Update on cancer predisposition syndromes and surveillance guidelines for childhood brain tumors.

Tumors of the central nervous system (CNS) comprise the second most common group of neoplasms in childhood. The incidence of germline predisposition among children with brain tumors continues to grow as our knowledge on disease aetiology increases. Some children with brain tumors may present with non-malignant phenotypic features of specific syndromes (e.g. nevoid basal cell carcinoma syndrome, neurofibromatosis type 1 and type 2, DICER1 syndrome, and constitutional mismatch repair deficiency), while others may present with a strong family history of cancer (e.g. Li-Fraumeni syndrome), or with a rare tumor commonly found in the context of germline predisposition (e.g. rhabdoid tumor predisposition syndrome). Approximately 50% of patients with a brain tumor may be the first in a family identified to have a predisposition. The past decade has witnessed a rapid expansion in our molecular understanding of CNS tumors. A significant proportion of CNS tumors are now well characterized and known to harbor specific genetic changes that can be found in the germline. Additional novel predisposition syndromes are also being described. Identification of these germline syndromes in individual patients has not only enabled cascade testing of family members and early tumor surveillance but increasingly has also impacted cancer management in those patients. Therefore, the AACR Cancer Predisposition Working Group chose to highlight these advances in CNS tumor predisposition and summarize and/or generate surveillance recommendations for established and more recently emerging pediatric brain tumor predisposition syndromes.

A Need for a Novel Survival Risk Scoring System for Intensive Care Admissions Due to Sepsis in Pediatric Hematology/Oncology Patients.

Background: Children with hemato-oncological diseases or following stem cell transplantation (SCT) are at high risk for life-threatening infections; sepsis in this population constitutes a substantial proportion of pediatric intensive care unit (PICU) admissions. The current pediatric prognostic scoring tools to evaluate illness severity and mortality risk are designed for the general pediatric population and may not be adequate for this vulnerable subpopulation. Methods: Retrospective analysis was performed on all PICU admissions for sepsis in children with hemato-oncological diseases or post-SCT, in a single tertiary pediatric hospital between 2008 and 2021 (n = 233). We collected and analyzed demographic, clinical, and laboratory data and outcomes for all patients, and evaluated the accuracy of two major prognostic scoring tools, the Pediatric Logistic Organ Dysfunction-2 (PELOD-2) and the Pediatric Risk of Mortality III (PRISM III). Furthermore, we created a new risk-assessment model that contains additional parameters uniquely relevant to this population. Results: The survival rate for the cohort was 83%. The predictive accuracies of PELOD-2 and PRISM III, as determined by the area under the curve (AUC), were 83% and 78%, respectively. Nine new parameters were identified as clinically significant: age, SCT, viral infection, fungal infection, central venous line removal, vasoactive inotropic score, bilirubin level, C-reactive protein level, and prolonged neutropenia. Unique scoring systems were established by the integration of these new parameters into the algorithm; the new systems significantly improved their predictive accuracy to 91% (p = 0.01) and 89% (p < 0.001), respectively. Conclusions: The predictive accuracies (AUC) of the PELOD-2 and PRISM III scores are limited in children with hemato-oncological diseases admitted to PICU with sepsis. These results highlight the need to develop a risk-assessment tool adjusted to this special population. Such new scoring should represent their unique characteristics including their degree of immunosuppression and be validated in a large multi-center prospective study.

Performance of the eHealth decision support tool, MIPOGG, for recognising children with Li-Fraumeni, DICER1, Constitutional mismatch repair deficiency and Gorlin syndromes.

