Myelodysplastic Syndromes (MDS)
Myelodysplastic syndromes (MDS) are a group of blood cancers related to abnormal blood cell formation. Normal blood cells (red cells, white cells, platelets) are produced from bone marrow stem cells. In MDS, damaged stem cells instead produce abnormally low numbers of blood cells.
MDS is more common with age; most people are over 60 at the time of diagnosis, though it can occur at any age. In most cases, the cause of MDS is unknown, but aging is associated with the accumulation of mutations in bone marrow stem cell genes. A small proportion of people who were treated with certain types of chemotherapy or radiation therapy may develop a type of MDS called therapy-related MDS.
The prognosis of MDS varies. Some people live for years with little or no treatment. In others, MDS is more aggressive and can progress to acute myeloid leukemia (AML), a disease with a poorer prognosis.
Symptoms of MDS
Symptoms depend on which blood cell type is most affected:
Red cells (erythrocytes): contain hemoglobin and carry oxygen. Their reduction (anemia) is the most common problem and causes pallor, fatigue, shortness of breath, and dizziness.
Platelets: involved in stopping bleeding from small vessels. Low platelets lead to bleeding tendency.
Neutrophils: a type of white blood cell that helps fight infections. Their reduction leads to increased susceptibility to infections, particularly bacterial.
Diagnosis
Diagnosing MDS can be difficult. Many patients are initially treated with iron or vitamins, which are ineffective.
Before treating any anemia, it is essential to confirm its type and, before giving iron, folic acid, or vitamin B12, laboratory confirmation of deficiency is mandatory.
Bone marrow testing is required for diagnosis. A sample is taken from the pelvic bone and examined for abnormal (“dysplastic”) cells, increased numbers of immature cells (“blasts”), and chromosomal and/or genetic abnormalities.
Genetic testing is crucial, as it helps determine the patient’s risk group and the likelihood of progression to acute leukemia, which strongly influences treatment choice.
Treatment
Treatment decisions depend mainly on the risk category.
Low-risk patients: may only need close monitoring if asymptomatic.
Higher-risk patients: benefit from treatment to control symptoms and reduce the risk of progression to leukemia.
Treatment aims to control symptoms, prevent complications, improve quality of life, and sometimes prolong survival. Age, overall health, and disease biology influence the treatment approach.
Treatment Options
Supportive (symptomatic) care
Transfusions (red blood cells, platelets) for dangerously low levels.
Antibiotics for infections.
Low-intensity therapy
Erythropoietin and thrombopoietin to stimulate blood cell production.
Low-intensity chemotherapy (e.g., azacitidine, decitabine).
Lenalidomide or thalidomide for specific subtypes.
Usually outpatient, with milder side effects.
High-intensity therapy
Intensive chemotherapy (similar to AML regimens).
Stem cell transplantation (the only potentially curative treatment).
Requires hospitalization, higher risks, but potentially higher benefit.
Supportive Care in Detail
Red blood cell transfusions: relieve anemia symptoms but may cause iron overload after >30 transfusions, requiring iron chelation therapy.
Platelet transfusions: prevent or treat bleeding. Needed more often since platelets survive only a few days.
Growth factors:
Recombinant erythropoietin: stimulates red blood cells.
G-CSF: stimulates white cells; rarely used, limited benefit.
Thrombopoietin agonists: raise platelets in selected cases.
Vaccines: inactivated vaccines recommended (e.g., annual flu, pneumococcal every 5 years). Live attenuated vaccines should be avoided.
Antibiotics: for infections.
Targeted / Specialized Approaches
Chromosome 5q- syndrome: often responds to lenalidomide or thalidomide.
Hypoplastic MDS: may respond to immunosuppressive therapy.
Other mutations: may be treated with targeted agents (under investigation).
High-Intensity Therapy
Intensive chemotherapy: used mainly in younger (<75 years), fit patients with high-risk MDS.
Stem cell transplantation:
Offers the best chance for long-term survival or cure.
Risks include graft-versus-host disease (GVHD) and treatment-related mortality.
Usually considered for high-risk MDS, not for low-risk patients.
Upper age limit ~75 years, but overall fitness is often more important than age.
Prognosis
Survival depends on risk category, comorbidities, and age. These are averages and cannot precisely predict individual outcomes. Prognosis is generally better in low-risk MDS, and varies widely between patients.
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