Myelodysplastic Syndromes (MDS)


Myelodysplastic syndromes (MDS) are a rare group of hematologic disorders characterized by ineffective hematopoiesis in the bone marrow, which results in peripheral blood cytopenias (low blood counts) and an increased risk of progression to acute myeloid leukemia (AML).1,2

Epidemiology of MDS

Myelodysplastic syndromes primarily affect older individuals, with a median age at diagnosis of around 70 years. MDS is more commonly observed in men than women, and its incidence increases with age. It is estimated that MDS affects approximately 4.9 cases per 100,000 individuals in the United States each year.1,3

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Pathophysiology of MDS

The pathophysiology of MDS involves a complex interplay of genetic and epigenetic abnormalities, as well as dysregulation of the bone marrow microenvironment. Somatic point mutations have been observed in MDS, including mutations in genes such as TP53, SF3B1, and TET2. These mutations contribute to the dysregulation of key cellular processes, leading to impaired hematopoiesis and the accumulation of immature and dysfunctional blood cells. Cytogenetic changes, such as the deletion of the long arm of chromosome 5 (5q), also contribute to the pathogenesis of MDS.1,3

Myelodysplastic syndromes can act as a primary disease or be secondary to other causes. Treatment with chemotherapeutic agents has been indicated as a cause of MDS, typically 2 to 7 years after exposure to these agents.1

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Signs and Symptoms of MDS

The signs and symptoms of MDS vary depending on the type of MDS. Common clinical manifestations include fatigue, weakness, pallor, and shortness of breath caused by a reduced red blood cell count. A decreased platelet count can result in increased bleeding and bruising tendencies, and a decreased white blood cell count can lead to an increased susceptibility to infections.4,5 

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Diagnosis of MDS

The diagnosis of MDS requires a comprehensive evaluation, including a detailed medical history and physical examination. Common causes of cytopenia need to be ruled out, and laboratory testing, including a complete blood count (CBC) and peripheral blood smear, along with bone marrow examination may be performed. Bone marrow aspiration allows clinicians to observe morphologic dysplasia and blasts, while bone marrow biopsy allows bone marrow cellularity and fibrosis to be studied.3,5

Additional tests, including flow cytometry and molecular genetic testing, may be performed to further characterize the disease. Non-random chromosomal abnormalities can be detected by conventional cytogenetic testing, including complex karyotypes and abnormalities like del(20q), del(5q), +8, and −7/del(7q).3,5

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Treatment of MDS

Lower-risk patients may not require immediate treatment. The goal of treating MDS is to improve cytopenia, anemia, and quality of life. Treatment options for MDS include3,5,6:

  • Supportive care for the management of complications, including: red blood cell, white blood cell, and platelet transfusions to increase the number of blood cells and control bleeding; the administration of erythropoiesis-stimulating agents to manage anemia; and antibiotic therapy to treat infections
  • Medications such as: hypomethylating agents Vidaza® (azacitidine) and Dacogen® (decitabine), which have been approved by the US Food and Drug Administration (FDA) for MDS management; immunosuppressive agents, such as antithymocyte globulin combined with cyclosporine; Revlimid® (lenalidomide) to manage MDS with isolated del(5q); and Reblozyl® (luspatercept) for the management of patients with MDS with ring sideroblasts
  • Chemotherapy with allogeneic stem cell transplantation, which despite being the only potentially curative treatment for MDS is usually reserved for younger patients and patients with high-risk disease
  • Follow-up testing, including a CBC every 3 to 6 months and bone marrow examination once a year or when clinically relevant

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Prognosis of MDS

The prognosis of MDS depends on several factors, such as the patient’s age, overall health, disease subtype, and cytogenetic abnormalities.1,5 Prognosis in MDS can be further refined using established prognostic scoring systems, such as the International Prognostic Scoring System (IPSS) or revised IPSS (IPSS-R).1

Patients with a 5q deletion generally have a better prognosis than those with MDS with monosomy 7. Patients with a worse prognosis typically present complex cytogenetics with more than 3 abnormalities or chromosome 7 abnormalities.1 Patients with higher-risk MDS present with a median life expectancy of less than 2 years.3

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References

  1. Dotson JL, Lebowicz Y. Myelodysplastic syndrome. In: StatPearls [Internet]. Treasure Island, FL: StatPearls Publishing; 2023. Updated July 18, 2022. Accessed June 6, 2023.
  2. Myelodysplastic syndromes. Genetic and Rare Diseases Information Center (GARD). Updated February 2023. Accessed June 6, 2023.
  3. Cazzola M. Myelodysplastic syndromes. N Engl J Med. 2020;383(14):1358-1374. doi:10.1056/NEJMra1904794
  4. Myelodysplastic syndrome (myelodysplasia). NHS. Accessed June 6, 2023.
  5. Myelodysplastic syndromes treatment (PDQ®)–patient version. National Cancer Institute. Updated March 31, 2023. Accessed June 6, 2023.
  6. Besa EC. Myelodysplastic syndrome (MDS) treatment & management. Medscape. Updated October 1, 2022. Accessed June 6, 2023.

Reviewed by Debjyoti Talukdar, MD, on 6/20/2023.