BACKGROUND: Cancer predisposition syndromes (CPSs) are responsible for at least 10% of cancer diagnoses in children and adolescents, most of which are not clinically recognised prior to cancer diagnosis. A variety of clinical screening guidelines are used in healthcare settings to help clinicians detect patients who have a higher likelihood of having a CPS. The McGill Interactive Pediatric OncoGenetic Guidelines (MIPOGG) is an electronic health decision support tool that uses algorithms to help clinicians determine if a child/adolescent diagnosed with cancer should be referred to genetics for a CPS evaluation. METHODS: This study assessed MIPOGG's performance in identifying Li-Fraumeni, DICER1, Constitutional mismatch repair deficiency and Gorlin (nevoid basal cell carcinoma) syndromes in a retrospective series of 84 children diagnosed with cancer and one of these four CPSs in Canadian hospitals over an 18-year period. RESULTS: MIPOGG detected 82 of 83 (98.8%) evaluable patients with any one of these four genetic conditions and demonstrated an appropriate rationale for suggesting CPS evaluation. When compared with syndrome-specific clinical screening criteria, MIPOGG's ability to correctly identify children with any of the four CPSs was equivalent to, or outperformed, existing clinical criteria respective to each CPS. CONCLUSION: This study adds evidence that MIPOGG is an appropriate tool for CPS screening in clinical practice. MIPOGG's strength is that it starts with a specific cancer diagnosis and incorporates criteria relevant for associated CPSs, making MIPOGG a more universally accessible diagnostic adjunct that does not require in-depth knowledge of each CPS.

Di-genic inheritance of germline POLE and PMS2 pathogenic variants causes a unique condition associated with pediatric cancer predisposition.

Polymerase proofreading-associated polyposis (PPAP) and Lynch syndrome, caused by mutated POLE and mismatch repair (MMR) genes, respectively, are associated with adult-onset cancer. PPAP and MMR-deficient tumors are both hypermutated, and each has a unique mutational signature. We describe a 4.5-year-old boy with multiple café au lait spots who presented with metastatic Sonic Hedgehog-activated medulloblastoma, with partial response to intensive chemotherapy and immunotherapy. The tumor showed microsatellite stability, loss of PMS2 nuclear expression, and an exceptionally high tumor mutational burden of 276 Mut/Mb. Germline molecular analysis revealed an inherited heterozygous pathogenic POLE variant and a de novo heterozygous PMS2 pathogenic variant. The tumor featured the MMR, POLE, and POLE+MMR mutational signatures. This is the first description of a di-genic condition, which we named "POL-LYNCH syndrome," manifested by an aggressive ultra-mutant pediatric medulloblastoma with a unique genomic signature.

Performance of the McGill Interactive Pediatric OncoGenetic Guidelines for Identifying Cancer Predisposition Syndromes.

IMPORTANCE: Prompt recognition of a child with a cancer predisposition syndrome (CPS) has implications for cancer management, surveillance, genetic counseling, and cascade testing of relatives. Diagnosis of CPS requires practitioner expertise, access to genetic testing, and test result interpretation. This diagnostic process is not accessible in all institutions worldwide, leading to missed CPS diagnoses. Advances in electronic health technology can facilitate CPS risk assessment. OBJECTIVE: To evaluate the diagnostic accuracy of a CPS prediction tool (McGill Interactive Pediatric OncoGenetic Guidelines [MIPOGG]) in identifying children with cancer who have a low or high likelihood of having a CPS. DESIGN, SETTING, AND PARTICIPANTS: In this international, multicenter diagnostic accuracy study, 1071 pediatric (<19 years of age) oncology patients who had a confirmed CPS (12 oncology referral centers) or who underwent germline DNA sequencing through precision medicine programs (6 centers) from January 1, 2000, to July 31, 2020, were studied. EXPOSURES: Exposures were MIPOGG application in patients with cancer and a confirmed CPS (diagnosed through routine clinical care; n = 413) in phase 1 and MIPOGG application in patients with cancer who underwent germline DNA sequencing (n = 658) in phase 2. Study phases did not overlap. Data analysts were blinded to genetic test results. MAIN OUTCOMES AND MEASURES: The performance of MIPOGG in CPS recognition was compared with that of routine clinical care, including identifying a CPS earlier than practitioners. The tool's test characteristics were calculated using next-generation germline DNA sequencing as the comparator. RESULTS: In phase 1, a total of 413 patients with cancer (median age, 3.0 years; range, 0-18 years) and a confirmed CPS were identified. MIPOGG correctly recognized 410 of 412 patients (99.5%) as requiring referral for CPS evaluation at the time of primary cancer diagnosis. Nine patients diagnosed with a CPS by a practitioner after their second malignant tumor were detected by MIPOGG using information available at the time of the first cancer. In phase 2, of 658 children with cancer (median age, 6.6 years; range, 0-18.8 years) who underwent comprehensive germline DNA sequencing, 636 had sufficient information for MIPOGG application. When compared with germline DNA sequencing for CPS detection, the MIPOGG test characteristics for pediatric-onset CPSs were as follows: sensitivity, 90.7%; specificity, 60.5%; positive predictive value, 17.6%; and negative predictive value, 98.6%. Tumor DNA sequencing data confirmed the MIPOGG recommendation for CPS evaluation in 20 of 22 patients with established cancer-CPS associations. CONCLUSIONS AND RELEVANCE: In this diagnostic study, MIPOGG exhibited a favorable accuracy profile for CPS screening and reduced time to CPS recognition. These findings suggest that MIPOGG implementation could standardize and rationalize recommendations for CPS evaluation in children with cancer.

