any clearly identifiable risk factor.
What are the symptoms of leukemia?
The symptoms of chronic leukemia can be pretty nonspecific: low grade fevers, fatigue, night sweats, occasionally some abdominal discomfort from an enlarged spleen. Occasionally, there is some loss of appetite or decreased weight. Patients oftentimes will have symptoms for three to six months of just some mild fatigue, maybe a low-grade fever, occasionally some night sweats.
How is leukemia diagnosed?
When a person displays a number of symptoms that suggest leukemia, a blood test is done. Because its symptoms are so nonspecific, chronic leukemia is often diagnosed during a routine checkup. When a blood count reveals signs of leukemia, the next test is a bone marrow biopsy. The bone marrow biopsy is very useful because that allows us to analyze the factory in which the cells of the blood are being made, and we can sometimes see abnormal changes in the bone marrow environment. Additionally, we perform what we call cytogenetic analysis, which looks for evidence of mutations in these cells, a surefire sign of leukemia.
How is leukemia treated?
Treatment options will vary based on the type of cancer a patient has, but treatments for leukemia range the full gamut from watchful waiting in some cases to bone marrow transplantation, which can be a very aggressive, but can cure some of these leukemias. Additionally, there are some new, exciting treatments being studied which target the abnormal cells directly.
Acute leukemias are treated with chemotherapy and/or a bone marrow transplant. For CLL, on the other hand, watchful waiting is often the first line of treatment because the disease tends to progress so slowly. However, as CLL progresses, it can be treated with a variety of chemotherapies. For CML, however, the current standard treatment is a targeted therapy called imatinib (Gleevec). Some younger patients will undergo a bone marrow transplant as a curative therapy.
How are treatment options improving?
In the 1950s and 60s, children lived no more than about six to twelve weeks after the diagnosis of ALL, but now the cure rate approaches 75 to 80 percent with new combinations of chemotherapy.
The biggest problem in treating leukemia is that we do not fully understand what drives the growth of leukemia cells. But as we understand more and more about each and every type of leukemia, it's very likely that, in the near future, we'll have many, many more of these targeted drugs that are going to be even more effective.
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