Cytogenetic Abnormalities and Their Impact on Treatment Outcome in Paediatric Acute Myeloid Leukaemia in Pakistan

Objective: To determine the impact of cytogenetic abnormalities on the treatment outcome of paediatric acute myeloid leukaemia (AML) at a tertiary care facility of Pakistan. Study Design: Retrospective Observational study. Place and Duration of Study: Paediatric Oncology Ward, Combined Military Hospital, Rawalpindi, from January 2012 to September 2019. Methodology: All registered cases of AML under 18 years of age, admitted to paediatric oncology ward in Combined Military Hospital, Rawalpindi, who had completed their treatment before 30th- September 2019 were included. Their demographic and clinical data including WBC counts, immunophenotyping, cytogenetic abnormalities and impact of cytogenetics on disease outcome was assessed. Data was analysed for descriptive statistics and association of proportions. Results: Data of 138 cases of de novo AML including 90 (65.2%) males and 48 (34.8%) females were analysed. The mean age was 6.37 +/- 3.51 years. Initial WBC of more than 50x10(9)/L was seen in 43 (31.2%) patients. The most common FAB subtype was M-2 in 74 (53.6%), followed by M-4 in 20 (14.5%) cases. The majority of cases 81 (58.7%) had normal cytogenetics followed by 42 (30.4%) favourable and 15 (10.8%) unfavourable abnormalities. Five-year overall survival was 82.4%, 56.5% and 55.6% for favourable, inter-mediate and unfavourable risk cytogenetics, respectively (p=0.039). Disease-free survival was 82.4%, 51.6% and 44.4% for favourable, intermediate and unfavourable risk cytogenetics (p=0.008). Conclusions: Identification of cytogenetic aberrations at diagnosis will help in risk stratification and predicting prognosis in AML. This will further assist in improving treatment strategies for different cytogenetic risk groups.