Table of ContentsView AllTable of ContentsWhat Is CMML?SymptomsTypesCausesDiagnosisTreatmentPrognosis
Table of ContentsView All
View All
Table of Contents
What Is CMML?
Symptoms
Types
Causes
Diagnosis
Treatment
Prognosis
Chronic myelomonocytic leukemia(CMML) symptoms include fatigue, unintended weight loss, easy bleeding, and an enlarged spleen.CMML is a rare cancer that begins in the blood-forming cells in the bone marrow. It is one of severalblood cancersthat causes the overproduction of white blood cells known asmonocytes.
There are different types of CMML, some of which are more aggressive than others. Although CMML can be cured with astem cell transplant, most cases are diagnosed in the late stages when such transplants are not viable. Even so,chemotherapyand other treatments may help extend disease-free survival.
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Chronic myelomonocytic leukemia is a form ofleukemia(cancer of blood-forming cells in thebone marrow). CMML is a rare disease that shares the characteristics of:
Because of this, CMML is classified as a distinct entity known as MDS/MPN.
With CMML, the bone marrow makes too manymonocytes(the largestwhite blood cellsthat help make up the body’s frontline defense) andblast cells(immature blood cells). The overproduction of these cells can damage the bone marrow and overburden other organs, leading to disease and illness.
As a chronic disease, CMML progresses slower than acute forms of cancer, such asacute myeloid leukemia (AML). Even so, it is associated with a shorter life expectancy.
CMML is less common than other types of leukemia, affecting only around four of every one million people in the United States each year.
The telltale sign of CMML is an enlarged spleen, also known assplenomegaly. This is caused when excessive monocytes settle in the spleen (which typically serves as a reservoir of these important white blood cells).
Symptoms of splenomegaly include:
An excess of monocytes can also crowd out other blood cells, includingred blood cellsandplatelets, causing symptoms such as:
In advanced stages, CMML can causepleural effusion(“water in the lungs”),pericardial effusion(fluid buildup around the heart muscle), andascites(buildup of fluid in the abdomen).
CMML is divided into two stages according to the number of blast cells in your blood and bone marrow:
Between 15% and 30% of CMML cases will develop into a far more aggressive form of cancer calledacute myeloid leukemia (AML). This occurs when your blood contains more than 20% blast cells. The progression to AML is associated with shorter survival times.
The distinction between CMML-1 and CMML-2 is important as it predicts life expectancy and helps direct the appropriate course of treatment.
CMML is distinctive as it does not involve the Philadelphia chromosome and its underlying cause is largely unknown. Certain genetic mutations are linked to CMML, likeKRASandJAK2gene mutations, but these occur with many other diseases as well.
Scientists believe that CMML may be the result of gene mutations paired with one or more triggering events. These may include exposure tocarcinogens(cancer-causing agents) like benzene and formaldehyde, ionizing radiation, orcytotoxic drugslike those used for chemotherapy. More research is needed.
The risk of CMML is greatest in people:
CMML can be difficult to diagnose because it is easy to confuse with other forms of leukemia, MDS, and MPN. The diagnosis largely involves a process of exclusion, investigating and excluding all other possible causes before the diagnosis can be considered definitive.
To diagnose CMML, your healthcare provider will order a battery of tests to check the composition of your blood cells and look for abnormalities in your bone marrow, spleen, and other organs. In addition to a physical exam and a review of your medical and family history, tests would include:
CMML is potentially curable, but most people diagnosed with CMML are either too old or in the advanced stages where such a transplant is non-viable. In most cases, the focus of treatment would be placed on extending life, managing symptoms, and maintaining the best possible quality of life.
Stem Cell Transplant
Astem cell transplantinvolves taking stem cells from a matched donor with the aim of curing CMML. It is a high-risk procedure in which normal and abnormal bone marrow cells are destroyed and replaced with normal blood-forming stem cells from a healthy donor.
Because the transplant carries a high risk of life-threatening side effects, most people aren’t eligible. Moreover, studies have found that the use of stem cell transplants doesn’t always increase survival time in people with CMML and may only serve to undermine a person’s health and quality of life.
