Objective: To delineate the natural history of splenic complications other than the loss of splenic function in children with sickle cell disease (SCD), we performed a retrospective chart review of patients with SCD treated at the Texas Children’s Hospital. Methods: We determined the dates of diagnoses of splenic complications, the number of ASSC events, and hydroxyurea treatment in patients with SCD. We also examined the association of hydroxyurea therapy with the onset and severity of ASSC. Results: The cumulative prevalence of splenic complications was 24.7% for splenomegaly, 24.2% for ASSC, 9.6% for hypersplenism, and 5.6% for splenectomy. The cumulative prevalence of all splenic complications was highest in patients with hemoglobin Sβ 0 (69.2%), intermediate in hemoglobin SS (33.3%), low in hemoglobin SC (9.0%), and non-existent in hemoglobin Sβ +. The overall event-rate of ASSC was 8.3 per hundred patient-years. The event-rate was 28.4 in the hemoglobin Sβ 0, 10.9 in hemoglobin SS, and 3.5 in hemoglobin SC Patients with hemoglobin SS and hemoglobin Sβ 0 on hydroxyurea therapy had a significantly higher occurrence of ASSC than those who were not, with event-rates of 14.2 and 3.1, respectively. The event-rate was also higher for children who started hydroxyurea before age 2 years than for those who started after this age (19.8 and 9.2 respectively). Conclusions: The prevalence and severity of splenic problems vary widely between different sickle cell genotypes, with hemoglobin Sβ 0 having the most severe complications. Hydroxyurea therapy is strongly associated with incidence of ASSC, particularly when initiated before two years of age.

Background: Recent data found a correlation between lymphopenia occurring early during craniospinal irradiation (CSI) and risk of disease recurrence in newly-diagnosed childhood medulloblastoma. 1 However, the population included patients that received myelosuppressive chemotherapy prior to or during RT. Here we investigate the effect of lymphopenia during RT in patients with newly-diagnosed pediatric medulloblastoma who did not receive myelosuppressive chemotherapy with RT. Procedure: We analyzed 54 patients with newly-diagnosed medulloblastoma (ages 2-21 years) treated between 1997-2013 with CSI. Log-rank tests were used to determine survival differences, and Cox proportional hazards regression was used to assess associations between patient characteristics and lymphopenia with disease recurrence risk. Results: 78% of patients (40/51) had grade ≥3 lymphopenia by RT week 3; 49% (23/47) improved to grade ≤2 lymphopenia by week 5. Similarly, the lowest median absolute lymphocyte count (ALC) occurred during RT week 3. Sixteen of 54 (30%) patients recurred an average of 30.2 months post-diagnosis. There was higher risk of disease recurrence in patients with grade ≥3 lymphopenia during weeks 4 (log-rank p=0.015; Cox p=0.03) and 5 (log-rank p=0.0009; Cox p=0.004) of RT. Recurrence-free survival was lower in patients with ALC Conclusions: Lymphopenia during RT weeks 4 and 5 correlates with increased risk of tumor recurrence in pediatric patients with newly-diagnosed medulloblastoma. Future studies should correlate baseline numbers of tumor-infiltrating lymphocytes with risks of lymphopenia during RT and tumor recurrence.

Objectives: Sickle cell disease (SCD) is well recognized as a hypercoagulable state, however venous thromboembolism (VTE) risk factors in children remain largely unknown. In this study, we aim to describe the clinical characteristics, outcomes and recurrence of hospital acquired VTE in patients younger than 21 years of age. Study Design/Methods: Data were extracted from electronic medical records over a 10-year period (2011-2021). Data regarding sickle cell genotype, demographics, reason for admission, location of thrombus, presence of central venous catheter (CVC), intensive care unit (ICU) admission, presence of thrombophilia risk factors, resolution of VTE, mortality, and bleeding outcomes on anticoagulation were collected. Recurrence of VTE at 1 and 5 years was assessed. Descriptive statistics were used as indicated. Results: We identified a total of 21 VTE events over the ten-year study period. Six of these events occurred in those younger than 12 years of age. Fifteen (71%) VTE events occurred in the HbSS or HbSβThal 0 genotypes compared to 8 (29%) in HbSC. Eleven (52%) patients were admitted with acute chest syndrome (ACS). Most VTE events were associated with ICU admissions (n=13, 62%) and presence of central venous catheter (n=12, 57%). Major bleeding on anticoagulation occurred in 10%.All patients had resolution of index VTE at 12 weeks. Recurrence rate for VTE at 5 years was 13%. One patient died from the VTE event. Conclusions: Our study highlights that VTE can complicate SCD in children and young adults. Hospital acquired VTE were most associated with ICU admission, CVC, and ACS, but larger studies are indicated to validate our findings.

High-dose methotrexate (HD-MTX) with rigorous supportive care is essential to the treatment of pediatric non-Hodgkin lymphomas (NHL). We describe the safety and tolerability of HD-MTX in patients with NHL treated at our center. In our cohort of 46 patients, the majority had at least one course of delayed clearance and/or creatinine elevation. Additionally, more than one-third of patients experienced an episode of grade ≥3 mucositis. Creatinine elevations and delayed clearance were independently associated with subsequent grade ≥3 mucositis. We advocate for greater availability of methotrexate monitoring to allow dose escalation of this essential modality around the world.

Background: Children with hematologic malignancies, especially those who receive intensive chemotherapy, are at high risk for invasive mold infections (IMI) that confer substantial mortality. Randomized controlled trials support the use of anti-fungal prophylaxis with anti-mold activity as an optimal strategy for risk reduction in this population, but studies outlining the practical application of evidence-based recommendations are lacking. Procedure: We conducted a 15-year, single-institution retrospective review of children with hematologic malignancies treated with chemotherapy to determine the incidence of proven or probable IMI diagnosed between 2006 and 2020 and to identify the host and disease factors associated with IMI risk. We then compared the incidence and type of IMI and related factors before and after 2016 implementation of an evidence-based, risk-adapted anti-fungal prophylaxis algorithm that broadened coverage to include molds in patients at highest risk for IMI. Multivariable linear regression was used to determine factors related to IMI risk. Results: We identified 61 cases of proven or probable IMI in 1,456 patients diagnosed with hematologic malignancies during the study period (4.2%). Implementation of an anti-fungal prophylaxis algorithm reduced the IMI incidence in this population from 4.8% to 2.9%. After multivariable analysis, both Hispanic ethnicity and cancer diagnosis prior to 2016 were significantly associated with risk for IMI. Conclusion: An evidence-based, risk-adapted approach to anti-fungal prophylaxis for children with hematologic malignancies is an effective strategy to reduce incidence of IMI.