Filed under: Cancer & Chemo
Chronic myelogenous leukemia (CML) is an uncommon type of cancer of the blood cells. The term "chronic" in chronic myelogenous leukemia indicates that this cancer tends to progress more slowly than acute forms of leukemia. The term "myelogenous" (mi-uh-LOJ-uh-nus) in chronic myelogenous leukemia refers to the type of cells affected by this cancer.
Chronic myelogenous leukemia can also be called chronic myeloid leukemia and chronic granulocytic leukemia. Chronic myelogenous leukemia typically affects older adults and rarely occurs in children, though it can occur at any age.
Signs and symptoms of chronic myelogenous leukemia may include:
When to see a doctor
Chronic myelogenous leukemia doesn't always reveal itself with obvious signs and symptoms during the early phase. It's possible to live with chronic myelogenous leukemia for months or years without realizing it.
Because people with chronic myelogenous leukemia tend to respond better to treatment when it's started early, make an appointment with your doctor if you have signs or symptoms that bother you.
Chronic myelogenous leukemia occurs when something goes awry in the genes of your blood cells. It's not clear what initially sets off this process, but doctors have discovered how it progresses into chronic myelogenous leukemia.
First, an abnormal chromosome develops
Human cells normally contain 23 pairs of chromosomes. These chromosomes hold the DNA that contains the instructions (genes) that control the cells in your body. In people with chronic myelogenous leukemia, the chromosomes in the blood cells swap sections with each other. A section of chromosome 9 switches places with a section of chromosome 22, creating an extra-short chromosome 22 and an extra-long chromosome 9.
The extra-short chromosome 22 is called the Philadelphia chromosome, named for the city where it was discovered. The Philadelphia chromosome is present in the blood cells of 90 percent of people with chronic myelogenous leukemia.
Second, the abnormal chromosome creates a new gene
The Philadelphia chromosome creates a new gene. Genes from chromosome 9 combine with genes from chromosome 22 to create a new gene called BCR-ABL. The BCR-ABL gene contains instructions that tell the abnormal blood cell to produce too much of a protein called tyrosine kinase. Tyrosine kinase promotes cancer by allowing certain blood cells to grow out of control.
Third, the new gene allows too many diseased blood cells
Your blood cells originate in the bone marrow, a spongy material inside your bones. When your bone marrow functions normally, it produces immature cells (blood stem cells) in a controlled way. These cells then mature and specialize into the various types of blood cells that circulate in your body — red cells, white cells and platelets.
In chronic myelogenous leukemia, this process doesn't work properly. The tyrosine kinase caused by the BCR-ABL gene causes too many white blood cells. Most or all of these contain the abnormal Philadelphia chromosome. The diseased white blood cells don't grow and die like normal cells. The diseased white blood cells build up in huge numbers, crowding out healthy blood cells and damaging the bone marrow.
Factors that increase the risk of chronic myelogenous leukemia:
Family history is not a risk factor
The chromosome mutation that leads to chronic myelogenous leukemia isn't passed from parents to offspring. This mutation is believed to be acquired, meaning it develops after birth.
Chronic myelogenous leukemia (CML) can cause a variety of complications, including:
Start by making an appointment with your family doctor or a general practitioner if you have any signs or symptoms that worry you. If blood tests or other tests and procedures suggest leukemia, your doctor may refer you to a specialist in the treatment of blood and bone marrow diseases and conditions (hematologist).
Because appointments can be brief, and because there's often a lot of ground to cover, it's a good idea to be well prepared. Here's some information to help you get ready, and what to expect from your doctor.
What you can do
Your time with your doctor is limited, so preparing a list of questions will help you make the most of your time together. List your questions from most important to least important in case time runs out. For chronic myelogenous leukemia, some basic questions to ask your doctor include:
What you can do in the meantime
Avoid anything that makes your symptoms worse. For instance, if you're feeling fatigued, rest as much as possible. Focus on only the essential tasks of each day. The nonessential tasks can wait for a later day.
