LOGGIC/FIREFLY-2: a phase 3, randomized trial of tovorafenib vs. chemotherapy in pediatric and young adult patients with newly diagnosed low-grade glioma harboring an activating RAF alteration.

BACKGROUND: Pediatric low-grade glioma (pLGG) is essentially a single pathway disease, with most tumors driven by genomic alterations affecting the mitogen-activated protein kinase/ERK (MAPK) pathway, predominantly KIAA1549::BRAF fusions and BRAF V600E mutations. This makes pLGG an ideal candidate for MAPK pathway-targeted treatments. The type I BRAF inhibitor, dabrafenib, in combination with the MEK inhibitor, trametinib, has been approved by the United States Food and Drug Administration for the systemic treatment of BRAF V600E-mutated pLGG. However, this combination is not approved for the treatment of patients with tumors harboring BRAF fusions as type I RAF inhibitors are ineffective in this setting and may paradoxically enhance tumor growth. The type II RAF inhibitor, tovorafenib (formerly DAY101, TAK-580, MLN2480), has shown promising activity and good tolerability in patients with BRAF-altered pLGG in the phase 2 FIREFLY-1 study, with an objective response rate (ORR) per Response Assessment in Neuro-Oncology high-grade glioma (RANO-HGG) criteria of 67%. Tumor response was independent of histologic subtype, BRAF alteration type (fusion vs. mutation), number of prior lines of therapy, and prior MAPK-pathway inhibitor use. METHODS: LOGGIC/FIREFLY-2 is a two-arm, randomized, open-label, multicenter, global, phase 3 trial to evaluate the efficacy, safety, and tolerability of tovorafenib monotherapy vs. current standard of care (SoC) chemotherapy in patients < 25 years of age with pLGG harboring an activating RAF alteration who require first-line systemic therapy. Patients are randomized 1:1 to either tovorafenib, administered once weekly at 420 mg/m2 (not to exceed 600 mg), or investigator's choice of prespecified SoC chemotherapy regimens. The primary objective is to compare ORR between the two treatment arms, as assessed by independent review per RANO-LGG criteria. Secondary objectives include comparisons of progression-free survival, duration of response, safety, neurologic function, and clinical benefit rate. DISCUSSION: The promising tovorafenib activity data, CNS-penetration properties, strong scientific rationale combined with the manageable tolerability and safety profile seen in patients with pLGG led to the SIOPe-BTG-LGG working group to nominate tovorafenib for comparison with SoC chemotherapy in this first-line phase 3 trial. The efficacy, safety, and functional response data generated from the trial may define a new SoC treatment for newly diagnosed pLGG. TRIAL REGISTRATION: ClinicalTrials.gov: NCT05566795. Registered on October 4, 2022.

Ophthalmic symptoms, clinical signs and diagnostic delay in infants diagnosed with brain tumours in Denmark between 2007 and 2017.

PURPOSE: To investigate ophthalmic onset manifestations and the impact of diagnostic delay on the prognosis in infants (<1 year) diagnosed with a brain tumour. METHODS: A retrospective population-based nationwide study of infants diagnosed with a brain tumour between 2007 and 2017 in Denmark. Data was retrieved from the Danish Childhood Cancer Registry, the National Danish Health registries, and medical files. Primary outcome measures included symptoms, clinical findings, time to diagnosis and survival. RESULTS: Thirty-seven infants were diagnosed with a brain tumour in Denmark between 2007 and 2017. In total, 19/37 infants (51%, 95% CI: 34-68) had ophthalmic manifestations at any time prior to or at diagnosis; and in 6/37 (16%, 95% CI: 6-32) ophthalmic manifestations were the initial symptom. The most common ophthalmic manifestations were strabismus (n = 7), sunset eyes (n = 6), nystagmus (n = 4), reduced pupillary light reflex (n = 4), and/or decreased vision (n = 4). The median number of symptoms per infant at the time of diagnosis was three (range 0-9). The median diagnostic delay was 26 days (range 0-283, IQR: 6;90). 5-year survival rate was 75% (95% CI: 61-90) and all children with diagnostic delay > 100 days (n = 9, 24%) were still alive at the end of follow-up (median 6.3 years, range 2.2-10.2). CONCLUSION: We provide an overview of symptoms and clinical signs in a nation-wide series of infants with CNS tumours and demonstrate that ophthalmic manifestations are frequently observed in infants prior to diagnosis, but, often in combination with other clinical signs. The diagnostic delay was substantial for a large part of the infants, but this was not associated with increased mortality.

Clinical outcome of pediatric medulloblastoma patients with Li-Fraumeni syndrome.

BACKGROUND: The prognosis for Li-Fraumeni syndrome (LFS) patients with medulloblastoma (MB) is poor. Comprehensive clinical data for this patient group is lacking, challenging the development of novel therapeutic strategies. Here, we present clinical and molecular data on a retrospective cohort of pediatric LFS MB patients. METHODS: In this multinational, multicenter retrospective cohort study, LFS patients under 21 years with MB and class 5 or class 4 constitutional TP53 variants were included. TP53 mutation status, methylation subgroup, treatment, progression free- (PFS) and overall survival (OS), recurrence patterns, and incidence of subsequent neoplasms were evaluated. RESULTS: The study evaluated 47 LFS individuals diagnosed with MB, mainly classified as DNA methylation subgroup "SHH_3" (86%). The majority (74%) of constitutional TP53 variants represented missense variants. The 2- and 5-year (y-) PFS were 36% and 20%, and 2- and 5y-OS were 53% and 23%, respectively. Patients who received postoperative radiotherapy (RT) (2y-PFS: 44%, 2y-OS: 60%) or chemotherapy before RT (2y-PFS: 32%, 2y-OS: 48%) had significantly better clinical outcome then patients who were not treated with RT (2y-PFS: 0%, 2y-OS: 25%). Patients treated according to protocols including high-intensity chemotherapy and patients who received only maintenance-type chemotherapy showed similar outcomes (2y-PFS: 42% and 35%, 2y-OS: 68% and 53%, respectively). CONCLUSIONS: LFS MB patients have a dismal prognosis. In the presented cohort use of RT significantly increased survival rates, whereas chemotherapy intensity did not influence their clinical outcome. Prospective collection of clinical data and development of novel treatments are required to improve the outcome of LFS MB patients.

LOGGIC Core BioClinical Data Bank: Added clinical value of RNA-Seq in an international molecular diagnostic registry for pediatric low-grade glioma patients.

BACKGROUND: The international, multicenter registry LOGGIC Core BioClinical Data Bank aims to enhance the understanding of tumor biology in pediatric low-grade glioma (pLGG) and provide clinical and molecular data to support treatment decisions and interventional trial participation. Hence, the question arises whether implementation of RNA sequencing (RNA-Seq) using fresh frozen (FrFr) tumor tissue in addition to gene panel and DNA methylation analysis improves diagnostic accuracy and provides additional clinical benefit. METHODS: Analysis of patients aged 0 to 21 years, enrolled in Germany between April 2019 and February 2021, and for whom FrFr tissue was available. Central reference histopathology, immunohistochemistry, 850k DNA methylation analysis, gene panel sequencing, and RNA-Seq were performed. RESULTS: FrFr tissue was available in 178/379 enrolled cases. RNA-Seq was performed on 125 of these samples. We confirmed KIAA1549::BRAF-fusion (n = 71), BRAF V600E-mutation (n = 12), and alterations in FGFR1 (n = 14) as the most frequent alterations, among other common molecular drivers (n = 12). N = 16 cases (13%) presented rare gene fusions (eg, TPM3::NTRK1, EWSR1::VGLL1, SH3PXD2A::HTRA1, PDGFB::LRP1, GOPC::ROS1). In n = 27 cases (22%), RNA-Seq detected a driver alteration not otherwise identified (22/27 actionable). The rate of driver alteration detection was hereby increased from 75% to 97%. Furthermore, FGFR1 internal tandem duplications (n = 6) were only detected by RNA-Seq using current bioinformatics pipelines, leading to a change in analysis protocols. CONCLUSIONS: The addition of RNA-Seq to current diagnostic methods improves diagnostic accuracy, making precision oncology treatments (MEKi/RAFi/ERKi/NTRKi/FGFRi/ROSi) more accessible. We propose to include RNA-Seq as part of routine diagnostics for all pLGG patients, especially when no common pLGG alteration was identified.

Glioneuronal tumor with ATRX alteration, kinase fusion and anaplastic features (GTAKA): a molecularly distinct brain tumor type with recurrent NTRK gene fusions.

Glioneuronal tumors are a heterogenous group of CNS neoplasms that can be challenging to accurately diagnose. Molecular methods are highly useful in classifying these tumors-distinguishing precise classes from their histological mimics and identifying previously unrecognized types of tumors. Using an unsupervised visualization approach of DNA methylation data, we identified a novel group of tumors (n = 20) that formed a cluster separate from all established CNS tumor types. Molecular analyses revealed ATRX alterations (in 16/16 cases by DNA sequencing and/or immunohistochemistry) as well as potentially targetable gene fusions involving receptor tyrosine-kinases (RTK; mostly NTRK1-3) in all of these tumors (16/16; 100%). In addition, copy number profiling showed homozygous deletions of CDKN2A/B in 55% of cases. Histological and immunohistochemical investigations revealed glioneuronal tumors with isomorphic, round and often condensed nuclei, perinuclear clearing, high mitotic activity and microvascular proliferation. Tumors were mainly located supratentorially (84%) and occurred in patients with a median age of 19 years. Survival data were limited (n = 18) but point towards a more aggressive biology as compared to other glioneuronal tumors (median progression-free survival 12.5 months). Given their molecular characteristics in addition to anaplastic features, we suggest the term glioneuronal tumor with ATRX alteration, kinase fusion and anaplastic features (GTAKA) to describe these tumors. In summary, our findings highlight a novel type of glioneuronal tumor driven by different RTK fusions accompanied by recurrent alterations in ATRX and homozygous deletions of CDKN2A/B. Targeted approaches such as NTRK inhibition might represent a therapeutic option for patients suffering from these tumors.

Genetic predisposition and evolutionary traces of pediatric cancer risk: a prospective 5-year population-based genome sequencing study of children with CNS tumors.

BACKGROUND: The etiology of central nervous system (CNS) tumors in children is largely unknown and population-based studies of genetic predisposition are lacking. METHODS: In this prospective, population-based study, we performed germline whole-genome sequencing in 128 children with CNS tumors, supplemented by a systematic pedigree analysis covering 3543 close relatives. RESULTS: Thirteen children (10%) harbored pathogenic variants in known cancer genes. These children were more likely to have medulloblastoma (OR 5.9, CI 1.6-21.2) and develop metasynchronous CNS tumors (P = 0.01). Similar carrier frequencies were seen among children with low-grade glioma (12.8%) and high-grade tumors (12.2%). Next, considering the high mortality of childhood CNS tumors throughout most of human evolution, we explored known pediatric-onset cancer genes, showing that they are more evolutionarily constrained than genes associated with risk of adult-onset malignancies (P = 5e-4) and all other genes (P = 5e-17). Based on this observation, we expanded our analysis to 2986 genes exhibiting high evolutionary constraint in 141,456 humans. This analysis identified eight directly causative loss-of-functions variants, and showed a dose-response association between degree of constraint and likelihood of pathogenicity-raising the question of the role of other highly constrained gene alterations detected. CONCLUSIONS: Approximately 10% of pediatric CNS tumors can be attributed to rare variants in known cancer genes. Genes associated with high risk of childhood cancer show evolutionary evidence of constraint.

Constitutional Microsatellite Instability, Genotype, and Phenotype Correlations in Constitutional Mismatch Repair Deficiency.

