Chronic myelomonocytic leukemia (CMML)

Chronic myelomonocytic leukemia (CMML) is a rare blood cancer that causes your bone marrow to make too many of a type of white blood cell called monocytes. The abnormal monocytes don’t leave room for healthy red blood cells, platelets, and white blood cells. This leads to your blood cells not working correctly, which may cause symptoms like fatigue. In some people, CMML can progress to acute myeloid leukemia.

Penn Medicine’s blood cancer care specialists excel at diagnosing and treating complex diseases like CMML. Because our doctors specialize in every type of leukemia, including chronic myelomonocytic leukemia, you’ll receive care from experts with a focus on your cancer. We also provide leading treatments for CMML and conduct clinical trials to study its causes and treatments. With a high level of expertise, you can count on us to help you effectively manage CMML.

Some people with CMML never experience symptoms and are diagnosed during routine blood tests. If symptoms do occur, they may include:

• An enlarged spleen or liver
• Weakness, fatigue, or shortness of breath
• Frequent infections or fevers
• Bruising or bleeding easily, like nosebleeds
• Weight loss without trying

Researchers have found that gene changes (mutations) in bone marrow cells are linked to CMML. These mutations aren’t passed down in families. Instead, they develop during your lifetime. Often, changes to several genes cause the cancer.

The risk of this type of cancer increases as you get older, with the average age of diagnosis around 75. It’s more common among people assigned male at birth and among people who have had treatment for previous cancer, like chemotherapy and radiation.

Doctors stage chronic myelomonocytic leukemia differently than they stage other cancers. Usually, the stage of cancer reflects how big the tumor is and whether it has spread. But CMML staging is based on how many blasts are in your blood. This can help your doctor plan the best treatment. CMML stages include:

• CMML-1: In this stage, a small number of cells in your blood (less than five percent) and bone marrow (under 10 percent) are immature cells.
• CMML-2: During this stage, a higher number of cells are immature. They make up five to 19 percent of the cells in your blood and 10 to 19 percent in your bone marrow.

Many people with chronic myelomonocytic leukemia continue to live full lives. Even in more advanced forms of CMML, better diagnostic tests, new therapies, and cancer research are helping improve your quality of life.

Penn Medicine offers the full spectrum of treatments for CMML and conducts clinical trials for blood cancers, helping to find newer therapies. Our compassionate care addresses both the cancer and the emotional aspects that may come with it. In addition to the latest medical treatments, we provide supportive therapies that can help you manage fatigue, stress, and other issues.