CML vs CLL: Similarities and Differences

In this article, you’ll learn how chronic myeloid leukemia (CML) and chronic lymphocytic leukemia (CLL) differ in the type of white blood cells affected, how they are treated, and what symptoms and complications they may cause.

Understanding the basics: What are CML and CLL?

CML and CLL are both long-developing blood cancers that begin in the bone marrow—the soft tissue inside bones that produces blood cells.

CML starts in cells called myeloid cells, which help the body respond to infections and regulate inflammation. Most people with CML have a genetic change called the Philadelphia chromosome, caused by parts of chromosomes 9 and 22 switching places. 

CLL begins in lymphocytes, a type of white blood cell that helps fight infections. While the exact cause of CLL isn’t known, it likely begins with genetic changes in early blood-producing cells. 

Knowing the cell type involved helps determine the best treatment approach and how the condition may progress. 

Symptoms can be similar

Many individuals with CML or CLL may not notice any symptoms at the time of diagnosis. Often, the cancer is discovered during routine blood tests.

When symptoms are present, they may include: 

• Fatigue
• Fever, chills, or night sweats
• Unexplained weight loss
• Bone or abdominal pain
• Feeling full quickly when eating

In addition, CLL may cause swollen lymph nodes, especially in the neck, underarms, or groin. 

These symptoms happen because the abnormal white blood cells don’t function normally and can build up in the body over time.

How CML and CLL affect healthy blood cell production

Both types of leukemia lead to the overproduction of abnormal white blood cells, which can crowd out healthy cells in the bone marrow. This can result in several complications:

• Anemia – a low red blood cell count, causing fatigue and shortness of breath
• Leukopenia – a low white blood cell count, raising infection risk
• Neutropenia – a decrease in neutrophils, the cells that target harmful microorganisms
• Thrombocytopenia – a shortage of platelets, which can cause easy bruising or bleeding

Understanding these complications helps individuals recognize how the cancer can impact everyday health and the importance of regular blood monitoring.

Treatment approaches are not the same

The type of treatment used for CML or CLL depends on the biology of the condition and how fast it is progressing.

CML treatment usually includes targeted therapy, especially a group of medicines called tyrosine kinase inhibitors (TKIs). These medicines block the activity of the BCR-ABL1 protein, which fuels the abnormal growth of myeloid cells.

Common TKIs for CML include:

• Imatinib (Gleevec, Novartis)
• Dasatinib (Sprycel, Bristol Myers Squibb)
• Nilotinib (Tasigna, Novartis)
• Bosutinib (Bosulif, Pfizer)
• Asciminib (Scemblix, Novartis)

In advanced cases or when TKI treatment is not effective, a stem cell transplant from a donor may be considered.

CLL treatment is often given only when treatment-indicating symptoms arise. Once treatment is needed, commonly used targeted therapies include:

• BTK inhibitors block signals that help CLL cells grow
• Venetoclax (Venclexta, AbbVie) helps trigger cell death in CLL cells
• Immunotherapies like obinutuzumab (Gazyva, Genentech) or CAR T-cell therapy liso-cel (Breyanzi, BMS), help the immune system target and remove CLL cells

In rare cases, a donor stem cell transplant may also be an option for CLL if other treatments stop working. 

These treatment differences are important because they reflect how each leukemia grows and responds to therapies.

Long-term outcomes

CLL typically has a higher five-year survival rate compared to CML, but this depends on the individual’s age, overall health, and the phase or risk group of the cancer.

CML, when treated early and effectively with TKIs, can often be managed for many years. People with CLL can also live for many years with sequenced therapies. 

Understanding treatment options and possible complications empowers people to take an active role in their care. 

Key takeaways

CML and CLL are slow-growing blood cancers that affect different types of white blood cells. While they may look similar at first, their origins, complications, and treatment options differ. By understanding these differences, individuals can better navigate their care choices and work with their healthcare team to manage their condition effectively. 

We need your help! Easily contribute to CLL or CML research

If you are living with CML or CLL, we need your help improving patient outcomes for all by taking simple, anonymous surveys that contribute to real-world research in HealthTree Cure Hub®. Click one of the buttons below to get started! 

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Sources: 

• Chronic lymphocytic leukemia
• Chronic myelogenous leukemia
• Chronic myelogenous leukemia treatments