Reirradiation in Pediatric Patients With Recurrent Brain Tumors: A Last Hope, But One With Greatly Feared Consequences

Reirradiation in Paediatric Tumours of the Central Nervous System: Outcome and Side Effects After Implementing National Guidelines

AIMS

Reirradiation is becoming more frequently used in paediatric tumours of the central nervous system (CNS). To fill the void of clinical guidelines, the Swedish Working Group of Paediatric Radiotherapy compiled consensus guidelines on reirradiation in 2019. The aim of this study was to evaluate the outcome of children reirradiated for CNS tumours since implementing the guidelines.

MATERIAL AND METHODS

All children in Sweden who were reirradiated for CNS tumours between 2019 and 2023 were retrospectively analysed. Data were collected on patient and treatment characteristics, outcome, and severe side effects. Radiation treatment plans were reviewed, and cumulative doses to organs at risk at reirradiation were extracted following rigid registration.

RESULTS

Thirty-one patients (male 55%, female 45%) were included, and the median age at start of reirradiation was 10.2 years. The median time between primary irradiation and reirradiation was 19 months (range 2-141). The most common treatment intent at reirradiation was palliative (68%), followed by curative (32%). With a median follow-up of 8.5 months (range 0-49), the median overall survival from the end of reirradiation was 11.4 months. In the 8 patients where the treatment goal at reirradiation was symptom relief, 6 patients (75%) had relief of symptoms. The median cumulative near maximum doses (D2%) to the brain, brainstem, and chiasm/optic nerves were 71 GyEQD2 (range 44-102), 72 GyEQD2 (range 0-94), and 40 GyEQD2 (range 0-76), respectively. Following reirradiation, only 2 patients had grade ≥3 side effects. One with transient neurological deficit and one with rapid onset of blindness that persisted.

CONCLUSION

The implementation of national guidelines has harmonised the way paediatric patients are reirradiated for CNS tumours in Sweden. A structured follow-up shows that severe side effects are rare despite high cumulative doses to organs at risk, and that reirradiation can offer relief of symptoms and/or local control for selected patients.

Children and adolescent solid tumours and high-intensity end-of-life care: what can be done to reduce acute care admissions?

Despite improvements in survival, cancer remains the leading cause of non-accidental death in children and adolescents, who risk receiving high-intensity end-of-life (HI-EOL) care.

OBJECTIVE

To analyse treatments for relapses (particularly in the last weeks of life), assess their impact on the EOL, identify patients most likely to receive HI-EOL care and examine whether palliative care services can contain the intensity of EOL care.

METHODS

This retrospective study involved patients treated at the paediatric oncology unit of the Istituto Nazionale Tumori in Milan who died between 2018 and 2020. The primary outcome was HI-EOL care, defined as: ≥1 session of intravenous chemotherapy <14 days before death; ≥1 hospitalisation in intensive care in the last 30 days of life and ≥1 emergency room admission in the last 30 days of life.

RESULTS

The study concerned 68 patients, and 17 had HI-EOL care. Patients given specific in-hospital treatments in the last 14 days of their life more frequently died in hospital. Those given aggressive EOL care were less likely to die at home or in the hospice. Patients with central nervous system (CNS) tumours were more likely to have treatments requiring hospitalisation, and to receive HI-EOL care.

CONCLUSION

These results underscore the importance of considering specific treatments at the EOL with caution. Treatments should be administered at home whenever possible.The early activation of palliative care, especially for fragile and complicated patients like those with CNS cancers, could help families cope with the many problems they face.

Brain and Brain Stem Necrosis After Reirradiation for Recurrent Childhood Primary Central Nervous System Tumors: A PENTEC Comprehensive Review

PURPOSE

Reirradiation is increasingly used in children and adolescents/young adults (AYA) with recurrent primary central nervous system tumors. The Pediatric Normal Tissue Effects in the Clinic (PENTEC) reirradiation task force aimed to quantify risks of brain and brain stem necrosis after reirradiation.

METHODS AND MATERIALS

A systematic literature search using the PubMed and Cochrane databases for peer-reviewed articles from 1975 to 2021 identified 92 studies on reirradiation for recurrent tumors in children/AYA. Seventeen studies representing 449 patients who reported brain and brain stem necrosis after reirradiation contained sufficient data for analysis. While all 17 studies described techniques and doses used for reirradiation, they lacked essential details on clinically significant dose-volume metrics necessary for dose-response modeling on late effects. We, therefore, estimated incidences of necrosis with an exact 95% CI and qualitatively described data. Results from multiple studies were pooled by taking the weighted average of the reported crude rates from individual studies.

RESULTS

Treated cancers included ependymoma (n = 279 patients; 7 studies), medulloblastoma (n = 98 patients; 6 studies), any CNS tumors (n = 62 patients; 3 studies), and supratentorial high-grade gliomas (n = 10 patients; 1 study). The median interval between initial and reirradiation was 2.3 years (range, 1.2-4.75 years). The median cumulative prescription dose in equivalent dose in 2-Gy fractions (EQD22; assuming α/β value = 2 Gy) was 103.8 Gy (range, 55.8-141.3 Gy). Among 449 reirradiated children/AYA, 22 (4.9%; 95% CI, 3.1%-7.3%) developed brain necrosis and 14 (3.1%; 95% CI, 1.7%-5.2%) developed brain stem necrosis with a weighted median follow-up of 1.6 years (range, 0.5-7.4 years). The median cumulative prescription EQD22 was 111.4 Gy (range, 55.8-141.3 Gy) for development of any necrosis, 107.7 Gy (range, 55.8-141.3 Gy) for brain necrosis, and 112.1 Gy (range, 100.2-117 Gy) for brain stem necrosis. The median latent period between reirradiation and the development of necrosis was 5.7 months (range, 4.3-24 months). Though there were more events among children/AYA undergoing hypofractionated versus conventionally fractionated reirradiation, the differences were not statistically significant (P = .46).

