Acute Myeloid Leukaemia in Children: Preliminary Results of a National Protocol in Casablanca, Morocco

Introduction:

The outcome of acute myeloid leukaemia (AML) in emerging countries is very dismal. In Morocco,the complete remission rate (CR) has improved from less of 10% in 1980s to more than 60% in 2000s. However this improvement is far from satisfactory to improve five year survival rate.

The aim of study was to evaluate preliminary outcomes of children ≤15years treated according to AML- MA 11protocol.

Methods:

Between the first January 2011 to December 2014, we carrieed a prospective study of all children aged 15 years or less, diagnosed AML. The diagnosis was according by cytological study with cytochemestry: MPO positive (FAB classification), supplemented by immunophenotyping. The prognosis is evaluated by conventional cytogenetic study.

AML-MA 2011 protocol consisted of prephase(whenwhite blood cell (WBC) count ≥ 50 G/l) by Hydroxyurea (HU) (50 mg/m2/day for 4 days). The response to HU was evaluated after 2 days; patients were considered responsers if >50% reduction of the initial WBC count. Then 2 inductions based on daunorubicin 50 mg/m2 (3 days), cytarabine 100mg/m2/12 hours (10 days) and etoposide 100 mg/m2 (5 days) for the second course, followed by 3 consolidations with high dose of cytarabine 1-3 g/m2/12 hours (3 days), with intrathecal therapy. The supportive care is assured during all phases of treatment.

Results:

Forty four patients were enrolled with a median age of 8 years [1-15] and M:F ratio of 1.2. The median WBC count was 22710 elements/mm3; it exceeded 50 000/mm3 in 18 % of cases, more than 100 000/mm3 in 13 % of cases.The cytological studies showed the predominance of AML subtype 2 (31%) followed by subtype 5 (11, 3%). The immunophenotyping was done in 88% of cases. Karyotype performed in 40 out of 44 cases revealed: 9 (22,5%) favorable risk group [8 had the t(8,21); 1 had inv16], 25 (62,5%) intermediate risk, and 6 (15%) unfavorable-risk group.

Seven patients received hydroxy urea with 5 good response (71% of cases; 2 patients had favorable risk and 3 had intermediate risk). Four of this patients died.

Thirty five patients were treated (3 death before treatment, 4 abandonment of treatment, 1 myelodysplasea syndroma, and 1 bad condition).

After the induction cycles; complete remission was achieved in 22 cases (62%), failure in 6 cases, and 7 children dead (20%) [4 septic choc, 2 haemorrhage and 1 acute pulmonary edema]. One patient died between 0 to 14 days during the cure and 6 others after 14 days of treatment.

After a mean follow-up of 9months (1 to 43 months), continuous complete remission was achieved in 45,7% of cases, failure in 20%, relapse in 11%, and death in 45,45 % of cases. (toxic death in 25% of cases with high frequence in induction phases: 88%). Theoverall survival rate in 2 years was 41,2%.

Conclusion:

With aggressive chemotherapy, it is feasible to achieve high CR even in emerging countries. If supportive care is optimal with particular focus on prevention and management of infection and with improved transfusion support, then it's feasible to improve the overall outcome of patients. Finally it is necessary to make the molecular biology in our patients topreciselyindividualize the pronostic groups.