Introduction and Objectives: Acute lymphoblastic leukaemia (ALL) has a worse prognosis in adults, associated with specific genetic profiles. In addition to the higher frequency of high-risk cytogenetics, 40-50% of adults harbour IKZF1 deletions, those alterations are negative prognostic markers in children. Patients aged 15-39 years-old, named Adolescents and Young Adults (AYA), have markedly worse results than younger counterparts. Besides biology disparities, therapeutic strategies contribute to these poor outcomes. In this study, we aim to characterize a consecutive series of ALL cases from a reference institution for the treatment of haematological diseases and evaluate the overall (OS) and event-free (EFS) survivals of these patients according to the age group, type of therapeutic protocol and cytogenetic–molecular characteristics (including IKZF1 deletions). Material and Method: Patients aged ≥15 years-old diagnosed with ALL, treated at HEMORIO between 2012-2020 were included. The patients’ follow-up data are currently being collected to enable the survival analyses to be carried out. Cytogenetic-molecular characterization is routinely performed by karyotyping, RT–PCR and FISH. IKZF1 status is being determined using MLPA and multiplex PCR. The OS and EFS will be determinate using the Kaplan-Meier method from the date of diagnosis until outcome (death, alive or last follow-up).
Variables known to be associated with prognosis, such as age, WBC count and genetic profiles will be evaluated and differences between survival distributions will be compared by the log-rank test. Results and Conclusion: To date, we included 97 patients, 47 women and 50 men with the majority aged 15-39 years-old (56.7%, AYA group). There was a predominance of B cell precursor (B-ALL) subtype (n=77) in comparison to T-cell (T-ALL) (n=20). The AYA group accounted for 70% of the T-ALL cases. Of the 50 B-ALL cases with available immunophenotypic subclassification, 4 were pro-B, 10 pre-B and 34 B-common. For the T-ALL patients, 3 were categorised as early T-cell precursor, 2 medullary and 4 cortical subtypes. Twenty-eight B-ALL patients (> 50x109/L) and 8 with T-ALL (> 100x109/L) presented high WBC. Cytogenetic-molecular analyses were performed in 68 patients, with 47% being BCR-ABL1, 3% KMT2A-r and 4 TCF3-PBX1. IKZF1 deletions were identified in 19.5% (19/97) of the cases, 13 of them evolved to death (4 due to disease relapse). Our preliminary data showed that 74% of the patients have died, with sepsis being the main cause of death (49%), followed by disease recurrence/progression (16%). The main protocols used were BFM (n=40) and HyperCVAD (n=39). The OS and EFS analyses are in progress. Even though we are aware that most of our cases are in the AYA group and that the adoption of paediatric protocols to treat these patients might result in an improved outcome, so far we were unable to observe this benefit, because the majority of our patients died due to sepsis.