Myelodysplastic syndrome

A myelodysplastic syndrome (MDS) is one of a group of cancers in which blood cells in the bone marrow do not mature, and as a result, do not develop into healthy blood cells. Early on, no symptoms are typically seen. Later symptoms may include fatigue, shortness of breath, bleeding disorders, anemia, or frequent infections. Some types may develop into acute myeloid leukemia.

Risk factors include previous chemotherapy or radiation therapy, exposure to certain chemicals such as tobacco smoke, pesticides, and benzene, and exposure to heavy metals such as mercury or lead. Problems with blood cell formation result in some combination of low red blood cell, platelet, and white blood cell counts. Some types of MDS cause an increase in the production of immature blood cells (called blasts), in the bone marrow or blood. The different types of MDS are identified based on the specific characteristics of the changes in the blood cells and bone marrow.

Treatments may include supportive care, drug therapy, and hematopoietic stem cell transplantation. Supportive care may include blood transfusions, medications to increase the making of red blood cells, and antibiotics. Drug therapy may include the medications lenalidomide, antithymocyte globulin, and azacitidine. Some people can be cured by chemotherapy followed by a stem-cell transplant from a donor.

Myelodysplastic syndrome (MDS) occurs primarily in older adults. The median age at diagnosis is around 73 years, and the incidence increases with age. Approximately 86% of cases are diagnosed in individuals aged 60 or more, while about 6% of cases are in those aged 50 or more. Although rare in children, the annual incidence is estimated at one to four cases per million each year, with the median age being 6.8 years in pediatric cases.

In the United States, an estimated 10,000-15,000 new cases of MDS are diagnosed annually. It is estimated that between 60,000 to 170,000 individuals currently live with MDS in the US. The overall annual incidence rate is approximately 4.0 to 4.9 per 100,000 people for the general population, increasing to more than 60 per 100,000 among individuals over 85 years of age.However, these figures are believed to underestimate the true incidence due to underdiagnosed or underreported patients.

MDS is more common in males than females, with a male-to-female incidence ratio around 4.5:2 per 100,000 individuals.The disease also appears more frequently in white populations compared to other racial and ethnic groups.

Most deaths among MDS patients come from the disease getting worse and turning into leukemia. It can transform into acute myeloid leukemia (AML) when accumulating genetic mutations cause immature blood cells to stop maturing, so instead they proliferate uncontrollably in the bone marrow. A study was done on 137 patients with MDS, who had died. Most deaths (27.4%) were from MDS progressing rapidly, turning into AML (21.7%), pneumonia (16%), and sepsis (8.5%) in high-risk groups.