Chronic myeloid leukemia (CML) and chronic lymphocytic leukemia (CLL) are slow-growing forms of leukemia. Both types of leukemia are much more common in adults than in children. About 15 percent of all leukemia cases are CML and 38 percent of leukemia cases are CLL.

There are many similarities between CML and CLL, but they’re not the same. Your symptoms and treatment options will be different with CML than they will with 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’ll take a long time for symptoms of either to develop and begin to affect you.

CML and CLL cause many of the same symptoms, but a few other symptoms may be present with CML that are not typical with CLL.

Night sweatsxx
Unexplained weight lossxx
Easy bleedingxx
Easy and unexplained bruisingxx
Enlarged lymph nodesxx
A feeling of fullness in your stomachx
Stomach painx
Swollen glandsx
Shortness of breathx
Swelling of your spleenx
Swelling of your liverx

CML and CLL are often discovered in lab work when no symptoms are present. When patients do have symptoms that bring them to a medical professional are often very similar and include fatigue, exercise intolerance, and unexpected weight loss.

But there can be a few differences. Patients with CML are more likely to seek medical help because they’ve been experiencing stomach pain and difficulties with digestion. On the other hand, patients with CLL are more likely to seek medical help for repeated infections and enlarged lymph nodes.

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.

Researchers believe that 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, treatment options can be discussed. The right treatment options for you’ll depend 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 will have different treatment options. Younger people who are able to be matched with a donor are candidates to receive a stem cell transplant. Stem cell transplants can cure CML, but they’re not an option for every patient. Younger patients 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 of the cancer. 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 that patients wait until symptoms develop.

CLL is generally treated with chemotherapy, radiation, and medications. Some patients with CLL receive a treatment called leukapheresis that separates white blood cells from your other blood cells. Stem cell transplants, as well as surgery to remove an enlarged spleen, are also options.

The survival rates for CML and CLL are improving as new cancer treatments become available. Currently, the 5-year relative survival rate for CML is around 70 percent and the 5-year relative survival rate for CLL is around 87 percent.

Survival rates are influenced by factors like:

  • 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 affected cells also live longer than normal white bloods. 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 all cancers 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 fight 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.
  • Case managers: CancerCare offers free case management from licensed social workers. You can call 1-800-813-4673 to reach a social worker and get started. You can also email to get more information.
  • 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 or by checking out this database from the National Cancer Institute.
  • 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 or schedule a video chat for face-to-face support.
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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 more research is conducted.