Myelodysplastic syndromes (MDS) are a group of disorders in which the bone marrow does not produce healthy blood cells effectively. Abnormal blood-forming cells can result in low levels of red blood cells, white blood cells, and platelets.

MDS primarily affects older adults, although it can occur at other ages. The condition varies significantly from person to person. Some forms progress slowly and may be managed for years, while higher-risk MDS can progress to acute myeloid leukemia (AML).

Early and accurate diagnosis is important because treatment depends on the specific type of MDS, its risk category, genetic characteristics, and the patient's overall health.

What Are Myelodysplastic Syndromes?

The bone marrow is the body's blood-cell production centre. It contains blood-forming stem cells that develop into red blood cells, white blood cells, and platelets.

In MDS, abnormal changes in blood-forming stem or progenitor cells interfere with normal blood-cell production. The bone marrow may contain abnormal cells, but fewer healthy mature blood cells reach the bloodstream.

This can lead to:

• Anemia due to low red blood cells

• Increased infections due to low or abnormal white blood cells

• Bleeding or bruising due to low platelets

MDS is not a single disease. It represents a group of related bone marrow disorders with different biological and genetic characteristics.

Types and Risk Categories of MDS

Modern classification systems use blood and bone marrow findings along with genetic and molecular information to classify MDS.

Doctors also assess the risk of the disease using factors such as:

• Blood cell counts

• Percentage of blasts in the bone marrow

• Chromosomal abnormalities

• Genetic mutations

• Severity of cytopenias

• Other disease-related features

MDS is generally categorised into lower-risk and higher-risk disease groups.

Lower-risk MDS may primarily cause persistent low blood counts and symptoms related to anemia or other cytopenias.

Higher-risk MDS has a greater likelihood of progressing to AML and generally requires more intensive treatment.

What Causes MDS?

In many patients, the exact cause of MDS is unknown.

MDS can develop because of acquired genetic changes in blood-forming cells. These changes are usually not inherited from parents.

Certain factors can increase the risk of developing MDS, including:

• Increasing age

• Previous chemotherapy

• Previous radiation therapy

• Exposure to certain chemicals

• Certain inherited disorders

• Previous treatment for another cancer

MDS that develops after previous chemotherapy or radiation is sometimes referred to as therapy-related MDS.

Having a risk factor does not mean that a person will definitely develop MDS.

Symptoms of Myelodysplastic Syndromes

Symptoms are often related to low blood-cell counts.

Symptoms of Anemia

Low red blood cell or hemoglobin levels can cause:

• Fatigue

• Weakness

• Shortness of breath

• Dizziness

• Pale skin

• Reduced ability to exercise

Symptoms Related to Low White Blood Cells

A low or abnormal white blood cell count may increase the risk of infections.

Possible symptoms include:

• Recurrent infections

• Persistent fever

• Frequent illness

• Slow recovery from infections

Symptoms Related to Low Platelets

Low platelet levels can increase the risk of bleeding.

Possible signs include:

• Easy bruising

• Frequent nosebleeds

• Bleeding gums

• Small red or purple spots on the skin

• Prolonged bleeding from minor injuries

Some people with MDS have no obvious symptoms and are diagnosed after an abnormal blood test performed for another reason.

How Is MDS Diagnosed?

A persistent unexplained reduction in one or more blood cell types may lead a doctor to investigate MDS.

Complete Blood Count

A complete blood count (CBC) measures red blood cells, white blood cells, hemoglobin, and platelets.

The results may show one or more low blood cell counts.

Peripheral Blood Smear

A blood smear allows a specialist to examine the appearance of blood cells under a microscope.

Certain abnormalities in the shape, size, or maturity of blood cells may provide clues to an underlying bone marrow disorder.

Bone Marrow Aspiration and Biopsy

A bone marrow examination is an important part of diagnosing MDS.

It allows doctors to evaluate:

• The number and appearance of developing blood cells

• Abnormal cell development, known as dysplasia

• Blast percentage

• Bone marrow cellularity

• Other abnormalities that may help distinguish MDS from other conditions

Cytogenetic and Molecular Testing

Genetic and molecular testing has become an important part of MDS evaluation.

Chromosome analysis and molecular tests can identify abnormalities that help:

• Confirm or refine the diagnosis

• Classify the disease

• Estimate disease risk

• Provide prognostic information

• Guide treatment decisions

How Is MDS Treated?

Treatment is individualised according to the patient's risk category, symptoms, blood counts, genetic findings, age, overall health, and treatment goals.

Some patients may initially require close monitoring, while others need active treatment.

Observation and Monitoring

Patients with lower-risk disease and limited symptoms may sometimes be monitored regularly.

This can include periodic blood tests and clinical assessment.

Treatment may begin if blood counts worsen, symptoms develop, transfusion requirements increase, or other signs indicate that intervention is needed.

Supportive Care

Supportive care focuses on managing the effects of low blood counts.

It may include:

• Red blood cell transfusions

• Platelet transfusions when required

• Treatment of infections

• Iron management in patients receiving repeated transfusions

• Medicines to improve blood-cell production in selected patients

Supportive care can play an important role in maintaining quality of life.

Growth Factors

Certain medicines can stimulate the bone marrow to produce more blood cells.

For selected patients with anemia, erythropoiesis-stimulating agents may help reduce transfusion requirements.

The decision to use these medicines depends on disease characteristics and individual patient factors.

Disease-Modifying Treatment

Certain medicines can modify the behaviour of abnormal bone marrow cells and are used particularly in higher-risk MDS.

Hypomethylating agents such as azacitidine and decitabine are important treatments for many patients with higher-risk disease.

Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation is currently the only treatment with established curative potential for MDS.

It involves replacing the patient's diseased blood-forming system with healthy stem cells from a donor.

However, transplantation is an intensive treatment and carries significant risks. It is therefore considered based on factors such as disease risk, age, overall health, donor availability, and the patient's suitability for transplantation.

Can MDS Progress to Leukemia?

Yes. Some forms of MDS can progress to acute myeloid leukemia (AML).

The risk depends on the specific type and biological characteristics of the MDS.

Higher-risk disease generally has a greater likelihood of progression than lower-risk disease.

This is one reason why accurate risk assessment and regular monitoring are important.

MDS and Anemia

Anemia is one of the most common problems associated with MDS.

However, not every case of anemia is caused by MDS.

Iron deficiency, vitamin B12 deficiency, chronic disease, kidney problems, blood loss, and several other conditions can also cause anemia.

Persistent anemia, particularly when it is unexplained or accompanied by abnormalities in other blood cell lines, may require evaluation by a hematologist.

Living With MDS

Living with MDS can vary significantly depending on the disease risk and treatment required.

Some patients may need only regular monitoring, while others may require frequent transfusions or active therapy.

Patients should maintain regular follow-up with their healthcare team and report symptoms such as:

• Fever

• New or worsening infections

• Unusual bleeding

• Significant fatigue

• Shortness of breath

• New unexplained bruising

A personalised care plan can help manage symptoms, reduce complications, and maintain quality of life.

When Should You See a Hematologist?

You may be referred to a hematologist if you have:

• Persistent unexplained anemia

• Low white blood cell counts

• Low platelet counts

• More than one abnormal blood cell type

• Abnormal findings on a peripheral blood smear

• Recurrent infections or unexplained bleeding

• Persistent blood count abnormalities without an identified cause

An abnormal blood test does not automatically mean that you have MDS. A hematologist can determine whether further testing, including a bone marrow examination, is appropriate.