High Incidence of Veno-Occlusive Disease With Myeloablative Chemotherapy Following Craniospinal Irradiation in Children With Newly Diagnosed High-Risk CNS Embryonal Tumors: A Report From the Children's Oncology Group (CCG-99702)

Evolution of Systemic Therapy in Medulloblastoma Including Irradiation-Sparing Approaches

The management of medulloblastoma in children has dramatically changed over the past four decades, with the development of chemotherapy protocols aiming at improving survival and reducing long-term toxicities of high-dose craniospinal radiotherapy. While the staging and treatment of medulloblastoma were until recently based on the modified Chang's system, recent advances in the molecular biology of medulloblastoma have revolutionized approaches in the management of this increasingly complex disease. The evolution of systemic therapies is described in this review.

Questions and answers in the management of children with medulloblastoma over the time. How did we get here? A systematic review

Introduction

Treatment of children with medulloblastoma (MB) includes surgery, radiation therapy (RT) and chemotherapy (CT). Several treatment protocols and clinical trials have been developed over the time to maximize survival and minimize side effects.

Methods

We performed a systematic literature search in May 2023 using PubMed. We selected all clinical trials articles and multicenter studies focusing on MB. We excluded studies focusing exclusively on infants, adults, supratentorial PNETs or refractory/relapsed tumors, studies involving different tumors or different types of PNETs without differentiating survival, studies including <10 cases of MB, solely retrospective studies and those without reference to outcome and/or side effects after a defined treatment.

Results

1. The main poor-prognosis factors are: metastatic disease, anaplasia, MYC amplification, age younger than 36 months and some molecular subgroups. The postoperative residual tumor size is controversial.2. MB is a collection of diseases.3. MB is a curable disease at diagnosis, but survival is scarce upon relapse.4. Children should be treated by experienced neurosurgeons and in advanced centers.5. RT is an essential treatment for MB. It should be administered craniospinal, early and without interruptions.6. Craniospinal RT dose could be lowered in some low-risk patients, but these reductions should be done with caution to avoid relapses.7. Irradiation of the tumor area instead of the entire posterior fossa is safe enough.8. Hyperfractionated RT is not superior to conventional RT9. Both photon and proton RT are effective.10. CT increases survival, especially in high-risk patients.11. There are multiple drugs effective in MB. The combination of different drugs is appropriate management.12. CT should be administered after RT.13. The specific benefit of concomitant CT to RT is unknown.14. Intensified CT with stem cell rescue has no benefit compared to standard CT regimens.15. The efficacy of intraventricular/intrathecal CT is controversial.16. We should start to think about incorporating targeted therapies in front-line treatment.17. Survivors of MB still have significant side effects.

Conclusion

Survival rates of MB improved greatly from 1940-1970, but since then the improvement has been smaller. We should consider introducing targeted therapy as front-line therapy.

Meta of classical chemotherapy compared with high-dose chemotherapy and autologous stem cell rescue in newly diagnosed medulloblastoma after radiotherapy

BACKGROUND

High-dose chemotherapy combined with autologous stem cell rescue (HDCT + ASCR) has been used to treat newly diagnosed medulloblastoma, but there was no high-level evidence to support its efficacy.

METHODS

Databases were retrieved, and patients were divided into 2 groups: group A was radiotherapy combined with HCDT + ASCR, and group B was classical radiotherapy and chemotherapy. The clinical benefit rate, progression-free survival (PFS), overall survival (OS) and toxicities data were extracted.

RESULTS

22 clinical trials met the inclusion criteria, 416 in group A and 2331 in group B. There was no difference in CBR between 2 groups (80.0% vs 71.5%, P.262). The 3-year PFS (3-y PFS) of group A was significantly better than group B (79.0% vs 69.5%, P = .004). The analysis found that there was no difference between the 2 groups of the standard risk group or the high-risk group. In the standard risk group, the 5-y PFS of group A was significantly better than group B (83.6% vs75.6%, P = .004). Comparison of 3-y OS and 5-y OS between 2 groups of all MB patients showed no difference (P = .086; P = .507), stratified analysis was the same result. The gastrointestinal toxicity in group A was significantly higher than that in group B (P = .016), and the level 3/4 ototoxicity in high-risk group A was higher than that in group B (P = .001).

