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Prognostic implications of cytogenetic studies in an intensively treated group of children with acute lymphoblastic
J A Fletcher1, V M Kimball, E Lynch
1Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115.
Insights
Cytogenetic analysis in childhood acute lymphoblastic leukemia (ALL) showed no significant differences in survival across most categories. However, Philadelphia chromosome (Ph) may indicate a poor prognosis, though further research is needed.
Area of Science:
- Pediatric Oncology
- Hematology
- Cancer Genetics
Background:
- Cytogenetic abnormalities in leukemia cells are crucial for prognosis.
- Previous studies suggest varying survival rates based on cytogenetic profiles in childhood acute lymphoblastic leukemia (ALL).
Purpose of the Study:
- To evaluate the prognostic significance of leukemia cell cytogenetics in children diagnosed with ALL.
- To determine if specific cytogenetic categories correlate with event-free survival (EFS) and overall survival (OS).
Main Methods:
- Bone marrow aspirates from 165 children with ALL were analyzed at diagnosis.
- Patients were categorized into six cytogenetic groups: hyperdiploid (>50 chromosomes), hyperdiploid (47-49 chromosomes), diploid, pseudodiploid, hypodiploid, and insufficient data.
- Survival outcomes were assessed at a median follow-up of 5 years.
Main Results:
- No statistically significant differences in EFS or OS were found among the main cytogenetic categories.
- Children with chromosomal translocations had similar outcomes to those without.
- The Philadelphia chromosome (Ph) showed a trend towards a poor prognosis, but lacked statistical significance due to small sample size.
Conclusions:
- Cytogenetic features did not demonstrate significant prognostic value in this cohort of childhood ALL patients.
- Improved therapies may have diminished the prognostic impact of traditional cytogenetic markers.
- Further investigation with larger cohorts is warranted, particularly for specific abnormalities like the Philadelphia chromosome.
Abstract:
We assessed the prognostic significance of leukemia cell cytogenetics by analyzing bone marrow aspirates obtained at time of diagnosis in 165 children on a single protocol for acute lymphoblastic leukemia (ALL). These children were assigned to six mutually exclusive cytogenetic categories as follows: (1) hyperdiploid, with 50 or more chromosomes (n = 35); (2) hyperdiploid, with 47 to 49 chromosomes (n = 11); (3) diploid (n = 42); (4) pseudodiploid (n = 34); (5) hypodiploid (n = 9); and (6) insufficient data (n = 34). At a median follow-up of 5 years, there were no statistically significant differences between any of these cytogenetic categories in either event-free or overall survival. Those children with chromosomal translocations (n = 26) appeared to fare the same as those lacking translocations (n = 105). The absence of karyotypic prognostic significance was observed not only within the overall group, but also when the results were stratified by standard-risk and high-risk status. Of the specific structural chromosome changes that we studied, only the Philadelphia chromosome (Ph) appeared to confer a poor prognosis, although there were too few such cases to achieve statistical significance. Although we did not detect the event-free survival differences that have been described previously in hyperdiploid, hypodiploid, and pseudodiploid childhood ALL, our findings must be viewed as preliminary given the small number of children in some of the cytogenetic categories. We think that the prognostic implications of these cytogenetic features might have been nullified by improvements in therapy.