Non-rhabdomyosarcoma soft tissue sarcomas diagnosed in patients at a young age. An overview of clinical, pathological, and molecular findings.

OBJECTIVE: Disease spectrum in pediatric sarcoma differs substantially from adults. We report a cohort of very young children with non-rhabdomyosarcoma soft tissue sarcoma (NRSTS) detailing their molecular features, treatment, and outcome. METHODS: We report features of consecutive children (age <2 years) with NRSTS (2000-2017). Archival pathological material was re-reviewed, with additional molecular techniques applied where indicated. RESULTS: Twenty-nine patients (16 females, 55%) were identified (median age 6 months; range 0-23). Most common diagnoses included infantile fibrosarcoma (IFS, n = 14, 48%), malignant rhabdoid tumor (MRT, n = 4, 14%), and undifferentiated sarcoma (n = 4, 14%). Twenty-seven of 29 (93%) had tumor molecular characterization to confirm diagnosis. Clinical presentation included a swelling/mass (n = 23, 79%). Disease extent was localized (n = 20, 69%), locoregional (n = 6, 21%), or metastatic (n = 3, 10%). Seventeen of 29 (59%) who underwent surgery achieved complete resection (R0). Other treatments included conventional chemotherapy (n = 26, 90%), molecularly targeted therapies (n = 3, 10%), and radiation (n = 5, 17%). At last follow-up (median 3 years; range 0.3-16.4), 23 (79%) were alive, disease-free and six (21%) had died of disease. All patients with IFS were alive and all those with MRT died. A cancer predisposition syndrome (CPS) was confirmed in three of 10 (30%) genetically tested patients. CONCLUSION: We recommend tumor molecular characterization in all young patients including evaluation for CPS to optimize treatment options and prognostication.

Genetic testing and surveillance in infantile myofibromatosis: a report from the SIOPE Host Genome Working Group.

Infantile myofibromatosis (IM), which is typically diagnosed in young children, comprises a wide clinical spectrum ranging from inconspicuous solitary soft tissue nodules to multiple disseminated tumors resulting in life-threatening complications. Familial IM follows an autosomal dominant mode of inheritance and is linked to PDGFRB germline variants. Somatic PDGFRB variants were also detected in solitary and multifocal IM lesions. PDGFRB variants associated with IM constitutively activate PDGFRB kinase activity in the absence of its ligand. Germline variants have lower activating capabilities than somatic variants and, thus, require a second cis-acting hit for full receptor activation. Typically, these mutant receptors remain sensitive to tyrosine kinase inhibitors such as imatinib. The SIOPE Host Genome Working Group, consisting of pediatric oncologists, clinical geneticists and scientists, met in January 2020 to discuss recommendations for genetic testing and surveillance for patients who are diagnosed with IM or have a family history of IM/PDGFRB germline variants. This report provides a brief review of the clinical manifestations and genetics of IM and summarizes our interdisciplinary recommendations.

Clinical Outcomes of Children With Adrenocortical Carcinoma in the Context of Germline TP53 Status.

