The International Prognostic Scoring System

Specific factors may affect the prognosis (likely outcome) of MDS, and help doctors determine when to start treatment and how intensive the treatment should be. These factors include:

  • MDS subtype
  • Number and severity of cytopenias (low blood cell counts)
  • Percent of blast cells in the bone marrow
  • Type and number of chromosome changes

Doctors use these prognostic factors to assign a risk score and risk group. Each prognostic factor is given a number based on its severity. A lower score generally indicates a better outlook. The scores for all the factors are then added together to create the overall risk score. The risk score describes how fast the disease is likely to progress, and is used to assign the patient to a particular risk group. Doctors use the information of a patient’s risk group to choose a treatment approach. 

There are three main prognostic scoring systems:

  • IPSS (International Prognostic Scoring System)
  • IPSS-R (Revised International Prognostic Scoring System)
  • IPSS-M (International Prognostic Scoring System-Molecular) 

International Prognostic Scoring System (IPSS)

The International Prognostic Scoring System (IPSS) was the first widely used scoring system for MDS. A patient’s score is based on three factors:  

  • The percentage of blasts (immature cells) in the bone marrow  
  • The type of chromosomal abnormalities in the cancer cells  
  • Low blood cell counts  

Each factor is given a score. Then the scores are added up to place patients into four risk groups:  

  • Low  
  • Intermediate-1  
  • Intermediate-2  
  • High 

International Prognostic Scoring System-Revised (IPSS-R)

The revised IPSS, known as the “IPSS-R,” covers the same disease factors as the IPSS, but the factors are identified in a more detailed way. The IPSS-R shows five disease factors: 

  • The percentage of blasts (immature cells) in the bone marrow 
  • The type of chromosomal abnormalities in the cancer cells 
  • The level of red blood cells (measured as hemoglobin) in the blood 
  • The level of platelets in the blood 
  • The level of neutrophils (a type of white blood cell) in the blood  

Based on these factors, patients are placed into the following risk groups: 

  • Very Low 
  • Low 
  • Intermediate 
  • High 
  • Very High 

International Prognostic Scoring System-Molecular (IPSS-M)

In 2022, the IPSS-R was updated to include MDS-associated gene mutations. The International Prognostic Scoring System-Molecular (IPSS-M) considers blood counts, such as anemia and low platelet counts, the percentage of bone marrow blasts and the presence of certain chromosomal abnormalities. Unlike the IPSS-R, the IPSS-M also considers whether certain gene mutations are present and how many are mutated. The IPSS-M classifies MDS into six risk groups:  

  • Very low  
  • Low  
  • Moderate Low  
  • Moderate High  
  • High  

For more detailed information on prognostic scoring systems for MDS, view the free LLS booklet Myelodysplastic Syndromes. 

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