Increased Incidence of TdT-negative Pre-B Acute Lymphoblastic Leukemia Associated With Poor Prognostic Features Among Mexican Children in Central Mexico.

Mexican and Hispanic children in Mexico and the United States, respectively, have the highest incidence and worst outcomes of pre-B acute lymphoblastic leukemia (ALL) compared with other racial/ethnic groups. Terminal deoxynucleotidyl transferase (TdT) is an intranuclear DNA polymerase normally present on immature lymphocytes (TdT-positive) and distinguishes ALL from mature lymphoid malignancies. We performed a multisite retrospective study to determine the incidence of TdT-negative precursor B-cell acute lymphoblastic leukemia (pre-B ALL) among Mexican, Caucasian, and US-born Hispanic children to correlate TdT expression with patient characteristics and known prognostic factors. Fisher exact test was performed for categorical variables and the Wilcoxon rank-sum test was used for continuous variables. TdT-negative pre-B ALL was most frequently identified in patients with National Cancer Institute high-risk disease ( P =0.014). TdT-negative expression was also most frequently associated with hypodiploid pre-B ALL ( P =0.001) and KMT2A gene rearrangement ( P =0.0012). Mexican children had the highest incidence of TdT-negative ALL compared with Caucasians and US Hispanics ( P <0.001), with an increased incidence of poor prognostic features as well. This study demonstrates significant differences in TdT-negative expression, genomic alterations, and leukemic ploidy based on race and ethnicity.

Therapeutic plasma exchange for multiorgan dysfunction among critically ill pediatric patients with leukemia: A single-institutional experience.

INTRODUCTION: Therapeutic plasma exchange (TPE) has well-documented applications in the adult population, outlined by the American Society for Apheresis (ASFA) 2019 guidelines. Limited data exist regarding the use of TPE in critically ill pediatric patients; however, these reports rarely include patients with oncological diseases. METHODS: We highlight the use of TPE in the acute management of seven pediatric patients with leukemia treated at Children's Mercy Hospital ICU from 2015 to 2020, including TPE specifications, baseline and interval laboratory evaluation, and outcome measures. Analysis compared those who did (n = 4) and did not (n = 3) survive 30 days post-TPE. RESULTS: Multiorgan failure (MOF) prompted the initiation of TPE in 85.7% of patients, 57.1% of whom were also diagnosed with hemophagocytic lymphohistiocytosis (HLH). Baseline laboratory evaluations prior to initiation of TPE were similar between the two groups. With subsequent TPE treatments, C-reactive protein (CRP) and lactic acid decreased. CRP and lactic acid following the last TPE treatment were significantly higher for those deceased 30 days post-TPE (P = .023 and .031, respectively). No TPE-associated adverse events necessitated discontinuation of TPE treatment. Several surviving patients required chemotherapy dose reductions or alterations. CONCLUSION: Our cohort demonstrated MOF and HLH consistently as indications for TPE, currently ASFA category III indications (optimal role of apheresis is not yet established). Recognition of this treatment modality earlier in the clinical course for critically ill oncological patients may lead to the development of formal protocols that may result in earlier initiation of TPE and improved outcomes.

Patient and health service factors associated with delays in cancer treatment for children without social security in Mexico.

BACKGROUND: The objective was to investigate factors associated with patient-related timing (PRT) to seek healthcare and health service-related timing (HSRT) to diagnose cancer and provide treatment to children without social security in Mexico. PROCEDURE: A cross-sectional survey was conducted in 13 Ministry of Health hospitals in the states of Chihuahua, Jalisco, Mexico City, Morelos, Oaxaca, Puebla, Queretaro, State of Mexico, and Tlaxcala. Study participants were parents of recently diagnosed pediatric cancer patients (≤ 17 years of age). Three groups of factors were investigated: (1) patients (child and parent characteristics); (2) healthcare providers (HCPs) (first-contact HCP, institution, perceptions of barriers to healthcare, etc.); and (3) disease factors (cancer type/site, stage/risk at diagnosis). PRT and HSRT-associated factors were identified using multiple negative binomial regressions. RESULTS: The study included 265 children; 49% sought care when symptoms first appeared. The median PRT was seven days, and the median HSRT was 40 days. Parents' perceptions of long wait times for appointments were associated with longer PRT and HSRT. Residing in the lowest or highest socioeconomic regions and persistent or worsening symptoms increased the probability of longer PRT. Older patient age, HCP requests for imaging tests or prescription for steroids, a higher number of doctors consulted, having a urinary tract cancer, and having an advanced stage or high-risk cancer increased the probability of longer HSRT. CONCLUSION: Strategies to shorten lag time from symptom onset to diagnosis and treatment are urgently needed for childhood cancers in Mexico.