PB1734: SURVIVAL OF ADULTS WITH ACUTE LYMPHOBLASTIC LEUKEMIA IN ECUADOR. AN ANALYSIS OF THE REAL WORLD

Topic: 2. Acute lymphoblastic leukemia - Clinical Background: Acute lymphoblastic leukemia (ALL) is the second most common acute leukemia in adults. In Ecuador, there are no survival studies of patients ≥15 years of age, whence, this is the first report. Aims: To describe clinical, and demographic characteristics, as well as overall survival associated to management and results. Methods: The medical records of 255 patients with acute lymphoblastic leukemia (ALL) over 15 years of age, diagnosed between January/2015 and December/2022, in 4 reference centers in Ecuador, were reviewed. It was defined as 1) high risk: age ≥ 35 years and/or leukocytes ≥ 30,000/mm3 and/or infiltration of the Central Nervous System (CNS) at debut; and 2) if none of these factors were present, it was classified as standard risk. Overall survival (OS), disease-free survival (DFS), and treatment-related mortality were evaluated. Results: 255 patients with ALL were evaluated. The demographic and clinical characteristics of the patients at diagnosis are summarized in Table 1. Complete hematological response (CHR) was achieved in 143/178 (80.3%), reaching negative minimal residual disease (MRD) <0.01% in 65/144 (45.1%) patients. 61/234 patients (26.1%) died during the induction phase and 24/234 patients (10.25%) during the consolidation phase, reaching a chemotherapy-related mortality of 36.3%. In addition, 8/107 (7.4%) patients considered as high risk who achieved CHR received hematopoietic stem cell transplantation (HSCT). OS for all patients with ALL at 5 years was 20%, with a median of 8 months (IQ 1 – 23 months). Median OS for patients who receiving intensive chemotherapy in the high-risk and standard-risk groups were 9 months (IQ 2-29 months) and 12 months (IQ 3-96 months), respectively, with no significant difference (p =0.83), showed in Figure 1. The 5-year OS of patients who presented the BCR:ABL fusion gene (n:22) were 36.1%, in those who received HSCT was 54.6% (median not reached), and for patients with T-cell ALL (n:12) was 14.9%. Summary/Conclusion: The OS rates reported in this cohort are considerably low compared to cohorts in the literature, probably related to high early mortality rates (related to treatment or early relapse); and the reduced number of patients who received HPCT. Table 1. Clinical demographic data of patients with acute lymphoblastic leukemia. - Variable n (%) 255 (100) Age in years Mean 38,3 (± 17,8 SD) Sex Female 124 (48,6) Male 131 (51,4) Lineage ALL-B 242 (94,9) ALL-T 12 (4,7) Ambiguous lineage 1 (0,4) BCR::ABL Fusión 159 (100) Negative 137 (86,2) Positive 22 (13,8) KMT2A rearrangement 70 (100) Negative 64 (91,4) Positive 6 (8,6) CNS infiltration 219 (100) No 159 (72,2) Yes 60 (27,3) Risk stratification 254 (100) Standard 62 (24,4) High 192 (75,6) Therapy with asparaginase 234 (100) No 54 (21,2) Yes 180 (70,6) SD Standard deviation; ALL Acute lymphoblastic leukemia; CNS central nervous system.Figure 1. Kaplan Meier curve of ALL patients with intensive chemotherapy according at-risk group. Overall survival at 5 years of the high risk group was 23.4% and of the standard risk group was 16.9%. Keywords: Treatment-related mortality, Survival, Acute lymphoblastic leukemia, Mortality