Acute and Chronic Leukemia: What Are the Differences?

Medically reviewed by Deborah Weatherspoon, Ph.D, MSN, RN, CRNA on July 8, 2016Written by Marjorie Hecht on July 8, 2016

Overview

Leukemia is a cancer of the blood. It forms when blood cells in the bone marrow malfunction and form cancerous cells. The cancerous blood cells then overrun the normal blood cells. This interferes with the body's ability to fight infections, control bleeding, and deliver oxygen to normal cells. The cancerous cells can also invade the spleen, liver, and other organs.

Chronic leukemia is a slow-growing leukemia. Acute leukemia is a fast-growing leukemia that progresses quickly without treatment.

Learn more: Leukemia »

Signs and symptoms

Signs and symptoms of chronic leukemia

Chronic leukemia develops slowly, and the early symptoms may be mild and go unnoticed. Acute leukemia develops quickly. This is because the cancerous cells multiply fast.

Chronic leukemia is most commonly diagnosed after a routine blood test. You may have low-level symptoms for years before it’s diagnosed. The symptoms may be vague and could occur due to many other medical conditions. The signs and symptoms may include:

  • general feelings of malaise, such as tiredness, bone and joint pain, or shortness of breath
  • weight loss
  • a loss of appetite
  • a fever
  • night sweats
  • anemia
  • infections
  • bruising or bleeding, such as nosebleeds
  • enlarged lymph nodes that aren’t painful
  • pain or a full feeling in the upper-left abdomen, which is where the spleen is located

Signs and symptoms of acute leukemia

The common signs and symptoms of acute leukemia are:

  • low white blood cell counts
  • infections
  • tiredness that doesn't go away with rest
  • shortness of breath
  • pale skin
  • sweating at night
  • a slight fever
  • bruising easily
  • bone and joint aches
  • slow healing of cuts
  • tiny red dots under the skin

Learn more: Symptoms of leukemia in pictures »

Causes

No one knows the cause of leukemia or why some people have chronic leukemia and others have an acute form of the condition. Both environmental and genetic factors are thought to be involved.

Leukemia may occur due to changes in the DNA of your cells. Chronic myeloid leukemia (CML) may also be associated with a gene mutation called the Philadelphia chromosome. This gene mutation isn’t inherited.

Some studies show that a combination of genetic and environmental factors are involved in childhood leukemia. Some children may not have inherited the particular version of genes that can get rid of harmful chemicals. Exposure to those chemicals might increase their risk for leukemia.

Risk factors

Possible risk factors for the different types of leukemia exist, but it’s possible to get leukemia even if you don’t have any of the known risk factors. Experts still don’t understand a lot about leukemia.

Some factors for developing chronic leukemia include:

  • being over age 60
  • being Caucasian
  • exposure to chemicals such as benzene or Agent Orange
  • exposure to high levels of radiation

Some risk factors for developing acute leukemia include:

  • smoking cigarettes
  • having chemotherapy and radiation therapy for other cancers
  • exposure to very high radiation levels
  • having genetic abnormalities, such as Down syndrome
  • having a sibling with acute lymphocytic leukemia (ALL)

Having one or more of these risk factors doesn’t mean that you’ll get leukemia.

How is leukemia diagnosed?

All types of leukemia are diagnosed by examining blood samples and bone marrow. A complete blood count will show the levels and types of:

  • white cells
  • leukemia cells
  • red cells
  • platelets

Bone marrow and other tests will give your doctor further information about your blood to confirm a diagnosis of leukemia. Your doctor may also look at a blood smear under a microscope to see the shape of the cells. Other tests may grow your blood cells to help your doctor identify changes to the chromosomes or genes.

Treatments

Your treatment plan will depend on the type of leukemia you have and how advanced it is at the time of your diagnosis. You may want to get a second opinion before starting treatment. It's important to understand what your treatment choices are and what you can expect.

Chronic leukemia

Chronic leukemia progresses slowly. You may not be diagnosed until symptoms, such as enlarged lymph nodes, appear. Chemotherapy, corticosteroids, and monoclonal antibodies may be used to control the cancer. Your doctor may use blood transfusions and platelet transfusions to treat the decrease in red blood cells and platelets. Radiation may help reduce the size of your lymph nodes.

If you have CML and also have the Philadelphia chromosome, your doctor may treat you with tyrosine kinase inhibitors (TKIs). TKIs block the protein produced by the Philadelphia chromosome. They may also use stem cell therapy to replace cancerous bone marrow with healthy bone marrow.

Acute leukemia

People with acute leukemia will generally begin treatment quickly following a diagnosis. This is because the cancer can progress quickly. Treatment may include chemotherapy, targeted therapy, or stem cell therapy, depending on the type of acute leukemia you have.

The treatment for acute leukemia is generally very intense in the beginning. The main goal of treatment is to kill the leukemia cells. Hospitalization is sometimes necessary. The treatment often causes side effects.

Your doctor will do regular blood and bone marrow tests to determine how well your treatment is killing the leukemia cells. They may try various mixtures of drugs to see what works best.

Once your blood has returned to normal, your leukemia will be in remission. Your doctor will continue to test you in case the cancerous cells return.

What is the outlook?

Each type of leukemia is different and will require different treatment. The outlook is also unique to the type of leukemia you have and how advanced it is when you begin treatment. Other factors that will affect your outlook are:

  • your age
  • your general health
  • how much the leukemia has spread in your body
  • how well you respond to treatment

Survival rates for leukemia have greatly improved in the last 50 years. New drugs and new types of treatments continue to be developed.

Your doctor will give you your outlook based on leukemia research findings from the past years. These statistics are based on people who had your type of leukemia, but each person is different. Try not to focus too much on these types of statistics if you receive a diagnosis of leukemia. Your outlook will depend on your age, your overall health, and the stage of your leukemia. The following were the five-year survival rates for people with different types of leukemia in the United States from 2005 to 2011:

  • CML: 63.2 percent
  • CLL: 84.8 percent
  • ALL: 70.1 percent overall and 91.2 percent for those under 15
  • AML, or acute myeloid leukemia: 26 percent overall and 66.5 percent for those under 15

The outlook for people with any type of leukemia will continue to improve as the research advances. Researchers in many ongoing clinical trials are testing new treatments for each type of leukemia.

Prevention

No early screening tests for leukemia are available. If you have risk factors and symptoms, ask your doctor about blood tests.

It's important to keep copies of your treatments, the dates, and the drugs that were used. These will help you and your future doctors if your cancer comes back.

Experts haven’t found ways to prevent leukemia. Being proactive and telling your doctor if you notice any symptoms of leukemia may improve your chances of recovery.

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