Myelodysplastic Syndrome (MDS) Prognostic Scores (Risk Groups)

For most types of cancer, the  stage  of the cancer – a measure of how far it has spread – is one of the most important factors in selecting treatment options and in determining a person’s outlook (prognosis).

But myelodysplastic syndromes (MDS) generally are widespread in the bone marrow and blood when they’re found. The outlook for these cancers isn't based on the size of a tumor or whether the cancer has spread. Because of this, doctors use other factors to help predict the outlook (prognosis) for people with MDS and to decide when (and how) to treat them.

Some of these factors have been combined to develop scoring systems that can help predict a person’s risk of the MDS progressing.

Revised International Prognostic Scoring System (IPSS-R)

The revised International Prognostic Scoring System (IPSS-R) is based on 5 factors:

• The percentage of blasts (very early forms of blood cells) in the bone marrow
• The type and number of chromosome abnormalities in the MDS 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

Each factor is given a score, with the lowest scores having the best outlook. Then the scores for the factors are added up to put people with MDS into 5 risk groups:

• Very low risk
• Low risk
• Intermediate risk
• High risk
• Very high risk

These risk groups can be used to help predict a person’s outlook, including how likely the MDS is to progress to acute myeloid leukemia (AML).

The risk groups can also be helpful when trying to determine the best treatment options. In general:

• MDS in the lower risk groups (very low, low, and some intermediate risk MDS) can often be treated less intensely.
• MDS in the higher risk groups (very high, high, and some intermediate risk group MDS) usually needs to be treated more intensely.

The IPSS-R has some important limitations. For example:

• It was developed before many of the current treatments for MDS were available, so it only considered people who were not treated for their MDS.
• It did not include people who have MDS as a result of getting chemotherapy or radiation (secondary MDS).
• It was developed before the importance of many of the gene and chromosome changes that can be found inside MDS cells was understood.

The IPSS-R is helpful and is still used widely, although it’s likely to be replaced over time with systems that also take into account more of the gene and chromosome changes that can happen in MDS cells, such as the IPSS-M (see next section).

Molecular International Prognostic Scoring System (IPSS-M)

The Molecular International Prognostic Scoring System (IPSS-M) is a newer system that takes into account many of the same factors as the IPSS-R, as well as the results of lab tests that look for gene and chromosome changes in the MDS cells. This information is used to divide people with MDS into 6 risk groups:

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

As with the IPSS-R, this system can be used (along with other factors) to help predict a person’s outlook, as well as which treatment options are likely to be best.

Again, for treatment purposes, doctors using this system often divide people with MDS into two groups:

• Lower-risk MDS includes very low, low, and moderate-low risk groups.
• Higher-risk MDS includes moderate-high, high, and very high-risk groups.

Both the IPSS-R and the IPSS-M can be complex, and different doctors might use different systems (or even other prognostic systems). If you have MDS, talk to your doctor about which system they use, which risk group you are in, and what it might mean for your treatment and outlook.

Other prognostic factors

Along with the factors used in these scoring systems, doctors have found some other factors that can also help predict a person’s outlook. Examples include:

• A person’s age
• A person’s performance status (how well they’re able to do normal daily activities)
• The results of certain blood tests, such as the serum ferritin level