Incidence and survival of childhood leukemia in Recife, Brazil: A population-based analysis

Association of the clinical profile and overall survival of pediatric patients with acute lymphoblastic leukemia

Introduction

The clarification of etiopathology, the improvement of chemotherapy regimens and their risk stratifications, and the improvement in treatment support have increased the survival of children and adolescents affected by Acute Lymphoblastic Leukemia (ALL) past few years. This study aimed to estimate overall survival (OS) and event-free survival (EFS) in an onco-hematology treatment center in Brazil, reports the main clinical-laboratory characteristics of patients at diagnosis, verify the frequency of treatment-related adverse effects and the main causes of death.

Material and methods

Retrospective analysis involving patients diagnosed with ALL, treated with the protocol of the Brazilian Group for Treatment of Leukemias in Childhood (GBTLI), between 2010 and 2020 was carried out; the outcomes (relapse, deaths, development of new neoplasms) were analyzed SPSS® software was used for the statistical analyses, and the p-value was considered significant when less than 0.05 for all analyses.

Results

109 patients were included in the study; the median age was 5 years, with a slight predominance of males. Sixty-six patients were classified as high-risk (HR) group and 43 patients were classified as low-risk (LR) group. After 5 years of diagnosis, the OS was 71.5%, and the EFS was 65%. No statistical difference was found between the HR and LR groups for OS and EFS, while leukocyte counts were statistically associated with the outcome of death (p = 0.028). Among the patients, 28 (25.6%) died due to infection accounting 46.4% of death causes. Among the 34 patients with unfavorable outcomes (death and/or relapse), 32 had no research for the minimal residual disease at the end of remission induction, and 25 were not investigated for the presence of chromosomal abnormalities. The most reported complications and treatment-related adverse effects were increased liver transaminases (85.9%), airway infection (79.4%), oral mucositis (67.2%), febrile neutropenia (64.4%), and diarrhea (36.4%).

Conclusions

The rates of OS and EFS obtained in this cohort are similar to those obtained in the few previous similar studies in Brazil and lower than those carried out in developed countries. The unavailability of prognostic tests may have hindered risk stratification and influenced the results obtained.

Acute promyelocytic leukemia in childhood and adolescence: treatment results of a modified AIDA protocol at a Brazilian center

INTRODUCTION

Acute promyelocytic leukemia currently presents an excellent chance of cure with protocols based on all-trans-retinoic acid (ATRA) and anthracycline or only differentiation agents. However, high early mortality rates continue to be reported METHODS: Between 2000 and 2018, patients were enrolled and retrospectively analyzed by medical records. A modified AIDA protocol, with a 1-year shortening of the treatment duration, reduction in the number of drugs and a strategy to reduce early mortality by the postponement of the initiation of anthracyclines were employed. Overall and event-free survival rates and toxicity were analyzed RESULTS: Thirty-two patients were enrolled, of whom 56% were female, with a median age of 12 years and 34% belonged to the high-risk group. Two patients had the hypogranular variant and three had another cytogenetic alteration, in addition to the t(15;17). The median start of the first anthracycline dose was 7 days. There were two early deaths (6%) due to central nervous system (CNS) bleeding. All patients achieved molecular remission after the consolidation phase. Two children relapsed and were rescued by arsenic trioxide and hematopoietic stem cell transplantation. The presence of disseminated intravascular coagulation (DIC) at diagnosis (p = 0.03) was the only factor with survival impact. The five-year event-free survival (EFS) was 84% and 5-year overall survival (OS) was 90% CONCLUSION: The survival results were comparable to those found in the AIDA protocol, with a low rate of early mortality in relation to the Brazilian reality.

L-Asparaginase as the gold standard in the treatment of acute lymphoblastic leukemia: a comprehensive review

L-Asparaginase is an antileukemic drug long approved for clinical use to treat childhood acute lymphoblastic leukemia, the most common cancer in this population worldwide. However, the efficacy and its use as a drug have been subject to debate due to the variety of adverse effects that patients treated with it present, as well as the prompt elimination in plasma, the need for multiple administrations, and high rates of allergic reactions. For this reason, the search for new, less immunogenic variants has long been the subject of study. This review presents the main aspects of the L-asparaginase enzyme from a structural, pharmacological, and clinical point of view, from the perspective of its use in chemotherapy protocols in conjunction with other drugs in the different treatment phases.

Therapy-Acquired Clonal Mutations in Thiopurine Drug-Response Genes Drive Majority of Early Relapses in Pediatric B-Cell Precursor Acute Lymphoblastic Leukemia

METHODS

Forty pediatric (0-12 years) B-ALL DNA samples (20 paired Diagnosis-Relapse) and an additional six B-ALL DNA samples (without relapse at 3 years post treatment), as the non-relapse arm, were retrieved from the biobank for advanced genomic analysis. Deep sequencing (1050-5000X; mean 1600X) was performed using a custom NGS panel of 74 genes incorporating unique molecular barcodes.

