How does WPSS differ from IPSS?

The original IPSS can only be applied at MDS diagnosis and uses blast percentage, karyotype, and cytopenia count. WPSS replaces blast percentage with WHO morphologic sub-type and cytopenia count with transfusion dependency, allowing it to be used dynamically at any point during the disease course.

What defines transfusion dependency in WPSS?

A patient is transfusion dependent if they require at least one red blood cell unit every 8 weeks over a 4-month observation period. Occasional transfusions for acute events such as surgery or bleeding do not qualify.

Which karyotypes fall into each cytogenetic risk group?

Good: normal karyotype, isolated del(5q), isolated del(20q), or -Y. Poor: complex karyotype (3 or more abnormalities) or chromosome 7 abnormalities (monosomy 7 or del(7q)). Intermediate: all other cytogenetic findings not classified as Good or Poor.

Can WPSS be recalculated after treatment?

Yes. A key advantage of WPSS over IPSS is that it supports dynamic reassessment. It can be recalculated at any time to reflect disease evolution or response to therapy.

What AML transformation risk does a Very High WPSS score carry?

A WPSS score of 5 or 6 (Very High risk) is associated with approximately 70% cumulative AML evolution risk at 5 years and a median overall survival of around 8 months in the original derivation cohort.

Is this tool a substitute for clinical judgment?

No. WPSS provides population-level prognostic estimates from the original derivation cohort. All results must be interpreted by a qualified hematologist or oncologist in the full clinical context of the individual patient.

WPSS MDS Score

Select WHO MDS category, karyotype risk group, and transfusion dependency to get the WPSS total score (0–6) and risk group with median survival and AML evolution estimate.

Educational use only. WPSS estimates are population-level figures from the original derivation cohort. All clinical decisions must be made by a qualified hematologist or oncologist.

WPSS Risk Group Reference

Score	Risk Group	Median OS	~5-yr AML Risk
0	Very Low	136 months (~11.3 yrs)	~3%
1	Low	63 months (~5.3 yrs)	~8%
2	Intermediate	44 months (~3.7 yrs)	~20%
3–4	High	19 months (~1.6 yrs)	~45%
5–6	Very High	8 months (~0.7 yrs)	~70%

Source: Malcovati L et al., J Clin Oncol 2007. Figures reflect the original derivation cohort and may differ in contemporary practice.

Summary

Select WHO MDS category, karyotype risk group, and transfusion dependency to get the WPSS total score (0–6) and risk group with median survival and AML evolution estimate.

How it works

Select the WHO MDS sub-type based on bone marrow morphology and peripheral blood findings.
Choose the cytogenetic risk group derived from bone marrow cytogenetic analysis.
Indicate whether the patient meets the transfusion dependency threshold (at least one RBC unit every 8 weeks over a 4-month period).
Click Calculate to sum the three component scores into a total WPSS score (0–6).
Review the risk group, median overall survival estimate, and approximate 5-year AML evolution risk.

Use cases

Estimate prognosis at diagnosis or at any point during the MDS disease course.
Guide treatment decisions between watchful waiting, disease-modifying therapy, and allogeneic stem cell transplant.
Risk-stratify patients for clinical trial eligibility or transplant evaluation.
Serial reassessment over time to detect disease progression.
Educate hematology trainees on MDS prognostic variables and the WPSS framework.

WPSS MDS Score

1 WHO MDS Category

2 Cytogenetic Risk Group

3 Transfusion Dependency

WPSS Score

Score Components

Clinical Notes