BACKGROUND & AIMS: Constitutional mismatch repair deficiency (CMMRD) is a rare recessive childhood cancer predisposition syndrome caused by germline mismatch repair variants. Constitutional microsatellite instability (cMSI) is a CMMRD diagnostic hallmark and may associate with cancer risk. We quantified cMSI in a large CMMRD patient cohort to explore genotype-phenotype correlations using novel MSI markers selected for instability in blood. METHODS: Three CMMRD, 1 Lynch syndrome, and 2 control blood samples were genome sequenced to >120× depth. A pilot cohort of 8 CMMRD and 38 control blood samples and a blinded cohort of 56 CMMRD, 8 suspected CMMRD, 40 Lynch syndrome, and 43 control blood samples were amplicon sequenced to 5000× depth. Sample cMSI score was calculated using a published method comparing microsatellite reference allele frequencies with 80 controls. RESULTS: Thirty-two mononucleotide repeats were selected from blood genome and pilot amplicon sequencing data. cMSI scoring using these MSI markers achieved 100% sensitivity (95% CI, 93.6%-100.0%) and specificity (95% CI 97.9%-100.0%), was reproducible, and was superior to an established tumor MSI marker panel. Lower cMSI scores were found in patients with CMMRD with MSH6 deficiency and patients with at least 1 mismatch repair missense variant, and patients with biallelic truncating/copy number variants had higher scores. cMSI score did not correlate with age at first tumor. CONCLUSIONS: We present an inexpensive and scalable cMSI assay that enhances CMMRD detection relative to existing methods. cMSI score is associated with mismatch repair genotype but not phenotype, suggesting it is not a useful predictor of cancer risk.

Survival and long-term socioeconomic consequences of childhood and adolescent onset of brain tumours.

AIM: To evaluate survival distributions, long-term socioeconomic consequences, and health care costs in patients with childhood and adolescent onset of brain tumours in a Danish nationwide prospective cohort study. METHOD: A search of national registries identified 2283 patients (1198 males, 1085 females; mean age 9 years 6 months [SD 5 years 7 months]) diagnosed with a brain tumour between 1980 and 2015 and aged no older than 18 years at diagnosis. These were compared with sex-, age-, and residency-matched comparison individuals. Patients with malignant tumours were compared with those with benign tumours. Survival distributions were estimated by the Kaplan-Meier method and hazard ratio by the Cox proportional hazard model. Socioeconomic data at age 20 and 30 years were assessed. RESULTS: The probability of mortality was highest during the first year after tumour diagnosis. In young adulthood, the patients were generally less likely to be married, had lower grade-point averages, educational levels, and income, were less likely to be in employment, and had higher health care costs than comparison individuals. Patients with malignant tumours had worse outcomes with respect to education, employment, and health care costs than those with benign tumours. INTERPRETATION: A diagnosis of brain tumour in childhood and adolescence adversely affects survival and has negative long-term socioeconomic consequences, especially in patients with malignant tumours. These patients require continuous social support.

Drug sensitivity profiling of 3D tumor tissue cultures in the pediatric precision oncology program INFORM.

The international precision oncology program INFORM enrolls relapsed/refractory pediatric cancer patients for comprehensive molecular analysis. We report a two-year pilot study implementing ex vivo drug sensitivity profiling (DSP) using a library of 75-78 clinically relevant drugs. We included 132 viable tumor samples from 35 pediatric oncology centers in seven countries. DSP was conducted on multicellular fresh tumor tissue spheroid cultures in 384-well plates with an overall mean processing time of three weeks. In 89 cases (67%), sufficient viable tissue was received; 69 (78%) passed internal quality controls. The DSP results matched the identified molecular targets, including BRAF, ALK, MET, and TP53 status. Drug vulnerabilities were identified in 80% of cases lacking actionable (very) high-evidence molecular events, adding value to the molecular data. Striking parallels between clinical courses and the DSP results were observed in selected patients. Overall, DSP in clinical real-time is feasible in international multicenter precision oncology programs.

