This article from the Journal of Hospital Medicine summarizes the key information about myelodysplastic syndromes that hospital-based physicians should understand. It is important for general medicine physicians to recognize the signs and symptoms of MDS, which can lead to referral to a hematologist as well as earlier diagnosis and treatment if indicated.
Myelodysplastic syndromes (MDS) represent a blood disorder characterized by ineffective production of cells leading to low blood counts and risk of development of acute myeloid leukemia. MDS is more common in the elderly, and the prevalence is increasing as the population lives longer.
Many patients with MDS do not have symptoms at diagnosis and only come to medical attention due to abnormal blood counts on routine examination. This is one of the reasons MDS is under-diagnosed. In addition, there is a misconception that anemia (a low red blood cell count) is normal in the elderly and that a workup is not warranted in an asymptomatic patient. However, anemia is not associated with aging and is not normal in older patients. A workup should include evaluation for nutritional deficiencies, kidney function, bleeding, inflammation, and review of a peripheral blood smear. Ultimately, the diagnosis of MDS requires a bone marrow aspirate and biopsy, which is a procedure where a small amount of fluid and piece of bone are collected from the patient and examined under the microscope. This procedure is commonly done as an outpatient.
The cause for MDS is not fully understood; however, there are complex genetic mechanisms that contribute and are the subject of current research. The disease varies greatly from patient to patient. There are several markers that can be used to assist in prognosis, including evaluation for chromosomal abnormalities, which occur in approximately half of patients and are routinely tested during bone marrow analysis. More recently, there has been an interest in testing for molecular mutations, including abnormalities in specific genes that may assist in determining prognosis. About 10% of patients with MDS develop the disorder as a result of previous chemotherapy or radiation as treatment for another malignancy. There are also associations with smoking, paint, insecticides, pesticides, and organic solvents.
There are several tools that can help physicians to assess prognosis of an MDS patient and determine the most appropriate treatment choice. The most widely used prognostic tool is the International Prognostic Scoring System (IPSS) that looks at several characteristics, including the percentage of immature cells in the bone marrow (blasts), number of cell lines affected by low blood counts (0-3), and variations in the chromosomal profile. Other factors play an important role as well, including the frequency of transfusions and the severity of low blood counts. A newer classification system called the revised IPSS (IPSS-R) was more recently developed to take into account some of these additional characteristics that are important in characterizing MDS.
Several factors are taken into account when deciding on treatment for MDS, including age, physical energy, co-existing medical problems, and patient preference. Generally, most patients are candidates for supportive therapy, which includes transfusion support, use of growth factors, and antibiotics as needed.
Using the IPSS classification system described above, MDS can be divided in 2 major risk categories: lower-risk and higher-risk disease. Treatment strategies often differ depending on risk category, ranging from supportive care to possible enrollment in clinical trials. In addition to supportive care, lower-risk patients are offered erythropoiesis-stimulating agents (ESAs), lenalidomide, and immununosuppressive therapy. ESAs are injections administered under the skin that are used to boost the red blood cell count in an effort to improve anemia and decrease the number of transfusions required. It is important to note that ESA therapy has not been associated with an increased risk of blood clots in MDS unlike in other malignancies. Lenalidomide (Revlimid®) has been used primarily in patients with a chromosomal abnormality of 5q- although it has also been shown to be effective in those without this deletion. It can produce transfusion independence and complete remissions in lower-risk MDS patients. In addition, some patients with lower-risk disease respond to therapies that suppress the immune system, including antithymocyte globulin (ATG) with or without cyclosporine.
For higher-risk patients, the goals of therapy include prolonging survival and halting progression of disease. There are three standard approaches, including agents such as azacitidine (Vidaza®) and decitabine (Dacogen®), intensive chemotherapy, and stem cell transplantation. Patients tend to tolerate azacitidine and decitabine fairly well. These agents appear to restore normal cell production in many MDS patients, although the effects are not permanent. Azacitidine and decitabine have been shown to improve blood counts, reduce transfusion needs, reduce infection rates, decrease risk of progression to leukemia, and improve quality-of-life compared to supportive care alone. Many patients are not candidates for intensive chemotherapy and stem cell transplant due to age and co-existing medical problems.
- MDS is a form of cancer that is more common in elderly patients and leads to low blood counts and increased risk of transformation to acute myeloid leukemia.
- MDS is under-diagnosed and should be considered in the workup of a patient with abnormal blood counts.
- There are a variety of treatment options for MDS patients depending on their concurrent medical problems, status of disease, and patient preference.