Clinical and biological landscape of constitutional mismatch-repair deficiency syndrome: an International Replication Repair Deficiency Consortium cohort study.

BACKGROUND: Constitutional mismatch repair deficiency (CMMRD) syndrome is a rare and aggressive cancer predisposition syndrome. Because a scarcity of data on this condition contributes to management challenges and poor outcomes, we aimed to describe the clinical spectrum, cancer biology, and impact of genetics on patient survival in CMMRD. METHODS: In this cohort study, we collected cross-sectional and longitudinal data on all patients with CMMRD, with no age limits, registered with the International Replication Repair Deficiency Consortium (IRRDC) across more than 50 countries. Clinical data were extracted from the IRRDC database, medical records, and physician-completed case record forms. The primary objective was to describe the clinical features, cancer spectrum, and biology of the condition. Secondary objectives included estimations of cancer incidence and of the impact of the specific mismatch-repair gene and genotype on cancer onset and survival, including after cancer surveillance and immunotherapy interventions. FINDINGS: We analysed data from 201 patients (103 males, 98 females) enrolled between June 5, 2007 and Sept 9, 2022. Median age at diagnosis of CMMRD or a related cancer was 8·9 years (IQR 5·9-12·6), and median follow-up from diagnosis was 7·2 years (3·6-14·8). Endogamy among minorities and closed communities contributed to high homozygosity within countries with low consanguinity. Frequent dermatological manifestations (117 [93%] of 126 patients with complete data) led to a clinical overlap with neurofibromatosis type 1 (35 [28%] of 126). 339 cancers were reported in 194 (97%) of 201 patients. The cumulative cancer incidence by age 18 years was 90% (95% CI 80-99). Median time between cancer diagnoses for patients with more than one cancer was 1·9 years (IQR 0·8-3·9). Neoplasms developed in 15 organs and included early-onset adult cancers. CNS tumours were the most frequent (173 [51%] cancers), followed by gastrointestinal (75 [22%]), haematological (61 [18%]), and other cancer types (30 [9%]). Patients with CNS tumours had the poorest overall survival rates (39% [95% CI 30-52] at 10 years from diagnosis; log-rank p<0·0001 across four cancer types), followed by those with haematological cancers (67% [55-82]), gastrointestinal cancers (89% [81-97]), and other solid tumours (96% [88-100]). All cancers showed high mutation and microsatellite indel burdens, and pathognomonic mutational signatures. MLH1 or MSH2 variants caused earlier cancer onset than PMS2 or MSH6 variants, and inferior survival (overall survival at age 15 years 63% [95% CI 55-73] for PMS2, 49% [35-68] for MSH6, 19% [6-66] for MLH1, and 0% for MSH2; p<0·0001). Frameshift or truncating variants within the same gene caused earlier cancers and inferior outcomes compared with missense variants (p<0·0001). The greater deleterious effects of MLH1 and MSH2 variants as compared with PMS2 and MSH6 variants persisted despite overall improvements in survival after surveillance or immune checkpoint inhibitor interventions. INTERPRETATION: The very high cancer burden and unique genomic landscape of CMMRD highlight the benefit of comprehensive assays in timely diagnosis and precision approaches toward surveillance and immunotherapy. These data will guide the clinical management of children and patients who survive into adulthood with CMMRD. FUNDING: The Canadian Institutes for Health Research, Stand Up to Cancer, Children's Oncology Group National Cancer Institute Community Oncology Research Program, Canadian Cancer Society, Brain Canada, The V Foundation for Cancer Research, BioCanRx, Harry and Agnieszka Hall, Meagan's Walk, BRAINchild Canada, The LivWise Foundation, St Baldrick Foundation, Hold'em for Life, and Garron Family Cancer Center.

Incorporation of patient-reported outcomes in early-phase clinical trials for childhood and adolescent cancer.