CONCLUSIONS

HDCT + ASCR can prolong 3-year PFS significantly, and prolong 5-y PFS significantly in the standard risk group, but increase gastrointestinal toxicity significantly for newly diagnosed medulloblastoma.

Tandem autologous hematopoietic stem cell transplantation for embryonal brain tumors in infants and very young children

Withdrawal of radiotherapy in patients with brain tumors under four years decreases chance for cure. AutoHSCT in a series of pilot studies demonstrated a potential to improve outcomes in these patients. The study included 50 patients with median age of 39 months (7-53). Medulloblastoma (n = 28, 56%), ETMR (n = 9, 18%) and other histological types (n = 13, 26%) were most commonly diagnosed. Forty two patients (84%) received tandem autoHSCT by HIT-MED protocol, and single autoHSCT was performed in eight children (16%). Adjuvant radiotherapy was administered in 25 (50%) children and treatment of relapse included radiotherapy in 6 (12%). Median follow-up was 39.6 months (6-121). Long-term CIR was 37%, and TRM - 6%. Five-year OS was 71% in medulloblastoma, 37% in ETMR and in other tumors - 51% (p = 0.07). Irradiation-free OS at 5 years for children with medulloblastoma was 24%. For the whole cohort of CNS tumors, independently of histology, OS and PFS at five years were 60% and 46%, respectively Young children with medulloblastoma, following tandem autoHSCT, demonstrate OS comparable to older children. Patients with other histological types demonstrate suboptimal long-term survival rates after autoHSCT and one should assess whether these patients benefit from autoHSCT.

Medulloblastoma: an Old Diagnosis with New Promises

PURPOSE OF REVIEW

Molecular subtyping in medulloblastoma (MB) has diagnostic and prognostic values which impact therapy. This paper provides guidance for the clinician caring for pediatric and adult patients with medulloblastoma in the modern era.

RECENT FINDINGS

Medulloblastoma comprises four molecularly distinct subgroups: wingless activated (WNT), sonic hedgehog activated (SHH), group 3, and group 4. Risk stratification before and after the discovery of molecular subgroups aims at minimizing toxicity by reducing radiation and chemotherapy doses in low-risk patients while maintaining favorable overall survival (OS). The mainstay of newly diagnosed medulloblastoma treatment is surgery, radiation therapy, and chemotherapy, except for children under 6 years of age, where high-dose chemotherapy with autologous stem cell rescue is used to avoid or delay radiotherapy, preventing neurocognitive sequelae. Management of recurrent/refractory medulloblastoma remains a challenge with immunotherapy and small-molecule inhibitors forming the backbone of novel strategies. Recent innovations in medulloblastoma research allow us to better understand pathogenesis and molecular characteristics resulting in advanced risk stratification models, new therapeutic approaches, and overall improved survival and quality of life.

Double-conditioning regimen consisting of high-dose thiotepa and melphalan with autologous stem cell rescue for high-risk pediatric solid tumors: A second report

BACKGROUND

Pediatric patients with high-risk, relapsed, or refractory solid tumors have a poor prognosis. We have previously reported a dose-finding experience of high-dose chemotherapy consisting of thiotepa and melphalan ("double-conditioning regimen"). Using doses derived from that study, we have treated patients since 2005. We now report a retrospective review of patients treated by this fixed dose.

PROCEDURE

We reviewed 50 patients (median 4 years; range 0-15 years) with high-risk or relapsed/refractory solid tumors treated by this dose-fixed, double-conditioning regimen from April 2005 to May 2014. Doses were thiotepa 800 mg/m² and melphalan 280 mg/m² for children ≥2 years of age, and 32 mg/kg and 6 mg/kg, respectively, for children <2 years of age. Further, doses were reduced according to creatinine clearance with poor renal function.

RESULTS

Nonhematological toxicity was mainly gastrointestinal-grade 3 mucositis (n = 41) and grade 3-4 diarrhea (n = 10). Neurological, renal, and endothelial cell toxicity and sinusoidal obstruction syndrome were not observed. There were two toxic deaths (interstitial viral pneumonia). This regimen demonstrated antitumor activity against several types of tumors. Although the frequency of gastrointestinal toxicity was high, other severe toxicity was not observed.

