Chronic myelogenous leukemia (CML) is an uncommon type of cancer of the bone marrow — the spongy tissue inside bones where blood cells are made. CML causes an increased number of white blood cells in the blood.
The term "chronic" in chronic myelogenous leukemia indicates that this cancer tends to progress more slowly than acute forms of leukemia. The term "myelogenous" (my-uh-LOHJ-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. It typically affects older adults and rarely occurs in children, though it can occur at any age.
Advances in treatment have contributed to a greatly improved prognosis for people with chronic myelogenous leukemia. Most people will achieve remission and live for many years after diagnosis.
Chronic myelogenous leukemia often doesn't cause signs and symptoms. It might be detected during a blood test.
When they occur, signs and symptoms may include:
- Bone pain
- Easy bleeding
- Feeling full after eating a small amount of food
- Feeling run-down or tired
- Weight loss without trying
- Loss of appetite
- Pain or fullness below the ribs on the left side
- Excessive sweating during sleep (night sweats)
When to see a doctor
Make an appointment with your doctor if you have any persistent signs or symptoms that worry you.
Chronic myelogenous leukemia occurs when something goes awry in the genes of your bone marrow cells. It's not clear what initially sets off this process, but doctors have discovered how it progresses into chronic myelogenous leukemia.
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.
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.
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 allows too many white blood cells to grow. Most or all of these cells 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:
- Older age
- Being male
- Radiation exposure, such as radiation therapy for certain types of cancer
Family history is not a risk factor
The mutation that leads to chronic myelogenous leukemia isn't passed from parents to children. This mutation is believed to be acquired, meaning it develops after birth.
Tests and procedures used to diagnose chronic myelogenous leukemia include:
- Physical exam. Your doctor will examine you and check such vital signs as pulse and blood pressure. He or she will also feel your lymph nodes, spleen and abdomen to determine whether they are enlarged.
- Blood tests. A complete blood count may reveal abnormalities in your blood cells, such as a very high number of white blood cells. Blood chemistry tests to measure organ function may also reveal abnormalities that can help your doctor make a diagnosis.
- Bone marrow tests. Bone marrow biopsy and bone marrow aspiration are used to collect bone marrow samples for laboratory testing. These tests involve collecting bone marrow from your hipbone.
- Tests to look for the Philadelphia chromosome. Specialized tests, such as fluorescence in situ hybridization (FISH) analysis and the polymerase chain reaction (PCR) test, analyze blood or bone marrow samples for the presence of the Philadelphia chromosome or the BCR-ABL gene.
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:
- Chronic. The chronic phase is the earliest phase and generally has the best response to treatment.
- Accelerated. The accelerated phase is a transitional phase when the disease becomes more aggressive.
- Blast. Blast phase is a severe, aggressive phase that becomes life-threatening.
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, treatment begins with targeted drugs that may help achieve a long-term remission of the disease.
Targeted drug therapy
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:
- Imatinib (Gleevec)
- Dasatinib (Sprycel)
- Nilotinib (Tasigna)
- Bosutinib (Bosulif)
- Ponatinib (Iclusig)
Targeted drugs are the initial treatment for people diagnosed with chronic myelogenous leukemia. Side effects of these targeted drugs include swelling or puffiness of the skin, nausea, muscle cramps, fatigue, diarrhea and skin rashes.
Blood tests to detect the presence of the BCR-ABL gene are used to monitor the effectiveness of targeted drug therapy. If the disease doesn't respond or becomes resistant to targeted therapy, doctors may consider other targeted drugs, such as omacetaxine (Synribo), or other treatments.
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 show remission of the disease. In certain situations, you and your doctor might consider stopping treatment with targeted drugs after considering the benefits and risks.
Bone marrow transplant
A bone marrow transplant, also called a stem cell 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 bone marrow transplants have risks and carry a high rate of serious complications.
During a bone marrow 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 are infused into your bloodstream. The new cells form new, healthy blood cells to replace the diseased cells.
