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Pediatric myelodysplasia: a study of 68 children and a new prognostic scoring system
S J Passmore1, I M Hann, C A Stiller
1Institute of Child Health, London, UK.
Insights
A revised classification and scoring system for pediatric myelodysplasia (MDS) improves prognostic accuracy. Incorporating fetal hemoglobin and cytogenetics into the French-American-British (FAB) system aids treatment decisions for childhood MDS.
Area of Science:
- Pediatric Hematology
- Oncology
- Clinical Genetics
Background:
- Myelodysplasia (MDS) in children presents diagnostic challenges.
- The French-American-British (FAB) classification system has limitations in pediatric MDS.
- Cytogenetic abnormalities are common in pediatric MDS.
Purpose of the Study:
- To evaluate the utility of the FAB classification for pediatric MDS.
- To develop a modified classification and scoring system for improved prognostication in pediatric MDS.
- To identify key prognostic factors in childhood MDS.
Main Methods:
- Retrospective analysis of 68 children with MDS.
- Morphologic, clinical, and cytogenetic data analysis.
- Development of a revised classification incorporating fetal hemoglobin (Hb F) and cytogenetics, and a prognostic scoring system (FPC).
Main Results:
- The FAB system had limited value, with 50% of cases classified as chronic myelomonocytic leukemia.
- Clonal cytogenetic abnormalities were detected in 55% of cases, with chromosome 7 abnormalities being most common.
- The modified FAB classification and FPC scoring system significantly stratified patient survival (P = .00009).
- The FPC score, based on Hb F, platelet count, and cytogenetic complexity, predicted 5-year survival (Score 0: 61.6%; Score 2-3: died within 4 years).
Conclusions:
- A modified FAB classification and a new scoring system (FPC) improve prognostication in pediatric MDS.
- Fetal hemoglobin levels, platelet counts, and cytogenetic complexity are crucial prognostic indicators.
- The revised system may aid in treatment decisions for pediatric MDS and requires prospective validation.
Abstract:
Clinical, morphologic, and cytogenetic features were examined in a group of 68 children with myelodysplasia (MDS) referred to a single institution between 1971-1991. The morphologic French-American-British (FAB) system of classification proved of limited value in this group of patients because 50% of the cases were categorized as chronic myelomonocytic leukemia and three patients with eosinophilia and MDS were unclassifiable. Cytogenetic analysis was performed in 63 cases and clonal abnormalities were detected in 55%; the most common chromosome involved was number 7. Modification of the FAB system to incorporate additional diagnostic features such as pretreatment fetal hemoglobin (Hb F) and cytogenetics allowed incorporation of the categories of juvenile chronic myeloid leukemia (JCML) and infantile monosomy 7 syndrome (IMo7). The resulting groups of patients had highly significant differences in survival (P = .00009). The overall 5-year survival for the patients was 31.9% (95% CI 21.7 to 44.1) and factors influencing prognosis included: modified FAB type, platelet count, Hb F level, and cytogenetic complexity. We developed a scoring system ("FPC") where each of the following findings at diagnosis scored one point: HbF greater than 10%, platelets < or = 40 x 10(9)/L, and complex karyotypic changes (two or more clonal structural/numerical abnormalities), which produced groups with highly significant differences, patients with a score of 0 having a 5-year survival of 61.6% (CI 33% to 84%), whereas those with a score of two or three all died within 4 years of diagnosis. The revised classification and scoring system may prove helpful in making treatment choices in pediatric MDS and now needs to be tested prospectively in large scale population-based studies.
