Introduction:
T-cell acute lymphoblastic leukemia (T-ALL) accounts for 15% of newly diagnosed cases of childhood acute lymphoblastic leukemia (ALL). Historically, T-ALL has had inferior event-free survival (EFS) and overall survival (OS) compared with precursor B-cell ALL (B-ALL). Patients with T-ALL often present with unfavorable clinical features, including older age, higher white blood cell count (Wbc), and extramedullary disease, especially in the central nervous system. Additionally, T-ALL was reported to have increased risk of induction failure. [1-4]
Outcomes for T-ALL have improved with contemporary risk and response-based treatment protocols: Early intensified therapy, with a 4-drug induction containing dexamethasone and an anthracycline followed by augmented BFM-like consolidation containing cyclophosphamide, asparaginase and methotrexate (MTX), but relapse rates remain higher and relapses often unsalvageable. [5-13]
The outcome of children and adolescents with T-ALL treated at our center per modified St. Jude total XV regimen was reported in 2014; the 5-year-OS and EFS for Early T-cell precursor acute lymphoblastic leukemia (ETP)were 77.1% and 79.6%; while for non-ETP, these estimates were 78.5% and 65.2%, respectively.[14]
In an attempt to improve the outcome of our patients we modified our regimen by using an early intensive post-induction chemotherapy composed of fludarabine, high dose cytarabine and etoposide. This approach was inspired by the augmented therapy in European protocols for high-risk leukemia. [7, 15]
We report here our results using both regimens (standard and augmented) in children and adolescents who presented to our center with untreated T-ALL over a period of over 16 years.