Chronic Myelogenous Leukemia (CML)


What is chronic myelogenous leukemia?

Chronic myelogenous leukemia (CML) is type of cancer that starts in the blood-forming cells of your bone marrow. The term “chronic” means that this cancer usually grows slower compared to acute myeloid leukemia (AML). “Myelogenous” refers to the type of cells affected by this type of cancer. The condition is sometimes called chronic myeloid leukemia or chronic granulocytic leukemia.

Who does chronic myelogenous leukemia affect?

CML usually affects older adults. However, it can occur in people of all ages.

How common is chronic myelogenous leukemia?

Statistically, one in 526 people will develop CML in their lifetime. Chronic myelogenous leukemia accounts for about 15% of all new leukemia cases in the United States.

How does chronic myelogenous leukemia develop?

CML starts due to a specific change in the bone marrow stem cell. Specifically, CML cancer cells contain an abnormal gene called BCR-ABL. This gene creates a protein that causes the cancer cells to grow out of control. As a result, the bone marrow produces too many granulocytes (a type of white blood cells). Over time, blasts — or immature white blood cells — accumulate. This makes it difficult for your bone marrow to produce normal red blood cells, white blood cells and platelets.

What’s the difference between chronic myelogenous leukemia (CML) and chronic lymphocytic leukemia (CLL)?

Both CML and CLL are cancers of the blood and bone marrow. The difference between the two is due to where the cancer cells originate. While chronic myelogenous leukemia starts in the myeloid stem cells, chronic lymphocytic leukemia (CLL) starts in the lymphoid stem cells.

Symptoms and Causes

What are common chronic myelogenous leukemia symptoms?

In most cases, CML doesn’t cause any symptoms. When warning signs occur, they may include:

  • Fever.
  • Bone pain.
  • Fatigue.
  • Unexplained weight loss.
  • Easy bleeding.
  • Loss of appetite.
  • Night sweats.
  • Fullness or discomfort below the ribs on the left side, which indicates an enlarged spleen.

What causes chronic myelogenous leukemia?

Experts know that chronic myelogenous leukemia occurs when chromosomal abnormalities develop in the bone marrow. However, it’s not understood why this process begins in the first place.

Diagnosis and Tests

How is chronic myelogenous leukemia diagnosed?

CML is most commonly found during a routine blood count. If your healthcare provider suspects that you may have CML, they will order more tests to confirm your diagnosis. These tests may include:

  • A physical examination. Your healthcare provider will check your vital signs and gently press around your abdomen and lymph nodes to see if anything feels abnormal.
  • Bone marrow biopsy. Bone marrow samples are taken — often from your hip bone — and sent to a pathology lab for analysis.
  • FISH (fluorescence in situ hybridization) analysis. This test uses fluorescence to detect and locate genetic material in your cells.
  • PCR (polymerase chain reaction) test. PCR can make millions of copies of a DNA segment. This is useful when more assessments need to be performed.

What are the chronic myelogenous leukemia phases?

Chronic myelogenous leukemia is categorized into stages. Each one reflects the aggressiveness of the cancer. There are three primary chronic myelogenous leukemia phases:

  1. Chronic. People in this early phase generally have the best response to treatment.
  2. Accelerated. During this transitional phase, the cancer becomes more aggressive.
  3. Blast. The last CML phase, blast is the most severe. At this point, the disease becomes life-threatening.

Management and Treatment

How is chronic myelogenous leukemia treated?

Targeted drug therapy is usually the first line of treatment against chronic myelogenous leukemia. This approach targets the cells that contain the abnormal BCR-ABL gene. Drugs used in this type of therapy are called tyrosine kinase inhibitors (TKIs) and they include Dasatinib (Sprycel), Imatinib (Gleevec), Ponatinib (Iclusig), Bosutinib (Bosulif) and Nilotinib (Tasigna). The goal of TKIs is to achieve a long-term remission of the cancer.