If you're having trouble eating because you feel full very quickly, choose smaller, more frequent meals. Consider sipping a nutritional supplement shake. These high-calorie shakes can help you temporarily to get the calories and nutrition you need if eating is uncomfortable.
Tests and procedures used to diagnose chronic myelogenous leukemia include:
Phases of chronic myelogenous leukemia
The phase of chronic myelogenous leukemia refers to the aggressiveness of the disease. Your doctor determines the phase by measuring the proportion of diseased cells to healthy cells in your blood or bone marrow. A higher proportion of diseased cells means chronic myelogenous leukemia is at a more advanced stage.
Phases of chronic myelogenous leukemia include:
The goal of chronic myelogenous leukemia treatment is to eliminate the blood cells that contain the abnormal BCR-ABL gene that causes the overabundance of diseased blood cells. For most people, it's not possible to eliminate all diseased cells, but treatment can help achieve a long-term remission of the disease.
Targeted drugs are designed to attack cancer by focusing on a specific aspect of cancer cells that allows them to grow and multiply. In chronic myelogenous leukemia, the target of these drugs is the protein produced by the BCR-ABL gene — tyrosine kinase. Targeted drugs that block the action of tyrosine kinase include:
Targeted drugs are the initial treatment for most people diagnosed with chronic myelogenous leukemia. If the disease doesn't respond or becomes resistant to the first targeted drug, doctors may consider other targeted drugs or other treatments. Side effects of these targeted drugs include swelling or puffiness of the skin, nausea, muscle cramps, rash, fatigue, diarrhea, and skin rashes.
Doctors haven't determined a safe point at which people with chronic myelogenous leukemia can stop taking targeted drugs. For this reason, most people continue to take targeted drugs even when blood tests reveal a remission of chronic myelogenous leukemia.
Blood stem cell transplant
A blood stem cell transplant, also called a bone marrow transplant, offers the only chance for a definitive cure for chronic myelogenous leukemia. However, it's usually reserved for people who haven't been helped by other treatments because blood stem cell transplants have risks and carry a high rate of serious complications.
During a blood stem cell transplant, high doses of chemotherapy drugs are used to kill the blood-forming cells in your bone marrow. Then blood stem cells from a donor or your own cells that were previously collected and stored are infused into your bloodstream. The new cells form new, healthy blood cells to replace the diseased cells.
Chemotherapy drugs are typically combined with other treatments for chronic myelogenous leukemia. Often, chemotherapy treatment for chronic myelogenous leukemia is given as a tablet you take by mouth. Side effects of chemotherapy drugs depend on what drugs you take.
Biological therapies harness your body's immune system to help fight cancer. The biological drug interferon is a synthetic version of an immune system cell. Interferon may help reduce the growth of leukemia cells. Interferon may be an option if other treatments don't work or if you can't take other drugs, such as during pregnancy. Side effects of interferon include fatigue, fever, flu-like symptoms and weight loss.
Clinical trials study the latest treatment for diseases or new ways of using existing treatments. Enrolling in a clinical trial for chronic myelogenous leukemia may give you the chance to try the latest treatment, but it can't guarantee a cure. Talk to your doctor about what clinical trials are available to you. Together you can discuss the benefits and risks of a clinical trial.
For many people, chronic myelogenous leukemia is a chronic disease they will live with for years. Many will continue treatment with imatinib indefinitely. Some days, you may feel sick even if you don't look sick. And some days, you may just be sick of having cancer. Self-care measures to help you adjust and cope with a chronic illness include:
No alternative medicines have been found to treat chronic myelogenous leukemia. But alternative medicine may help you cope with the stress of a chronic condition and the side effects of cancer treatment. Talk to your doctor about your options, such as:
Chronic myelogenous leukemia often is a chronic disease and requires long-term treatments. To help you cope with your cancer journey, try to: