The prognostic implications of t(9;22)(q34;q11) were assessed at a median follow-up of 3.5 years in 434 children receiving intensive treatment for acute lymphoblastic leukemia (ALL). Four-year event-free and overall survivals were 81% and 88%, respectively, in 419 children lacking t(9;22), but were 0% and 20%, respectively, in 15 children with t(9;22) (P less than .001). Poor outcome for children with t(9;22)- positive ALL was particularly notable because we have reported improved survival in other historically poor prognosis ALL cytogenetic categories when treated with similarly intensive therapy. We recommend that very intensive treatment approaches, including bone marrow transplantation in first remission, be considered for all children with t(9;22)-positive ALL.
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.
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