MDS Overview
MDS by the Numbers
Myelodysplastic syndromes (MDS) are an often unrecognized, under-diagnosed, rare group of bone marrow failure disorders, where the body no longer makes enough healthy, normal blood cells in the bone marrow. The disease is also recognized as a form of blood cancer.
10,000 to 15,000 new cases in the US every year
It's hard to know exactly how many people are diagnosed with MDS in the United States every year. While some estimates suggest about 10,000–15,000 new cases per year, other data suggest that it could be much higher.
60,000 to 170,000 people live with MDS in the US
The estimated number of people living with MDS in the United States ranges from 60,000 to 170,000. This wide range is due to differences in how MDS is diagnosed, how cases are reported, and how studies are conducted across various populations.
Average age of patients with MDS is 73
MDS is uncommon before age 50. Although MDS is rare in children, there are 1 to 4 cases per million each year, with the median age of affected children being 6.8 years.
86% of patients with MDS are older than 60
The risk of MDS increases as people age. It typically begins to appear in individuals over 65 and is most commonly diagnosed in those in their 70s.
Men 2x as likely to develop MDS as women
Overall, males are twice as likely to develop MDS as females. The incidence ratio of males to females is 4.5:2 per 100,000 individuals.
1 in 3 people with MDS develop AML
In about a third of people, MDS can progress to a rapidly growing cancer of bone marrow cells called acute myeloid leukemia (AML).
Understanding the Disease
What is MDS?
Myelodysplastic Syndromes (MDS) are a group of diverse bone marrow disorders in which the bone marrow does not produce enough healthy blood cells. MDS is often referred to as a "bone marrow failure disorder". MDS is primarily a disease of the elderly (most patients are older than age 65), but MDS can affect younger patients as well. To help you better understand MDS, it might be helpful to first consider some basics about bone marrow and blood.
The bone marrow functions as a factory that manufactures three kinds of blood cells: red blood cells, white blood cells, and platelets. Healthy bone marrow produces immature blood cells — called stem cells, progenitor cells, or blasts — that normally develop into mature, fully functional red blood cells, white blood cells, and platelets. In MDS, these stem cells may not mature and may accumulate in the bone marrow or they may have a shortened life span, resulting in fewer than normal mature blood cells in the circulation.
Low blood cell counts, referred to as cytopenias, are a hallmark feature of MDS and are responsible for some of the symptoms that MDS patients experience — infection, anemia, spontaneous bleeding, or easy bruising. Anemia (low red blood cell counts), neutropenia (low white blood cell counts), and thrombocytopenia (low platelet counts) are the major types of blood cell cytopenias, and are discussed below. In addition to reduced numbers of blood cells, the mature blood cells circulating in the blood may not function properly because of dysplasia. The formal definition of dysplasia is the abnormal shape and appearance, or morphology, of a cell. The prefix myelo- is from the Greek and it means marrow; so myelodysplasia refers to the abnormal shape and appearance — or morphology — of the mature blood cells. Syndromes comes from the Greek and means a set of symptoms that occur together.
Failure of the bone marrow to produce mature healthy cells is a gradual process, and therefore MDS is not necessarily a terminal disease. Some patients do succumb to the direct effects of the disease: reduced blood cell and/or reduced platelet counts may be accompanied by the loss of the body's ability to fight infections and control bleeding. In addition, for roughly 30% of the patients diagnosed with MDS, this type of bone marrow failure syndrome will progress to acute myeloid leukemia (AML).
You and MDS
Introducing the MDS Foundation's online patient education resource, "You and MDS: An Animated Patient's Guide to Myelodysplastic Syndromes." Embark on a journey of understanding by clicking the button below.
Explore You and MDSExploring Causes
What Causes MDS?
With a few exceptions, the exact causes of MDS are unknown. Some evidence suggests that certain people are born with a tendency to develop MDS. This tendency can be thought of as a switch that is triggered by an external factor. If the external factor cannot be identified, then the disease is referred to as “primary MDS”.
Radiation and chemotherapy for cancer are among the known triggers for the development of MDS. Patients who take chemotherapy drugs or who receive radiation therapy for potentially curable cancers, such as breast or testicular cancers, Hodgkin's disease and non-Hodgkin's lymphoma, are at risk of developing MDS for up to 10 years following treatment. MDS that develops after use of cancer chemotherapy or radiation is called “secondary MDS” and is usually associated with multiple chromosome abnormalities in cells in the bone marrow. This type of MDS often develops rapidly into AML.
Long term exposure to certain environmental or industrial chemicals, such as benzene, can also trigger MDS. While benzene use is now highly regulated, it is not clear which other chemicals may predispose individuals to MDS, although certain occupations have been labeled “at risk” for the development of MDS or AML (e.g., painters, coal miners, embalmers). There are no known food or agricultural products that cause MDS. While alcohol consumed on a daily basis may lower red blood cell and platelet counts, alcohol does not cause MDS. Tobacco smoke/use has been linked to the development of MDS. One of the primary components of tobacco is benzene, which is highly regulated by federal agencies and there are published guidelines for exposure limits.
Patients and their families often worry that MDS might be contagious. No evidence exists to suggest that a virus causes MDS; thus, MDS cannot be transmitted to loved ones.
MDS is not inherited. In fact, it is a very rare occasion when family members, including siblings, are diagnosed with MDS.
Understanding Common Symptoms
What Are The Symptoms?
In the early stages of MDS patients may experience no symptoms at all. A routine blood test may reveal a reduced red cell count, or low hematocrit, sometimes along with reduced white cell and/or reduced platelet counts. On occasion, the white cell and platelet counts may be low while the hematocrit remains normal. However, some patients, particularly those with blood cell counts well below normal, experience definite symptoms. These symptoms, described below, depend on which blood cell type is involved as well as the level of the cell count.
Low white cell count
(neutropenia)
A reduced white cell count lowers the body’s resistance to bacterial infection. Patients with neutropenia may be susceptible to skin infections, sinus infections (symptoms include nasal congestion), lung infections (symptoms include cough, shortness of breath), or urinary tract infections (symptoms include painful and frequent urination). Fever may accompany these infections.
Low red cell count
(anemia)
The majority of individuals are anemic when they are initially diagnosed with MDS. Anemia is characterized by a persistently low hematocrit (a measure of the body’s red blood cells) or persistently low levels of hemoglobin (the blood protein that carries oxygen to the body’s tissues). Anemic patients generally experience fatigue, shortness of breath, pale skin, and palpitations.
Low platelet count
(thrombocytopenia)
Patients with thrombocytopenia have an increased tendency to bruise and bleed even after minor bumps and scrapes. Nosebleeds are common and patients often experience bleeding of the gums, particularly after dental work. Before having dental work, consultation with your hematologist, who may prescribe antibiotics, is recommended since infection and bleeding pose a risk for most MDS patients.