To be considered for stem cell transplantation, you must:
Hypomethylating Agents
Chemotherapy
Chemotherapyis also an option for treating CMML.While it can’t cure CMML, it can help kill abnormal bone marrow cells and help achieve short-termremission. Your healthcare provider may prescribe the chemo drughydroxyureato help reduce the number of monocytes.
Blood Transfusions and Erythropoietin
A blood transfusion may be recommended to reduce symptoms of CMML, including severeanemia. You may also be given Procrit (erythropoietin), an injectable drug that stimulates red blood cell production, along with a platelet infusion to improve clotting and reduce abnormal bleeding.
CMML is associated with reduced survival times. The median survival time for CMML-1 is 20 months, while those with CMML-2 have a median survival time of 15 months. Hypomethylating agents can extend survival times to around 29 months, although not everyone responds to treatment.
Some people survive much longer than this. In fact, around 20% of those with CMML-1 will live more than five years, and around 10% of those with CMML-2 will live longer than five years.
CMML can be resistant to chemotherapy. Around 40% of those who receive chemotherapy will achieve remission, but remissions tend to be short with a relapse rate of around 90%.
Between 20% and 50% of people who undergo a stem cell transplant will achieve a durable cure.
Summary
12 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.American Cancer Society.Chronic myelomonocytic leukemia.Penn Medicine Abramson Cancer Center.Chronic myelomonocytic leukemia (CMML).Cancer Research UK.What is chronic myelomonocytic leukaemia (CMML)?American Cancer Society.What causes chronic myeloid leukemia?Valent P, Orazi A, Savona MR, et al.Proposed diagnostic criteria for classical chronic myelomonocytic leukemia (CMML), CMML variants and pre-CMML conditions.Haematologica. 2019 May 2;104(10):1935–1949. doi:10.3324/haematol.2019.222059Leukemia & Lymphoma Society.CMML stem cell transplantation.Pophali P, Matin A, Mangaonkar AA, et al.Prognostic impact and timing considerations for allogeneic hematopoietic stem cell transplantation in chronic myelomonocytic leukemia.Blood Cancer J. 2020;10(11):121. doi:10.1038/s41408-020-00387-yZeidan AM, Hu X, Long JB, et al.Hypomethylating agent therapy use and survival in older patients with chronic myelomonocytic leukemia in the United States: a large population-based study.Cancer. 2017;123(19):3754-3762. doi:10.1002/cncr.30814Leukemia & Lymphoma Society.CMML chemotherapy and drug therapy.Liapis K, Kotsianidis I.Approaching first-line treatment in patients with advanced CMML: hypomethylating agents or cytotoxic treatment?Front Oncol. 2021;11:801524. doi:10.3389/fonc.2021.801524American Cancer Society.Growth factors for treating chronic myelomonocytic leukemia.American Cancer Society.Survival rates for chronic myelomonocytic leukemia.Additional ReadingLeukemia and Lymphoma Society.Chronic Myelomonocytic Leukemia: Treatment.NIH National Cancer Institute.Chronic Myelomonocytic Leukemia definition.
