Helical tomotherapy craniospinal irradiation in primary brain tumours: Toxicities and outcomes in a peadiatric and adult population

Objective

As craniospinal irradiation (CSI) is delivered more frequently by helical tomotherapy (HT) with few reports about late effects, we analysed all patients treated in our centre over an 11-year period.

Methods and materials

Our study included all patients that underwent CSI by HT, between September 2009 and January 2020, in the Department of Radiation Oncology of the Toulouse Cancer Institute. Acute radiotherapy toxicities were reported and medium- to long-term outcomes analysed.

Results

Among the 79 patients included, 70.9 % were younger than 18 years at diagnosis, the median age was 13 (range: 1-52) at the time of radiation therapy, 67.1 % of patients had medulloblastoma. Half of them (49.4 %) had a metastatic disease at diagnosis. The median dose of CSI was 36 Gy (range, 18-36). Seventy-seven patients received a radiation boost to the original location of the primary tumour (97.5 %), 32 patients also received a boost to their metastatic sites (40.5 %). Median follow-up was 55.5 months (95 %CI = [41.2; 71.8]). The 3-year event-free survival rate was 66.3 % (95 %CI = [54.2; 75.9]). Most patients presented with acute haematological toxicities during CSI (85.9 %), predominantly severe thrombocytopenia (39.7 %). Among the 64 patients assessed for medium- and long-term outcomes, 52 survived and 47 were alive and disease-free at the latest follow-up visit on record. There were 3.8 % secondary tumours: two meningiomas and one diffuse intrinsic pontine glioma. Adult and paediatric patients respectively presented with secondary cataract (4.3 % vs 22.0 %), persistent hearing disorders (26.1 % vs 29.3 %), pulmonary or cardiac late effects (4.3 % vs 2.4 %), hormonal pituitary gland deficiencies (30.0 % vs 56.8 %) and psycho-cognitive disorders (56.5 % vs 53.7 %).

Conclusion

CSI dispensed by HT, did not result in any additional acute or late toxicities when compared to 3D-CSI. There was no increase in the secondary tumour rate compared to that reported in the literature.

The long-term impact of irradiation on functional connectivity in brain circuits involved in memory processes after pediatric posterior fossa tumor

PURPOSE

Memory is one of the main specific cognitive domains impaired with attention and processing speed after a pediatric brain tumor. This work explored the long-term impact of radiotherapy in children with posterior fossa tumor (PFT) on brain connectivity in neural circuits involved in memory using resting-state functional magnetic resonance imaging (rs-fMRI).

METHODS

A total of 20 irradiated and 15 non-irradiated PFT survivors, and 21 healthy controls, prospectively included in the IMPALA study (NCT04324450), performed memory tests assessing episodic, procedural, and working memories and were subjected to an rs-fMRI. We manually contoured main structures involved in memory to explore connectivity at rest in a seed-to-voxel analysis. The groups were compared and differences in connectivity were correlated with behavioral scores and irradiation doses.

RESULTS

The performance of all mnesic tasks was lower in PFT survivors with a greater alteration in working and episodic memory in irradiated patients. Irradiated survivors had atypical connectivities in all memory circuits compared to controls and in cortico-caudate and cortico-cerebellar circuits compared to non-irradiated survivors. Non-irradiated survivors had only atypical connectivities in the cortico-cerebellar circuits compared to controls. In irradiated survivors, atypical connectivities in cortico-hippocampal circuits were linked with episodic memory scores and dose of irradiation to the left hippocampus and in cortico-striatal circuits with procedural memory scores and dose of irradiation to the striatum.

CONCLUSION

The results of this study highlight that irradiation has a long-term impact on brain connectivity in brain circuits involved in memory after pediatric PFT with a specific radiation-dose effect in supratentorial structures.

A new subtype of diffuse midline glioma, H3 K27 and BRAF/FGFR1 co-altered: a clinico-radiological and histomolecular characterisation

Diffuse midline gliomas (DMG) H3 K27-altered are incurable grade 4 gliomas and represent a major challenge in neuro-oncology. This tumour type is now classified in four subtypes by the 2021 edition of the WHO Classification of the Central Nervous System (CNS) tumours. However, the H3.3-K27M subgroup still appears clinically and molecularly heterogeneous. Recent publications reported that rare patients presenting a co-occurrence of H3.3K27M with BRAF or FGFR1 alterations tended to have a better prognosis. To better study the role of these co-driver alterations, we assembled a large paediatric and adult cohort of 29 tumours H3K27-altered with co-occurring activating mutation in BRAF or FGFR1 as well as 31 previous cases from the literature. We performed a comprehensive histological, radiological, genomic, transcriptomic and DNA methylation analysis. Interestingly, unsupervised t-distributed Stochastic Neighbour Embedding (tSNE) analysis of DNA methylation profiles regrouped BRAFV600E and all but one FGFR1MUT DMG in a unique methylation cluster, distinct from the other DMG subgroups and also from ganglioglioma (GG) or high-grade astrocytoma with piloid features (HGAP). This new DMG subtype harbours atypical radiological and histopathological profiles with calcification and/or a solid tumour component both for BRAFV600E and FGFR1MUT cases. The analyses of a H3.3-K27M BRAFV600E tumour at diagnosis and corresponding in vitro cellular model showed that mutation in H3-3A was the first event in the oncogenesis. Contrary to other DMG, these tumours occur more frequently in the thalamus (70% for BRAFV600E and 58% for FGFR1MUT) and patients have a longer overall survival with a median above three years. In conclusion, DMG, H3 K27 and BRAF/FGFR1 co-altered represent a new subtype of DMG with distinct genotype/phenotype characteristics, which deserve further attention with respect to trial interpretation and patient management.

Respective Roles of Surgery, Chemotherapy, and Radiation Therapy for Recurrent Pediatric and Adolescent Ependymoma: A National Multicentric Study

PURPOSE

Half of the children and adolescents treated for intracranial ependymoma experience recurrences that are not managed in a standardized manner. This study aimed to retrospectively evaluate recurrence treatments.

METHODS AND MATERIALS

We assessed overall survival (OS) and progression-free survival (PFS) after a first relapse in a population of patients from the Pediatric Ependymoma Photons Protons and Imaging study (PEPPI study) who were treated with surgery and radiation therapy in French Society of Childhood Cancer reference centers between 2000 and 2013. Data were analyzed using the Cox model as well as a landmark analysis at 4 months that accounted for the guarantee-time bias.

