If you've been recently diagnosed with chronic myeloid leukemia, you probably have a lot of questions. Find out about this type of cancer, including how it starts and its causes.

Chronic myeloid leukemia is sometimes called chronic myelogenous leukemia, or just CML. Leukemia is a type of cancer that begins in the blood-forming cells inside the bone marrow before spreading through the blood.

Understanding Bone Marrow

Bone marrow is a soft substance found inside the bones in the body. It’s made up of several types of cells, including blood stem cells. These cells develop into all the cells that make up blood, such as white blood cells, red blood cells, and platelets. Some white blood cells are called lymphocytes, and work to fight infection. The other blood cells, including remaining white cells, red cells, and platelets, are called myeloids.

Chronic Myeloid Leukemia: What Is It?

CML is referred to as “chronic” because it is a long-term disorder in which the cancerous cells build up over an extended period of time. The cells are allowed to partly develop, but don’t fully mature. The “myeloid” classification comes from the type of cells affected.

There are three phases of CML: chronic, accelerated, and blast crisis. Most people are usually diagnosed during the first phase when cells are growing slowly. During the accelerated phase, the diseased cells begin growing more quickly. If left untreated, CML may progress into the blast crisis phase. This is when the bone marrow fails and serious bleeding and infection can develop.

Symptoms of CML

Symptoms tend to develop gradually. They can vary depending on which phase of CML you’re in, but often include:

  • fatigue, most likely due to anemia
  • rash
  • bruising or bleeding easily
  • bone and joint pain
  • enlarged spleen
  • increased risk of infection

How Does It Start?

CML appears to be mostly genetic. Most people who are diagnosed have an abnormal chromosome called the Philadelphia chromosome that creates a new gene. This gene tells the blood cells to make too much of the tyrosine kinase protein. This allows the diseased blood cells to reproduce too quickly and live too long. As these cells build up, they don’t leave enough room for healthy blood cells. This process can take a long time. Sometimes people don’t even know they have CML until years after the cancer cells began to develop.

What Are the Causes and Risk Factors?

Although CML is usually associated with a gene mutation, it’s important to note that it’s not hereditary. It’s believed that the gene mutation happens at some point after the person is born. While it’s still not clear exactly how or why this mutation happens, some risk factors include:

  • male gender
  • older age
  • exposure to radiation, including some types of cancer radiation treatment

Most people with CML are treated with drugs called tyrosine kinase inhibitors, or TKIs. These are pills that target the protein made by the Philadelphia chromosome. In some cases, oral chemotherapy drugs are also used to reduce the number of abnormal white blood cells. These drugs, alone or in combination, are often enough to put the leukemia into remission. Other procedures can also be considered, including stem cell transplants or bone marrow transplants.

What Now?

Take the time to sit down with your doctor and talk about your diagnosis. Understanding your CML, including what phase you’re in and what treatment is best for you, can help you feel more prepared.