Chronic myeloid leukemia (CML) and chronic lymphocytic leukemia (CLL) are slow-growing forms of leukemia. But they affect different blood cells and have different treatments.

There are similarities between CML and CLL, but they’re not the same. Both types of leukemia have different symptoms and treatment options. CML has an accelerated phase that is more aggressive, which can impact treatment.

Both types of leukemia are much more common in adults than in children. About 15% of all leukemia cases are CML and 25% of leukemia cases are CLL.

In this article, we’ll explain the differences in causes, treatments, and more.

Both CML and CLL are slow-growing cancers. They’re normally found when routine blood work is ordered for another concern or condition. It typically takes a long time for symptoms to develop and begin to affect you.

CML and CLL cause many of the same symptoms, depending on where the enlarged lymph nodes occur.

These symptoms can include:

  • night sweats
  • fever
  • fatigue
  • unexplained weight loss
  • easy bleeding
  • easy or unexplained bruising
  • enlarged lymph nodes
  • frequent infections
  • a feeling of fullness in your stomach
  • stomach pain
  • swollen glands
  • shortness of breath
  • swelling of your spleen
  • swelling of your liver
  • anemia

CML and CLL are often discovered in lab work when no symptoms are present. When people have symptoms that bring them to a medical professional, they typically include:

  • fatigue
  • decreased ability to do exercise or physical activity
  • unexpected weight loss

Doctors use blood work and other tests to determine a diagnosis, whether CML, CLL, or another cause.

CML and CLL are caused by genetic mutations that affect the way your body produces blood cells.

In CML the first changes occur in immature myeloid cells located in your bone marrow. Your myeloid cells are responsible for producing blood cells.

The genetic mutation causes the cells to make cancerous white blood cells instead. Over time, these cells overwhelm the other cells in your bone marrow and begin to spread to the rest of your body.

CLL occurs when a mutation causes immune cells called B lymphocytes to divide and reproduce at an abnormal rate. Currently, medical scientists aren’t sure what causes this extra production of B lymphocytes.

Research suggests the extra production is often triggered by a reaction to an antigen, such as a germ. The B lymphocytes begin to reproduce normally but don’t stop reproducing. But it’s not known what causes the B lymphocytes to react this way.

CML and CLL are very slow-growing cancers. You might not need treatment right away. In some cases, you might not need treatment at all. But if your CLL or CML is progressing and causing symptoms, a doctor may recommend starting treatment. Treatment typically depends on:

  • the progression of your cancer
  • your age
  • your overall health
  • how your body responds to treatment


In CML, people who are otherwise young and healthy can have different treatment options. Younger people who are able to be matched with a donor are candidates to receive a bone marrow transplant. These transplants can cure CML, but they’re not an option for everyone. Younger people also have the option to pursue chemotherapy to treat CML.

In many other cases of CML, the goal is to relieve symptoms and slow the progression. This can be done with treatments like:

  • blood transfusions
  • medications to help your body produce healthy blood cells
  • antibiotics for any infections


Unlike most types of cancer, researchers haven’t found it beneficial to treat CLL early. Instead, most medical professionals recommend waiting until symptoms develop.

Doctors generally treat CLL with chemotherapy, radiation, and other medications. Some people with CLL receive a treatment called leukapheresis which separates white blood cells from other blood cells.

Treatment can also include bone marrow transplants or surgery to remove an enlarged spleen.

Currently, the 5-year relative survival rate for CML is around 70.6%, and the 5-year relative survival rate for CLL is around 88%. These numbers are based on data from people diagnosed with CML and CLL at least 5 years ago.

The survival rates for CML and CLL are improving as new cancer treatments become available.

Your individual outlook with CML or CLL can depend on many other factors, including:

  • your age at diagnosis
  • your overall health
  • your specific genetics
  • the progression of your cancer

Leukemias are often classified as chronic or acute. Chronic leukemias like CLL or CML develop slowly over a long period of time. It can take years for any symptoms to occur, and treatment isn’t needed right away.

In chronic leukemias, the affected white blood cells are still able to partially mature. This means that they don’t fight infection as well as normal white blood cells. The cancerous cells also live longer than noncancerous white blood cells. This allows them to eventually overtake your normal blood cells.

Conversely, acute leukemia develops quickly and aggressively. Treatment is needed immediately. Without treatment, acute leukemia could lead to death in as little as a few months. The affected blood cells in acute leukemia don’t mature. They reproduce rapidly and build up in your body.

New research and treatments for leukemia are continually being developed.

Survival rates for many types of cancer have increased significantly in the past several decades. This trend is expected to continue as medical science continues to learn more about cancer and how to treat it. That means that more people diagnosed with cancer will be able to live full, healthy lives.

Even with new treatments available, getting a cancer diagnosis can be overwhelming and frightening. It’s important to have support.

Beyond friends and family, there are numerous resources you look into to get the support and encouragement you need during treatment.

Support options include:

  • Local support groups: The Leukemia & Lymphoma Society has support groups all around the country. You can find your local chapter on their website to learn about meetings near you.
  • Online support groups: Online support groups are a great way to connect with other cancer patients at any time of day. You can start with the blood cancers patient support group.
  • The American Cancer Society: You can call the American Cancer Society 24 hours a day 7 days a week for support, educational information, resources, and more. You can call 1-800-227-2345.
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What is the difference between CLL and CML?

Chronic myeloid leukemia (CML, sometimes called chronic myelogenous leukemia) and chronic lymphocytic leukemia (CLL) are both different types of leukemia. CML occurs in myeloid cells, while CLL occurs in lymphocytes. Both CML and CLL are slow-growing but have differences in how they start and how doctors treat them.

What is the difference between CML and CMML leukemia?

CML, or chronic myeloid leukemia, and CMML, or chronic myelomonocytic leukemia, are two different types of leukemia.

What are the 4 types of leukemia?

The four most common types of leukemia include:

  • Acute lymphocytic leukemia (ALL)
  • Acute myeloid leukemia (AML)
  • Chronic lymphocytic leukemia (CLL)
  • Chronic myeloid leukemia (CML)

CML and CLL are slow-growing forms of leukemia. There’s a significant overlap in the symptoms and treatment of CML and CLL. But some unique symptoms set the conditions apart. Treatment courses are also often very different.

CLL treatment generally begins with chemotherapy and radiation, while CML treatment often focuses on managing symptoms and slowing the cancer progression.

Survival rates for CML and CLL have risen over the past few decades and are expected to continue to rise as treatments improve.