INTRODUCTION: The assessment of quality of life (QoL) should be one of the main objectives in paediatric clinical trials. Even though researchers, regulators and advocates support the use of patient-reported outcomes (PROs), this has not been fully implemented. The aim of this study is to assess the measurement of QoL and the usage of PROs, palatability assessments and medication diaries in early-phase clinical trials for childhood and adolescent cancer. METHODS: Early-phase clinical trials for children and adolescents with cancer opened between 2005 and 2022 at the Royal Marsden Hospital (London, UK) and Vall d'Hebron University Hospital (Barcelona, Spain) were interrogated for trial characteristics and the use of QoL questionnaires, PROs, palatability assessments and medication diaries. RESULTS: Overall, 72 clinical trials were analysed: 12 (16.7%) evaluated QoL and eight (11.1%) evaluated PROs. Palatability was tested in 21/40 (52.5%) trials of oral drugs and 23/72 (31.9%) incorporated medication diaries. No studies mentioned patient involvement in the trial protocol. Use of PROs increased from one of 36 (2.8%) to seven of 36 (19.4%) between the first period (2005-2016) and the second period (2017-2022) (p = .02). Implementation of medication diaries increased from seven of 36 (19.4%) to 16/36 (44.4%) in each period, respectively (p = .02). CONCLUSION: Only a minor proportion of the international/multicentric early-phase trials evaluated included QoL/PROs and medication diaries or palatability questionnaires to help assess these, although this trend seems to be increasing over recent years. Greater implementation of QoL/PROs has the potential to improve the patient's wellbeing and facilitate symptom control, to enhance patient/parent involvement in future trial designs and to provide information for drug prioritisation.

Implications of deferred diagnosis of paediatric intracranial germ cell tumours.

AIMS: This study analysed the clinical features of a cohort of children with intracranial germ cell tumours (IC-GCTs). We retrospectively reviewed timelag between symptoms onset, clinic-radiological findings, diagnosis and outcomes. METHODS: Symptoms at diagnosis were divided into four groups: (1) raised intracranial pressure (RICP); (2) visual impairment; (3) endocrinopathies; (4) other. Total diagnostic interval (TDI), defined as the interval between symptom onset (including retrospective recall of symptoms) and definitive diagnosis of IC-GCT, was calculated and compared to survival rates. RESULTS: Our cohort included 55 children with median follow-up of 78.9 months (0.5-249.9). The majority (63.6%) had germinomas and 10.9% were metastatic at diagnosis. IC-GCTs were suprasellar (41.8%), pineal (36.4%), bifocal (12.7%) or in atypical sites (9.1%). The most common presenting symptoms were related to RICP (43.6%); however, by the time of tumour diagnosis, 50.9% of patients had developed endocrine dysfunctions. All pineal GCTs manifested with RICP or visual impairment. All suprasellar GCTs presented with endocrinopathies. TDI ranged between 0.25 and 58.5 months (median 4 months). Pineal GCTs had the shortest TDI (median TDI 1 month versus 24 months in suprasellar GCTs, p < .001). TDI > 6 months was observed in 47.3% of patients and was significantly associated with endocrine presenting symptoms. No statistically significant difference was found in progression-free survival and overall survival between patients with TDI > 6 months and with TDI ≤ 6 months. CONCLUSION: Approximately half of the IC-GCT patients in this cohort had TDI > 6 months. These presented mostly with endocrine deficits. TDI > 6 months was not associated with increased relapse or mortality rates.

Access to early-phase clinical trials for children with relapsed and refractory neuroblastoma: A multicentre international study.