RESULTS

The median follow-up of the whole population of 202 patients was 105.1 months, with a 10-year OS of 68.2% and PFS of 45.5%. Among the 100 relapse cases, 68.0% were local relapses, 20.0% were metastatic, and 12.0% were combined (local and metastatic). Relapses were treated by surgery (n = 79) and/or reirradiation (n = 52) and/or chemotherapy (n = 22). The median follow-up after relapse was 77.8 months. The OS and PFS at 5 years were 43.1% and 16.2%, respectively. After surgery or radiation therapy of the first relapse, OS and PFS were more favorable, whereas treatments that included chemotherapy with or without focal treatment were associated with worse OS and PFS. In the multivariate analysis, stereotactic hypofractionated reirradiation after surgery was associated with a significantly better outcome (OS, P = .030; PFS, P = .008) and chemotherapy with a worse outcome (OS, P = .028; PFS, P = .033).

CONCLUSIONS

This analysis of relapse treatments within the PEPPI study determined that irrespective of whether the relapse was localized or metastatic, treatments that included surgery and/or reirradiation had better outcomes.

Impact of a pediatric posterior fossa tumor and its treatments on motor procedural learning

INTRODUCTION

Posterior fossa tumor (PFT) survivors have difficulty learning new skills. Procedural memory is a skill learning system that allows, through training, the automatization of procedures and progressive improvement of performance. It underlies most of the motor procedures in everyday life that we perform automatically, such as riding a bike or writing. Motor procedural memory is divided into two components: motor sequence learning involving mainly cortico-striatal networks, and motor adaptation involving mainly cortico-cerebellar networks. The aim of this work was to explore the impact of a tumor and its treatment during childhood on procedural learning hypothesizing that sequence learning would be impaired in PFT survivors who have been treated with radiotherapy, whereas motor adaptation would be impaired in all PFT survivors.

METHOD

22 irradiated survivors of PFT, 17 non-irradiated survivors and 21 healthy controls from the IMPALA study (NCT04324450) performed a motor sequence learning task and a motor adaptation task. Doses received by striatal and cerebellar structures were reported from the initial dosimetry plans.

RESULTS

Sequence learning was preserved in both tumor groups, but at the individual level 7/22 irradiated, and 4/17 non-irradiated participants failed to learn the motor sequence. Motor adaptation was impaired in both tumor groups, predominantly in the irradiated group.

CONCLUSION

This study sheds new light on the long-term impact of PFT treatments in childhood on a rarely-studied part of memory, which is perceptual-motor procedural learning. Our results suggest that the cerebellum and striatum could be considered as organs at risk with regard to procedural learning.

Phase I Study of a Combination of Fluvastatin and Celecoxib in Children with Relapsing/Refractory Low-Grade or High-Grade Glioma (FLUVABREX)

Preclinical data support the activity of celecoxib and fluvastatin in high-grade (HGG) and low-grade gliomas (LGG). A phase I trial (NCT02115074) was designed to evaluate the safety of this combination in children with refractory/relapsed HGG and LGG using four dose levels of fluvastatin with a fixed daily dose of celecoxib. A Continual Reassessment Method was used for fluvastatin dose escalation. Dose-limiting toxicities (DLT) were determined on the first treatment cycle. Twenty patients were included. Ten LGG and ten HGG patients received a median of 3.5 treatment cycles. Two DLTs were reported: one grade 3 maculopapular rash (4 mg/kg dose level) and one grade 4 increase of Creatine Phospho-Kinase (6 mg/kg dose level). We identified the dose of 6 mg/kg/day as the recommended phase II dose (RP2D) of fluvastatin with celecoxib. Four patients with LGG continued treatment beyond 12 cycles because of stable disease, including one patient who received 23 treatment cycles. In children with refractory/relapsed glioma, the RP2D of fluvastatin with celecoxib is 6 mg/kg/day. The long-term stable diseases observed in LGG suggest a possible role of the combination in a maintenance setting, given its good tolerance and low cost for children living in low- and middle-income countries.

Unusual circumstance for craniopharyngioma discovery on meningoencephalitis: a pediatric case report

BACKGROUND

Craniopharyngioma is a rare condition in children, but it is the most frequent tumor that occurs in the hypothalamic pituitary region. Chemical meningitis has been described as an uncommon postoperative complication, but no chemical meningitis due to a spontaneous rupture leading to craniopharyngioma diagnosis in children has been reported.

CASE PRESENTATION

This is a case of a 13-year-old boy presenting with fever, vomiting and headache for two days. The CT scan revealed a suprasellar lesion, and lumbar puncture showed aseptic meningitis. The cerebral MRI suggested a craniopharyngioma and the cerebrospinal fluid cholesterol concentration was abnormally high. A thorough medical history indicated some visual disturbance, which improved at the onset of meningitis, and an inflection of the growth curve. The anatomopathological analysis of the tumor confirmed the diagnosis of craniopharyngioma.

CONCLUSIONS

This case is the first to report the discovery of a craniopharyngioma with meningoencephalitis caused by the rupture of a craniopharyngioma cyst in a child. Diagnosis was facilitated by determining the cholesterol level in the cerebrospinal fluid, as well as fine anamnesis to identify visual and growth disturbances.

MEDB-84. The French experience of ELP1-related medulloblastomas

Medulloblastoma (MB), the most frequent embryonic tumor of the cerebellum is classified into four molecular subgroups (WNT group, SHH group, group 3 and group 4). Although the vast majority of MB are sporadic, predisposing genetic diseases have been described in rare WNT MB and more frequently in the SHH group. In a recent pediatric series of SHH-MB, germline alterations of the ELP1 gene have been described in 14% of cases, making this gene the most frequent genetic predisposition in MB. We have investigated the potential interest of ELP1 immunostaining on a large cohort of 132 MB. A complete loss of ELP1 staining was observed in 12 SHH MB (among 57 total SHH MB: 21%). The loss of ELP1 immunostaining was well correlated with the presence of a bi-allelic alteration of the gene except for one case for which the MB had a loss of ELP1 protein expression demonstrated by immunohistochemistry (IHC) and confirmed by whole proteome analysis, although no obvious genetic alteration in the coding sequence of ELP1 could be found. Molecular analysis of a large “molecular” cohort of 266 MB from French centers for which somatic ELP1 was sequenced allows to identify 12 additional MB with bi-allelic ELP1 genetic alterations. Our results demonstrate the benefit of the ELP1 IHC as an accurate and reliable tool to screen ELP1-deficient MB. This new immunohistochemical tool will now be advantageously used to screen SHH MB upfront for genetic alteration in ELP1, and will subsequently help orientating these patients towards genetic counseling.

