Introduction:
Acute Lymphoblastic Leukaemia (ALL), is one of the most common
malignancy diagnosed in children and is characterized by diffuse
replacement of bone marrow and peripheral blood with neoplastic cells
and constitutes for more than a quarter of all pediatric cancers(1, 2).
Front-line treatment in ALL is considered a major success and one of the
most curable cancers in children with an overall survival rate
> 80%, these favourable survival outcomes are attributable
to several strategies including combination of chemotherapeutic agents,
risk-based stratification and allocation of treatment and prophylactic
CNS therapy.(3, 4) Despite substantial improvements in the treatment
strategies, approximately 20% of the patients are predicted to relapse
and with high incidence of ALL in children, recurrent leukaemia is a
relatively common diagnosis being managed by pediatric oncologists(1,
3).
Certain risk-determining factors for relapse have been identified
guiding the treating pediatric oncologists in planning treatment
strategies (intensity) and prognosis, factors those have been
extensively reported in the literature includes time to relapse from
first complete remission (< 36 months from
diagnosis) , site of relapse and immunophenotype (B-cell vs.
T-cell). Survival amongst relapsed patients is generally predicted by
site of relapse and duration of first complete remission, with bone
marrow and early relapse reported to be associated with inferior
prognosis when compared to isolated extra-medullary or late relapse.
Although, clinical remission can be accomplished in majority of
relapses, however, long-term survival rates ranges from 40% -50% (5,
6).
Treatment of relapsed patients involves reinduction with conventional
agents identical to the one’s used at initial diagnosis, and
Hematopoietic stem-cell transplantation (HSCT) is widely adapted as
consolidation therapy in relapsed ALL patients, however benefit of stem
cell tranplant in late or multiple relapses needs to established firmly.
Therefore, given the overall suboptimal outcomes with conventional,
high-dose therapy involved in treating relapsed or refractory patients
warrants new therapeutic agents and strategies (3, 7).
Risk-stratified approach is adapted at our institution when treating
pediatric patients with relapse or resistance to first-line therapy and
through this study we report outcomes from a single tertiary care
centre.