Most people with chronic myeloid leukemia have the Philadelphia chromosome. It’s an abnormal chromosome that’s made when parts of two chromosomes swap places with each other. This produces a new gene called BCR-ABL.
The gene change causes too many immature white blood cells called blasts to multiply in the bone marrow and blood. These abnormal cells crowd out healthy blood cells and can spread to other parts of the body. The lack of healthy blood cells leads to symptoms like tiredness, bleeding, anemia, and infections.
As you consider your treatment options for chronic myeloid leukemia, there are a few things you should know.
Chronic myeloid leukemia is different from acute myeloid leukemia (AML). While chronic myeloid leukemia grows slowly, acute myeloid leukemia develops very quickly. You could live with chronic myeloid leukemia for many years without having any symptoms or medical issues. However, in rare cases, CML can turn into AML.
2. Chronic myeloid leukemia has three phases
Doctors categorize CML into three phases based on how many abnormal white blood cells called blasts are in the blood and bone marrow. Knowing your phase will help your doctor find the right treatment and predict your outlook.
- Chronic phase: Less than 10% of cells in the blood or bone marrow are blasts.
- Accelerated phase: Between 10% to 19% of cells in the blood and bone marrow are blasts.
- Blast phase: Abnormal blood cells make up 20% or more of cells in the blood and bone marrow.
3. Tyrosine kinase inhibitors (TKIs) are the main treatment
TKIs are targeted drugs. They block a protein called tyrosine kinase that helps the cancer cells multiply. Bosutinib (Bosulif), dasatinib (Sprycel), imatinib (Gleevec), and nilotinib (Tasigna) are approved TKI inhibitors for chronic myeloid leukemia. These medications come as a tablet or capsule that you take by mouth once or twice per day. If the first TKI you try does not work or you have side effects that you cannot tolerate, your doctor can increase the dose or switch you to a different medication in this class.
4. Additional treatments are available
If chronic myeloid leukemia does not respond to a TKI inhibitor or it stops responding, you can talk with your healthcare team about trying another type of treatment. One possibility is interferon, a drug that stops leukemia cells from growing and dividing. Another option is chemotherapy — strong medications that prevent cancer cells from dividing and kills them. A stem cell transplant replaces the abnormal blood-forming cells in your blood and bone marrow with healthy blood cells from a donor.
5. Your doctor will monitor treatment progress
You’ll have regular checkups to see how you’re responding to the medication. One test is called polymerase chain reaction (PCR). It shows how much of the BCR-ABL gene you have. Your bone marrow will also be tested for the Philadelphia chromosome.
According to the Leukemia & Lymphoma Society, your doctor will likely monitor you every 3 months for the first 2 years and then every 3 to 6 months after that to make sure your chronic myeloid leukemia is well managed.
6. Taking your medication can improve your outlook
The ACS reports that most people have a complete cytogenic response (CCyR) within 1 year of starting a TKI. CCyR means your blood cell count is back to normal, and there are no blasts in your blood. It’s not the same thing as a cure. You may need to stay on a TKI inhibitor long term.
Research indicates that people who take all their medication as prescribed have better outcomes and are less likely to relapse than those who skip doses or stop the medicine entirely.
7. You can always join a clinical trial
Clinical trials are how researchers test the safety and effectiveness of new CML medications or drug combinations. Joining one of these studies could let you try a new and possibly more effective medication than what’s currently available. You can take part in a clinical trial at any stage of your treatment. Ask your doctor if any studies that are underway are a good match for you.