Improved Long-Term Survival of Patients with Recurrent Medulloblastoma Treated with a "MEMMAT-like" Metronomic Antiangiogenic Approach.

Medulloblastoma (MB) recurrence is usually incurable despite intensive therapy including high-dose chemotherapy. An evolving alternative approach to conventional chemotherapy aims at interfering with tumor angiogenesis at different levels. We report on a novel combinatorial metronomic antiangiogenic approach. The study is a retrospective observational study of 29 consecutive patients with first or multiple recurrences prospectively treated according to the MEMMAT strategy ("MEMMAT-like") before the formal protocol (MEMMAT; ClinicalTrials.gov Identifier: NCT01356290) started. The study period was 11/2006 to 06/2016. Treatment consisted of daily oral thalidomide, fenofibrate, celecoxib, and alternating 21-day cycles of low-dose oral etoposide and cyclophosphamide supplemented by IV bevacizumab and intraventricular therapy consisting of alternating etoposide and liposomal cytarabine. Median overall survival (OS) after recurrence for the whole group was 29.5 months, OS was 48.3 ± 9.3% at three years and 34.5 ± 8.8% at five years, and progression-free survival was 42.0 ± 9.5% at three years and 29.4 ± 9% at five years. As of 07/2022, 9/29 patients are alive 86 to 164 months after the recurrence that prompted the "MEMMAT-like" therapy. Treatment was primarily out-patient and generally well-tolerated. Toxicities did occur but were manageable. In conclusion, antiangiogenic therapy according to the MEMMAT strategy increased median OS of patients with recurrent MB and may lead to long-term survival. Adherence to the protocol, including intraventricular therapy, appears important.

Left-handedness should not be overrated as a risk factor for postoperative speech impairment in children after posterior fossa tumour surgery: a prospective European multicentre study.

PURPOSE: Cerebellar mutism syndrome (CMS) is a severe neurological complication of posterior fossa tumour surgery in children, and postoperative speech impairment (POSI) is the main component. Left-handedness was previously suggested as a strong risk factor for POSI. The aim of this study was to investigate the relationship between handedness and the risk of POSI. METHODS: We prospectively included children (aged < 18 years) undergoing surgery for posterior fossa tumours in 26 European centres. Handedness was assessed pre-operatively and postoperative speech status was categorised as either POSI (mutism or reduced speech) or habitual speech, based on the postoperative clinical assessment. Logistic regression was used in the risk factor analysis of POSI as a dichotomous outcome. RESULTS: Of the 500 children included, 37 (7%) were excluded from the present analysis due to enrolment at a reoperation; another 213 (43%) due to missing data about surgery (n = 37) and/or handedness (n = 146) and/or postoperative speech status (n = 53). Out of the remaining 250 (50%) patients, 20 (8%) were left-handed and 230 (92%) were right-handed. POSI was observed equally frequently regardless of handedness (5/20 [25%] in left-handed, 61/230 [27%] in right-handed, OR: 1.08 [95% CI: 0.40-3.44], p = 0.882), also when adjusted for tumour histology, location and age. CONCLUSION: We found no difference in the risk of POSI associated with handedness. Our data do not support the hypothesis that handedness should be of clinical relevance in the risk assessment of CMS.

ATRT-SHH comprises three molecular subgroups with characteristic clinical and histopathological features and prognostic significance.

