Fatigue, night sweats, and left-sided rib pain may be early symptoms of CML. As the disease progresses, you may experience unintentional weight loss, frequent infections, and bone pain.

Chronic myeloid leukemia (CML) is a type of cancer that affects cells in your bone marrow that produce blood.

CML can start slowly. You may not notice any symptoms when cancerous cells called blasts begin to multiply and take over healthy bone marrow cells.

But as CML progresses and blasts appear in your blood or bone marrow samples, you might experience symptoms like fatigue, bone pain, and fever in what’s called the chronic phase of CML.

Your symptoms may change as blasts make up more and more of your blood or marrow samples, meaning that the condition has become more severe and entered a new phase.

Read on to learn more about what symptoms to expect during each phase of CML and whether you can help slow the disease’s progression.

In the chronic phase of CML, cancerous blast cells typically make up less than 10% of the cells found in blood tests or bone marrow biopsy samples.

CML often has no symptoms in the chronic phase. However, some initial signs and symptoms may include:

Symptoms are typically mild in the chronic phase. But they can start to get worse over time without treatment to help slow disease progression.

CML enters the accelerated phase when blasts make up between 10% and 19% of your blood or bone marrow samples.

Other criteria, such as changes in the leukemia cells, increased basophils, or reduced platelets, may also signify progression to the accelerated phase.

Symptoms you’ve experienced in the chronic phase may become more severe in this phase. Other symptoms you might start to notice during the accelerated phase include:

CML enters the blast phase (or blast crisis phase) when blasts make up 20% or more of your blood or bone marrow samples, and blasts have spread to other organs and tissues.

Many of the symptoms you experience during the accelerated phase become more severe at this stage. Fevers or infections may become especially dangerous or life threatening.

Some of the severe symptoms of the blast phase may include:

  • bone pain
  • extreme fatigue
  • losing an excessive amount of weight

CML progresses slowly, but it’s best to seek treatment as early as possible to slow the growth of blasts in your bone marrow.

Taking a tyrosine kinase inhibitor (TKI) is the most effective treatment to slow the progression of CML. The oldest and most common first-line TKI for treating CML is imatinib (Gleevec).

A 2017 study found that 80% of people taking imatinib lived for 10 years without CML progressing.

Doctors can use TKIs in combination with other CML treatments, such as:

A doctor may also take other factors into account to find the best treatment for slowing CML progression, including:

  • how much blast cells have damaged your bones
  • whether your spleen is enlarged
  • how high your blood levels of eosinophils and basophils are
  • how low or high your platelet counts are
  • how old you are (people over 60 years face higher risks from certain treatments)

What does CML bone pain feel like?

People describe CML bone pain as feeling like:

  • sharp, sudden pains
  • dull, throbbing aches
  • persistent no matter how much you move

You may notice CML bone pain in more than one area of your body at a time.

How fast does CML progress?

CML might progress slowly and may not show any symptoms at first. But scientists aren’t really sure how fast the disease usually progresses prior to diagnosis.

Without treatment, CML typically progresses to accelerated and blast phases within 3 to 5 years.

What is the life expectancy of CML with treatment?

People who receive a CML diagnosis in its early stages may have a near-typical life expectancy with treatment and monitoring of symptoms. About 90% of people taking imatinib live as long as people without CML.

But life expectancy can vary depending on your stage of CML. In a 2019 study of people with CML undergoing treatment, people in the blast phase with more than 30% blasts had a median survival of 1.6 years.

Is CML fatal?

CML can be fatal, especially if you receive a diagnosis in the accelerated or blast phase. The long-term survival rate is around 90% if you receive a diagnosis in the chronic phase.

CML may not show symptoms at first, but they can progress and become more severe as CML advances.

More frequent headaches, infections, and bleeding are common features of the accelerated phase. Symptoms like bone pain, worsening fatigue, and excessive weight loss may suggest progression to the blast phase.

Early diagnosis is important to get the treatment you need to live long and have a high quality of life with CML.