New Risk Model for MDS Applies to All Stages of Disease

A new risk model for myelodysplastic syndrome (MDS) provides survival projections for all stages of the disease and has proven superior to the International Prognostic Scoring System (IPSS) that has been traditionally used. The results of this study were presented at the annual meeting of the American Society of Hematology on December 8, 2008 in San Francisco, California.[1]

Myelodysplastic syndromes (MDS) are a group of diseases marked by abnormal production of blood cells by the bone marrow. Healthy bone marrow produces immature blood cells-called blasts-that then develop into red blood cells, white blood cells, and platelets. MDS disrupts this normal process so that the bone marrow is overactive, producing many immature cells. These blasts, however, do not fully develop into mature blood cells. As a result patients with MDS have fewer mature blood cells, and those they do have may be abnormal and not function properly.

Some patients may survive with MDS, though approximately one-third will have their disease progress to acute myeloid leukemia (AML). AML that develops from MDS is a difficult disease to treat. In order to better plan treatment, doctors try to identify how quickly patients are likely to progress to acute myeloid leukemia (AML).

Historically, physicians have used the IPSS to assign a score to patients based on their likelihood to progress; a higher score is associated with a type of MDS that is likely to progress to leukemia more quickly. The IPSS was developed before there were many treatment options for MDS. One limitation of this model is that it applies only to newly diagnosed patients and therefore is not helpful in guiding treatment decisions once therapy has been initiated.

Researchers at M. D. Anderson Cancer Center have developed a new risk model that includes different subsets of the disease not included in the IPSS and also applies to patients throughout all stages and treatment of MDS. In order to develop this model, they analyzed 1,915 patients over a period of 12 years.

Whereas the IPSS takes into account three factors (percentage of bone marrow blasts, genetic abnormalities, and severity of low blood cell counts), the new model adjusts for duration of disease, prior therapy, development of secondary MDS and the presence of chronic myelomonocytic leukemia. In addition, the new model assigns points based on a combination of age, platelet count, anemia, percentage of bone marrow blasts, and chromosomal abnormalities.

In this study patients were randomly divided into a study group (958) and a test group (957). The researchers used the new risk model to divide the 958 patients in the study group into four prognostic groups: low-risk, intermediate 1, intermediate 2, and high-risk. (See Table 1.)

Table 1: Four Distinct Prognostic Groups with New MDS Risk Model



Number of Patients

Median Survival

3-year Survival




54 months

63 months

Intermediate 1



25 months

34 months

Intermediate 2



14 months

16 months




6 months

4 months

The results of the model were then validated in the test group of 957 patients. The researchers then compared the new model to the IPSS and found that “applying the prognostic score of the new model within the four IPSS risk groups, overall and in primary MDS without prior therapy, was highly prognostic in each. Applying the IPSS within each of the four risk groups of the new MDS model was not prognostic.”

The researchers concluded that the new risk model is superior to the IPSS. Further validation will be needed, but at this point M. D. Anderson has adopted this risk model for use in its clinical setting.


[1] Kantarjian HM, O’Brien S, Ravandi F, et al. Development and validation of a new prognostic model for meylodysplastic syndrome (MDS) that accounts for events not considered by the International Prognostic Scoring System (IPSS). Blood. 2008; 112 (126): Abstract 635.

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