Myelodysplastic Syndromes (MDS) are a group of cancers affecting the bone marrow, where blood cells are produced. These conditions disrupt the normal production of healthy blood cells, leading to a shortage of functional red blood cells, white blood cells, or platelets. MDS is also referred to as myelodysplasia or myelodysplastic neoplasms. Abnormal cells in the blood and/or bone marrow are a characteristic feature.
Understanding Myelodysplastic Syndromes (MDS)
Myelodysplastic Syndromes originate in the bone marrow when hematopoietic stem cells, the foundational cells for all blood cell types, become abnormal. This leads to “ineffective hematopoiesis,” where the bone marrow produces defective blood cells that do not mature properly. Many defective cells die prematurely within the bone marrow, resulting in low numbers of mature, healthy blood cells in the bloodstream.
The produced cells can also appear abnormal under a microscope, a condition known as dysplasia. This disruption leads to cytopenias, which are reductions in blood cell numbers. A significant concern with MDS is its potential to progress to acute myeloid leukemia (AML), a fast-growing cancer of bone marrow cells. This transformation occurs in about 30% of patients.
Recognizing the Signs of MDS
The symptoms of Myelodysplastic Syndromes often emerge gradually and can be non-specific. As the disease progresses and healthy blood cell counts decrease, various signs may appear.
A reduction in red blood cells, known as anemia, commonly causes fatigue, weakness, shortness of breath, and unusual skin paleness. Low levels of white blood cells, particularly neutrophils, can lead to frequent infections that are challenging to treat. A decrease in platelets, essential for blood clotting, can manifest as easy bruising, frequent nosebleeds, or pinpoint-sized red spots under the skin called petechiae.
Diagnosing Myelodysplastic Syndromes
Diagnosing Myelodysplastic Syndromes typically begins when a healthcare provider suspects the condition due to persistent low blood counts or symptoms. A complete blood count (CBC) is usually the first step, providing a profile of red blood cells, white blood cells, and platelets. If these counts are low, further investigations rule out other potential causes.
A peripheral blood smear is then examined under a microscope to assess blood cell shape and size, looking for abnormal appearances characteristic of MDS. The definitive diagnosis often requires a bone marrow aspiration and biopsy, where samples of marrow fluid and solid tissue are collected. These samples are analyzed for abnormal cell morphology, the percentage of immature blood cells (blasts) which must be less than 20% for an MDS diagnosis, and chromosomal abnormalities that can indicate MDS or help classify its subtype.
Treatment Options for MDS
Treatment for Myelodysplastic Syndromes is tailored to the individual, considering the specific MDS subtype, risk of progression, age, and overall health. Supportive care is a primary component, aiming to alleviate symptoms and improve blood cell counts. This often involves blood transfusions for anemia or low platelet counts, and growth factors like erythropoietin or granulocyte colony-stimulating factor to stimulate the bone marrow to produce more red or white blood cells.
Low-intensity therapies are often used for lower-risk MDS or for patients who may not tolerate aggressive treatments. Hypomethylating agents, such as azacitidine and decitabine, are common drug therapies. They influence gene expression in bone marrow cells, helping them mature more normally and reducing the risk of progression to AML. Lenalidomide is another low-intensity option, particularly effective for patients with a specific chromosomal abnormality known as deletion 5q, where it can significantly improve red blood cell levels.
For higher-risk MDS, or when the disease progresses, more intensive therapies may be considered. Chemotherapy, often involving drugs like cytarabine, aims to eliminate abnormal cells in the bone marrow. Hematopoietic stem cell transplantation, also known as bone marrow transplantation, is currently the only potentially curative option for MDS. It replaces abnormal stem cells with healthy ones from a matched donor. This intensive procedure is generally reserved for younger and fitter patients due to its associated risks.