Prognostic relevance of clinical and molecular risk factors in children with high-risk medulloblastoma treated in the phase II trial PNET HR+5

BACKGROUND

High-risk medulloblastoma is defined by the presence of metastatic disease and/or incomplete resection and/or unfavorable histopathology and/or tumors with MYC amplification. We aimed to assess the 3-year progression-free survival (PFS) and define the molecular characteristics associated with PFS in patients aged 5-19 years with newly diagnosed high-risk medulloblastoma treated according to the phase II trial PNET HR+5.

METHODS

All children received postoperative induction chemotherapy (etoposide and carboplatin), followed by 2 high-dose thiotepa courses (600 mg/m2) with hematological stem cell support. At the latest 45 days after the last stem cell rescue, patients received risk-adapted craniospinal radiation therapy. Maintenance treatment with temozolomide was planned to start between 1-3 months after the end of radiotherapy. The primary endpoint was PFS. Outcome and safety analyses were per protocol (all patients who received at least one dose of induction chemotherapy).

RESULTS

Fifty-one patients (median age, 8 y; range, 5-19) were enrolled. The median follow-up was 7.1 years (range: 3.4-9.0). The 3 and 5-year PFS with their 95% confidence intervals (95% CI) were 78% (65-88) and 76% (63-86), and the 3 and 5-year OS were 84% (72-92) and 76% (63-86), respectively. Medulloblastoma subtype was a statistically significant prognostic factor (P-value = 0.039) with large-cell/anaplastic being of worse prognosis, as well as a molecular subgroup (P-value = 0.012) with sonic hedgehog (SHH) and group 3 being of worse prognosis than wingless (WNT) and group 4. Therapy was well tolerated.

CONCLUSIONS

This treatment based on high-dose chemotherapy and conventional radiotherapy resulted in a high survival rate in children with newly diagnosed high-risk medulloblastoma.

What does a non-response to induction chemotherapy imply in high-risk medulloblastomas?

PURPOSE

High-risk medulloblastomas (HR-MB) may not respond to induction chemotherapy, with either post-induction stable (SD) or progressive disease (PD). There is no consensus regarding their optimal management.

METHODS

A retrospective, multicentre study investigated patients with non-responder HR-MB treated according to the PNET HR + 5 protocol (NCT00936156) between 01/01/2009 and 31/12/2018. After two courses of etoposide and carboplatin (induction), patients with SD or PD were analyzed. Upon clinician's decision, the PNET HR + 5 protocol was either pursued with tandem high-dose chemotherapy (HDCT) and craniospinal irradiation (CSI) (continuation group) or it was modified (switched group).

RESULTS

Forty-nine patients were identified. After induction, 37 patients had SD and 12 had PD. The outcomes were better for the SD group: the 5-y PFS and OS were 52% (95% CI 35-67) and 70% (95% CI 51-83), respectively, in the SD group while the 2-y PFS and OS were 17% (95% CI 3-41) and 25% (95% CI 6-50), respectively, in the PD group (p < 0.0001). The PNET HR + 5 strategy was pursued for 3 patients in the PD group, of whom only one survived. In the SD group, it was pursued for 24/37 patients whereas 13 patients received miscellaneous treatments including a 36 Gy CSI in 12 cases. Despite that continuation and switched group were well-balanced for factors impacting the outcomes, the latter were better in the continuation group than in the switched group: the 5-y PFS were 78% (95% CI 54-90) versus 0% (p < 0.001), and the 5-y OS were 78% (95% CI 54-90) versus 56% (95% CI 23-79) (p = 0.0618) respectively. In the SD group, multivariate analysis revealed that MYC amplification, molecular group 3, and a switched strategy were independent prognostic factors for progression.

CONCLUSION

Patients with post-induction SD may benefit from HDCT and CSI, whereas patients with early PD will require new therapeutic approaches.

Prospective phase II study of children affected by bilateral intraocular retinoblastoma with macular involvement of both eyes or in the only preserved eye. Macular tumor control, eye preservation rate, and visual outcome

BACKGROUND

Conservative treatments of intraocular retinoblastoma often consist of chemotherapy and focal treatments. The protocols vary and currently may combine two or three drugs, with different number of cycles, associated to the ocular treatments. In case of macular/paramacular involvement, tumor location and retinal scars induced by focal treatments often have a major negative impact on final visual outcome.

METHODS

This study aimed to include children affected by bilateral intraocular macular/paramacular retinoblastoma in a prospective phase II study. The protocol consisted of six cycles of a three-drug combination (vincristine, etoposide, carboplatin), and the addition of macula-sparing transpupillary thermotherapy (TTT) to the third cycle. The primary endpoint was the local control rate without external beam radiotherapy (EBR) and/or enucleation.

RESULTS

Nineteen patients (26 eyes) were included from July 2004 to November 2009. Thirteen eyes belonged to group V of the Reese-Ellsworth classification and 10 to group D of the International Intraocular Retinoblastoma Classification. Macular/paramacular tumors were treated with chemotherapy alone in nine eyes, and with chemotherapy associated with macula-sparing TTT in 17 eyes. Four eyes experienced macular relapse. At a median follow up of 77 months, 23 eyes (88.5%) were saved without EBR, two were enucleated and one received EBR. The median visual acuity of the 24 saved eyes was 20/50. No severe adverse effect was observed.

CONCLUSION

Six cycles of a three-drug combination associated with macula-sparing TTT achieved good tumor control, improved eye preservation rates without EBR, and decreased macular damage, often providing satisfactory visual results with long-term follow up.

