Leukemia causes uncontrollable growth and reproduction of cells called leukocytes. In acute leukemia, leukocytes are less mature, develop fast, and become dysfunctional cells called blasts as they leave the bone marrow. In chronic leukemia, leukocytes develop more slowly, potentially taking years to cause symptoms.

Also, chronic leukemia mostly involves more mature, functional cells and does not typically involve high numbers of blasts.

Leukemia is a general term for any type of cancer that affects specific cells in a person’s bone marrow, blood, or lymphatic system. In the United States, leukemia rates have been steadily increasing since 2006.

This article discusses acute and chronic forms of leukemia, comparing their symptoms, causes, prevention, diagnosis, and treatment. It also provides information about living with leukemia.

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Leukemia is a condition in which cells in the bone marrow develop in an uncontrolled and harmful manner. The way in which this process occurs determines whether an individual has acute or chronic leukemia.

The terms acute and chronic leukemia do not refer to the duration of the disease.

When a person has acute leukemia, their bone marrow produces many dysfunctional cells called blasts. These cells are less mature and develop quickly, crowding out healthy bone marrow cells. This leads to a fast onset of leukemia symptoms.

By contrast, chronic leukemia tends to affect more mature, functional cells and develop slowly. A person could have leukemia for several years without experiencing any symptoms.

Other types and subtypes

Doctors also distinguish between myelogenous and lymphocytic leukemia. These terms indicate the predominant type of cell that the condition affects.

More specifically, the terms describe whether the main cell involved is myeloid or lymphoid.

There are four main subtypes of these types of leukemia:

Chronic and acute leukemia may cause similar symptoms. However, in chronic leukemia, symptoms may develop later. A person may not notice symptoms until several years after the onset of the condition.

Acute leukemia

Symptoms of acute leukemia may begin sooner, and the condition can progress rapidly. Symptoms may also be more severe in acute leukemia and can include:

Chronic leukemia

Chronic leukemia symptoms are usually less severe and develop more slowly than those of acute leukemia.

Some people may not have symptoms at all. However, they may appear as the cancer spreads and may include:

Learn more about symptoms and early signs of leukemia here.

Leukemia develops when there has been an interruption or blockage in the life cycle of a cell.

The American Cancer Society distinguishes between chronic and acute leukemia in the following ways:

  • Chronic leukemia: This type of leukemia is due to a failure in the cell life cycle after the cells have become mature. As a result, they do not protect the body against infection as effectively.
  • Acute leukemia: This type of the condition develops when there has been a blockage in the cell’s early development. Cells do not mature properly and can build up excessively.

Cancers can develop due to a combination of genetic and environmental factors. However, scientists do not exactly know what causes this type of condition.

Leukemia may be a result of DNA changes in the cells. For instance, there may be a link between CML and a gene mutation called the Philadelphia chromosome. However, people cannot inherit this gene mutation.

Genes can control how the body destroys and rids itself of dangerous chemicals. If a person has such a gene, and it does not work properly, they are more at risk of damage from these chemicals. That is because their body may not be able to break down harmful chemicals properly if they come into contact with them.

Learn more about the genetic element of leukemia here.

It can be difficult for doctors to diagnose leukemia. The diagnostic process often requires performing multiple tests, such as:

Doctors diagnose acute leukemia slightly differently than they do chronic leukemia. Acute leukemia often requires a bone marrow biopsy, which checks for the number of blast cells. This is not always necessary for diagnosing chronic leukemia.

Learn what to expect during a bone marrow biopsy here.

Treatment can vary depending on whether a person has acute or chronic leukemia and which subtype of the condition they have.

Chronic leukemia

Some people with chronic leukemia will not need treatment until symptoms appear, which can take years. However, they do need to consult a doctor every so often to monitor their condition.

Since chronic leukemia tends to develop in older adults, doctors use targeted therapies to kill cancer cells without affecting other cells, thus decreasing the risk of side effects.

Chemotherapy vs. targeted therapy

Chemotherapy works by destroying not only cancerous cells but also healthy cells. With chemotherapy, doctors aim to kill the cancer cells and let the healthy cells recover.

However, this type of treatment can cause complications throughout the rest of the body, which is why older adults or people with other health conditions may not tolerate it so well.

By contrast, targeted therapies only attack cancer cells and therefore reduce a person’s risk of complications.

Learn about treatment options by phase for CML here.

Acute leukemia

Treatment for acute leukemia will depend on how aggressive the condition is and what its unique genetic characteristics are.

Doctors may begin treatment with a targeted therapy drug or chemotherapy.

Next, they will ensure all the harmful cells are gone either by administering more chemotherapy or by carrying out a stem cell transplant.

Learn about chemotherapy for AML here.

The outlook for people with leukemia varies greatly and depends on a number of factors, such as a person’s age, the presence of other health conditions, and the subtype of leukemia they have.

Chronic leukemia

Although chronic leukemia is unlikely to be curable, a person with the condition can live a normal life.

For example, some people with chronic leukemia do not experience symptoms for years and will require treatment only when the symptoms start occurring.

Acute leukemia

This is a more aggressive, fast-growing type of leukemia, but there have been enormous advances in its treatment.

Authors of a 2021 review explain that the treatment of ALL has drastically improved outcomes in the last 40 years.

Before the year 1990, the overall 5-year survival rate for this condition was 51%. Since 2010, this has increased to 72%. The survival rates for children up to 14 years of age have improved from 73% to 93% in the same time frame.

The survival rate refers to the proportion of people who are still alive for a length of time after receiving a particular diagnosis. For example, a 5-year survival rate of 50% means that 50%, or half, of the people are still alive 5 years after receiving the diagnosis.

It is important to remember that these figures are estimates and are based on the results of previous studies or treatments. A person can consult a healthcare professional about how their condition is going to affect them.

Learn about leukemia survival rates by age here.

Acute leukemia occurs when leukocytes are less mature and fast-developing and become dysfunctional cells called blasts as they leave the bone marrow.

By contrast, chronic leukemia occurs when leukocytes develop more slowly, potentially taking years to cause symptoms. Chronic leukemia mostly involves more mature, functional cells and does not typically involve high numbers of blasts.

People with a diagnosis of chronic leukemia can live a normal life, and the outlook is positive.

Acute leukemia is more aggressive and develops much more quickly. However, research on treatment is quickly advancing, increasing the number of treatment options and thus improving the outlook.