What is chronic myelomonocytic leukemia (CMML)?
Chronic myelomonocytic leukemia (CMML) is cancer of the blood. CMML is considered to be one of the myeloproliferative neoplasms (MPNs), a type of chronic blood cancer in which a person’s bone marrow does not make blood effectively. MDS/MPN have both “dysplastic” and “proliferative” features that cannot be classified as either myelodysplastic syndromes (MDS) or myeloproliferative neoplasms (MPN), and for this reason have been categorized as an overlap syndrome with its own distinct characteristics (MDS/MPN).
In people with CMML, their bone marrow makes too many white blood cells (monocytes). CMML should not be confused with CML, or chronic myelogenous leukemia, which is caused by a specific genetic change called the Philadelphia chromosome, and is treated very differently.
In CMML, there is no Philadelphia chromosome; instead CMML is caused by different genetic alterations.
Types of chronic myelomonocytic leukemia
The type of myeloproliferative neoplasm is based on whether too many red blood cells, white blood cells, or platelets are being made.
- Chronic myelogenous leukemia (CML), in which immature cells that would be red blood cells, white blood cells, or platelets overtake the bone marrow and blood.
- Essential thrombocythemia, in which too many platelets are made in the bone marrow
- Myelofibrosis (also called primary or chronic idiopathic myelofibrosis), in which abnormal blood cells and scarring build up within the bone marrow
- Polycythemia vera, in which too many red blood cells are formed in the bone marrow
Chronic myeloproliferative disorders sometimes can become acute leukemia, in which too many immature abnormal white blood cells are made. This is a rare event. Other, less common, myeloproliferative disorders include:
- Chronic eosinophilic leukemia
- Chronic neutrophilic leukemia
- Mastocytosis
- Myeloproliferative/myelodysplastic syndromes
- Neoplasms with eosinophilia and abnormalities of PDGFRA, PDGFRB or FGFR1 genes
CMML symptoms and signs
Some people with CMML never experience symptoms, and are diagnosed during routine blood tests. Others do experience leukemia symptoms. Symptoms of CMML may include:
- Enlarged spleen
- Feeling tired, shortness of breath
- Frequent infections
- Bleeding or bruising easily
- Weight loss without trying
How is CMML diagnosed?
Tests that examine the blood and bone marrow are used to detect (find) and diagnose chronic myelomonocytic leukemia (CMML). The Penn hematopathology service is a national leader in the diagnosis of leukemia and neoplastic and reactive hematologic disorders, with broad expertise in myelodysplastic syndromes (MDS).
Working closely with the clinical team, Penn hematopathologists provide integrative, state-of-the art analysis using histology and a wide array of ancillary techniques, including:
- Medical history
- Physical exam
- Flow cytometry
- Immunohistochemistry
- Complete blood count (CBC)
- Cytogenetics
- Peripheral blood smear
- Blood chemistry studies
- Bone marrow biopsy
- Specific genetic mutation testing
- Genetic sequencing
- The latest molecular studies (ranging from single gene assays to next generation sequencing) to ensure the most accurate and precise diagnosis for every patient.
Staging Chronic Myelomonocytic Leukemia
Chronic myelomonocytic leukemia (CMML) is grouped into two categories after diagnostic testing:
- CMML 1: Immature blood cells make up less than 5 percent of white blood cells in the blood and less than 10 percent in the bone marrow.
- CMML 2: Immature blood cells make up 5 to 19 percent of white blood cells in the blood and 10 to 19 percent in the bone marrow.
Chronic myelomonocytic leukemia diagnosis at Penn Medicine
CMML treatment options
Our physicians are part of a multidisciplinary leukemia treatment team whose approach to cancer and blood disorders is to personalize the treatment plan for each patient and to treat them holistically, focusing on the whole person and not just on their disease.
There are different types of treatments for patients with chronic myelomonocytic leukemia (CMML). In addition to standard therapies, there are novel therapies available through clinical trials. It is important to discuss any questions you have about clinical trials, or to let your doctor know if you are interested in participating in a clinical trial. Some people with CMML do not require active treatment of their disorder for a long time, and others will.
Living with CMML
Many patients with chronic myelomonocytic leukemia (CMML) continue to live full lives after their diagnosis and are minimally affected by their disease.
Patients with more advanced types of CMML frequently have more symptoms, and may experience side effects related to their treatment. However, even with more advanced forms of CMML, patients are living longer lives because of better diagnosis, new therapies, and cancer research.
Penn Medicine specialists can help you manage anxiety, blood count, pain, depression, eating habits, fatigue, stress, and communicating with family and friends.
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Penn Medicine’s Abramson Cancer Center is a world leader in cancer research, patient care, and education. Our status as a national leader in cancer care is reflected in our continuous designation as a Comprehensive Cancer Center by the National Cancer Institute (NCI) since 1973, one of 7 such centers in the United States. The ACC is also a member of the National Comprehensive Cancer Network, one of a select few cancer centers in the U.S., that are working to promote equitable access to high-quality, advanced cancer care.