Myelodysplastic Syndromes (MDS)

Myelodysplastic syndromes (MDS) are a group of diseases that affect the bone marrow hematopoietic (blood forming) stem cells.  The blood forming cells in the marrow slow down or stop making red blood cells, white blood cells and platelets.  Most patients with MDS will develop anemia (low red blood cell numbers).  Some patients have low numbers of white blood cells (which fight infections) and platelets (which help blood clot).  Some types of MDS are mild and easily managed, while other types are severe and life-threatening.  Mild MDS can evolve to become more severe over time and can also develop into fast-growing severe leukemia called acute myelogenous leukemia (AML). 

MDS can affect people of any age, but the majority of patients are older than 60 years.  Exposure to industrial chemicals or radiation may increase the risk of developing MDS.  In some cases MDS is caused by chemotherapy used to treat a different disease.  This is called secondary MDS.  The cause of MDS in most cases is unknown.  There are many different types of MDS.  Detailed evaluation of the blood and bone marrow is needed to determine the type of MDS.

A blood or marrow transplant is the only cure for MDS, but indications and timing are controversial.  The type of transplant used for MDS is an allogeneic transplant which uses healthy blood forming cells from a family member or an unrelated donor.  Whether a transplant is right for a specific patient depends on patient age, overall health, the type of MDS and the risk score of the MDS.

The patient’s risk score is based on several aspects of the disease including how many blasts (immature white blood cells) are in the bone marrow, peripheral blood counts, cytogenetic testing.  MDS risk scores are grouped into five categories:  very low, low, intermediate, high and very-high.  Patients in the very low and low risk groups have mild disease and may not receive any treatments.  They will likely have frequent blood tests to see if the MDS is stable or becoming worse.

Patients in all other risk categories will likely receive one or more drugs that help treat the MDS to improve blood counts.  These drugs cannot cure MDS, but help increase blood counts for some patients and improve quality of life. 

There are medical guidelines for when someone should be referred for a transplant consultation, whether or not the patient might need a transplant at that time.