Survival of childhood leukemia in Singapore

Global characteristics of childhood acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) comprises approximately 5-10% of childhood acute myeloid leukemia (AML) cases in the US. While variation in this percentage among other populations was noted previously, global patterns of childhood APL have not been thoroughly characterized. In this comprehensive review of childhood APL, we examined its geographic pattern and the potential contribution of environmental factors to observed variation. In 142 studies (spanning >60 countries) identified, variation was apparent-de novo APL represented from 2% (Switzerland) to >50% (Nicaragua) of childhood AML in different geographic regions. Because a limited number of previous studies addressed specific environmental exposures that potentially underlie childhood APL development, we gathered 28 childhood cases of therapy-related APL, which exemplified associations between prior exposures to chemotherapeutic drugs/radiation and APL diagnosis. Future population-based studies examining childhood APL patterns and the potential association with specific environmental exposures and other risk factors are needed.

Improved outcome in childhood acute myeloid leukemia in Singapore with the MRC AML 10 protocol

BACKGROUND

The introduction of the United Kingdom Medical Research Council's 10th AML trial (MRC AML 10) protocol incorporating high-dose anthracycline therapy has improved outcome of children with acute myeloid leukemia (AML). In this study, we review the results of childhood AML therapy in a Singapore university hospital over the last 17 years emphasizing toxicity and outcome.

PROCEDURE

Retrospective analysis revealed 34 children with AML between 1988 and 2003. Prior to September 1996, therapy consisted of: POG-8498 (n = 10), others (n = 9). From September 1996, all but one of 15 children received MRC AML 10 treatment.

RESULTS

At the time of analysis, 17 had died from disease, and 17 patients were alive among whom 2 had relapsed. MRC AML 10-treated patients (n = 14) had significantly better 3-year overall, event-free, and disease-free survival (74% vs. 35%, 77% vs. 20%, 83% vs. 31%; P = 0.019, P = 0.002, and P = 0.010, respectively) and were likelier to achieve complete remission (CR) than non-MRC AML 10 patients (P = 0.102). Among patients who achieved CR, MRC AML 10-treated patients were significantly more likely to achieve CR after only one cycle of chemotherapy (P = 0.016). Hematologic toxicity was similar among the different regimens (P = 0.9).

CONCLUSIONS

These findings suggest that MRC AML 10 treatment results in significantly superior survival, without excess toxicity. Future studies should attempt to elucidate the relative importance of individual MRC AML 10 components and reduce the high cumulative anthracycline dose without compromising outcome.

Outcomes and prognostic factors of Chinese children with acute lymphoblastic leukemia in Hong Kong: preliminary results

BACKGROUND

The Chinese population is the biggest ethnic group in the world. However, there are few reports on the treatment outcome of childhood acute lymphoblastic leukaemia (ALL) among the Chinese population.

PROCEDURE

Sixty-five children with ALL were treated with a modified protocol of the Medical Research Council United Kingdom Acute Lymphoblastic Leukaemia protocol X(MRC UKALL X) at the Prince of Wales Hospital, Hong Kong. Most patients were ethnic Chinese. They were divided into groups A and B, depending on whether their presenting leucocyte count being was less or greater than 50 x 10(9)/l, respectively. Group A patients of received induction, early intensification (week 5), cranial irradiation, and maintenance for 3 years. Group B patients received an additional late intensification (week 20).

RESULTS

The median follow-up duration was 6.8 years(range: 3.4-10.1 years). The event-free and overall survival rates of all patients at 7 years were 66% (confidence interval [CI] 53-76) and 75% (CI 63-84), respectively. The event-free survival rates of groups A and B at 7 years were 67% (CI 52-79) and 60% (CI 32-80), respectively (P= 0.39). The overall survival rates of groups A and B at 7 years were 80% (CI 66-89) and 60% (CI 32-80), respectively (P = 0.07). With this treatment protocol, the factors which adversely affected the outcome were age (<2 years and >10 years) and T-cell subtype. Sex, white blood count at diagnosis, and FAB subtypes were not statistically significant prognostic factors.

CONCLUSIONS

The treatment outcomes were comparable with those reported from the MRC UKALL X trials.

Immunophenotyping pediatric leukemias in Kelantan, Malaysia

This study reviewed the immunophenotyping results of children with acute leukemia in Kelantan, Malaysia. In the 3.5-year period (January 1994 to June 1997), 45 cases were identified. All children were under the age of 12 years and the predominant ethnic group was Malay. Thirty-six cases (80%) were acute lymphoblastic leukemia (ALL) and 9 cases (20%) were acute myeloblastic leukemia (AML). Of the ALL cases, 3% were of B-cell and 22% of T-cell origin, and 96% of the B-lineage ALL were CD10 positive. All the AML cases expressed CD33 and 78% were positive for CD13. The incidence of mixed-lineage leukemias was 13.8% for My+ ALL and 11.1% for Ly+ AML.