EPCT-11. PHASE 1 STUDY OF FLUVASTATIN-CELECOXIB COMBINATION IN CHILDREN WITH RELAPSING/REFRACTORY OPTICO-CHIASMATIC LOW-GRADE GLIOMA OR HIGH-GRADE GLIOMAS (FLUVABREX): FINAL RESULTS

BACKGROUND

Preclinical data support the activity of celecoxib and fluvastatin in high grade (HGG) and low grade gliomas (LGG). A Phase I study was designed to evaluate this combination in children with refractory/relapsed glioma. AIM: To assess the safety, pharmacokinetics (PK), maximum tolerated dose, Recommended Dose for Phase II (RDP2). METHOD: Multicenter phase I trial, including patients aged 6 to 21 year old. Fluvastatin starting dose was 2 mg/kg/day, 14/28 days, with fixed dose of celecoxib (200–800 mg /day). Four dose levels of fluvastatin (2, 4, 6, 8 mg/kg/day) were evaluated. A Continual Reassessment Method was used for dose escalation. Dose-limiting toxicities (DLT) were determined on the 1st cycle. PK samples were obtained at D1 and D14 of cycle 1, pre-dose of cycle 2.

RESULTS

20 patients were enrolled with a median age of 12 years (5.9–19). They previously received a median of 3 (1–7) lines of treatment. Ten patients were treated for LGG and 10 for HGG, receiving a median of 3.5 cycles (1–21). Patients with LGG received a median of 9 cycles (1–21). Among the 17 patients evaluable for DLT, 2 DLTs were reported: 1 grade 3 maculo-papular rash (4 mg/kg), and 1 grade 4 increase of CPK (6 mg/kg). The RP2D of fluvastatin is 6 mg/kg/day.

CONCLUSION

In children with refractory/relapsed glioma, the RDP2 of fluvastatin associated with celecoxib is 6 mg/kg/day. This combination is well tolerated encouraging a phase 2 study in LGG.

MBCL-29. PHASE I/II STUDY OF SEQUENTIAL HIGH-DOSE CHEMOTHERAPY WITH STEM CELL SUPPORT IN CHILDREN YOUNGER THAN 5 YEARS OF AGE WITH HIGH-RISK MEDULLOBLASTOMA

PURPOSE

To assess the 3-year EFS rate of children younger than 5 years of age with high-risk medulloblastoma (MB) treated according to the prospective multicenter trial HR MB-5.

PATIENTS AND METHODS

After surgery, all children received 2 cycles of Etoposide- Carboplatine. If partial (PR) or complete response (CR) was achieved after induction chemotherapy, children received 2 courses of thiotepa (600mg/m²) with stem cell rescue. For patients in CR after high-dose chemotherapy, they received one course of Cyclophosphamide – Busilvex with stem cell rescue (Phase I part). The others patients (not in PR after induction or in CR after thiotepa) were treated with 2 cycles of Temozolomide-Irinotecan followed by age-adapted craniospinal irradiation and maintenance treatment.

RESULTS

28 children (2 to 4 years; median: 3.0 years) were enrolled. Group 3 MB were most common (57%). The response rate to Etoposide-Carboplatine was 60.7%. Among 20 patients treated with Thiotepa, 13 children were in CR and received Cyclophosphamide – Busilvex without radiotherapy. Out of them, 9 patients (45%) are alive in CR without craniospinal irradiation (median follow-up 5 years). Among 15 patients treated with radiotherapy, 8 patients are alive (median follow-up 3.8 years). The study was prematurely stopped for an excess of events. The median follow-up was 4 years (range 1.5 - 6.1). The 3-year EFS and OS were 42.3% [25.9 - 60.6] and 71.3% [52.7 - 84.7], respectively.

CONCLUSIONS

This risk-adapted strategy did not improve EFS in young children with high-risk MB. However, the study shows that good responders to chemotherapy can be cured without recourse to irradiation.

Phase I study of vinblastine in combination with nilotinib in children, adolescents, and young adults with refractory or recurrent low-grade glioma

Background

New rescue regimens are needed for pediatric refractory/recurrent low-grade glioma. Nilotinib is a tyrosine kinase inhibitor that has potential synergistic effects with vinblastine on angiogenesis, tumor cell growth, and immunomodulation.

Methods

This phase I trial aimed to determine the recommended doses of this combination for phase II trials (RP2D) using the dual-agent Bayesian continual reassessment method. Nilotinib was given orally twice daily (BID) in combination with once-weekly vinblastine injections for a maximum of 12 cycles of 28 days (clinicaltrials.gov, NCT01884922).

Results

Thirty-five pediatric patients were enrolled across 4 dose levels. The median age was 7 years and 10 had neurofibromatosis type 1. Patients had received a median of 3 prior treatment lines and 25% had received more than 4 previous treatment lines. Dose-limiting toxicity (DLT) during cycle 1 was hematologic, dermatologic, and cardiovascular. The RP2D was identified at 3 mg/m² weekly for vinblastine with 230 mg/m² BID for nilotinib (estimated probability of DLT = 18%; 95% credibility interval, 7-29%). Fifteen patients completed the 12 cycles; 2 stopped therapy prematurely due to toxicity and 18 due to disease progression. Three patients achieved a partial response leading to an objective response rate of 8.8% (95% confidence interval [CI], 1.9-23.7), and the disease control rate was 85.3% (95% CI, 68.9-95.1). The 12-month progression-free survival was 37.1% (95% CI, 23.2-53.67).

Conclusions

Vinblastine and nilotinib combination was mostly limited by myelosuppression and dermatologic toxicity. The efficacy of the combination at the RP2D is currently evaluated in a randomized phase II trial comparing this regimen to vinblastine alone.

Maternal and perinatal characteristics, congenital malformations and the risk of wilms tumor: the ESTELLE study

PURPOSE

Wilms tumor (WT), or nephroblastoma, is an embryonic tumor that constitutes the most common renal tumor in children. Little is known about the etiology of WT. The aim of this study was to investigate whether maternal or perinatal characteristics were associated with the risk of WT.

METHODS

The ESTELLE study is a national-based case-control study that included 117 cases of WT and 1,100 controls younger than 11 years old. The cases were children diagnosed in France in 2010-2011 and the controls were frequency matched with cases by age and gender. The mothers of case and control children responded to a telephone questionnaire addressing sociodemographic and perinatal characteristics, childhood environment, and lifestyle. Unconditional logistic regression models adjusted on potential cofounders were used to estimate the odds ratios (OR) and their confidence intervals (95% CI).

RESULTS

High birth weight and the presence of congenital malformation were associated with WT (OR 1.9 [95% CI 1.0-3.7] and OR 2.5 [95% CI 1.1-5.8], respectively). No association with breastfeeding or folic acid supplementation was observed.