CONCLUSIONS

Our double-conditioning regimen was very well tolerated and demonstrated antitumor activity. We are moving forward with multi-institutional trials now.

Management of high-risk medulloblastoma

Medulloblastoma is the most common malignant brain tumors in children. Current management combines surgery, radiotherapy, and chemotherapy. Current treatment of medulloblastoma is based on a clinical risk-stratification system that takes into account age, extent of resection and metastatic status. High-risk medulloblastoma patients are defined by the presence of metastatic disease and/or an incomplete resection with a residual amount of tumour>1.5 cm². This review describes the evolution in the management of high-risk medulloblastoma patients during recent 4 decades and recent changes in the definition of high-risk patients as a result of major advances in the understanding of the molecular heterogeneity of medulloblastomas.

Thrombotic and hemorrhagic complications in children and young adult recipients of Hematopoietic Stem Cell Transplant (HSCT)

BACKGROUND

Overall incidence of hemostatic complications in pediatric recipients of Hematopoietic Stem Cell Transplant (HSCT) is scarcely studied. This retrospective review explored the incidence and underlying risk factors of bleeding and thrombotic complications in children.

PROCEDURE

Clinical characteristics, hemorrhagic events (HE), thrombotic events (TE) and follow up data were abstracted from medical records on patients aged <21 years undergoing HSCT during January 2000-June 2015.

RESULTS

From start of conditioning until last follow up, 238 pediatric patients were reviewed during this study. There were 16 symptomatic thrombotic complications in 15 patients, along with 13 major bleeding events. Incidence of HE or TE was higher in allogeneic HSCT compared to autologous HSCT (p = 0.02). Severe thrombocytopenia could not be identified as a major contributor to bleeding. All patients with HE had platelets between 20,000-50,000 × 10⁹/L, except one patient, who had platelets <20,000 × 10⁹/L. All patients with hemorrhagic cystitis (n = 7) had received cyclophosphamide (Cy). For patients with sinusoidal obstruction syndrome, conditioning included either busulfan (Bu)/Cy (n = 5), Cy with total body irradiation (n = 4), or thiotepa (n = 2). Among allogeneic HSCT recipients, 60% of HE and 92% with TE had underlying myeloid neoplasms. Graft versus Host disease contributed to both types of complications (p = 0.07), although not reaching statistical significance.

CONCLUSIONS

Allogeneic pediatric HSCT patients had higher overall risk of hemorrhagic or thrombotic complications compared to autologous recipients in this study. HSCT for myeloid malignancies was a risk factor for higher complications.

Diagnosis and severity criteria for sinusoidal obstruction syndrome/veno-occlusive disease in pediatric patients: a new classification from the European society for blood and marrow transplantation

The advances in hematopoietic cell transplantation (HCT) over the last decade have led to a transplant-related mortality below 15%. Hepatic sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) is a life-threatening complication of HCT that belongs to a group of diseases increasingly identified as transplant-related, systemic endothelial diseases. In most cases, SOS/VOD resolves within weeks; however, severe SOS/VOD results in multi-organ dysfunction/failure with a mortality rate >80%. A timely diagnosis of SOS/VOD is of critical importance, given the availability of therapeutic options with favorable tolerability. Current diagnostic criteria are used for adults and children. However, over the last decade it has become clear that SOS/VOD is significantly different between the age groups in terms of incidence, genetic predisposition, clinical presentation, prevention, treatment and outcome. Improved understanding of SOS/VOD and the availability of effective treatment questions the use of the Baltimore and Seattle criteria for diagnosing SOS/VOD in children. The aim of this position paper is to propose new diagnostic and severity criteria for SOS/VOD in children on behalf of the European Society for Blood and Marrow Transplantation.