Some people with chronic myelogenous leukemia may need other treatments, such as:

  • Chemotherapy. During this treatment, anti-cancer drugs are taken in pill form or given through a vein. Sometimes chemotherapy is combined with targeted drug therapy. It may also be recommended if TKIs stop working as well.
  • Interferon therapy. Interferons are substances created naturally by your immune system. Interferon therapy uses a synthetic drug (interferon alpha) which mimics the natural interferons found in your body. This helps reduce the growth of leukemia cells. Before tyrosine kinase inhibitors, interferon therapy was the best treatment available for CML.
  • Stem cell transplant. Because TKIs are the most effective treatment against CML, stem cell transplants are performed far less often these days. However, your provider may recommend a stem cell transplant if you’re not responding well to TKIs.
  • Radiation therapy. This approach isn’t usually recommended for people with CML, but it may be beneficial in certain situations. For example, individuals who undergo a stem cell transplant may receive radiation therapy beforehand to prepare their body for the procedure.
  • Though surgery isn’t an option for directly treating CML, a splenectomy may be necessary if the leukemia spreads to the spleen. When leukemia affects the spleen, it can become so enlarged that it puts excess pressure on nearby organs. It’s important to note, however, that surgery has no role in treating chronic myelogenous leukemia.

How long does it take to recover from chronic myelogenous leukemia treatment?

Length of treatment is unique to each specific case. People who are on targeted drug therapy for CML should take their medication exactly as prescribed by their healthcare provider. In most cases, people with chronic myelogenous leukemia will stay on TKIs for at least two to three years. At this point, some individuals may be able to discontinue the medication and attempt treatment-free remission. Others may need to stay on TKIs indefinitely. It’s important that you talk with your healthcare provider about what to expect in your unique situation.


Can chronic myelogenous leukemia be prevented?

No, most cases of chronic myelogenous leukemia cannot be prevented. The only risk factor for CML is exposure to high levels of radiation — and this applies to very few people.

Outlook / Prognosis

What can I expect if I have chronic myelogenous leukemia?

If you’ve been diagnosed with CML, you’ll likely be prescribed medications that will keep your cancer at bay. You should take these medications exactly as directed by your healthcare provider. Most people with CML attend frequent, routine appointments to see how well their treatment is working.

Is CML fatal?

In the past, CML was considered a deadly disease. Today, modern treatment options have significantly improved the outlook of people with CML. Before the advent of targeted drug therapy, the five-year survival rate for people with CML was only 22%. Today, the overall five-year survival rate is 90%. (This means that 90% of people diagnosed with CML are still alive five years later.) This statistical improvement is largely due to the TKIs used in targeted drug therapy.

Keep in mind that survival rates are estimates based on the outcomes of people with CML in the past. These numbers cannot tell you how long you’ll live or what to expect in your specific case. To learn more about survival rates, talk with your healthcare provider.

Living With

When should I see my healthcare provider?

If you develop symptoms, such as bone pain, fatigue, night sweats or other symptoms of CML, schedule a consultation with your healthcare provider right away. If you’re currently undergoing treatment for CML, call your provider anytime you develop new side effects. They can find ways to ease your symptoms and improve your quality of life.

What questions should I ask my healthcare provider?

If you’ve been diagnosed with CML, gaining an understanding of your situation can help you make informed decisions regarding treatment. Here are some questions to consider asking your healthcare provider:

  • What phase of chronic myelogenous leukemia do I have?
  • What are my treatment options?
  • What will my treatment feel like?
  • Will I be able to work during my treatment?
  • How often will you perform blood tests to see how my treatment is working?
  • Would a stem cell transplant be helpful in my case?
  • How common is it for CML to come back after remission?
  • Who can I talk to about managing my treatment costs?

A note from Cleveland Clinic

A CML diagnosis can be shocking, scary and frustrating. Fortunately, advanced treatment options have drastically improved the survival rate for this type of leukemia. Talking with your healthcare provider about your situation can empower you and help you take control of your health. You may also want to consider joining a local support group, which can offer mental, emotional and spiritual encouragement during this challenging time.

Last reviewed by a Cleveland Clinic medical professional on 10/04/2021.


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