OBJECTIVES: Neuroblastoma is the most common extracranial tumour in children, and prognosis for refractory and relapsed disease is still poor. Early-phase clinical trials play a pivotal role in the development of novel drugs. Ensuring adequate recruitment is crucial. The primary aim was to determine the rate of participation trials for children with refractory/relapsed neuroblastoma in two of the largest drug development European institutions. METHODS: Data from patients diagnosed with refractory/relapsed neuroblastoma between January 2012 and December 2018 at the two institutions were collected and analysed. RESULTS: Overall, 48 patients were included. A total of 31 (65%) refractory/relapsed cases were enrolled in early-phase trials. The main reasons for not participating in clinical trials included not fulfilling eligibility criteria prior to consent (12/17, 70%) and screening failure (2/17, 12%). Median time on trial was 4.3 months (range 0.6-13.4). Most common cause for trial discontinuation was disease progression (67.7%). Median overall survival was longer in refractory (28 months, 95% CI: 20.9-40.2) than in relapsed patients (14 months, 95% CI: 8.1-20.1) (p = .034). CONCLUSIONS: Although two thirds of children with refractory/relapsed neuroblastoma were enrolled in early-phase trials, recruitment rates can still be improved. The main cause for not participating on trials was not fulfilling eligibility criteria prior to consent, mainly due to performance status and short life expectancy. This study highlights the hurdles to access to innovative therapies for children with relapsed/refractory neuroblastomas, and identifies key areas of development to improve recruitment to early-phase trials.

Clinical research tools in pediatric oncology: challenges and opportunities.

Survival for childhood cancers has improved significantly over the last decades. However, patient outcomes have plateaued over the last decade for difficult-to-treat diseases. With high cure rates, decreasing long-term toxicities and sequelae remains crucial. Since many advances in childhood cancer research come from the adult oncology world, one of the key areas is improving the adaptation of tools that are essential for clinical trial conduct that were developed for adults into pediatrics. These include tools to evaluate toxicity, quality of life, radiological response, statistical methodology, or indicators of cancer care quality. In this review, we present ongoing international efforts to validate and adapt these tools for children and adolescents and discuss remaining challenges. These efforts will hopefully accelerate and improve the quality of pediatric oncology research in the upcoming years.

A case series of Diffuse Glioneuronal Tumours with Oligodendroglioma-like features and Nuclear Clusters (DGONC).

In this study, we report three paediatric cases of Diffuse Glioneuronal Tumours with Oligodendroglioma-like features and Nuclear Clusters (DGONC).

Constitutional mismatch repair deficiency (CMMRD) presenting with high-grade glioma, multiple developmental venous anomalies and malformations of cortical development-a multidisciplinary/multicentre approach and neuroimaging clues to clinching the diagnosis.

Constitutional mismatch repair deficiency syndrome (CMMRD) is a rare cancer-predisposition syndrome associated with a high risk of developing a spectrum of malignancies in childhood and adolescence, including brain tumours. In this report, we present the case of an 8-year-old boy with acute headache, vomiting and an episode of unconsciousness in whom brain imaging revealed a high-grade glioma (HGG). The possibility of an underlying diagnosis of CMMRD was suspected radiologically on the basis of additional neuroimaging findings, specifically the presence of multiple supratentorial and infratentorial developmental venous anomalies (DVAs) and malformations of cortical development (MCD), namely, heterotopic grey matter. The tumour was debulked and confirmed to be a HGG on histopathology. The suspected diagnosis of CMMRD was confirmed on immunohistochemistry and genetic testing which revealed mutations in PMS2 and MSH6. The combination of a HGG, multiple DVAs and MCD in a paediatric or young adult patient should prompt the neuroradiologist to suggest an underlying diagnosis of CMMRD. A diagnosis of CMMRD has an important treatment and surveillance implications not only for the child but also the family in terms of genetic counselling.

High grade gliomas in young children: The South Thames Neuro-Oncology unit experience and recent advances in molecular biology and targeted therapies.

