Long-term results of Tokyo Children's Cancer Study Group trials for childhood acute lymphoblastic leukemia, 1984-1999

Clinical outcome of children with newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia treated between 1995 and 2005

PURPOSE

In a previous analysis of 326 children with Philadelphia chromosome (Ph) -positive acute lymphoblastic leukemia (ALL) treated between 1986 and 1996, hematopoietic stem-cell transplantation from HLA-matched related donors, but not from unrelated donors, offered a superior outcome than chemotherapy alone. To evaluate the impact of recent improvements in chemotherapy and transplantation, we performed a similar analysis on patients treated in the following decade.

PATIENTS AND METHODS

We analyzed 610 patients with Ph-positive ALL treated between 1995 and 2005 without tyrosine kinase inhibitor therapy. The median follow-up duration was 6.3 years.

RESULTS

Complete remission was achieved in 89% of patients. The 7-year event-free survival and overall survival rates were superior in the present cohort compared with the previous cohort (32.0% ± 2.0% v 25.0% ± 3.0, respectively, P = .007; and 44.9% ± 2.2% v 36.0% ± 3.0%, respectively, P = .017). Compared with chemotherapy alone, transplantation with matched related donors or unrelated donors in first remission (325 patients) showed an advantage with increasing follow-up, suggesting greater protection against late relapses (hazard ratio at 5 years, 0.37; P < .001). In the multivariate Cox regression analysis accounting for treatment (transplantation v no transplantation), age, leukocyte count, and early response had independent impact on treatment outcome.

CONCLUSION

Clinical outcome of children and adolescents with Ph-positive ALL has improved with advances in transplantation and chemotherapy. Transplantations with matched related donors and unrelated donors were equivalent and offered better disease control compared with chemotherapy alone. Age, leukocyte count, and early treatment response were independent prognostic indicators. The results of this study will serve as a historical reference to evaluate the therapeutic impact of tyrosine kinase inhibitors on the outcome of Ph-positive ALL.

Frequencies of ETV6-RUNX1 fusion and hyperdiploidy in pediatric acute lymphoblastic leukemia are lower in far east than west

BACKGROUND

Both ETV6-RUNX1 (TEL-AML1) fusion and hyperdiploidy (>50 chromosomes) in transformed lymphoblasts are favorable genetic features in childhood acute lymphoblastic leukemia (ALL).

PROCEDURE

Among 433 Taiwanese children with ALL diagnosed at our hospitals between 1997 and 2007, the ETV6-RUNX1 fusion was found in 15.8%, and hyperdiploidy (>50 chromosomes) in 14.1% of the patients. These frequencies were lower than those reported in the West, leading us to conduct a meta-analysis of ETV6-RUNX1 fusion and hyperdiploidy frequencies in childhood ALL based on published reports.

RESULTS

The frequency of ETV6-RUNX1 fusion in the Far East (Japan, Korea, China, Hong Kong, Chinese in Singapore, and Taiwan) was 13.4% (177/1,321, range: 9-23%, median 13%), significantly lower than the 22.8% (1,664/7,291, range: 19-26%, median 23%) in the West (West Europe and the United States) (P < 0.001, odds ratio = 2.0, 95% CI: 1.7-2.4). Similarly, the frequency of hyperdiploidy in Japan and Taiwan was 14.3% (333/2,334, range: 12-20%, median 16%), significantly lower than the 25.2% in the West (5,173/20,510, range: 18-34%, median 23.5%; P < 0.001, odds ratio = 2.0, 95% CI: 1.8-2.3).

CONCLUSIONS

This meta-analysis demonstrates lower frequencies of ETV6-RUNX1 fusion and hyperdiploidy among leukemia patients in the Far East compared with the West. The integral relationship of these genetic features with a favorable outcome in childhood ALL warrants further study of potentially important epidemiologic factors, including placental exposure to leukemogenic agents, and host pharmacogenetics.