CONCLUSIONS

Although potential recall bias cannot be excluded, our findings reinforce the hypothesis that high birth weight and the presence of congenital malformation may be associated with an increased risk of WT. Further investigations are needed to further elucidate the possible role of maternal characteristics in the etiology of WT.

A Phase I and Pharmacokinetic Study of Oral Dabrafenib in Children and Adolescent Patients with Recurrent or Refractory BRAF V600 Mutation-Positive Solid Tumors

PURPOSE

The 2-part, phase I/IIa, open-label study (NCT01677741) sought to determine the safety, tolerability, pharmacokinetics, and preliminary activity of dabrafenib in pediatric patients with advanced BRAF V600-mutated cancers.

PATIENTS AND METHODS

This phase I dose-finding part treated patients ages 1 to <18 years with BRAF V600 mutation-positive tumors with oral dabrafenib 3 to 5.25 mg/kg/day to determine the RP2D based on safety and drug exposure target.

RESULTS

Between May 2013 and November 2014, 27 patients [12 male; median age, 9 years (range, 1-17 years)] with BRAF V600-mutant solid tumors recurrent/refractory to treatment (low- or high-grade glioma, Langerhans cell histiocytosis, neuroblastoma, or thyroid cancer) were enrolled. The median treatment duration was 75.6 weeks (range, 5.6-148.7 weeks), with 63% treated for >52 weeks and 52% undergoing treatment at data cutoff date. The most common grade 3/4 adverse events suspected to be related to study drug were maculopapular rash and arthralgia (2 patients each). No dose-limiting toxicities were observed. Pharmacokinetic analyses showed a dose-dependent increase in AUC0-12 and achievement of adult exposure levels at the recommended phase II doses of 5.25 mg/kg/day (age <12 years) and 4.5 mg/kg/day (age ≥12 years) divided into 2 equal doses daily, not exceeding 300 mg daily.

CONCLUSIONS

In this first clinical trial in pediatric patients with pretreated BRAF V600-mutant tumors, dabrafenib was well tolerated while achieving target exposure levels; the average treatment duration was >1 year with many patients still on treatment. The phase II component is also closed and will be reported separately.

PDTM-36. WHOLE EXOME SEQUENCING (WES) OF DIPG PATIENTS FROM THE BIOMEDE TRIAL REVEALS NEW PROGNOSTIC SUBGROUPS WITH SPECIFIC ONCOGENIC PROGRAMMES

BACKGROUND & METHODS. The BIOlogical MEdicines for DIPG Eradication (BIOMEDE) trial is a randomized multi-arm multi-stage program (drop-the-loser adaptive design). The first trial was an open-label phase-II trial comparing three drugs (everolimus, dasatinib, erlotinib) combined with irradiation, allocated according to the presence of their specific targets. All patients underwent a biopsy at diagnosis to confirm the DIPG molecularly and establish the expression of pre-specified biomarkers. Patient samples were explored by WES with a sequencing depth average >100X for the tumor and >60X for the blood. RESULTS. Unsupervised clustering of copy-number-variations (CNV) identified 4 groups corresponding to a new stratification of DIPG: cluster 1 (n=42) with high CNV, cluster 2 (n=23) with chromosome 1q + chromosome 2 gains, cluster 3 (n=9) with low CNV and cluster 4 (n=21) with isolated 1q gain. Clusters 1 had higher hazard-ratio for death than the others (mean HR 1.959, range 1.054–3.643, p< 0.0001, adjusted Cox model). Extensive structural rearrangements/chromotrypsis were significantly more frequent in TP53-mutated samples. Indeed, when stratiftying patients in 4 groups based on type of histone H3 mutated at K27 and the presence of a TP53 pathway alteration the subgroup with TP53 altered pathway had a significantly higher hazard-ratio for death than the others (mean HR 3.450, p=0.0017, adjusted Cox model). Additional drug targets were identified, especially in the DNA repair machinery that could be exploited for new targeted therapies. CONCLUSION. WES at diagnosis was feasible in most patients and brings new prognostic and theranostic informations. This allows a better patients stratification and the development of personalized medicine in DIPG.

Multinodular goitre is a gateway for molecular testing of DICER1 syndrome

BACKGROUND

DICER1 syndrome is an autosomal dominant disorder that predisposes individuals to develop benign or malignant tumours from infancy to adulthood. There is low-to-moderate penetrance of tumour development, which is sex- and age-dependent. Multinodular goitre (MNG) is among the most highly penetrant phenotype of the disorder, especially in females.

PATIENTS AND METHODS

We report a series of eight families referred for childhood-onset of MNG or DICER1-related tumours with familial history of MNG in relatives. No additional families with these criteria stated were identified during the same date. We screened DNA samples from the probands and members of their family (40) for constitutional DICER1 variants using Next Generation Sequencing tools.

RESULTS

Germline pathogenic DICER1 gene variants were identified in all probands and several of their relatives: 64% presented with MNG/thyroidectomy as the phenotypic expression of the syndrome. DICER1 gene variants were identified in the RNAseIII and the PAZ domains. All tumour tissues studied presented clonal pathogenic variants in hotspot regions. Early identification of DICER1 variant carriers has permitted diagnosis and therapeutic scheme correction for two patients and cascade testing in relatives.

CONCLUSIONS

Multinodular goitre is uncommon in children. Childhood-onset MNG, multiple occurrences of the disease within the same family, or its association with rare benign or malignant tumours should raise suspicions of anomalies in the DICER1 gene, as proposed by recent international recommendations. Early detection of DICER1 pathogenic variants has important consequences in terms of therapeutic strategy, early tumour screening, and genetic counselling.