High grade gliomas (HGG) have a dismal prognosis with survival rates of 15-35%. Approximately 10-12% of pediatric HGG occur in young children and their molecular biology and clinical outcomes differ from those arising at older ages. We report on four children aged <5 years newly diagnosed with non-brainstem HGG between 2011 and 2018 who were treated with surgery and BBSFOP chemotherapy. Two died of tumor progression. The other two are still alive without radiotherapy at 3.8 and 3.9 years from diagnosis: one of whom remains disease-free off treatment; and the other one, whose tumor harbored a KCTD16:NTRK2 fusion, went on to receive larotrectinib. Additionally we review the general management, outcomes and latest updates in molecular biology and targeted therapies for young children with HGG. Infant gliomas can be stratified in molecular subgroups with clinically actionable oncogenic drivers. Chemotherapy-based strategies can avoid or delay the need for radiotherapy in young children with HGG. Harnessing the potential of NTRK, ALK, ROS1 and MET inhibitors offers the opportunity to optimize the therapeutic armamentarium to improve current outcomes for these children.

Tumour-agnostic drugs in paediatric cancers.

The recognition that new cancer drugs can be truly tumour-agnostic based on mechanism-of-action is important for paediatric cancers, where access to novel targeted therapies developed for adult indications has sometimes been problematic. The recently approved drug larotrectinib is an excellent case study of the development of a tumour-agnostic drug relevant to children.

Radiological pseudoprogression post-radiotherapy in a child with pineal germ cell tumour.

Little is known about pseudoprogression in brain tumours other than gliomas. A 9-year-old male child with a pineal teratoma/germinoma underwent surgical resection followed by adjuvant chemo-radiotherapy. The magnetic resonance imaging scan 4 months post-radiotherapy showed a contrast-enhancing lesion within the surgical cavity suspicious of recurrence. These radiological findings subsequently resolved without any specific intervention. The child continues in remission 2 years post-treatment. This case illustrates the occurrence of pseudoprogression post-radiotherapy in intracranial GCT and highlights an unmet need for greater implementation of functional imaging techniques in paediatric neuro-oncology to avoid undue discontinuation of effective treatments or inappropriate enrolment in clinical trials.

Challenging the indiscriminate use of temozolomide in pediatric high-grade gliomas: A review of past, current, and emerging therapies.

Pediatric high-grade gliomas (pHGG) constitute 8% to 12% of primary brain tumors in childhood. The most widely utilized treatment encompasses surgical resection followed by focal radiotherapy and temozolomide. However, experiences over past decades have not demonstrated improved outcomes. pHGG have been classified into different molecular subgroups defined by mutations in histone 3, IDH gene, MAPK pathway, and others, thereby providing a rationale for various targeted therapies. Additionally, immunotherapy and drug repurposing have also become attractive adjunctive treatments. This review focuses on past, present, and emerging treatments for pHGG integrating molecular research with the mainstream pediatric drug development in Europe and the United States to sketch a way forward in the development of novel therapeutic approaches. The implementation of randomized clinical trials with adaptive designs, underpinned by a robust biological rationale, and harnessing collaboration between the pharmaceutical industry, academia, regulators and patients/parents organizations will be essential to improve the outcomes for these children.

Sorafenib in pediatric hepatocellular carcinoma from a clinician perspective.

Hepatocellular Carcinoma (HCC) is a rare tumor in children and normally carries poor outcomes. The most frequently employed chemotherapy regimen includes cisplatin and doxorubicin (PLADO), but this combination offers limited efficacy. Sorafenib is a multi-tyrosine kinase inhibitor which, following positive studies in adults with HCC, has begun to be introduced in conjunction with PLADO in pediatric oncology with some encouraging results. Based on these findings, the use of sorafenib is become more common in children with unresectable and/or metastatic HCC. The care of patients receiving sorafenib requires appropriate expertise and standardized pediatric guidelines are lacking. An increasing number of children with HCC are expected to receive sorafenib in the years to come. Pediatric oncology clinicians have a key role in identifying side effects early and clinicians caring for children receiving sorafenib need to be familiar with these. This review article provides suitable and practical information on sorafenib for educational development to optimize clinical care and facilitate enhanced patient/parent education. The article addresses specific areas including mechanisms of action, pre-clinical and clinical evidence, dosing and drug administration and toxicities of sorafenib. Clinical research and recommendations for managing sorafenib-related side effects are discussed. Underpinned by research, this article provides pediatric oncology clinicians with the knowledge required to deliver optimal care to children receiving sorafenib.

