Criteria of Cheson et al for Cytogenetic Response Following Therapy for a Myelodysplastic Syndrome (International Working Group to Standardize Response Criteria)
Cheson and other members of the International Working Group (IWG) to Standardize Response Criteria reported criteria for a cytogenetic response following therapy of a patient with a myelodysplastic syndrome.
At least 20 metaphases are required to evaluate a patient for a cytogenetic abnormality. Fluorescent in situ hybridization (FISH) targeting a specific defect is an acceptable alternative.
Cytogenetic Abnormality
Number of Metaphases Required for Diagnosis
structural abnormality
>= 2
additional chromosome (trisomy)
>= 2
chromosomal loss (monosomy)
>= 3
The response to therapy is determined by comparing the cytogenetic findings before and after therapy.
Type of Response
Requirement
complete
disappearance of the abnormality
minor response (partial response)
>= 50% reduction of abnormal metaphases
Since a dysplastic cell may have multiple cytogenetic abnormality, each would need to be assessed for its response.
To read more or access our algorithms and calculators, please log in or register.