RESULTS

A total 47 major clones (>25% VAF) and 188 minor clones were noted in 40 cases after bioinformatic data filtering. Of the forty-seven major clones, eight (17%) were diagnosis-specific, seventeen (36%) were relapse-specific and 11 (23%) were shared. In the control arm, no pathogenic major clone was noted in any of the six samples. The most common clonal evolution pattern observed was therapy-acquired (TA), with 9/20 (45%), followed by M-M, with 5/20 (25%), m-M, with 4/20 (20%) and unclassified (UNC) 2/20 (10%). The TA clonal pattern was predominant in early relapses 7/12 (58%), with 71% (5/7) having major clonal mutations in the NT5C2 or PMS2 gene related to thiopurine-dose response. In addition, 60% (3/5) of these cases were preceded by an initial hit in the epigenetic regulator, KMT2D. Mutations in common relapse-enriched genes comprised 33% of the very early relapses, 50% of the early and 40% of the late relapses. Overall, 14/46 (30%) of the samples showed the hypermutation phenotype, of which the majority (50%) had a TA pattern of relapse.

CONCLUSIONS

Our study highlights the high frequency of early relapses driven by TA clones, demonstrating the need to identify their early rise during chemotherapy by digital PCR.

Modeling the Antileukemia Activity of Ellipticine-Related Compounds: QSAR and Molecular Docking Study

The antileukemia cancer activity of organic compounds analogous to ellipticine representes a critical endpoint in the understanding of this dramatic disease. A molecular modeling simulation on a dataset of 23 compounds, all of which comply with Lipinski's rules and have a structure analogous to ellipticine, was performed using the quantitative structure activity relationship (QSAR) technique, followed by a detailed docking study on three different proteins significantly involved in this disease (PDB IDs: SYK, PI3K and BTK). As a result, a model with only four descriptors (HOMO, softness, AC1RABAMBID, and TS1KFABMID) was found to be robust enough for prediction of the antileukemia activity of the compounds studied in this work, with an R² of 0.899 and Q² of 0.730. A favorable interaction between the compounds and their target proteins was found in all cases; in particular, compounds 9 and 22 showed high activity and binding free energy values of around -10 kcal/mol. Theses compounds were evaluated in detail based on their molecular structure, and some modifications are suggested herein to enhance their biological activity. In particular, compounds 22_1, 22_2, 9_1, and 9_2 are indicated as possible new, potent ellipticine derivatives to be synthesized and biologically tested.

Survival and risk factors for mortality in pediatric patients with acute myeloid leukemia in a single reference center in low-middle-income country

Despite advances in therapy and care for children with acute myeloid leukemia (AML), survival rates for children in low- and middle-income countries (LMICs) remain poor. We studied risk factors for mortality and survival in children with AML in a LMIC to develop strategies to improve survival for AML children in these countries. This retrospective cohort (2000-2014) analyzed newly diagnosed AML patients (age < 19 years) at a reference center in Brazil. Demographic and clinical variables were reviewed by AML subtype: acute promyelocytic leukemia (APL), AML with Down syndrome (AML-DS), and other AML subtypes. Cumulative hazard risk for early death (ED) until 6 weeks of treatment and risk factors for mortality were determined by the multivariate Cox hazard models. Survival was assessed for each AML subtypes. A total of 220 patients were diagnosed: APL 50 (22.7%), AML-DS 16 (7.3%), and other AML subtypes 154 (70.0%). The cumulative hazard function values for ED for all patients with AML were 12.5% (95% CI 8.5-18.4%); for each AML patients subtypes: APL, 21.7% (95% CI 11.7-40.5%); AML-DS, 6.2% (95% CI 0.9-44.4%); and other AML subtypes, 10.2% (95% CI 6.2-17.0%). White blood cell count (cutoff 10 × 10⁹/L for APL and 100 × 10⁹/L for other AML subtypes) and Afro-descendance were significant risk factors for mortality in APL and other AML subtypes, respectively. Overall survival for patients with APL, AML-DS, and other AML subtypes was 66.8%, 62.5%, and 38.0%, respectively. APL patients had the highest incidence of ED and those with other subtypes had increased relapse risk. We also observed high rates of death in complete remission mainly due to infection. Better risk classification and identification of risk factors for infection may improve the survival of these patients.

Childhood and Adolescent Cancer in the State of Pernambuco, Brazil: Incidence, Geographical Distribution, and Association With Environmental Health Indicators

Cases of childhood and adolescent cancer diagnosed from 2009 to 2012 in the state of Pernambuco, Brazil, were analyzed considering the patients' sex and age, the type of cancer and the municipality of living to determine the incidence, geographical distribution, and association with environmental health indicators. The spatial distribution pattern of the cancer incidence was estimated using the Global Moran's index. The association between environmental health indicators and cancer incidence was evaluated by multiple regression. From 2009 to 2012, 1261 new cases of cancer were diagnosed in patients younger than 20 years old in the state of Pernambuco. Leukemia/lymphoma were the most common type of cancer contemplating 45.28% of the cases. The average age-adjusted incidence rate was 113 cases per million with no spatial distribution pattern. The municipalities were clustered according to their degree of inequality (P=0.017), human development index (P=0.001), population growth rate (P=0.008), urbanization level (P=0.001), number of agricultural crops per capita (P=0.001), and number of industries per capita (P=0.030). However, only urbanization level was positive correlated with incidence of pediatric cancer (P=0.009) likely because in more developed cities, people are more exposed to potential oncogenic factors, such as air and water pollution and processed and ultraprocessed food. The better access to specialized health services, which increases the chances of early diagnosis, may also contributes for a higher number of cases in more developed cities.