12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.American Cancer Society.Chronic myelomonocytic leukemia.Penn Medicine Abramson Cancer Center.Chronic myelomonocytic leukemia (CMML).Cancer Research UK.What is chronic myelomonocytic leukaemia (CMML)?American Cancer Society.What causes chronic myeloid leukemia?Valent P, Orazi A, Savona MR, et al.Proposed diagnostic criteria for classical chronic myelomonocytic leukemia (CMML), CMML variants and pre-CMML conditions.Haematologica. 2019 May 2;104(10):1935–1949. doi:10.3324/haematol.2019.222059Leukemia & Lymphoma Society.CMML stem cell transplantation.Pophali P, Matin A, Mangaonkar AA, et al.Prognostic impact and timing considerations for allogeneic hematopoietic stem cell transplantation in chronic myelomonocytic leukemia.Blood Cancer J. 2020;10(11):121. doi:10.1038/s41408-020-00387-yZeidan AM, Hu X, Long JB, et al.Hypomethylating agent therapy use and survival in older patients with chronic myelomonocytic leukemia in the United States: a large population-based study.Cancer. 2017;123(19):3754-3762. doi:10.1002/cncr.30814Leukemia & Lymphoma Society.CMML chemotherapy and drug therapy.Liapis K, Kotsianidis I.Approaching first-line treatment in patients with advanced CMML: hypomethylating agents or cytotoxic treatment?Front Oncol. 2021;11:801524. doi:10.3389/fonc.2021.801524American Cancer Society.Growth factors for treating chronic myelomonocytic leukemia.American Cancer Society.Survival rates for chronic myelomonocytic leukemia.Additional ReadingLeukemia and Lymphoma Society.Chronic Myelomonocytic Leukemia: Treatment.NIH National Cancer Institute.Chronic Myelomonocytic Leukemia definition.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
American Cancer Society.Chronic myelomonocytic leukemia.Penn Medicine Abramson Cancer Center.Chronic myelomonocytic leukemia (CMML).Cancer Research UK.What is chronic myelomonocytic leukaemia (CMML)?American Cancer Society.What causes chronic myeloid leukemia?Valent P, Orazi A, Savona MR, et al.Proposed diagnostic criteria for classical chronic myelomonocytic leukemia (CMML), CMML variants and pre-CMML conditions.Haematologica. 2019 May 2;104(10):1935–1949. doi:10.3324/haematol.2019.222059Leukemia & Lymphoma Society.CMML stem cell transplantation.Pophali P, Matin A, Mangaonkar AA, et al.Prognostic impact and timing considerations for allogeneic hematopoietic stem cell transplantation in chronic myelomonocytic leukemia.Blood Cancer J. 2020;10(11):121. doi:10.1038/s41408-020-00387-yZeidan AM, Hu X, Long JB, et al.Hypomethylating agent therapy use and survival in older patients with chronic myelomonocytic leukemia in the United States: a large population-based study.Cancer. 2017;123(19):3754-3762. doi:10.1002/cncr.30814Leukemia & Lymphoma Society.CMML chemotherapy and drug therapy.Liapis K, Kotsianidis I.Approaching first-line treatment in patients with advanced CMML: hypomethylating agents or cytotoxic treatment?Front Oncol. 2021;11:801524. doi:10.3389/fonc.2021.801524American Cancer Society.Growth factors for treating chronic myelomonocytic leukemia.American Cancer Society.Survival rates for chronic myelomonocytic leukemia.
American Cancer Society.Chronic myelomonocytic leukemia.
Penn Medicine Abramson Cancer Center.Chronic myelomonocytic leukemia (CMML).
Cancer Research UK.What is chronic myelomonocytic leukaemia (CMML)?
American Cancer Society.What causes chronic myeloid leukemia?
Valent P, Orazi A, Savona MR, et al.Proposed diagnostic criteria for classical chronic myelomonocytic leukemia (CMML), CMML variants and pre-CMML conditions.Haematologica. 2019 May 2;104(10):1935–1949. doi:10.3324/haematol.2019.222059
Leukemia & Lymphoma Society.CMML stem cell transplantation.
Pophali P, Matin A, Mangaonkar AA, et al.Prognostic impact and timing considerations for allogeneic hematopoietic stem cell transplantation in chronic myelomonocytic leukemia.Blood Cancer J. 2020;10(11):121. doi:10.1038/s41408-020-00387-y
Zeidan AM, Hu X, Long JB, et al.Hypomethylating agent therapy use and survival in older patients with chronic myelomonocytic leukemia in the United States: a large population-based study.Cancer. 2017;123(19):3754-3762. doi:10.1002/cncr.30814
Leukemia & Lymphoma Society.CMML chemotherapy and drug therapy.
Liapis K, Kotsianidis I.Approaching first-line treatment in patients with advanced CMML: hypomethylating agents or cytotoxic treatment?Front Oncol. 2021;11:801524. doi:10.3389/fonc.2021.801524
American Cancer Society.Growth factors for treating chronic myelomonocytic leukemia.
American Cancer Society.Survival rates for chronic myelomonocytic leukemia.
Leukemia and Lymphoma Society.Chronic Myelomonocytic Leukemia: Treatment.NIH National Cancer Institute.Chronic Myelomonocytic Leukemia definition.
Leukemia and Lymphoma Society.Chronic Myelomonocytic Leukemia: Treatment.
NIH National Cancer Institute.Chronic Myelomonocytic Leukemia definition.
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