Atypical teratoid/rhabdoid tumor (ATRT) is an aggressive central nervous system tumor characterized by loss of SMARCB1/INI1 protein expression and comprises three distinct molecular groups, ATRT-TYR, ATRT-MYC and ATRT-SHH. ATRT-SHH represents the largest molecular group and is heterogeneous with regard to age, tumor location and epigenetic profile. We, therefore, aimed to investigate if heterogeneity within ATRT-SHH might also have biological and clinical importance. Consensus clustering of DNA methylation profiles and confirmatory t-SNE analysis of 65 ATRT-SHH yielded three robust molecular subgroups, i.e., SHH-1A, SHH-1B and SHH-2. These subgroups differed by median age of onset (SHH-1A: 18 months, SHH-1B: 107 months, SHH-2: 13 months) and tumor location (SHH-1A: 88% supratentorial; SHH-1B: 85% supratentorial; SHH-2: 93% infratentorial, often extending to the pineal region). Subgroups showed comparable SMARCB1 mutational profiles, but pathogenic/likely pathogenic SMARCB1 germline variants were over-represented in SHH-2 (63%) as compared to SHH-1A (20%) and SHH-1B (0%). Protein expression of proneural marker ASCL1 (enriched in SHH-1B) and glial markers OLIG2 and GFAP (absent in SHH-2) as well as global mRNA expression patterns differed, but all subgroups were characterized by overexpression of SHH as well as Notch pathway members. In a Drosophila model, knockdown of Snr1 (the fly homologue of SMARCB1) in hedgehog activated cells not only altered hedgehog signaling, but also caused aberrant Notch signaling and formation of tumor-like structures. Finally, on survival analysis, molecular subgroup and age of onset (but not ASCL1 staining status) were independently associated with overall survival, older patients (> 3 years) harboring SHH-1B experiencing relatively favorable outcome. In conclusion, ATRT-SHH comprises three subgroups characterized by SHH and Notch pathway activation, but divergent molecular and clinical features. Our data suggest that molecular subgrouping of ATRT-SHH has prognostic relevance and might aid to stratify patients within future clinical trials.

9p21.3 Microdeletion involving CDKN2A/2B in a young patient with multiple primary cancers and review of the literature.

Germline pathogenic variants in CDKN2A predispose to various cancers, including melanoma, pancreatic cancer, and neural system tumors, whereas CDKN2B variants are associated with renal cell carcinoma. A few case reports have described heterozygous germline deletions spanning both CDKN2A and CDKN2B associated with a cancer predisposition syndrome (CPS) that constitutes a risk of cancer beyond those associated with haploinsufficiency of each gene individually, indicating an additive effect or a contiguous gene deletion syndrome. We report a young woman with a de novo germline 9p21 microdeletion involving the CDKN2A/CDKN2B genes, who developed six primary cancers since childhood, including a very rare extraskeletal osteosarcoma (eOS) at the age of 8. To our knowledge this is the first report of eOS in a patient with CDKN2A/CDKN2B deletion.

Constitutional POLE variants causing a phenotype reminiscent of constitutional mismatch repair deficiency.

Heterozygous POLE or POLD1 germline pathogenic variants (PVs) cause polymerase proofreading associated polyposis (PPAP), a constitutional polymerase proofreading deficiency that typically presents with colorectal adenomas and carcinomas in adulthood. Constitutional mismatch-repair deficiency (CMMRD), caused by germline bi-allelic PVs affecting one of four MMR genes, results in a high propensity for the hematological, brain, intestinal tract, and other malignancies in childhood. Nonmalignant clinical features, such as skin pigmentation alterations, are found in nearly all CMMRD patients and are important diagnostic markers. Here, we excluded CMMRD in three cancer patients with highly suspect clinical phenotypes but identified in each a constitutional heterozygous POLE PV. These, and two additional POLE PVs identified in published CMMRD-like patients, have not previously been reported as germline PVs despite all being well-known somatic mutations in hyper-mutated tumors. Together, these five cases show that specific POLE PVs may have a stronger "mutator" effect than known PPAP-associated POLE PVs and may cause a CMMRD-like phenotype distinct from PPAP. The common underlying mechanism, that is, a constitutional replication error repair defect, and a similar tumor spectrum provide a good rationale for monitoring these patients with a severe constitutional polymerase proofreading deficiency according to protocols proposed for CMMRD.

Postoperative speech impairment and surgical approach to posterior fossa tumours in children: a prospective European multicentre cohort study.

