Peripheral blood stem cell harvesting in young children weighing less than 15 kg.

Autologous peripheral blood stem cell (PBSC) transplantation is crucial in pediatric cancer treatment, and tandem transplantation is beneficial in certain malignancies. Collecting PBSCs in small children with low body weight is challenging. We retrospectively analyzed data of pediatric cancer patients weighing <15 kg who underwent autologous PBSC harvesting in our hospital. Collections were performed in the pediatric intensive care unit over 2 or 3 consecutive days, to harvest sufficient stem cells (goal ≥2 × 106 CD34+ cells/kg per apheresate). From April 2006 to August 2021, we performed 129 collections after 50 mobilizations in 40 patients, with a median age of 1.9 (range, 0.6-5.6) years and a body weight of 11.0 (range, 6.6-14.7) kg. The median CD34+ cells in each apheresate were 4.2 (range, 0.01-40.13) × 106/kg. 78% and 56% of mobilizations achieved sufficient cell dose for single or tandem transplantation, respectively, without additional aliquoting. The preapheresis hematopoietic progenitor cell (HPC) count was highly correlated with the CD34+ cell yield in the apheresate (r = 0.555, P < 0.001). Granulocyte colony-stimulating factor alone was not effective for mobilization in children ≥2 years of age, even without radiation exposure. By combining the preapheresis HPC count ≥20/µL and the 3 significant host factors, including age <2 years, no radiation exposure and use of chemotherapy, the prediction rate of goal achievement was increased (area under the curve 0.787).

High dose chemotherapy with autologous stem cell rescue in children and young adults with high-risk Ewing sarcoma: A single institute experience in Taiwan.

BACKGROUND: A combination treatment of surgery, chemotherapy, and radiotherapy can improve the survivals of pediatric patients with Ewing sarcoma (ES). However, prognosis remains poor for patients with metastatic disease at diagnosis or recurrence. Other high-risk (HR) features include large tumor burden, tumors of the axial skeleton and poor histologic response. Several studies have documented high dose chemotherapy with autologous stem cell rescue (HDC-ASCR) to be effective in such patients. In this retrospective study, we present the results of HDC-ASCR for high-risk Ewing sarcoma in children and young adults in a single institute. METHODS: From March 2004 to March 2021, patients with ES, Ewing-like sarcoma, or round cell sarcoma received HDC-ASCR as part of treatment were included. The patients' characteristics, disease status, stem cell dose, engraftment status, post-transplant complications, and outcomes were analyzed. RESULTS: Twenty patients receiving HDC-ASCR at complete response (n = 6), partial response (n = 13), and stable disease (n = 1) were enrolled. The male to female ratio was 11:9. Median age at diagnosis and transplant was 15.6 years old (range: 3.3-28.9) and 16.2 (range: 4.2-29.9), respectively. The conditioning regimens included ifosfamide-based in two and melphalan-based in 19. All patients achieved successful engraftment without tansplant-related mortality. The 5-year progression-free and overall survival (OS) rate were 35% and 54.5%, respectively. The causes of death (n = 8) were all contributed to disease progression. Patients in the complete response group or with localized HRES exhibited a higher 5-year OS (p = 0.047 and 0.05, respectively). Compared to the historical cohort without HDC-ASCR as part of primary treatment, the current cohort had a significantly better 5-year OS (p = 0.018). CONCLUSION: HDC-ASCR seems promising as an alternative treatment for HRES in improving OS in this retrospective study with limited case number.

Donor lymphocyte infusion for prophylaxis and treatment of relapse in pediatric hematologic malignancies after allogeneic hematopoietic stem cell transplant.

BACKGROUND: Donor lymphocyte infusion (DLI) is effective for managing patients with hematologic malignancies after allogeneic hematopoietic stem cell transplant (HSCT). However, few studies have explored its optimal use in pediatric populations. Herein, we report our single-center experiences of DLI and factors for predicting its outcomes. METHODS: This retrospective study included pediatric patients who had received DLI (between June 1998 and December 2022) after allogeneic HSCT. Data regarding patient characteristics, preemptive DLI disease status, and DLI characteristics were collected. The primary outcomes were overall survival (OS), event-free survival (EFS), and graft-vs-host-disease (GVHD) development. RESULTS: The study cohort comprised 17 patients with acute leukemia, 3 with chronic leukemia, and 3 with lymphoma. Prophylactic, preemptive, and therapeutic DLI were used in seven, seven, and nine patients, respectively. Patients' median age and DLI dose were 9 years and 4.6 × 10 7 CD3 + cells/kg, respectively. The 5-year OS, EFS, and nonrelapse mortality were 43.5%, 38.3%, and 13.3%, respectively. Approximately 39% of the patients developed grade III or IV acute GVHD, whereas moderate/severe chronic GVHD (cGVHD) occurred in 30% of the evaluable patients. Patients' disease status before HSCT ( p = 0.009) and DLI ( p = 0.018) were the key factors influencing EFS. The implementation of a dose escalation schedule was associated with a marginal reduction in the risk of moderate/severe cGVHD ( p = 0.051). A DLI dose of ≥5 × 10 7 CD3 + cells/kg was significantly associated with a high moderate to severe cGVHD risk ( p = 0.002) and reduced OS ( p = 0.089). CONCLUSION: Patients' disease status before HSCT and DLI may help predict EFS. The use of DLI as a prophylactic and preemptive modality leads to a favorable 5-year EFS. To safely deliver DLI in children, clinicians must maintain vigilant monitoring and prepare patients in advance when escalating the dose to ≥5 × 10 7 CD3 + cells/kg.

A case series and literature review on 98 pediatric patients of germ cell tumor developing growing teratoma syndrome.

INTRODUCTION: Malignant germ cell tumors (MGCTs) can develop either extracranially or intracranially. Growing teratoma syndrome (GTS) may develop in these patients following chemotherapy. Reports on the clinical characteristics and outcomes of GTS in children with MGCTs are limited. METHODS: We retrospectively collected the data, including the clinical characteristics and outcomes of five patients in our series and 93 pediatric patients selected through a literature review of MGCTs. This study aimed to analyze survival outcomes and risk factors for subsequent events in pediatric patients with MGCTs developing GTS. RESULTS: The sex ratio was 1.09 (male/female). In total, 52 patients (53.1%) had intracranial MGCTs. Compared with patients with extracranial GCTs, those with intracranial GCTs were younger, predominantly boys, had shorter intervals between MGCT and GTS, and had GTS mostly occurring over the initial site (all p < 0.001). Ninety-five patients (96.9%) were alive. However, GTS recurrence (n = 14), GTS progression (n = 9), and MGCT recurrence (n = 19) caused a substantial decrease in event-free survival (EFS). Multivariate analyses showed that the only significant risk factors for these events were incomplete GTS resection and different locations of GCT and GTS. Patients without any risk had a 5-year EFS of 78.8% ± 7.8%, whereas those with either risk had 41.7% ± 10.2% (p < 0.001). CONCLUSION: For patients with high-risk features, every effort should be made to closely monitor, completely remove, and pathologically prove any newly developed mass to guide relevant treatment. Further studies incorporating the risk factors into treatment strategies may be required to optimize adjuvant therapy.