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Chronic Myeloid Leukemia

What Is Chronic Myeloid Leukemia?

Chronic myeloid leukemia (CML) is a rare cancer that affects blood cells and bone marrow. That’s the soft part inside the bone where blood cells are made.

Treatment may help you go into remission. For most people, that doesn't mean the cancer is completely gone, but it does mean that it’s less active than before. Remission can last for many years.

CML usually starts in middle age or later. Its symptoms tend to come on gradually. Many of them, like being tired, losing weight without trying, or having fevers, can also be signs of other illness, so learning that you have it may come as a surprise.

CML is sometimes also called chronic myelogenous leukemia.

It starts with a problem in the genes of your blood cells. Sections of two different chromosomes switch places and produce a new one.

This new chromosome starts your body making white blood cells that don’t work as they should, and too many of them. They’re called leukemia cells. This leaves less room for healthy white and red cells and platelets, the three different types of blood cells.


Most people will never know what caused them to get CNL. You don’t get it from your parents, or from infections. Your smoking habits and diet don’t seem to raise your chance of getting it either.

The only known risk is exposure to high levels of radiation.


CML has three phases: chronic, accelerated, and blastic. Your symptoms depend on which phase you are in.

Chronic phase. This is the earliest phase and the easiest to treat. You might not even have symptoms.

Accelerated phase. In this phase, the number of blood cells that don’t work right increases. You're more likely to notice some of these symptoms:

  • Being very tired
  • Fever
  • Bruising
  • Night sweats
  • Shortness of breath
  • Surprising weight loss
  • Appetite loss
  • Swelling or pain on your left side (which could be a sign of an enlarged spleen)
  • Bone pain

Other symptoms may include stroke, visual changes, ringing in the ears, feeling like you’re in a daze, and prolonged erections.

Blastic phase. This is the most serious CML phase. The leukemia cells grow and crowd out healthy blood cells and platelets.

In this phase, you'll have more severe symptoms, including:

  • Infections
  • Bleeding
  • Skin changes including bumps, tumors
  • Swollen glands
  • Bone pain


Getting a Diagnosis

If you do have symptoms your doctor will want to know:

  1. What problems have you been having?
  2. How long have you been noticing these symptoms?
  3. Do your symptoms come and go or are they constant?
  4. What makes you feel better or worse?
  5. Are you taking any medication?

Your doctor may do more tests to confirm the diagnosis:

  • A complete blood count to see how many white blood cells, red blood cells, and platelets you have
  • Bone marrow tests to check how advanced the cancer is. Doctors use a needle to take a sample, usually from your hip bone.
  • A very detailed lab test of your genes, called fluorescence in situ hybridization (FISH), to measure the number of cells containing the Philadelphia chromosome
  • Ultrasound or CT scan to check the size of your spleen. Ultrasounds use sound waves to make images that doctors and other medical professionals can read. A CT, or computed tomography, scan is an X-ray that takes a series of pictures inside your body. These are processed in a computer to create a layered image with lots of detail.
  • Another specific lab test called polymerase chain reaction, to look for the BCR-ABL gene. This gene is involved in the process that tells your body to make too many of the wrong kind of white blood cells.

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