BACKGROUND: Brain tumours are the most common solid tumours in childhood. Half of these tumours occur in the posterior fossa, where surgical removal is complicated by the risk of cerebellar mutism syndrome, of which postoperative speech impairment (POSI) is a cardinal symptom, in up to 25% of patients. The surgical approach to midline tumours, mostly undertaken by transvermian or telovelar routes, has been proposed to influence the risk of POSI. We aimed to investigate the risk of developing POSI, the time course of its resolution, and its association with surgical approach and other clinical factors. METHODS: In this observational prospective multicentre cohort study, we included children (aged <18 years) undergoing primary surgery for a posterior fossa tumour at 26 centres in nine European countries. Within 72 h of surgery, the operating neurosurgeon reported details on the tumour location, surgical approach used, duration of surgery, use of traction, and other predetermined factors, using a standardised surgical report form. At 2 weeks, 2 months, and 1 year after surgery, a follow-up questionnaire was filled out by a paediatrician or neurosurgeon, including neurological examination and assessment of speech. Speech was classified as mutism, reduced speech, or habitual speech. POSI was defined as either mutism or severely reduced speech. Ordinal logistic regression was used to analyse the risk of POSI. FINDINGS: Between Aug 11, 2014, and Aug 24, 2020, we recruited 500 children. 426 (85%) patients underwent primary tumour surgery and had data available for further analysis. 192 (45%) patients were female, 234 (55%) patients were male, 81 (19%) patients were aged 0-2 years, 129 (30%) were aged 3-6 years, and 216 (51%) were aged 7-17 years. 0f 376 with known postoperative speech status, 112 (30%) developed POSI, 53 (14%) developed mutism (median 1 day [IQR 0-2]; range 0-10 days), and 59 (16%) developed reduced speech after surgery (0 days [0-1]; 0-4 days). Mutually adjusted analyses indicated that the independent risk factors for development of POSI were younger age (linear spline, p=0·0087), tumour location (four levels, p=0·0010), and tumour histology (five levels, p=0·0030); surgical approach (six levels) was not a significant risk factor (p=0·091). Tumour location outside the fourth ventricle and brainstem had a lower risk of POSI (with fourth ventricle as reference, odds ratio (OR) for cerebellar vermis 0·34 [95% CI 0·14-0·77] and OR for cerebellar hemispheres 0·23 [0·07-0·70]). Compared with pilocytic or pilomyxoid astrocytoma, a higher risk of POSI was seen for medulloblastoma (OR 2·85 [1·47-5·60]) and atypical teratoid rhabdoid tumour (10·30 [2·10-54·45]). We did not find an increased risk of POSI for transvermian surgical approach compared with telovelar (0·89 [0·46-1·73]). Probability of speech improvement from mutism reached 50% around 16 days after mutism onset. INTERPRETATION: Our data suggest that a midline tumour location, younger age, and high-grade tumour histology all increase the risk of speech impairment after posterior fossa tumour surgery. We found no evidence to recommend a preference for telovelar over transvermian surgical approach in the management of posterior fossa tumours in children in relation to the risk of developing POSI. FUNDING: The Danish Childhood Cancer Foundation, the Swedish Childhood Cancer Foundation, the UK Brain Tumour Charity, the Danish Cancer Society, Det Kgl Kjøbenhavnske Skydeselskab og Danske Broderskab, the Danish Capitol Regions Research Fund, Dagmar Marshall Foundation, Rigshospitalet's Research Fund, and Brainstrust.

Brain tumours result in sleep disorders in children and adolescents.

