Chronic myeloid (myelogenous) leukemia (CML) is blood cancer that starts in the blood-forming myeloid cells or stem cells in your bone marrow. Healthcare providers treat CML with innovative therapies that have turned CML from being a potentially life-threatening illness into a chronic illness.
Chronic myeloid leukemia (CML) is blood cancer that starts in the blood-forming myeloid cells or stem cells in your bone marrow. The condition has other names: chronic myelogenous leukemia or chronic granulocytic leukemia. Many people with CML may have normal life spans, thanks to therapy that has turned the condition from a life-threatening illness into a chronic illness that medication can manage.
CML is relatively common. About 1 in 565 people in the U.S. will develop the condition. Chronic myeloid leukemia represents about 15% of all types of leukemia. You can develop CML at any age, but it typically affects older adults.
It takes a long time for CML to get worse. You can have this condition for years before noticing symptoms. Many people learn they have CML after routine blood test results show unusual blood cell counts. Prompt treatment keeps CML from getting worse. Without treatment, chronic myeloid leukemia can become a life-threatening illness within three to four years.
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You can have CML without having noticeable symptoms. Chronic myeloid leukemia symptoms are mild and get worse over time. Common CML symptoms may include:
People with CML have an acquired genetic mutation or change in myeloid stem cells growing in their bone marrow. Acquired mutations aren’t present at birth and aren’t something you can inherit. Acquired mutations happen during your lifetime.
In genetic mutations, mutated or changed genes give cells new instructions on what to do. In this case, the mutation creates a new fused gene, BCR-ABL. The new gene triggers the following chain of events that lead to chronic myeloid leukemia:
The only risk factor for CML is exposure to high levels of radiation — and this applies to very few people.
People with CML may develop:
Yes, it can. People with CML may have an increased risk of other types of cancer (second cancers). A recent study showed about 30% of people with chronic myeloid leukemia developed second cancers, including:
Healthcare providers may suspect you have CML if you have unusual blood test results. But they actually diagnose CML with chromosome or genetic tests that identify genetic changes or mutations. Common tests for CML include:
Unlike many types of cancer, healthcare providers don’t characterize chronic myeloid leukemia by cancer stages. They characterize CML as being in one of four phases:
Healthcare providers typically treat chronic phase CML with tyrosine kinase inhibitors (TKIs). TKIs are a type of targeted therapy. In CML, the targets are the abnormal BCR-ABL enzymes that let abnormal white blood cells divide and multiply uncontrollably. TKIs block the enzymes so that CML cells start to die.
TKIs have made a huge difference for people with chronic myeloid leukemia. Before TKIs, only about 20% of people with the condition were alive five years after diagnosis. TKIs changed that outcome for people with early (chronic) CML.
TKIs put chronic myeloid leukemia into remission. (Remission means you don’t have CML symptoms and tests don’t find signs of the disease.) Most people take TKIs for the rest of their lives. However, recent studies show CML remains in remission even after people stop taking TKIs. This is treatment-free remission. Common TKIs to treat chronic phase CML include:
Side effects vary based on the specific TKI but may include:
If TKIs aren’t effective, providers may use chemotherapy along with or instead of a TKI.
No, it can’t. Medical researchers know CML happens when a specific gene mutates, but they haven’t discovered why that mutation happens.
That depends on your situation. If treatment puts chronic myeloid leukemia into remission, you won’t have symptoms or signs of disease, but you’ll need medication to keep CML in remission. Most people with CML attend frequent, routine appointments to see how well their treatment is working.
Treatment-free remission (TFR) means you don’t have CML symptoms or signs even after you stop taking a TKI. Recent studies show about 40% of people who stop treatment remain in remission for several years. But TFR is a relatively recent approach to treating chronic myeloid leukemia. Not everyone is a candidate. If you have chronic myeloid leukemia, it’s important that you talk to your provider before stopping treatment.
Right now, allogeneic stem cell transplantation is the only way to “cure” chronic myeloid leukemia. Allogeneic stem cell transplantation uses donated stem cells. It’s a complicated medical treatment. Its side effects are more serious than targeted therapy side effects. For that reason, providers typically only use stem cell transplantation to treat resistant CML.
When you think about survival rates, it’s important to remember that survival rates can’t predict how long you’ll live. Survival rates are based on other peoples’ experiences. What was true for them may not be true for you.
That being said, overall, 90% of people with CML are alive five years after diagnosis. (Before TKI, only 22% of people with CML were alive at the five-year mark.) If you have CML, your healthcare provider is your best resource for information about what you can expect.
If you have chronic myeloid leukemia, you may need to take medication for the rest of your life. You’ll also need regular checkups so your healthcare provider can monitor your overall health. They’ll look for signs that CML has come back and for signs of second cancers.
In general, you should expect to see your provider every few months for the rest of your life.
CML (chronic myeloid leukemia) and CLL (chronic lymphocytic leukemia) are both types of leukemia that develop in your blood or bone marrow. The difference is that CML starts in your myeloid stem cells. CLL starts in your lymphoid stem cells.
A note from Cleveland Clinic
Chronic myeloid leukemia (CML) is cancer in your blood and bone marrow. CML is a serious illness. Thanks to innovative treatments that put some types of CML into long-term remission, CML may become a chronic illness. (Remission means you don’t feel sick and tests don’t find signs of cancer.) Many people with CML may live as long as people who don’t have the condition. And even better, recent research shows there’s reason to believe (and hope) that for some people, CML that goes into remission with treatment stays in remission even after treatment stops. It’s important to remember that not everyone will have this opportunity. If you have CML, ask your healthcare provider if newer treatments or clinical trials may give you a chance to live free of CML.
Last reviewed by a Cleveland Clinic medical professional on 02/14/2023.
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