Post-radiotherapy apparent diffusion coefficient (ADC) in children and young adults with high-grade gliomas and diffuse intrinsic pontine gliomas.

Objectives: Diffusion-weighted magnetic resonance imaging (DW-MRI) offers potential to monitor response and predict survival in high-grade gliomas (HGG) and diffuse intrinsic pontine gliomas (DIPG). We hypothesized that post-radiotherapy DW-MRI may provide prognostic imaging biomarkers in children and young adults with these tumors. Methods: Patients aged ≤21 years diagnosed between 2005 and 2012 were eligible. The tumor median apparent diffusion coefficient (ADC) and its 5th percentile (C5-ADC) were determined at the first post-radiotherapy scan and at the time of radiological progression. DW-MRI parameters were correlated with survival endpoints, temozolomide use and pseudoprogression, when it occurred. Results: Out of 40 patients (20 HGG, 20 DIPG), 23 had evaluable DW-MRI post-radiotherapy and 25 at radiological progression. There were 6 episodes of pseudoprogression. Hazard ratios (95%CI) for progression-free survival were 0.998 (0.993-1.003) for median ADC and 1.003 (0.996-1.010) for C5-ADC. Hazard ratios (95%CI) for overall survival were 1.0009 (0.996-1.006) for median ADC and 0.998 (0.992-1.004) for C5-ADC. Post-radiotherapy median and C5-ADC values were not significantly different between patients treated with radiotherapy alone versus radiotherapy/temozolomide. The median and C5-ADC values were not significantly different at the time of pseudoprogression compared to those at tumor progression. Conclusions: Post-radiotherapy median ADC and C5-ADC were not prognostic, nor able to differentiate radiosensitization with temozolomide or occurrence of pseudoprogression in this cohort of HGG and DIPG patients. Further exploration of alternative DW parameters, study timepoints or data modeling may contribute to the development of prognostic/predictive imaging biomarkers for children and young adults with HGG or DIPG.

Outcome of children and adolescents with central nervous system tumors in phase I trials.

Central nervous system (CNS) tumors are a leading cause of death in pediatric oncology. New drugs are desperately needed to improve survival. We evaluated the outcome of children and adolescents with CNS tumors participating in phase I trials within the Innovative Therapies for Children with Cancer (ITCC) consortium. Patients with solid tumors aged < 18 years at enrollment in their first dose-finding trial between 2000 and 2014 at eight ITCC centers were included retrospectively. Survival was evaluated using univariate/multivariate analyses. Overall, 114 patients were included (109 evaluable for efficacy). Median age was 10.2 years (range 1.0-17.9). Main diagnoses included: medulloblastoma/primitive neuroectodermal tumors (32.5%) and high-grade gliomas (23.7%). Complete/partial responses (CR/PR) were reported in 7.3% patients and stable disease (SD) in 23.9%. Performance status of 90-100%, school/work attendance, normal ALT/AST and CR/PR/SD correlated with better overall survival (OS) in the univariate analysis. No variables assessable at screening/enrollment were associated with OS in the multivariate analysis. Five patients (4.5%) were discontinued from study due to toxicity. No toxic deaths occurred. Median OS was 11.9 months with CR/PR, 14.5 months with SD and 3.7 months with progressive disease (p < 0.001). The enrollment of children and adolescents with CNS tumors in phase I trials is feasible, safe and offers potential benefit for the patients. Sustained disease stabilization has a promising role as a marker of anti-tumor activity in children with CNS tumors participating in phase I trials.

Repeatability of derived parameters from histograms following non-Gaussian diffusion modelling of diffusion-weighted imaging in a paediatric oncological cohort.

