LONG-TERM OUTCOMES OF CHILDHOOD ACUTE LYMPHOCYTIC LEUKEMIA (ALL) TREATED WITH MODIFIED BERLIN-FRANKFURT-MÜNSTER (BFM) PROTOCOLS IN RIO DE JANEIRO, BRAZIL: A MULTICENTRIC HOSPITAL-BASED SURVIVAL ANALYSIS STUDY

Background: /Objectives Acute lymphocytic leukemia (ALL) is the most common pediatric cancer, more incident in Hispanics. The Berlin-Frankfurt-Münster (BFM) protocol for ALL began to be used in hospitals from Rio de Janeiro in the 1980’s. The aim of this study was to determine survival probabilities and prognostic factors for children and adolescents with ALL in the state of Rio de Janeiro (RJ) and to compare these results with other BFM studies. Design: /Methods We conducted a survival analysis study with a retrospective cohort of 695 patients aged from zero to 19 years treated with a modified BFM protocols between 1998 and 2018 in four reference hospitals in RJ. Prognostic factors included age, sex, leukocyte count, early response to treatment and cytogenetic risk. The cohort was divided into two periods. We calculated the five- and ten-years event-free survival (EFS), the overall survival (OS) and performed a multivariate analysis using Cox proportional hazards models. Results: In the 1 st period the five-year EFS was 50.3% (±3.0) and the OS was 61.5 (±2.9). These rates for high-risk patients (HR) were 33.4% and 47.7%, respectively. In the 2 nd period, the five-year EFS was 61.6% (±2.8) and the OS was 70.5% (±10.6). These rates for HR patients were 57.9% and 63.8%. In the cohort, 51.2% of patients were HR based on BFM classification, 54.7% were HR based on the National Cancer Institute classification, 27.1% had a leukocyte count greater than 50,000 and 28.6% were aged less than one or greater than 10 years. Conclusions: Our results led us to hypothesize that delays in treatment, overestimated risk classification on the 8 th day of treatment and/or unique genetic features of our population may be causing a higher leukocyte count at the time of diagnosis and an increased prevalence of HR classification compared to other BFM studies mainly composed by Caucasians.