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Detailed Guide: Myelodysplastic Syndrome
How Is Myelodysplastic Syndrome Staged?

Doctors often group cancers into different stages based on the size of the tumor and how far the cancer has spread from the original site in the body. The stage of a cancer can help predict the outlook for a cancer. Often, the stage of a cancer is used to decide which treatment is needed.

However, myelodysplastic syndrome (MDS) is a disease of the bone marrow. It cannot be staged by looking at the size of a tumor like some other cancers. In MDS, other factors are used instead. These factors include the patient's blood counts, the appearance of their bone marrow, their age, and certain chromosome changes.

International Prognostic Scoring System

The International Prognostic Scoring System (IPSS) is a system developed for staging MDS. It was intended for use with the FAB classification system. It rates 3 factors:

  1. the percentage of blasts in the bone marrow (scored from zero to 2)
  2. chromosome abnormalities (scored from zero to 1)
  3. the patient's blood counts. (scored as zero or 0.5)

Each factor is given a score; with the lowest scores have the best outlook. Then the scores for the factors are added together to make the IPSS score.

The IPSS puts people with MDS into 4 groups:

  • low risk,
  • intermediate - 1 risk (Int-1) ,
  • intermediate - 2 risk (Int-2),
  • high risk

Below is a table for the outlook for each group:


IPSS risk group 5-year survival* Risk of leukemia +
Low 55% 15%
Int-1 35% 30%
Int-2 7% 65%
High 0% 100%

*The 5-year survival rate refers to the percentage of people who live at least 5 years after they are diagnosed with MDS. The 5-year rate is used to produce a standard way of discussing outlook. Of course, many people live much longer than 5 years.

+The percentage of people who will develop leukemia within 5 years of diagnosis of MDS.

WHO prognostic scoring system (WPSS)

More recently, a scoring system was developed based on 3 factors:

  • the type of MDS based on the WHO classification
  • chromosome abnormalities
  • whether or not the patient requires transfusions

  No points 1 point 2 points 3 points
WHO type RA, RARS,
(del)5q 		RCMD,
RCMD-RS 		RAEB-1 RAEB-2
Chromosomes Good Intermediate Poor  
Needs Transfusions No Yes    

This system puts patients with MDS into 5 groups
Very low risk (score = 0)
Low risk (score = 1)
Intermediate (score = 2)
High risk (score = 3 or 4)
Very high risk (score = 5 or 6)
Risk Group Median Survival* Risk of Leukemia (within 5 years)+
Very low 12 years 3%
Low 5.5 years 14%
Intermediate 4 years 33%
High 2 years 54%
Very high 9 months 84%

*Median survival is the amount of time for half the patients in the group to die. This is a middle value -- half the patients live longer than this, and half do not live this long. Median survival is another standard way to indicate outlook..

+ The percentage of people who will develop leukemia within 5 years of being put into this risk group.

Last Revised: 12/07/2006