PB1769: REAL WORLD DATA OUTCOMES IN A SINGLE MEXICAN PUBLIC INSTITUTION. ADOLESCENTS AND YOUNG ADULTS (AYAS) WITH NEWLY DIAGNOSED OF ACUTE LYMPHOBLASTIC LEUKEMIA:COMPARATIVE RESULTS OF DIFFERENT PROTOCOLS

Abstract

Background: Acute lymphoblastic leukemia (ALL) is a hematopoietic neoplasm with arrest in lymphoid lineage differentiation. Adolescents and young adults (AYA) account for 50-67.3% of cases. Pediatric chemotherapy has increased survival from 48 to 70% in High income countries. Aims: Primary objective is to compare Overall survival (OS) and event-free survival (EFS) in AYA with ALL treated with pediatric chemotherapy protocol versus adult chemotherapy protocol. Prognostic factors were evaluated as a secondary objective. Methods: A Retrospective analytical observational study was conducted from January 1, 2018, to December 31, 2020 in Hospital IMSS UMAE 25 Monterrey, Mexico. OS and EFS were analyzed using Kaplan Meier method. Prognostic factors were evaluated with univariate and multivariate logistic regression (Odds Ratio, OR) and Hazard Ratio (HR) with Cox regression, p value of <0.05 (C 95%) was deemed statistically significant. The complete statistical analysis was conducted using SPSS version 20.0 (IBM, NY, USA). Results: We include 61 patients (female 59%, male 41%) with median age 25 years (15-38). Rest of demographics is described in Table 1. Median follow-up was 12 months (8.7-15.1). Global OS and EFS at 2 years was 32 % and 19% respectively. Thirty seven patients (64%) were treated with pediatric protocol (BFM-like); OS and EFS at 2 year was 38% and 22 % respectively, with median follow up of 10 months(5-5-19.5). Twenty four patients (36%) were treated with HyperCVAD protocol; OS was 22% and EFS at 2 years was 16 %, with median follow up of 8.8 months (8.7- 17.1).There were no significant differences in OS and EFS between the groups compared. In univariate and multivariate analysis of prognostic factors the following results were found: hiperleukocytosis, OR 4.7 (IC 95% 0.9-23.0); positive BCR/ABL, OR 1.6 (IC 95% 1.04-1-3,); central nervous system infiltration, OR 1.9 (IC 95% 1.1-1.35); extramedullary infiltration, OR 1.9 (IC 95% 1.1-1.35). Induction failure (IF) was the only statistically significant risk factor with an OR 8.0 (IC 95% 1.6-39.3), p value 0.025. When stratified by risk factors twenty-two patients (36.1%) were found to be standard risk and 2-year OS was 45.5% with median 28.5 months (4.3-52.7); with a single risk factor the 2-years OS was 30% with median survival of 14 months (8.6-19.4); two or more risk factors the 2- year OS was 5% with median of 5.9 months (4.1-11). (Log Rank p=<0.001). Two year OS in IF patients was 8 % compared to 55% in those who achieved remission (HR 14.95, p =<0.001). Patients who achieved remission with pediatric regimens had better OS at 2 years compared with those who were treated with HyperCVAD (62% vs 34%, p=0.007). Image:Summary/Conclusion: In conclusion, no significant difference was found in OS with none of the protocols; however, those patients who achieve remission with the pediatric regimen had better two-year survival compared with patients receiving HyperCVAD. Response rates in our population, are lower compared to high income countries reports, which could suggest that biology of the disease in Latin American patients may have adverse prognostic markers that confer greater aggressiveness and chemo-resistance in our entity. We cannot forget to mention the great difference on supportive therapies and access to new, more effective drugs, that are practically impossible to access in low- and middle-income countries as ours, and have a direct impact on survival.