Myelodysplastic Syndromes - MDS: Subtypes and Classification

Approved by the Cancer.Net Editorial Board, 05/2023

ON THIS PAGE: You will learn about how doctors describe myelodysplastic syndromes (MDS). This is called MDS subtype and classification. Use the menu to see other pages.


How is MDS classified?

MDS classifications are a way of describing the disease, its severity, the need for treatment, and how long a person with MDS is expected to live, which is called a prognosis.

Doctors use diagnostic tests to find out the subtype and classification of MDS, so this may not be complete until all of the tests are finished. Knowing the classification helps the doctor recommend the best kind of treatment. It can also help predict a patient's prognosis, which is the chance of recovery. Each classification and prognostic system is described in more detail below.

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Systems for MDS classification

There are several different systems of classifying MDS and the prognosis for people with MDS. Your doctor may use one or more of these systems to understand how you are affected by MDS.

WHO system for MDS subtypes. The World Health Organization (WHO) developed a classification system for MDS to standardize the definitions of the different subtypes. This classification system was updated in 2022 and includes 6 different subtypes divided into two categories.

International Consensus Classification (ICC) system. This classification system was developed in collaboration with the Society for Hematopathology and the European Association for Haematopathology. The ICC system classifies different myeloid neoplasms (blood cancers), including MDS, and acute leukemias. It also includes 6 different subtypes.

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Systems for determining prognosis

There is no staging system for MDS. However, there are scoring systems that doctors use to help predict a person's risk of developing AML and overall prognosis. Each system uses three factors, based on results of different tests (see Diagnosis):

  • Low blood counts measured by hemoglobin level in red blood cells, platelet number, and neutrophil level. Neutrophil is a type of white blood cell.

  • Percentage of blasts in the bone marrow

  • Genetic changes from chromosome testing and molecular testing

There are two systems in place for determining the prognosis of a person with MDS. Both systems determine a person's risk on a range from "very low" to "very high." These system's help predict a person's risk of developing AML and overall survival. The types of treatment a person with MDS receives depends on their prognostic score. Your doctor may use either system for determining prognosis. Be sure to ask your doctor any questions you may have about which system they use and what this means for you.

Revised International Prognostic Scoring System (IPSS-R). This system looks at factors such as the percentage of blasts found in the bone marrow, type and extent of chromosomal changes, and levels of hemoglobin found in red blood cells, platelets, and a type of white blood cell called neutrophils.

Poor prognostic factors include:

  • Certain types and higher numbers of chromosomal changes

  • Higher percentage of blasts in the bone marrow

  • Low levels of hemoglobin, platelets, and neutrophils

The total IPSS-R score places people with MDS into 5 distinct groups:

  • Very low risk

  • Low risk

  • Intermediate risk

  • High risk

  • Very high risk

Molecular International Prognostic Scoring System (IPSS-M) uses the same data as the IPSS-R system and also uses the results of molecular testing. This can only be calculated if molecular testing has been completed. The information is entered in a calculator which will place the disease in 1 of 6 risk groups:

  • Very low

  • Low

  • Moderate low

  • Moderate high

  • High

  • Very high

People with a lower IPSS-R or IPSS-M score have the best outlook for survival and need less aggressive treatment. For patients with lower scores, overall survival rates tend to be lower when they need red blood cell transfusions. A red blood cell transfusion is a procedure in which blood cells from a healthy person, called a donor, are given to another person who has anemia, which means too few red blood cells. A person diagnosed with a high-risk subtype of MDS and whose prognostic score is high usually needs more intensive treatment.

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Recurrent MDS

Recurrent MDS is MDS that has come back after a period of remission, or absence of symptoms, also called “no evidence of disease” or NED. If the MDS does return, there will be another round of tests to learn about the extent of the recurrence. These tests and scans are often similar to those done at the time of the original diagnosis.

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Information about the subtype and classification will help the doctor recommend a specific treatment plan. The next section in this guide is Types of Treatment. Use the menu to choose a different section to read in this guide.