EWSR1-PATZ1 gene fusion may define a new glioneuronal tumor entity

We investigated the challenging diagnostic case of a ventricular cystic glioneuronal tumor with papillary features, by RNA sequencing using the Illumina TruSight RNA Fusion panel. We did not retrieve the SLC44A1-PRKCA fusion gene specific for papillary glioneuronal tumor, but an EWSR1-PATZ1 fusion transcript. RT-PCR followed by Sanger sequencing confirmed the EWSR1-PATZ1 fusion. It matched with canonic EWSR1 fusion oncogene, juxtaposing the entire N-terminal transcriptional activation domain of EWSR1 gene and the C-terminal DNA binding domain of a transcription factor gene, PATZ1. PATZ1 protein belongs to the BTB-ZF (broad-complex, tramtrack and bric-à-brac -zinc finger) family. It directly regulates Pou5f1 and Nanog and is essential to maintaining stemness by inhibiting neural differentiation. EWSR1-PATZ1 fusion is a rare event in tumors: it was only reported in six round cell sarcomas and in three gliomas of three exclusively molecular studies. The first reported glioma was a BRAF^V600E negative ganglioglioma, the second a BRAF^V600E negative glioneuronal tumor, not otherwise specified and the third, very recently reported, a high grade glioma, not otherwise specified. In our study, forty BRAF^V600E negative gangliogliomas were screened by FISH using EWSR1 break-apart probes. We performed methylation profiling for the index case and for seven out of the ten FISH positive cases. The index case clustered apart from other pediatric low grade glioneuronal entities, and specifically from the well-defined ganglioglioma methylation group. An additional pediatric intraventricular ganglioglioma clustered slightly more closely with ganglioglioma, but showed differences from the main ganglioglioma group and similarities with the index case. Both cases harbored copy number variations at the PATZ1 locus. EWSR1-PATZ1 gene fusion might define a new type of glioneuronal tumors, distinct from gangliogliomas.

Germline SUFU mutation carriers and medulloblastoma: clinical characteristics, cancer risk, and prognosis

Background

Germline mutations of suppressor of fused homolog (SUFU) predispose to sonic hedgehog (SHH) medulloblastoma. Germline SUFU mutations have been reported in nevoid basal cell carcinoma syndrome (NBCCS), but little is known about the cancer risk and clinical spectrum.

Methods

We performed a retrospective review of all patients with medulloblastoma and a germline SUFU mutation in France.

Results

Twenty-two patients from 17 families were identified with medulloblastoma and a germline SUFU mutation (median age at diagnosis: 16.5 mo). Macrocrania was present in 20 patients, but only 5 met the diagnostic criteria for NBCCS. Despite treatment with surgery and chemotherapy, to avoid radiotherapy in all patients except one, the outcome was worse than expected for SHH medulloblastoma, due to the high incidence of local relapses (8/22 patients) and second malignancies (n = 6 in 4/22 patients). The 5-year progression-free survival and overall survival rates were 42% and 66%. Mutations were inherited in 79% of patients, and 34 additional SUFU mutation carriers were identified within 14 families. Medulloblastoma penetrance was incomplete, but higher than in Patched 1 (PTCH1) mutation carriers. Besides medulloblastoma, 19 other tumors were recorded among the 56 SUFU mutation carriers, including basal cell carcinoma (BCC) in 2 patients and meningioma in 3 patients.

Conclusion

Germline SUFU mutations strongly predispose to medulloblastoma in the first years of life, with worse prognosis than usually observed for SHH medulloblastoma. The clinical spectrum differs between SUFU and PTCH1 mutation carriers, and BCC incidence is much lower in SUFU mutation carriers. The optimal treatment of SUFU mutation-associated medulloblastoma has not been defined.

Childhood brain tumours, early infections and immune stimulation: A pooled analysis of the ESCALE and ESTELLE case-control studies (SFCE, France)

BACKGROUND

Few studies have investigated whether early infections and factors potentially related to early immune stimulation might be involved in the aetiology of childhood brain tumours (CBT). In this study, we investigated the associations between CBT with early day-care attendance, history of early common infections, atopic conditions (asthma/wheezing, eczema, allergic rhinitis), early farm residence/visits and contact with animals.

METHODS

We pooled data from two nationwide French case-control studies, the ESCALE and ESTELLE studies. Children with a CBT diagnosed between 1 and 14 years of age were identified directly from the French National Registry of Childhood Cancers, while population controls were recruited from telephone subscribers. Odds-ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression adjusted for potential confounders.

RESULTS

The analyses included 469 cases and 2719 controls. We found no association between attending a day-care centre (OR: 0.9, 95%CI: 0.7-1.2) or having had repeated common infections (OR: 0.9, 95%CI: 0.7-1.2) in the first year of life and the risk of CBT. There was also no association with a history of asthma/wheezing (OR: 0.8, 95%CI: 0.56-1.1). Farm visits (OR: 0.6, 95%CI: 0.5-0.8) as well as contact with pets (OR: 0.8, 95%CI: 0.6-1.0) in the first year of life were inversely associated with CBT.

CONCLUSIONS

Our findings suggest a protective effect of early farm visits and contact with pets, but not with other markers of early immune stimulation. This might be related to immune stimulation but needs further investigation.

Embryonal tumors with multilayered rosettes in children: the SFCE experience

PURPOSES

The purpose of this study was to retrospectively study embryonal tumors with multilayered rosettes (ETMR), a rare new entity that gathers ETAN-TR (embryonal tumor with abundant neuropil and true rosettes), ependymoblastomas, and medulloepitheliomas, in order to improve their descriptions and try to better define therapeutic modalities.

METHODS

Patients with ETMR, ETAN-TR, ependymoblastoma, and medulloepithelioma treated in SFCE centres (Société Française de lutte contre les Cancers et les leucémies de l'Enfant et de l'adolescent) since 2000 were collected. Data were retrieved from clinical charts.

RESULTS

Thirty-eight patients were included in the analysis. Seventeen had an ETAN-TR, 13 had a medulloepithelioma, and 8 had an ETMR. No ependymoblastoma was included. The median age at diagnosis was 31 months (range, 2.8-141 months). The predominant tumor location was supratentorial (66%); 18.4% patients had metastatic lesion. LIN28A expression was positive in 11/11 patients. Amplification of the locus 19q13.42 was positive in 10/12 patients. Thirty patients were treated according to the primitive neuroectodermal tumors of high risk (PNET-HR) protocol. The median time of follow-up was 0.9 years (range 0.1 to 15.3 years). The 1-year event-free survival (EFS) and overall survival (OS) were, respectively, 36% CI 95% (23-55) and 45% CI 95% (31-64). On multivariate analysis, complete surgical resection, radiotherapy, and high-dose chemotherapy were associated with a better overall survival with a relative risk of, respectively, 7.9 CI 95% (2.6-23.5) p < 0.0002, 41.8 CI 95% (9.4-186) p < 0.0001, and 3.5 CI 95% (1.3-9.5) p = 0.012.