Chemotherapy is a drug treatment that kills fast-growing cells in the body, including leukemia cells. Chemotherapy drugs are sometimes combined with targeted drug therapy to treat aggressive chronic myelogenous leukemia. Side effects of chemotherapy drugs depend on what drugs you take.
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 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:
- Talk to your doctor about your side effects. Powerful cancer medications can cause many side effects, but those side effects often can be managed with other medications or treatments. You don't necessarily have to tough them out.
- Don't stop treatment on your own. If you develop unpleasant side effects, such as skin rashes or fatigue, don't simply quit your medication without consulting your health care professionals. Likewise, don't stop taking your medications if you feel better and think your disease may be gone. If you stop taking medication, your disease can quickly and unexpectedly return, even if you've been in remission.
- Ask for help if you're having trouble coping. Having a chronic condition can be emotionally overwhelming. Tell your doctor about your feelings. Ask for a referral to a counselor or other specialist with whom you can talk.
No alternative medicines have been found to treat chronic myelogenous leukemia. But alternative medicine may help you cope with fatigue, which is commonly experienced by people with chronic myelogenous leukemia.
You might experience fatigue as a symptom of your disease, a side effect of treatment or as part of the stress that comes with living with a chronic condition. Your doctor can treat fatigue by controlling the underlying causes, but often medications alone aren't enough.
You may find relief through alternative therapies, such as:
- Journal writing
- Relaxation techniques
Talk to your doctor about your options. Together you can devise a plan to help you cope with fatigue.
Chronic myelogenous leukemia often is a chronic disease and requires long-term treatments. To help you cope with your cancer journey, try to:
Learn enough about chronic myelogenous leukemia to make decisions about your care. The term "leukemia" can be confusing, because it refers to a group of cancers that affect the bone marrow and blood. Don't waste time gathering information that doesn't apply to your kind of leukemia.
Ask your health care professionals to write down information about your specific disease. Then narrow your search and seek out only trusted, reputable sources, such as the Leukemia & Lymphoma Society.
- Turn to family and friends for support. Stay connected to family and friends for support. It can be tough to talk about your diagnosis, and you'll likely get a range of reactions when you share the news. But talking about your diagnosis and passing along information about your cancer can help. So can the offers of practical help that often result.
- Connect with other cancer survivors. Consider joining a support group, either in your community or on the internet. A support group of people with the same diagnosis can be a source of useful information, practical tips and encouragement.
Start by making an appointment with your family doctor 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
- Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance, such as restrict your diet.
- Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
- Write down key personal information, including any major stresses or recent life changes.
- Make a list of all medications, vitamins or supplements that you're taking.
- Consider taking a family member or friend along. Sometimes it can be difficult to take in all the information provided during an appointment. Someone who accompanies you may remember something that you missed or forgot.
- Write down questions to ask your doctor.
Your time with your doctor is limited, so preparing a list of questions will help make the most of your time together. List questions from most important to least important in case time runs out. For chronic myelogenous leukemia, some basic questions to ask your doctor include:
- Can you explain what my test results mean?
- Do you recommend any other tests or procedures?
- What is the phase of my CML?
- What are my treatment options?
- What side effects are likely with each treatment?
- How will treatment affect my daily life?
- Which treatment options do you think are best for me?
- How likely is it that I'll achieve remission with the treatments you recommend?
- How quickly must I make a decision on my treatment?
- Should I get a second opinion from a CML specialist? What will that cost, and will my insurance cover it?
- Are there brochures or other printed material that I can take with me? What websites do you recommend?
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask other questions that occur to you.
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may allow time later to cover other points you want to address. Your doctor may ask:
- When did you first begin experiencing symptoms?
- Have your symptoms been continuous or occasional?
- How severe are your symptoms?
- What, if anything, seems to improve your symptoms?
- What, if anything, appears to worsen your symptoms?