OBJECTIVES: To examine repeatability of parameters derived from non-Gaussian diffusion models in data acquired in children with solid tumours. METHODS: Paediatric patients (<16 years, n = 17) were scanned twice, 24 h apart, using DWI (6 b-values, 0-1000 mm-2 s) at 1.5 T in a prospective study. Tumour ROIs were drawn (3 slices) and all data fitted using IVIM, stretched exponential, and kurtosis models; percentage coefficients of variation (CV) calculated for each parameter at all ROI histogram centiles, including the medians. RESULTS: The values for ADC, D, DDCα, α, and DDCK gave CV < 10 % down to the 5th centile, with sharp CV increases below 5th and above 95th centile. K, f, and D* showed increased CV (>30 %) over the histogram. ADC, D, DDCα, and DDCK were strongly correlated (ρ > 0.9), DDCα and α were not correlated (ρ = 0.083). CONCLUSION: Perfusion- and kurtosis-related parameters displayed larger, more variable CV across the histogram, indicating observed clinical changes outside of D/DDC in these models should be interpreted with caution. Centiles below 5th for all parameters show high CV and are unreliable as diffusion metrics. The stretched exponential model behaved well for both DDCα and α, making it a strong candidate for modelling multiple-b-value diffusion imaging data. KEY POINTS: • ADC has good repeatability as low 5th centile of the histogram distribution. • High CV was observed for all parameters at extremes of histogram. • Parameters from the stretched exponential model showed low coefficients of variation. • The median ADC, D, DDC α , and DDC K are highly correlated and repeatable. • Perfusion/kurtosis parameters showed high CV variations across their histogram distributions.

Feasibility and applicability of diffusion-weighted and dynamic contrast-enhanced magnetic resonance imaging in routine assessments of children with high-grade gliomas.

Diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) have been used as imaging biomarkers in adults with high-grade gliomas (HGGs). We incorporated free-breathing DW-MRI and DCE-MRI, at a single time point, in the routine follow-up of five children (median age 9 years, range 8-15) with histologically confirmed HGG within a prospective imaging study. It was feasible to incorporate DW-MRI and DCE-MRI in routine assessments of children with HGG. DW and DCE parameters were repeatable in paediatric HGG. Higher median ADC100-1000 significantly correlated with longer survival in our sample.

Spinal adrenal cortical adenoma associated with Beckwith-Wiedemann syndrome: case report and review of the literature.

PURPOSE: Ectopic adrenal cortical adenoma in the spinal region is extremely rare. The majority of cases of ectopic adrenocortical tissue are found along the path of embryonic migration within the urogenital tract. Beckwith-Wiedemann syndrome (BWS) is a pediatric overgrowth disorder involving a predisposition to tumor development, including adrenal lesions. To date, only eight spinal cases have been reported. This is the third reported case in pediatric population, the first one associated with genetic syndrome and the first benign to recur. We review the current literature on this topic. CASE DESCRIPTION: We present a 2-year-old boy affected by Beckwith-Wiedemann syndrome who developed a tumor at L4-L5 level. He underwent a gross total resection with MRI post-surgery demonstrating non-residual tumor. Histology disclosed an ectopic adrenal cortical adenoma with oncocytic features. Immunohistochemically was positive for inhibin-alpha, synaptophysin, and melan-A. It was negative for chromogranin A, GFAP, S-100, and other markers. One year later, he developed a recurrence at the same level being necessary a second surgery leaving a small sheet of residual tumor. CONCLUSION: Spinal adrenocortical adenomas are exceptional, and its behavior could be related to other conditions such as BWS. Gross total resection can be curative but a tight follow-up is needed. Immunohistochemical studies that include inhibin-alpha, synaptophysin, and melan-A can be useful in differential diagnosis as ultrastructural study. The decision on how to treat these patients is difficult given the low number of cases.