[Prognosis and chromosomal abnormalities in 79 children with t (8;21) acute myeloid leukemia].

OBJECTIVE

To investigate the chromosomal abnormalities and evaluate the prognostic value of post-remission chemotherapy in children with t (8;21) acute myeloid leukemia (AML).

METHODS

The diagnosis of AML and its subtyping were performed using morphological, immunological, and cytogenetic methodologies in 79 children. Induction therapies included homoharringtonine and cytarabine (HA), daunorubicin and cytarabine (DA), or homoharringtonine and daunorubicin and cytarabine (HAD). Allogeneic stem cell transplantation or 5-6 cycles of intensive chemotherapy was performed after remission therapy.

RESULTS

Additional chromosomal abnormalities, including loss of sex chromosome (n = 40, 50.6%), del (9q) (n = 9, 11.4%), and complex abnormality (n = 7, 8.9%) were identified in 55 patients (69.6%). Three patients had more than 90 chromosomes and duplicate t (8;21) tetraploid karyotype, and their prognoses were poor. The complete remission (CR) rates were 81.7% (49/60) and 94.8% (55/58), respectively, after one and two cycles of induction chemotherapy. The 3-year event-free survival rate (EFS), disease-free survival rate (DFS), and overall survival rate (OS) were (26.2 +/- 6.8)%, (31.3 +/- 6.7)%, and (27.6 +/- 6.6)%, respectively. Twenty-nine patients received 5 or more cycles of chemotherapy after CR and demonstrated an improved 3-year DFS [(51.7 +/- 9.3)%]. The 3-year DFS was not significantly differently in patients with or without additional abnormalities other than sex chromosome (P = 0.36). Post-remission consolidation by high dose cytarabine (HDAC) was significantly superior to standard chemotherapy (66.7% vs. 27.3%, P = 0.03).

CONCLUSION

Most children with t (8;21) AML have additional chromosomal abnormalities, although they do not affect the prognosis and long-term survival. Few patients have more than 90 chromosomes and duplicate t (8;21) tetraploid karyotype, which may result in poor prognosis. Childhood t (8;21) AML usually has high CR rate with relatively good prognosis, and post-remission consolidation by HDAC can improve the survival.