Chronic myeloid leukemia (CML)

Sometimes CML causes no symptoms and is found when a blood test shows too many white blood cells. The first tests are a full blood count, with a look at the cells under a microscope, and blood chemistry tests. The doctor also checks the size of the spleen and liver.

The diagnosis is confirmed by finding the Philadelphia chromosome or the BCR::ABL1 gene change it creates. A chromosome test (cytogenetics) and a test called FISH can find the swapped pieces of chromosomes 9 and 22. A PCR test finds the BCR::ABL1 gene message itself. It also shows which form of the change is present, which matters for later monitoring.

European expert guidelines call for a bone marrow sample at diagnosis. It shows the share of very young cells (blasts), which helps set the phase: chronic, accelerated or blast phase. It can also show extra chromosome changes. NCI's summary notes that some experts question whether every newly diagnosed person needs a marrow test. The European guidelines also list a heart tracing (ECG) before treatment. After treatment starts, a quantitative PCR blood test measures how much BCR::ABL1 is left.

Tyrosine kinase inhibitors (TKIs) target BCR::ABL1 and are the foundation of chronic-phase treatment. The initial choice takes account of disease risk, other health conditions, potential side effects and access. Molecular monitoring shows how well a medicine is suppressing the leukemia.

If the response is inadequate or side effects prevent treatment, the team checks adherence, interactions and possible resistance mutations before choosing another approach. Selected patients with a sustained deep molecular response may try treatment-free remission. This means stopping the medicine while having regular tests afterward, because the leukemia can return even 2 to 3 years later.

Allogeneic transplantation is considered for resistance or intolerance to available TKIs and for advanced disease. Donor search can start before all drug options are exhausted when high-risk features or progression make a transplant likely. In blast phase, treatment commonly aims to regain disease control before transplant.

Targeted medicines called tyrosine kinase inhibitors (TKIs) have changed the outlook for CML. NCI says that with these medicines, median survival is expected to come close to normal life expectancy for most people. A Swedish study that counted everyone diagnosed in the country reached a similar finding.

Two things shape the outlook: the phase of CML and how well the medicine works. European experts say most people in chronic phase now have a normal life expectancy. Blast phase is much harder to treat. Care teams check BCR::ABL1 levels at 3, 6 and 12 months against expert targets. Missing a target can lead the team to change medicine. NCI lists older age, extra chromosome changes, more blasts and anemia as signs of a shorter chronic phase on TKIs.

The U.S. five-year figure below counts everyone diagnosed with CML, at every age and phase.