Chronic myeloid leukemia (CML) is a type of blood cancer that people may also refer to as chronic myelogenous leukemia. Doctors diagnose the stage of CML based on the number of leukemia cells, or blast cells, present in the blood.

Leukemia develops when immature blood cells change and grow incorrectly. CML occurs when there are too many white blood cells forming.

This article looks at the diagnostic criteria and tests for CML. It also discusses the possible symptoms of CML and the treatment options.

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Up to 50% of people with CML are asymptomatic, meaning that they have no symptoms, and only receive a diagnosis after a routine blood exam.

Healthcare professionals can confirm a diagnosis of CML using the results of a complete blood count (CBC) test. This test measures the number of red blood cells, platelets, and white blood cells present in a sample of a person’s blood.

The Leukemia & Lymphoma Society notes that those with CML will have:

  • an increased white blood cell count
  • a decreased red blood cell count
  • an increase or decrease in platelet numbers, depending on the severity of CML

The CBC should also include a differential, which measures the different types of white blood cells.

A person with CML will have increased levels of a type of white blood cell called granulocytes, along with an increase in immature white blood cells.

In CML, the white blood cells partially mature and, therefore, look relatively normal. However, they typically do not fight infection as well as their noncancerous counterparts. Also, they tend to live longer, which means that they overcrowd the normal cells in the bone marrow.

Genetic testing

Following the CBC, healthcare professionals may perform genetic tests to look for the BCR-ABL gene, which is a fusion gene, and a type of genetic mutation known as the Philadelphia chromosome.

The tests include the following:

  • Conventional cytogenetics: This test looks for the Philadelphia chromosome, which is present in more than 95% of people with CML.
  • Fluorescent in situ hybridization (FISH): FISH uses fluorescent dyes that attach to specific genes or parts of the chromosomes. It can help locate sections of the BCR-ABL gene.
  • Polymerase chain reaction (PCR): This is a sensitive test that can detect small amounts of BCR-ABL if healthcare professionals are unable to find the Philadelphia chromosome.

The National Cancer Institute (NCI) states that CML develops slowly and has three phases of development: chronic, accelerated, and blastic.

Healthcare professionals will look at the number of leukemia cells, or blast cells, in the blood to determine which stage a person has reached.

Most people will receive a diagnosis during the chronic phase.

Not all doctors agree on where the cut-offs are for each phase, but according to the NCI, the phases are as follows:

  • Chronic phase: Fewer than 10% of the cells in a person’s blood or bone marrow sample are blast cells. At this point, a person will have mild or no symptoms.
  • Accelerated phase: In this phase, 10–19% of the cells in the blood or bone marrow are blast cells. A person may experience weight loss, bone pain, tiredness, sweating, and a high temperature during the night.
  • Blastic phase: At least 20% of the cells in the blood and bone marrow are blast cells. If this number reaches more than 30%, healthcare professionals call this a blast crisis. A person in this phase may experience tiredness, fever, and an enlarged spleen.

Alongside a CBC test and genetic testing, a person may have to undergo the following diagnostic tests:

Bone marrow samples

As leukemia begins in the bone marrow, a healthcare professional will test the bone marrow for leukemia cells. They will perform two tests at the same time: a bone marrow aspiration and a bone marrow biopsy.

A healthcare professional will remove bone marrow, blood, and a small piece of bone from the hip or breastbone. They will numb the area before both procedures, but some pain or discomfort may still occur.

A bone marrow aspiration involves the insertion of a hollow needle through the bone and into the bone marrow. The healthcare professional will then use the syringe to withdraw a small amount of liquid bone marrow.

A bone marrow biopsy requires a wider needle to remove a small part of the bone alongside the marrow.

Imaging tests

Imaging tests allow healthcare professionals to look at a person’s spleen or other organs, helping them diagnose CML.

Imaging tests that aid the diagnosis of CML include:

In some cases, X-rays may be useful to rule out other health conditions.

According to the NCI, there are six main types of treatment for CML:

  • Targeted therapy: This attacks specific cells without causing as much harm to regular healthy cells.
  • Chemotherapy: Chemotherapy can either kill the cancer cells or stop them from dividing further.
  • Immunotherapy: This treatment uses a person’s immune system to attack the cancer cells.
  • High dose chemotherapy with stem cell transplant: A person receives chemotherapy in combination with donor stem cells.
  • Donor lymphocyte infusion (DLI): This procedure involves the transfusion of a type of white blood cell called a lymphocyte into the person with CML.
  • Surgery: A person may require surgery to remove their spleen.

Learn more about the treatment options for each stage of CML.

Receiving a cancer diagnosis can be stressful for both the individual and their loved ones, and it may necessitate certain lifestyle changes.

As well as regularly speaking about their treatment and outlook with specialist doctors and other healthcare professionals, people can reach out to friends and family for support.

They may also wish to consider attending counseling or joining support groups to discuss their feelings in a more in-depth way.

The NCI offers a variety of resources for coping with a diagnosis of cancer or leukemia. The American Cancer Society also provides a wide range of advice for the same purpose.

A person can find out more about how to pay for cancer treatment using resources from the following organizations:

Some people with CML may receive a diagnosis during a routine blood test before they show any symptoms.

In other cases, a person may experience various symptoms, including:

  • fatigue
  • dizziness
  • shortness of breath
  • more frequent infections
  • fever
  • enlarged spleen
  • bone pain
  • night sweats
  • unexplained weight loss

If a person with CML is symptomatic, they may confuse the symptoms as being due to other, milder conditions, such as the flu.

As a result, anyone experiencing any of the above symptoms may wish to consider getting a blood test.

Chronic myeloid leukemia is a type of blood cancer that may not produce any symptoms until it has progressed to more advanced stages.

Healthcare professionals typically diagnose CML during a routine blood test.

If a person has CML, they will have an elevated white blood cell count, a decreased red blood cell count, and either an increase or decrease in platelet count.

Healthcare professionals will then confirm the diagnosis using genetic testing to look for the Philadelphia chromosome or the BCR-ABL gene.

Regular medical checkups are important for allowing healthcare professionals to detect any irregularities in the blood as soon as possible.