Myelodysplastic Syndrome: Signs, Diagnosis, and Modern Treatment

What is Myelodysplastic Syndrome (MDS)?

Myelodysplastic syndrome (MDS) is a group of hematopoietic system disorders in which the bone marrow does not produce enough healthy blood cells. Instead, it produces immature, defective cells that cannot function normally. These abnormal (dysplastic) cells often die prematurely, leading to a deficiency of mature, functional blood cells in the body. MDS is considered a pre-cancerous condition, as it can progress to acute myeloid leukemia (AML) in a significant number of patients.

Causes and Risk Factors for MDS

In most cases, MDS occurs spontaneously, without an obvious cause, and is called primary MDS. However, there are known risk factors that may contribute to the development of the disease:

• Age: MDS is most commonly diagnosed in older adults, with the median age at diagnosis being around 70 years.
• Prior chemotherapy or radiation therapy: People who have received cancer treatment have an increased risk of developing secondary MDS.
• Exposure to toxins: Prolonged contact with certain chemicals, such as benzene, pesticides, or heavy metals, may increase the risk.
• Genetic syndromes: Less commonly, MDS is associated with hereditary conditions such as Fanconi anemia or Down syndrome.

Symptoms and Signs of MDS

Symptoms of MDS often develop gradually and can be non-specific, which complicates early diagnosis. They are directly related to the deficiency of healthy blood cells:

• Anemia (red blood cell deficiency):
  • Chronic fatigue and weakness
  • Pale skin
  • Shortness of breath, especially during physical exertion
  • Dizziness, headaches
• Thrombocytopenia (platelet deficiency):
  • Increased bleeding (easy bruising, nosebleeds, bleeding gums)
  • Petechiae (small pinpoint hemorrhages on the skin)
• Neutropenia (deficiency of neutrophils, a type of white blood cell):
  • Frequent and recurrent infections that are difficult to treat
  • Fever without an apparent cause

In some patients, MDS may be asymptomatic and discovered incidentally during routine blood tests.

Diagnosis of Myelodysplastic Syndrome

Diagnosing MDS requires a comprehensive approach and involves several stages:

1. Complete Blood Count (CBC): This is the first and most important step. A CBC usually shows a decrease in one or more types of blood cells (cytopenia) – anemia, leukopenia (especially neutropenia), or thrombocytopenia. Abnormal cell forms may be detected.
2. Peripheral blood smear examination: Allows for the identification of dysplastic changes in blood cells, such as abnormalities in the shape and size of red blood cells, neutrophils with hyposegmented nuclei (pseudo-Pelger-Huët anomaly), or abnormal platelets.
3. Bone marrow biopsy and aspiration: This is a key procedure for confirming the diagnosis. Bone marrow samples are examined under a microscope to assess cellularity, the presence of dysplastic changes in precursor cells (erythroid, myeloid, megakaryocytic lineages), and to determine the percentage of blast cells.
4. Cytogenetic analysis: Examination of chromosomal abnormalities in bone marrow cells. Certain chromosomal changes (e.g., 5q deletion, monosomy 7) are characteristic of MDS and have prognostic significance.
5. Molecular genetic testing: Searching for mutations in genes associated with MDS (e.g., SF3B1, TET2, ASXL1, TP53). These mutations help refine the diagnosis, classify the MDS subtype, and predict treatment response and prognosis.

Treatment of MDS: Modern Approaches

The choice of MDS treatment strategy depends on many factors, including the MDS subtype, the risk of progression to AML (determined by the International Prognostic Scoring System – IPSS or IPSS-R), the patient's age, overall health status, and the presence of comorbidities.

• Supportive care:
  • Blood transfusions: To correct anemia (red blood cell transfusions) and thrombocytopenia (platelet transfusions).
  • Chelation therapy: Frequent blood transfusions can lead to iron overload, which must be treated.
  • Antibiotics: To treat infections, especially in the presence of neutropenia.
  • Growth factors: Erythropoietin (EPO) to stimulate red blood cell production and granulocyte colony-stimulating factor (G-CSF) to increase neutrophil counts.
• Immunosuppressive therapy: In some patients, especially younger ones with hypocellular MDS, drugs that suppress the immune system, such as antithymocyte globulin (ATG) or cyclosporine, may be effective.
• Hypomethylating agents (HMAs): Azacitidine and decitabine are the primary drugs for patients with intermediate- and high-risk MDS. They alter epigenetic mechanisms in cancer cells, promoting their differentiation and reducing proliferation.
• Lenalidomide: Effective in patients with low-risk MDS associated with a 5q deletion.
• Hematopoietic stem cell transplantation (HSCT): This is the only potentially curative method for MDS. It is considered for younger patients with high-risk MDS and good overall health who have a suitable donor.

Prognosis and Monitoring

The prognosis for MDS varies significantly and depends on the disease subtype, cytogenetic abnormalities, the number of blast cells in the bone marrow, and the degree of cytopenia. Regular monitoring of blood and bone marrow status is necessary to assess treatment efficacy and detect disease progression in a timely manner.

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Disclaimer: The information provided in this article is for reference purposes only and is not intended for self-diagnosis or self-treatment. Always consult a qualified medical professional for diagnosis and the selection of an optimal treatment plan.