Sinusoidal obstruction syndrome/veno-occlusive disease after high-dose intravenous busulfan/melphalan conditioning therapy in high-risk Ewing Sarcoma

This mono-institutional observational study was conducted to determine incidence, severity, risk factors, and outcome of sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) in high-risk Ewing sarcoma (ES) patients treated with intravenous busulfan and melphalan (BU-MEL) followed by autologous stem cell transplantation (ASCT). During the past 10 years, 75 consecutive ES patients resulted evaluable for the analysis. After diagnosis of SOS/VOD, defibrotide therapy was started as soon as the medication was available. The variables analyzed as potential risk factors were: gender, patient's age at diagnosis, primary tumor site, disease stage, and prior radiation therapy (RT) given, focusing on RT liver exposure. The median age at diagnosis was 18.8 years. Five patients developed moderate to severe SOS/VOD (cumulative incidence, 6.67%). None of 32 pediatric patients (≤17 years) developed SOS/VOD (p = 0.0674). In univariate analysis, prior RT liver exposure resulted statistically significant (p = 0.0496). There was one death due to severe SOS/VOD. This study reports the largest series of high-risk ES patients treated with intravenous BU-MEL before ASCT. The incidence of SOS/VOD was lower when compared with other studies that used oral busulfan. Any prior RT liver exposure should be avoided. Earlier defibrotide treatment confirms to be effective.

Tandem thiotepa with autologous hematopoietic cell rescue in patients with recurrent, refractory, or poor prognosis solid tumor malignancies

BACKGROUND

The purpose of this study was to determine the feasibility and tolerability of tandem courses of high-dose thiotepa with autologous hematopoietic cell rescue (AHCR) in patients with recurrent, refractory solid tumors who were ineligible for a single course of high-dose therapy due to greater than minimal residual disease. Patients with decreased hearing or poor renal function were eligible.

PROCEDURE

Thiotepa was administered intravenously at a dose of 200 mg/m² /day (6.67 mg/kg/day) daily for 3 days followed by AHCR. A second course of thiotepa was given 4 weeks later provided blood counts recovered sufficiently without evidence of tumor progression.

RESULTS

Fifty-eight patients received 96 courses. Thirty-eight (65%) patients received two courses of therapy. Twenty-seven courses (28%) were administered completely in the outpatient setting. A toxic mortality rate of 3.4% was observed. Five of 26 patients with medulloblastoma were alive at a median of 35 months, whereas 21 patients died at a median of 11.7 months. Four of five patients with central nervous system germ cell tumors (CNS GCT) were alive 68-103 months following AHCR.

CONCLUSIONS

Two cycles of high-dose thiotepa with AHCR were well tolerated even in these heavily pretreated patients. This therapy may provide prolonged survival in patients with recurrent malignant brain tumors, particularly medulloblastoma and CNS GCT.

The kinesin KIF14 is overexpressed in medulloblastoma and downregulation of KIF14 suppressed tumor proliferation and induced apoptosis

Medulloblastoma (MB) is the most common malignant brain tumor in childhood. At present, there is no well-established targeted drug for majority of patients. The kinesin family member 14 (KIF14) is a novel oncogene located on chromosome 1q and is dysregulated in multiple cancers. The objectives of this study were to evaluate KIF14 expression and chromosome 1q copy number in MB, and to delineate its biological functions in MB pathogenesis. By quantitative RT-PCR and immunohistochemistry, we found KIF14 was overexpressed in MB. Increased KIF14 expression at protein level was strongly associated with shorter progression-free survival (P=0.0063) and overall survival (P=0.0083). Fluorescence in situ hybridization (FISH) analysis confirmed genomic gain of chromosome 1q in 17/93 (18.3%) of MB. Combined genetic and immunohistochemical analyses revealed that 76.5% of MB with 1q gain showed consistent overexpression of KIF14, and a tight link between chromosome 1q gain and KIF14 overexpression (P=0.03). Transient, siRNAs-mediated downregulation of KIF14 suppressed cell proliferation and induced apoptosis in two MB cell lines. Stably KIF14 knockdown by shRNAs inhibited cell viability, colony formation, migration and invasion, and tumor sphere formation in MB cells. We conclude that KIF14 is dysregulated in MB and is an adverse prognostic factor for survival. Furthermore, KIF14 is part of MB biology and is a potential therapeutic target for MB.