Chronic myeloid leukemia (CML) is a type of blood cancer. It can affect a person’s red blood cell and platelet count and can also cause a person’s white blood cells to function incorrectly.

CML is also known as chronic myelogenous leukemia. It can cause a person to become anemic, and may put them at risk of certain infections.

According to the American Cancer Society, 15% of new leukemia cases are CML. It also states that around 1 out of every 526 people in the United States will develop CML in their lifetime.

CML is a type of cancer that begins in certain blood-forming cells in the bone marrow. These cells are called myeloid cells. They make red blood cells, platelets, and most types of white blood cells (excluding lymphocytes).

When a person has CML, a genetic change will take place in early or immature myeloid cells. This causes an abnormal gene to form called BCR-ABL. This gene turns the myeloid cell into a CML cell.

These leukemia cells can then divide and grow and can build up inside a person’s bone marrow. They can then spill over into the person’s bloodstream and spread around the body.

In this article, we look at the history of CML in medicine and the current treatments available for CML.

Rudolf Virchow observing an operation in Paris, 1900.Share on Pinterest
Rudolf Virchow observing an operation in Paris, France, in 1900. Bettmann/Getty Images

Medical professionals first recognized people with enlarged spleens and abnormally high leukocyte counts in France, Germany, and Scotland in the 1840s.

In 1845 in Edinburgh, Scotland, pathologist John Hughes Bennett reported a case of a person who died who had an enlarged spleen and liver, citing the cause of death as “suppuration of the blood.” Not long after, Rudolf Virchow published a very similar case in Berlin. These two cases may be the earliest descriptions of the disease.

Bennet believed that the patient had an infection. However, Virchow stated that he believed the patient had a neoplastic disorder that he called white blood disease or leukemia.

According to the American Cancer Society, chemotherapy with cytotoxic drugs was once a very common treatment for CML. However, the development of newer approaches means that doctors now use it less frequently for treating CML.

Doctors will often choose to use chemotherapy once other treatment options have stopped working.

Cytotoxic drugs enter the bloodstream and can travel all around the body. This is useful when treating CML because leukemia cells can spread throughout the body.

These cytotoxic drugs mostly kill cells that are growing and rapidly dividing. However, this means that the drugs can also attack a range of normal cells that also rapidly divide, including:

  • cells in the bone marrow
  • cells in the mouth lining
  • cells in the intestines
  • cells in the hair follicles

This can cause a number of side effects, including:

  • hair loss
  • mouth sores
  • loss of appetite
  • nausea
  • vomiting
  • leukopenia
  • thrombocytopenia
  • anemia

Medical professionals sometimes use hydroxyurea (Hydrea) to treat CML. A person takes this drug as a pill, and it can lower very high white blood cell counts and help shrink a person’s enlarged spleen.

Other cytotoxic drugs approved to treat CML include:

  • cytarabine (Ara-C)
  • busulfan
  • cyclophosphamide (Cytoxan)
  • vincristine (Oncovin)
  • omacetaxine (Synribo)

Stem cell transplants also were once a common treatment option for people with CML. However, since the development of more modern treatments, they are now less common.

Stem cells are able to transform into most other types of cells present in the human body.

Stem cells in the bone marrow make red blood cells, white blood cells, and platelets. This is useful in treating CML, as people with CML can have low numbers of these cells or damaged cells.

Before a stem cell transplant takes place, a person will receive high doses of chemotherapy to kill the leukemia cells. They may also receive a low dose of radiation therapy. These treatments may also damage regular bone marrow cells.

The person will then receive a stem cell transplant. During this procedure, a doctor injects healthy stem cells into the bone marrow or blood. These cells then restore the person’s ability to create new blood cells.

A person may receive stem cells from their own blood or bone marrow, or from someone else’s.

CML cells contain the abnormal gene BCR-ABL. This gene makes the protein BCR-ABL, which causes the CML cells to grow and spread. This protein is also known as a tyrosine kinase.

Tyrosine kinase inhibitors (TKIs) are able to target that protein and inhibit the spread of cancer cells.

Common TKIs include:

These drugs do not tend to make the CML go away permanently. Some people may need to take them for the rest of their life.

Many people respond well to this treatment, and some are able to stop taking the drugs or lower their dose.

People take TKIs in pill form, and they should take them exactly as their doctor has ordered for the best outcomes. If a person skips some doses, or adjusts them, this may affect the way the drugs work.

TKIs can also interact with some other drugs, as well as certain foods. A person should always inform their doctor if they are taking any:

  • other prescription medications
  • over-the-counter (OTC) drugs
  • vitamins
  • herbal supplements

TKIs can also harm a fetus if a pregnant person takes them.

Side effects of TKIs vary depending on which specific drug a person is taking. Common side effects include:

Rare side effects include:

  • fluid build-up around the eyes, feet, or abdomen
  • fluid build-up in the lungs or around the heart
  • lowered white blood cell count
  • lowered platelet count
  • prolonged QT syndrome, which affects the rhythm of the heart
  • pulmonary arterial hypertension, which is high blood pressure in the lungs’ arteries
  • blood clots

If a person believes they are experiencing side effects after taking TKIs, they should speak to their doctor right away.

Roughly half the people with CML do not have any symptoms, meaning medical professionals can only diagnose them through a routine complete blood count.

Many symptoms of CML are similar to the symptoms of other cancers, including:

  • weakness and fatigue
  • night sweats
  • weight loss
  • fever
  • painful bones
  • enlarged spleen
  • stomach pain
  • a sense of “fullness” in the stomach
  • feeling full even after eating small amounts of food

These symptoms can be vague and make diagnosis difficult.

CML causes leukemia cells to replace the normal blood-making cells. This means that the person cannot make enough red blood cells or platelets and that their white blood cells may not function properly.

This can cause a number of problems, including:

  • Anemia: This is a shortage of red blood cells and can cause a person to feel weak, tired, and get short of breath.
  • Leukopenia: This is a shortage of white blood cells and can increase a person’s risk of infections. The person may have a high white blood cell count, but these cells do not function properly and do not defend against infection in the same way regular white blood cells do.
  • Neutropenia: This means that the level of working neutrophils is low. Neutrophils are a type of white blood cell that is important in fighting off bacterial infections. A person with neutropenia is at a higher risk of getting serious bacterial infections.
  • Thrombocytopenia: This is a shortage of blood platelets. This can cause a person to bruise easily or have frequent bleeding such as nosebleeds or bleeding gums. Some people with CML may have too many blood platelets, which do not function properly, so the same symptoms of bruising and bleeding still arise.

In people with chronic leukemias, such as CML, problems can take a long time to arise. This means that most people can live for a number of years with CML.

However, chronic leukemias are generally more difficult to cure than acute leukemias.

Chronic myeloid leukemia (CML) is a type of cancer that affects blood-forming cells in the blood and bone marrow. This can cause a person to produce fewer red blood cells and platelets. CML may also cause a person’s white blood cells to not function correctly.

The leukemia cells can divide and spread throughout a person’s body via their bloodstream.

Common symptoms of CML are similar to those of many other types of cancer. This includes fatigue, weakness, weight loss, and fever.

However, a person may also experience symptoms associated with a lack of red blood cells or platelets, and the abnormality of their white blood cells. These symptoms include anemia, leukopenia, neutropenia, and thrombocytopenia.

The most common treatment for CML is the use of tyrosine kinase inhibitors. Other treatment options include chemotherapy and stem cell transplants.