Chronic Myelogenous Leukemia

Chronic myelogenous leukemia (also called chronic myeloid 

leukemia) is a rare cancer that affects bone marrow. That's 

where blood cells are produced. CML leads to the production 

of many abnormal white blood cells, which do not fight infection 

as well as normal white blood cells. As they build up in the 

blood and bone marrow, the abnormal cells crowd out healthy 

white blood cells, red blood cells, and platelets.

The Philadelphia Chromosome

People with CML have an abnormal chromosome called the 

Philadelphia chromosome. Chromosomes carry genes, which 

tell cells what to do. In CML, pieces of chromosomes 9 and 22 

break and switch places. The changed chromosome 22 is 

called the Philadelphia chromosome. It carries a new gene 

called bcr-abl. Bcr-abl calls for a protein (tyrosine kinase) to be 

made, triggering stem cells to create abnormal white blood 

cells found in CML.

Chronic Phase

The chronic phase is the first period of CML.  

Most people in this phase don't have any 

symptoms. They're usually diagnosed during 

a routine blood test. Because there are only a 

small number of abnormal white blood cells in 

the blood and bone marrow, the body is still 

able to fight infection. Even though you might 

not feel sick now, it's important to get treated 

so CML doesn't progress to the next phase.

Accelerated Phase

During the accelerated phase, you may 

develop symptoms such as fatigue, weight loss, shortness of breath, or fever. This means the number of abnormal blood cells has increased. Once in this phase, it may become harder to achieve remission with CML treatments. The accelerated CML phase can lead to the most serious and aggressive phase of the cancer, blast phase.

Blast Phase

By the blast phase of CML, the number of 

abnormal blood cells in the bone marrow and 

blood is high. Meanwhile, the number of 

healthy red and white blood cells and 

platelets has dropped. With fewer disease-

fighting white blood cells, you're more likely to 

get infections. You may have anaemia or 

uncontrolled bleeding. This stage is severe 

and life-threatening.

Targeting the Abnormal CML Protein

The chronic phase of CML is first treated with 

targeted drugs called tyrosine kinase inhibitors (TKIs). They kill off CML blood cells by blocking the protein produced by the abnormal gene bcr-abl. Side effects can include rashes and swollen skin, nausea, muscle cramps, and diarrhea. When TKIs can't control the disease, there are other treatment options.

Stem Cell Transplant

A stem cell transplant is an option for some 

people who don't respond to TKIs. First, you 

get high doses of chemotherapy drugs to kill 

blood-forming cells (stem cells) in your bone 

marrow. Then, you receive stem cells from a 

matched donor, called an allogeneic 

transplant. These cells will form new, healthy 

blood cells. A stem cell transplant is the only 

way to cure CML. But newer treatments that 

target bcr-abl can also normalize the 

Philadelphia chromosome and help many 

people with CML achieve remission.

The best candidates for a stem cell transplant:

Are younger rather than older patients

Are in the chronic phase of CML

Are in overall good health

Have a matched stem cell donor (preferably a close relative, such as a brother or sister)

Treatment Options

If TKIs aren't working and you're not a 

candidate for a stem cell transplant, other 

treatment options include:

Chemotherapy drugs taken by mouth to kill 

abnormal cells throughout your body, such as 

hydroxyurea or busulfan

Biological therapies, like interferon, that 

stimulate your own immune system to fight off 

the cancer

Continuous Monitoring Is Necessary

When you have CML, you'll see your doctor at least every few months to monitor treatment and check for side effects. CML tests include:

Complete blood count and bone marrow tests to measure red and white blood cells and platelets

Fluorescent in situ hybridization (FISH) test to see how many cells contain the Philadelphia chromosome

Polymerase chain reaction (PCR) test to look for the bcr-abl gene.

Questions About Your CML Treatment

Here are a few questions to ask your doctor while you're undergoing treatment for CML:

What CML phase am I in?

What are my treatment options and what side effects might I experience?

Should I get a second opinion?

Can I enroll in a clinical trial of an experimental treatment?

How to Cope with CML

During your treatment for CML, here are a few ways to help yourself feel better:

Go to all of your check-ups so your doctor can change treatment if it's not working.

Tell your doctor about any side effects you're experiencing.

If you're struggling with your illness, get support from friends, family members, or your medical team.

Signs Your Treatment Is Working

When you go for regular checkups, your doctor will be looking for these signs that your treatment is working:

Hematologic response: An improvement in the number of healthy white blood cells and platelets

Cytogenic response: Fewer Philadelphia chromosome-positive cells in your blood and bone marrow

You are considered to be in CML remission when:

Your blood cell count is normal (complete hematologic response).

No cells with the Philadelphia chromosome can be found in your blood or bone marrow (complete cytogenic response).

None of the abnormal gene can be found in your blood (complete molecular response).

Being in remission isn't the same as being cured. A stem cell transplant is the only proven cure for CML.

Signs of Relapse

CML can come back even after it has been successfully treated. Signs of relapse include fatigue or weakness, weight loss, fever, night sweats, bone pain, swelling or pain on the left side (a sign of an enlarged spleen), and a feeling of fullness in the belly. If you have any of these symptoms, call your doctor.

Why Isn't My Treatment Working?

CML therapy works well for most people, but not everyone. Reasons why treatment might stop working include:

The cancer cells change (mutate).

Not enough medication is getting into your bloodstream.

If your treatment isn't effective, your doctor may adjust your drug doses or switch you to another therapy.