Q: My sister-in-law was diagnosed with Myelodysplastic Syndrome. What is this?
A: The three major types of blood cells are produced in the bone marrow and include red blood cells (RBCs) that carry oxygen, white blood cells (WBCs) that fight infection and platelets that help the blood clot to prevent excessive bleeding. Myelodysplastic Syndrome (MDS) is a disorder of the bone marrow, so this disease manifests as inadequate amounts of one or more of these cell types.
MDS is thought to occur when a progenitor blood cell (a cell that can differentiate into any type of blood cell precursor) mutates into an abnormal cell; several different genetic mutations that may lead to MDS have been identified. About one third of MDS patients “progress” into acute myeloid leukemia (AML), showing that there is overlap in these diseases.
Although more than 80 percent of MDS cases arise spontaneously (that is, no cause is identified), having been treated with certain chemotherapy drugs or radiation therapy, exposure to certain chemicals (such as benzene), certain viral infections, certain genetic syndromes and smoking have all been identified as risk factors that may trigger a cell mutation leading to MDS.
MDS is diagnosed in about four to five per 100,000 Americans every year. It becomes more common as people age, and it is more common in men than women.
Many people with early MDS have no symptoms, but when symptoms manifest they are driven by which cell lines are involved. Low RBCs may cause fatigue and even shortness of breath, low WBCs may predispose someone to acquiring infections and low platelet counts may make them bleed more easily. If any of these are severe they can be life threatening.
Since MDS affects blood cells and how they are produced in the bone marrow, when someone has symptoms suggestive of it (or has low counts of one or more blood cell types noted when a blood test is done for some other reason) a complete blood count, evaluation of the bone marrow (with a bone marrow aspiration and bone marrow biopsy) and genetic evaluation of the affected cells are done to diagnose the condition.
Several different scoring systems have been designed to characterize (stage) MDS; these are useful to help guide treatment decisions and to assess a patient’s prognosis. These systems score the type and severity of a patient’s MDS depending on how many cell lines are involved (for example if only the RBC count is low or if there are other cell types affected as well), what percent of the bone marrow is infiltrated with abnormal cells (called blast cells) and what genetic mutation is identified (the patient’s karyotype).
Low-risk patients (with lower scores) have a median survival from time of diagnosis of about six years, very high-risk patients have a guarded prognosis with median survival of half a year and intermediate risk patients have a prognosis between these. The average time for MDS to “transform” into AML also correlates with the risk level as assessed by these scoring systems.
Page 2 of 2 - Many patients do not require any specific treatment except supportive care, which may include transfusions of RBCs and/or platelets as needed. Antibiotics may be needed if an infection develops. Some patients may be treated with supplemental iron, copper and/or vitamin B12 if they are deficient in any of these, and all patients should be vaccinated as needed to help prevent infections. Selected patients may benefit from medications that stimulate their own production of specific blood cells lines.
In addition to supportive care, some patients may require treatment with chemotherapeutic agents, treating their MDS just as certain types of cancer are treated. The specific chemotherapy agent utilized depends on the specifics of the patient’s condition.
Bone marrow transplantation (BMT) is a treatment option for some carefully selected patients (those who would likely be able to tolerate this aggressive treatment regimen), and is the only treatment with a potential to “cure” their condition. BMT involves eradicating the cells in the patient’s bone marrow with aggressive chemotherapy then transfusing them with bone marrow cells from a matched donor to repopulate their bone marrow. This aggressive treatment option carries with it a significant mortality (up to 20 percent), and 10-40 percent of patients relapse despite an initial response to treatment.
Patients with MDS should be closely followed by a specialist to assess what treatments are best for them and if/when their treatment plan should be modified. Even patients who have responded to a BMT need close follow-up to determine if they have relapsed and if further treatment may be indicated.
Jeff Hersh, Ph.D., M.D., can be reached at DrHersh@juno.com.