BACKGROUND AND OBJECTIVES: Sleep disturbances are frequently reported in children with brain tumours. The objective of our cross-sectional study was to systematically examine sleep in these children. We hypothesised that children with tumours involving the sleep-wake-regulatory areas have an altered sleep-wake-regulation. METHODS: Sixty-one patients aged 0-18 years and with a diagnosis of a primary brain or cervical medullary tumour were included. They were categorised based upon tumour location into two groups - those affecting the sleep-wake regulatory regions, i.e. brain stem, basal forebrain, hypothalamus, thalamus, and posterior fossa compressing the brain stem and those that did not. Sleep history, questionnaire surveys, polysomnography, and multiple sleep latency test were used, as indicated clinically. Surveys included Pediatric Daytime Sleepiness Scale, Children's Sleep Habits Questionnaire, Strengths and Difficulties Questionnaire, and Pediatric Quality of Life Inventory, Multidimensional Fatigue Scale and Generic Core Scale. RESULTS: Patients with tumours involving the sleep-wake regulatory areas were sleepier/more fatigued (p = 0.03). Sleep apnoea was observed in 86% of all the patients and comorbid narcolepsy in 8%, without group differences (p ≥ 0.12). Patients with tumours involving the sleep-wake-regulatory areas had more emotional problems (p = 0.04), were more affected by mental health problems (p < 0.001), and had poorer quality of life (p ≤ 0.03). CONCLUSIONS: Many children with brain tumours suffer from disturbed sleep, poor mental health, and low quality of life. We recommend that systematic sleep evaluation is included in their routine care along with psychological and social support.

Brain tumours in children and adolescents may affect the circadian rhythm and quality of life.

AIM: Children with brain and cervical medulla tumours may experience circadian abnormalities and poor health. We aimed to examine their circadian rhythm, fatigue and quality of life (QoL). METHODS: Children with a brain or cervical medulla tumour were recruited from the Paediatric Department, Rigshospitalet, Copenhagen, Denmark, between 2016 and 2020. They were grouped by tumour location involving the circadian regulatory system, defined as diencephalon, pineal gland, brain stem and cervical medulla, or other areas. Saliva melatonin and cortisol concentrations were measured. Sleep diaries and actigraphy assessed sleep-wake patterns. The Pediatric Quality of Life Inventory, Multidimensional Fatigue Scale and Generic Core Scale measured fatigue and QoL. RESULTS: We included 68 children (62% males) with a median age (25th-75th percentiles) of 12.2 (7.7-16.3) years. Children with tumours involving the circadian regulatory system typically had a lower melatonin peak (p=0.06) and experienced significantly more fatigue and poorer QoL. Low melatonin profiles were observed in 31% and 4% had a phase-shifted daytime peak, compared with 14% and 0%, respectively, in children with tumours located elsewhere. Children with low melatonin profiles had significantly lower inter-daily stability than those with normal profiles. CONCLUSION: Tumours involving the circadian regulatory system adversely affected circadian function, fatigue and QoL.

Clinical evidence for a biological effect of epigenetically active decitabine in relapsed or progressive rhabdoid tumors.

BACKGROUND: Refined therapy has helped to improve survival rates in rhabdoid tumors (RT). Prognosis for patients with chemoresistant, recurrent, or progressive RT remains dismal. Although decitabine, an epigenetically active agent, has mainly been evaluated in the management of hematologic malignancies in adults, safety in children has also been demonstrated repeatedly. MATERIALS AND METHODS: A retrospective series of patients who received decitabine upon relapse or progression following therapy according to the EU-RHAB regimen is presented. Due to the retrospective nature of analyses, response was defined as measurable regression of at least one lesion on imaging. 850k methylation profiling was done whenever tumor tissue was available. RESULTS: A total of 22 patients with RT of any anatomical localization were included. Most patients (19/22) presented with metastases. All received low-dose decitabine with or preceding conventional chemotherapy. Patients received a median of two (1-6) courses of decitabine; 27.3% (6/22) demonstrated a radiological response. Molecular analyses revealed increased methylation levels in tumors from responders. No excessive toxicity was observed. Clinical benefits for responders included eligibility for early phase trials or local therapy. Responders showed prolonged time to progression and overall survival. Due to small sample size, statistical correction for survivorship bias demonstrated no significant effect on survival for responders. CONCLUSIONS: Patients with RT demonstrate promising signs of antitumor activity after multiagent relapse therapy including decitabine. Analyses of methylation data suggest a specific effect on an epigenetic level. We propose to consider decitabine and other epigenetic drugs as candidates for further clinical investigations in RT.