CONCLUSION

Prognosis of ETMR remains dismal despite multimodal therapy. LIN28A immunostaining and 19q13.42 amplification should be systematically done to secure the diagnosis. Complete surgical resection, radiotherapy, and high-dose chemotherapy are associated with better outcome.

Mortality in Children with Optic Pathway Glioma Treated with Up-Front BB-SFOP Chemotherapy

BACKGROUND

In terms of overall survival (OS), limited data are available for the very long-term outcomes of children treated for optic pathway glioma (OPG) with up-front chemotherapy. Therefore, we undertook this study with the aim of clarifying long-term OS and causes of death in these patients.

METHODS

We initiated and analyzed a historical cohort study of 180 children with OPG treated in France with BB-SFOP chemotherapy between 1990 and 2004. The survival distributions were estimated using Kaplan-Meier method. The effect of potential risk factors on the risk of death was described using Cox regression analysis.

RESULTS

The OS was 95% [95% CI: 90.6-97.3] 5 years after diagnosis and significantly decreased over time without ever stabilizing: 91.6% at 10 years [95% CI: 86.5-94.8], 80.7% at 15 years [95% CI: 72.7-86.8] and 75.5% [95% CI: 65.6-83] at 18 years. Tumor progression was the most common cause of death (65%). Age and intracranial hypertension at diagnosis were significantly associated with a worse prognosis. Risk of death was increased by 3.1[95% CI: 1.5-6.2] (p=0.002) for patients less than 1 year old at diagnosis and by 5.2[95% CI: 1.5-17.6] (p=0.007) for patients with initial intracranial hypertension. Boys without diencephalic syndrome had a better prognosis (HR: 0.3 [95% CI: 0.1-0.8], p=0.007).

CONCLUSIONS

This study shows that i) in children with OPG, OS is not as favorable as previously described and ii) patients can be classified into 2 groups depending on risk factors (age, intracranial hypertension, sex and diencephalic syndrome) with an OS rate of 50.4% at 18 years [95% CI: 31.4-66.6] in children with the worst prognosis. These findings could justify, depending on the initial risk, a different therapeutic approach to this tumor with more aggressive treatment (especially chemotherapy) in patients with high risk factors.

Clinicopathologic prognostic factors in childhood atypical teratoid and rhabdoid tumor of the central nervous system: a multicenter study

BACKGROUND

The objective of this study was to describe the clinical and pathologic features and to identify prognostic factors in patients with atypical teratoid/rhabdoid tumors (AT/RT) of the central nervous system (CNS).

METHODS

Patients aged <18 years with newly diagnosed CNS AT/RT who were treated in France between 1998 and 2008 were retrospectively identified. The study included all patients who had a diagnosis of AT/RT confirmed by pathologic review, including immunostaining for INI 1, tumor protein 53 (p53), β-catenin, claudin-6, and Ki-67 and analysis for SMARCB1/hSNF5/INI1 mutation.

RESULTS

Fifty-eight patients with confirmed AT/RT were eligible for the current analysis. The median age at diagnosis was 1.4 years (range, 14 days to 8.5 years). The site of the primary tumor was supratentorial in 26 patients, infratentorial in 28 patients and spinal in 4 patients. Loss of INI1 nuclear expression was observed in 49 of 50 evaluable tumors. Positive claudin-6 was observed in 37 of 42 assessed tumors and, in 12 of those tumors, the staining was strong and diffuse. Positive nuclear immunoreactivity for β-catenin was observed in 24 of 44 tumors, and P53 was overexpressed in 31 of 44 tumors. Primary adjuvant therapy included chemotherapy in 47 patients and radiotherapy in 16 patients. The median follow-up was 58 months (range, 9-125 months), and the median survival was 9 months. Multivariate analysis identified age <2 years (P = .01), metastasis at diagnosis (P = .03), and strong immunopositivity for claudin-6 (P = .03) as prognostic factors for the risk of death.

CONCLUSIONS

AT/RT tumors in children carry a dismal prognosis. Age <2 years, metastasis at diagnosis, and strong claudin-6 positivity appeared to be independent prognostic factors for outcome.

Treatment of medulloblastoma with postoperative chemotherapy alone: an SFOP prospective trial in young children

BACKGROUND

Morbidity and mortality are high in young children with medulloblastoma who receive craniospinal radiotherapy. We aimed to assess whether adjuvant treatment with protracted chemotherapy alone could replace radiotherapy.

METHODS

We enrolled 79 children aged younger than 5 years who had had surgical resection of medulloblastoma onto a multicentre trial. Patients were treated with combination chemotherapy, which did not include methotrexate, for more than 16 months irrespective of the extent of disease. Early postoperative imaging defined three groups: R0M0 (no residual disease, no metastasis), R1M0 (radiological residual disease alone), and RXM+ (presence of metastases). Patients who did not relapse did not receive radiotherapy. Patients who relapsed or had disease progression received salvage treatment, which consisted of high-dose chemotherapy and stem-cell transplantation followed by local or craniospinal radiotherapy. For children classified as R0M0, the primary endpoint was 5-year overall survival and the secondary endpoint was 5-year progression-free survival. For children classified as R1M0 or RXM+, the primary endpoint was best radiological response and the secondary endpoints were 5-year overall survival and 5-year progression-free survival. Analyses were done by intention to treat.

FINDINGS

Two of 15 patients classified as RXM+ and four of 17 patients classified as R1M0 had a complete radiological response. 5-year progression-free survival was 29% (95% CI 18-44) in the R0M0 group, 6% (1-27) in the R1M0 group, and 13% (4-38) in the RXM+ group. 5-year overall survival was 73% (59-84) in the R0M0 group, 41% (22-64) in the R1M0 group, and 13% (4-38) in the RXM+ group. In the R0M0 group, 5-year progression-free survival was 41% (26-58) for the 34 patients who underwent gross total resection compared with 0% for the 13 patients who had subtotal resection (relative risk 2.7 [1.3-5.6], p=0.0065).

INTERPRETATION

Conventional chemotherapy alone can be used to cure children with non-metastatic medulloblastoma who have gross total resection confirmed by early radiological assessment, but is not sufficient for treatment of those with metastatic or incompletely resected medulloblastoma. Salvage treatment followed by posterior-fossa radiotherapy can effectively treat local relapses or progression.