CONCLUSIONS

Existing reports suggest that in children/AYA with recurrent brain tumors, reirradiation with a total EQD22 of about 112 Gy is associated with an approximate 5% to 7% incidence of brain/brain stem necrosis after a median follow-up of 1.6 years (with the initial course of radiation therapy being given with conventional prescription doses of ≤2 Gy per fraction and the second course with variable fractionations). We recommend a uniform approach for reporting dosimetric endpoints to derive robust predictive models of late toxicities following reirradiation.

Clinical outcomes of pediatric patients receiving multimodality treatment of second central nervous system relapse of neuroblastoma

BACKGROUND

In high-risk neuroblastoma, multimodality therapy including craniospinal irradiation (CSI) is effective for central nervous system (CNS) relapse. Management of post-CSI CNS relapse is not clearly defined.

PROCEDURE

Pediatric patients with neuroblastoma treated with CSI between 2000 and 2019 were identified. Treatment of initial CNS disease (e.g., CSI, intraventricular compartmental radioimmunotherapy [cRIT] with ¹³¹ I-monoclonal antibodies targeting GD2 or B7H3) and management of post-CSI CNS relapse ("second CNS relapse") were characterized. Cox proportional hazards models to evaluate factors associated with third CNS relapse and overall survival (OS) were used.

RESULTS

Of 128 patients (65% male, median age 4 years), 19 (15%) received CSI with protons and 115 (90%) had a boost. Most (103, 81%) received cRIT, associated with improved OS (hazard ratio [HR] 0.3, 95% confidence interval [CI]: 0.1-0.5, p < .001). Forty (31%) developed a second CNS relapse, associated with worse OS (1-year OS 32.5%, 95% CI: 19-47; HR 3.8; 95% CI: 2.4-6.0, p < .001), and more likely if the leptomeninges were initially involved (HR 2.5, 95% CI: 1.3-4.9, p = .006). Median time to second CNS relapse was 6.8 months and 51% occurred outside the CSI boost field. Twenty-five (63%) patients underwent reirradiation, most peri-operatively (18, 45%) with focal hypofractionation. Eight (20%) patients with second CNS relapse received cRIT, associated with improved OS (HR 0.1; 95% CI: 0.1-0.4, p < .001).

CONCLUSIONS

CNS relapse after CSI for neuroblastoma portends a poor prognosis. Surgery with hypofractionated radiotherapy was the most common treatment. Acknowledging the potential for selection bias, receipt of cRIT both at first and second CNS relapse was associated with improved survival. This finding necessitates further investigation.

Medulloblastoma in the Modern Era: Review of Contemporary Trials, Molecular Advances, and Updates in Management

Critical discoveries over the past two decades have transformed our understanding of medulloblastoma from a single entity into a clinically and biologically heterogeneous disease composed of at least four molecularly distinct subgroups with prognostically and therapeutically relevant genomic signatures. Contemporary clinical trials also have provided valuable insight guiding appropriate treatment strategies. Despite therapeutic and biological advances, medulloblastoma patients across the age spectrum experience tumor- and treatment-related morbidity and mortality. Using an updated risk stratification approach integrating both clinical and molecular features, ongoing research seeks to (1) cautiously reduce therapy and mitigate toxicity in low-average risk patients, and (2) thoughtfully intensify treatment with incorporation of novel, biologically guided agents for patients with high-risk disease. Herein, we review important historical and contemporary studies, discuss management updates, and summarize current knowledge of the biological landscape across unique pediatric, infant, young adult, and relapsed medulloblastoma populations.

Diffuse Intrinsic Pontine Glioma: Molecular Landscape, Evolving Treatment Strategies and Emerging Clinical Trials

Diffuse intrinsic pontine glioma (DIPG) is a type of intrinsic brainstem glial tumor that occurs primarily in the pediatric population. DIPG is initially diagnosed based on clinical symptoms and the characteristic location on imaging. Histologically, these tumors are characterized by a heterogenous population of cells with multiple genetic mutations and high infiltrative capacity. The most common mutation seen in this group is a lysine to methionine point mutation seen at position 27 (K27M) within histone 3 (H3). Tumors with the H3 K27M mutation, are considered grade 4 and are now categorized within the H3 K27-altered diffuse midline glioma category by World Health Organization classification. Due to its critical location and aggressive nature, DIPG is resistant to the most eradicative treatment and is universally fatal; however, modern advances in the surgical techniques resulting in safe biopsy of the lesion have significantly improved our understanding of this disease at the molecular level. Genomic analysis has shown several mutations that play a role in the pathophysiology of the disease and can be targeted therapeutically. In this review, we will elaborate on DIPG from general aspects and the evolving molecular landscape. We will also review innovative therapeutic options that have been trialed along with new promising treatments on the horizon.