Diagnosis and Prognosis of Myelodysplastic Syndrome (MDS)
The diagnosis of MDS ultimately depends on microscopic examination of your bone marrow and the analysis of damage to the chromosomes or DNA of bone marrow cells. For this exam, you'll need to have a bone marrow biopsy. But before your doctor will recommend this biopsy, he or she will ask about your symptoms and medical history, perform a physical exam, and do some testing. However, MDS tends to produce nonspecific symptoms and the bone marrow biopsy will be necessary for diagnosis.
The diagnosis and prognosis of MDS includes the following:
Review of Medical History
Your doctor will ask about your symptoms and medical history. Your answers may point in any of three directions: to your red blood cells that suggest anemia, to your blood clotting mechanisms if you are bruising or bleeding, or to your immune system if you are having worrisome infections. Rarely, patients may present during an acute infection that signifies an infection-fighting deficit. In this case, a persistent sore throat or nonhealing infection elsewhere may be the first sign of difficulty.
There may be little or nothing to discover from your physical exam. You may have bruising, an active infection somewhere in your body, or findings such as pale skin and a rapid heartbeat that suggest anemia. Your spleen, lymph glands, and/or liver may be enlarged.
Your first set of laboratory tests will probably be very general and may include the following:
- Blood chemistry and urinalysis —A sample of your blood and a sample of your urine are tested. These tests will be done as a routine and may reveal abnormalities, but they will not be specific.
- Complete blood count (CBC) —A blood count may reveal multiple abnormalities and be the basis for further investigations. Your blood will be analyzed on an automated cell counter to determine the number and type of white blood cells, red blood cells, and platelets.
- Peripheral blood smear —Your blood sample will be examined in the laboratory under a microscope. If you have MDS, some or all of your blood cells will be either abnormal or deformed when examined under magnification. The most common abnormality is one of quantity; that is, patients with MDS most often have low amounts of one or more blood cell types. Occasionally the number may be increased and the relative counts may fluctuate over time.
If there are abnormalities in your blood tests, your doctor will likely refer you to a hematologist (a physician who specializes in disorders of the blood), who will do a bone marrow biopsy.
For this procedure, you'll be given local anesthesia, then a needle is inserted into the back of the pelvis to the right or left of the midline, or your sternum (breastbone). A sample of the bone marrow tissue is suctioned out for testing in two parts. The first part is called the aspiration where 1-2 teaspoons of bone marrow liquid is removed. The second part involves removing a small core of tissue (biopsy) to examine the architecture surrounding the cells. The exam of the bone marrow tissue will not only confirm a diagnosis, it will also characterize the type of MDS and provide treatment and prognostic information. Some of the aspiration material is also sent for molecular and chromosome analysis. This procedure may cause some discomfort, but it is brief.
Cytology is the study of cells. The cytology of cancer cells differs significantly from normal cells, and physicians use the unique cellular features seen on biopsy samples to determine the diagnosis and assess the prognosis of a cancer. With MDS, the bone marrow produces enough cells, but the cells are abnormal and unable to function properly. Any or all of the cell types in the marrow may show abnormalities that will confirm your diagnosis with precision. However, a few cell types are critical to the final classification of the several forms of MDS:
- A “blast” is the most immature form of any of the cell types. More than 30% blasts in the bone marrow traditionally signifies the presence of acute leukemia.
- A “ringed sideroblast” is from the red blood cell series.
Tests can also be done to look at the cells’ chromosomes. MDS can be diagnosed when there are missing or abnormal chromosomes.
Staging is the process by which physicians determine the prognosis of a cancer that has already been diagnosed. Staging is essential for making treatment decisions (eg, surgery vs. chemotherapy). Several features of the cancer are used to arrive at a staging classification, the most common being the size of the original tumor, extent of local invasion, and spread to distant sites (metastasis). Low staging classifications (0-1) imply a favorable prognosis, whereas high staging classifications (4-5) imply an unfavorable prognosis.
Since MDS is a bone marrow disease, it can not be classified using the traditional staging method. Instead, there are two different staging systems used for MDS: International Prognostic Scoring System (IPSS) and WHO (World Health Organization) Scoring System (WPSS).
International Prognostic Scoring System (IPSS)
The IPSS rates three factors to stage MDS:
- Percentage of blasts in the bone marrow
- Chromosome abnormalities
- Patient blood counts
Patients are given a score for each of the three factors. The lower the score the better the prognosis. The scores are added together to get an overall IPSS score. There are four categories of IPSS scores:
- Low risk
- Intermediate-1 risk
- Intermediate-2 risk
- High risk
The IPSS scoring uses the following five classifications of bone marrow appearance:
- Refractory anemia with ringed sideroblasts (RARS)
- Refractory anemia (RA)
- Chronic myelomonocytic leukemia (CMML)
- Refractory anemia with excess blasts (RAEB)
- Refractory anemia with excess blasts in transformation (RAEB-t)
Each of these types has criteria for definition, including the presence of ring sideroblasts and the percentage of cells that are called blasts. In general, the greater the damage, the more the chromosomal damage, and the greater the number of blasts in the bone marrow, the greater the chance of progressing to acute leukemia.
WHO (World Health Organization) Scoring System (WPSS)
This system uses three factors to score risk:
- Type of MDS based on eight WHO classifications
- Chromosome abnormalities
- Patient need for transfusions
Once scored, patients are placed into one of five groups:
- Very low risk
- Low risk
- Intermediate risk
- High risk
- Very high risk
The WHO scoring systems uses the WHO classification system for type of MDS:
- Refractory anemia
- Refractory anemia with ringed sideroblasts
- Refractory cytopenia with multilineage dysplasia
- Refractory cytopenia with multilineage dysplasia and ringed sideroblasts
- Refractory anemia with excess blasts-1
- Refractory anemia with excess blasts-2
- Myelodysplastic syndrome, unclassified
- Myelodysplastic syndrome associated with isolated del(5q)
Prognosis is a forecast of the probable course and/or outcome of a disease or condition. Prognosis is most often expressed as the percentage of patients who are expected to survive over five or ten years. Cancer prognosis is a notoriously inexact process. This is because the predictions are based on the experience of large groups of patients suffering from cancers at various stages. Using this information to predict the future of an individual patient is always imperfect and often flawed, but it is the only method available. Prognoses provided in this monograph and elsewhere should always be interpreted with this limitation in mind. They may or may not reflect your unique situation.
The table below gives the 5-year survival rate and risk of leukemia according to IPSS risk groups.
|IPSS Risk Group||5-year Survival||Risk of Leukemia|
The table below gives the median survival and risk of leukemia according to WPSS risk groups.
|Risk Group||Median Survival||Risk of Leukemia Within Five Years|
|Very low||12 years||3%|
|Very high||9 months||84%|
Castro-Malaspina H, O’Reilly RJ. Aplastic anemia and the myelodysplastic syndromes. In: Harrison's Principles of Internal Medicine. 14th ed. McGraw-Hill; 1998.
Detailed guide: myelodysplastic syndrome. American Cancer Society website. Available at: http://www.cancer.org/docroot/CRI/CRI_2_3x.asp?dt=65. Accessed April 2, 2009.
Silverman LR. Myelodysplastic syndrome. In: Cancer Medicine. American Cancer Society website. Available at: http://www.nci.nih.gov/cancer_information/ . Accessed November 30, 2002.
Last reviewed April 2009 by
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