A 22-year French experience with solid tumors in children with Down syndrome

Malignant solid tumors have rarely been reported in children with Down syndrome (DS) and are not well known. The authors collected from 1980 to 2001 all cases of solid tumors observed in DS patients aged from birth to 19 years within the network of the Société Française d'Oncologie Pédiatrique (SFOP). Only 21 cases were observed, with a peculiar distribution: a lack of intracranial tumors and embryonal neoplasms combined with an overrepresentation of lymphomas and germ cell tumors. The treatment of solid tumors in DS is difficult, due to physical and psychological impairments, different pharmacogenetic profile, and associated malformations.

Neoadjuvant chemotherapy for extensive unilateral retinoblastoma

AIM

The role of neoadjuvant chemotherapy was studied when first line enucleation cannot be safely performed in unilateral extensive retinoblastoma (major buphthalmia or radiologically detectable optic nerve involvement).

METHODS

Six patients, referred for unilateral retinoblastoma, presented with major buphthalmia (two) or optic nerve invasion (four): they were treated by neoadjuvant chemotherapy using etoposide and carboplatin.

RESULTS

Good tumour response was observed in the two patients with buphthalmia and in three of four cases with optic nerve involvement. Meningeal progressive disease was observed in the last patient. The five patients without disease progression were then operated on: anterior enucleation in the patients with buphthalmia and enucleation via a double neurosurgical and ophthalmological approach with prechiasmatic optic nerve section in the other three cases. Postoperative chemotherapy was performed in these five patients. Local radiotherapy to the chiasmatic region and posterior part of the optic canal was necessary in only one patient. The non-operated patient died with disease progression 6 months after the diagnosis. The other five patients are alive with a follow up of 12, 15, 21, 36, and 40 months after stopping treatment.

CONCLUSION

Neoadjuvant chemotherapy can be useful in extensive unilateral retinoblastoma with buphthalmia and/or radiological optic nerve invasion at diagnosis.

[Hemophagocytic syndrome associated with neutropenia after chemotherapy]

MATERIAL AND METHODS

This retrospective study reports 15 cases of hemophagocytic syndrome in children treated in our department during a eight-year period.

RESULTS

Underlying diseases were acute lymphoblastic leukemia (n = 8) acute myeloblastic leukemia (n = 6) and Burkitt lymphoma (n = 1). Hemophagocytic syndrome was suspected after chemotherapy, in case of an unusual prolonged febrile neutropenia (n = 14) or isolated thrombocytopenia (n = 1). That fever was associated with cutaneous, pulmonary, hematologic, digestive and cardiac signs. Biological disorders included hypoprotidemia, hyponatremia, increased liver enzymes and fibrinopenia. Thrombocytopenia was observed in all patients and was associated with neutropenia for 14 of them. Diagnosis of hemophagocytic syndrome was always confirmed by bone marrow aspiration (infiltration with activated macrophages). Infection was documented in eight children. The treatment of hemophagocytic syndrome relied on steroids and resolution of symptoms occurred within three days of therapy. No recurrence of hemophagocytic syndrome was observed with a median follow up of two years and a half.

CONCLUSION

Such complication should be suspected in cases of prolonged febrile neutropenia and/or thrombocytopenia, and confirmed by bone marrow aspiration. Indeed, steroid therapy is effective and chemotherapy can be then pursued.

Granulocyte colony-stimulating factor in induction treatment of children with non-Hodgkin's lymphoma: a randomized study of the French Society of Pediatric Oncology

PURPOSE

To determine whether granulocyte colony-stimulating factor (G-CSF; lenograstim) decreases the incidence of febrile neutropenia after induction courses in treatment of childhood non-Hodgkin's lymphoma (NHL).

PATIENTS AND METHODS

Patients were randomized to receive (G-CSF+) or not receive (G-CSF-) prophylactic G-CSF, 5 microg/kg/d, from day 7 until an absolute neutrophil count > or = 500/microL was sustained over 48 hours, after two consecutive induction courses of cyclophosphamide 1.5 or 3 g/m(2), vincristine 2 mg/m(2), prednisone 60 mg/m(2)/d x 5, doxorubicin 60 mg/m(2), high-dose methotrexate 3 or 8 g/m(2), and intrathecal injections (COPAD[M]) on protocols LMB89, LMT89, and HM91 of the French Society of Pediatric Oncology.

RESULTS

One hundred forty-eight patients were assessable, 75 G-CSF+ and 73 G-CSF-. Although duration of neutropenia less than 500/microL was 3 days shorter in G-CSF+ patients (P = 10(-4)), incidence of febrile neutropenia (89% v. 93% in the first course, 88% v. 88% in the second course), durations of hospitalization and antimicrobial therapy, percentages of infections, mucositis, and transfusions were not significantly different. Although the percentage of G-CSF+ patients commencing the following course on day 21 was significantly higher (84% v 68% after the first and 57% v. 38% after the second course; P <.05), the median delay between the two courses was only 1 day less in G-CSF+ patients (median delay after first COPAD(M), 19 v. 20 days, P =.01; after second, 21 v. 22 days, P = not significant). Remission and survival rates were similar in both arms.

CONCLUSION

This study demonstrates that G-CSF did not decrease treatment-related morbidity, nor increase the dose-intensity in children undergoing COPAD(M) induction chemotherapy for NHL.

[Testicular feminization, germinal tumor, NK lymphoma: what is the relationship?]

CASE REPORT

The authors report the case of a ten-year-old girl, who had been treated for a malignant germinal tumour five years before, presenting with a leukaemia-like syndrome associating bone pain, liver and spleen nodules and bone marrow involvement. The cyto-pathological analysis showed undifferentiated cells and CD56 and protein S100 were found as the only positive markers. The child received several subsequent lines of chemotherapy and ultimately died of the disease.

COMMENTS

Particular cytogenetic abnormalities were observed (iso1q10, iso6p10) and were in favor of an unusual NK cell lymphoma.

CONCLUSION

This analysis revealed a XY genotype (testicular feminization syndrome).

[Palliative care in pediatric oncology]

Improving the management of dying children has always been a common desire among staff who take care of children with incurable life-threatening diseases. Pediatric oncologists are beginning to structure their practice based upon the approach to palliative care given to adults. In the first part of this report, the authors focus on technical care: comfort control and symptoms. The second part is devoted to pain management, a major aspect of pediatric palliative care. In the third part, psychosocial issues are developed, taking into account the point of view of children, siblings, parents and staff.