Adrenocortical carcinoma (ACC) is a rare, aggressive malignancy of the adrenal cortex. This study characterizes a single-institution cohort of children treated for ACC, and explores the relationship between clinical outcomes of ACC and germline TP53 mutation status. We performed a retrospective chart review of 23 consecutive pediatric patients with ACC treated at The Hospital for Sick Children, Toronto, Canada, between 1977 and 2017. Clinical, biochemical, radiologic, pathologic, and genetic data were collected for each patient. ACC diagnosis followed a bimodal age distribution of 0 to 6 (n=17) and 12+ (n=6) years, with a female:male ratio of 3.6:1. Ten of 20 patients tested for germline TP53 status carried a pathogenic (9) or likely pathogenic (1) variant, including all but 1 male patient. Only 3 patients died of ACC-related causes, each 5 months post-diagnosis. When treated with resection and combination chemotherapy, carriers of germline TP53 mutations may respond more favorably than their wild-type counterparts. In addition, the survival of patients reported in our cohort with high-stage ACC was appreciably greater than previously described (100.0% for stage II, 50.0% for stage III, and 42.9% for stage IV), favoring aggressive intervention in these patient populations.

Causes of death in pediatric neuro-oncology: the sickkids experience from 2000 to 2017.

PURPOSE: Primary benign and malignant central nervous system (CNS) tumors are the most frequent solid tumors in the pediatric age and represent the leading cause of death by cancer in children in high income countries. However, information regarding specific causes of death in this population is still limited. The objective of this work was to investigate mortality in a large cohort of children diagnosed at our institution. METHODS: We identified patients consecutively diagnosed with CNS tumor and treated at a Tertiary Care Canadian Children's Hospital between January 2000 and December 2017. Patient charts were reviewed and different variables such as tumor diagnosis, location, gender, age at diagnosis, age at death and cause of death collected. RESULTS: Of 1274 patients, 306 (24%) succumbed to their disease. Mortality rate varied significantly according to tumor subtype, ranging from 3.1% in low grade glioma (LGG) to 97.8% in diffuse intrinsic pontine glioma (DIPG). While high grade gliomas (HGG) and DIPG represented only 6.3 and 7.1% of total diagnoses respectively, together they accounted for 49.3% of total deaths (n = 151). Median time from diagnosis to death was 15 months (4 days to 15 years) and shortest for DIPG (11 months). Two hundred and ninety patients (94.8%) died as a result of the primary disease, 4 of treatment-related toxicity, two patients' deaths were unrelated to the primary disease (idiopathic encephalopathy and domestic fire) whereas 10 patients succumbed to a secondary malignancy. Of note, four of these ten patients had a confirmed underlying cancer predisposition syndrome. CONCLUSION: Disease progression is the main cause of death in children with brain tumor, while treatment related mortality is low in this series. Research should continue to focus on improving treatment strategies for patients whose prognosis remains dismal.

Primary immunodeficiencies and their associated risk of malignancies in children: an overview.

Primary immunodeficiency disorders represent a heterogeneous spectrum of diseases, predisposing to recurrent infections, allergy, and autoimmunity. While an association between primary immunodeficiency disorders and increased risk of cancer has been suggested since the 1970s, renewed attention has been given to this topic in the last decade, largely in light of the availability of large registries as well as advances in next generation sequencing. In this narrative review, we will give an insight of the primary immunodeficiencies that are commonly responsible for the greater number of cancers in the primary immunodeficiency disorders population. We will describe clinical presentations, underlying genetic lesions (if known), molecular mechanisms for carcinogenesis, as well as some management considerations. We will also comment on the future directions and challenges related to this topic.Conclusion: The awareness of the association between several primary immunodeficiencies and cancer is crucial to provide the best care for these patients.What is Known: • Patients with primary immunodeficiency have an increased risk of malignancy. The type of malignancy is highly dependent on the specific primary immunodeficiency disorder.What is New: • Survival in patients with primary immunodeficiency disorders has been improving, and conversely also their lifetime risk of malignancy. • International collaboration and multinational registries are needed to improve our knowledge and therapeutic strategies.

Bevacizumab for NF2-associated vestibular schwannomas of childhood and adolescence.

Seventeen children at six institutions with neurofibromatosis type 2 (NF2)-related vestibular schwannomas received bevacizumab. Eight of the 13 patients with initial hearing loss (61%) showed objective hearing improvement within six months of treatment. No patients showed hearing deterioration during therapy; however, only two patients showed objective radiological response. Seven of eight patients had tumor progression or worsening hearing loss upon cessation of treatment. Bevacizumab was well tolerated with no patients discontinuing therapy. Bevacizumab appears to postpone hearing loss in childhood NF2-associated vestibular schwannomas, but responses are not durable, suggesting that either longer maintenance therapy or new strategies are required.

Indolent course of brainstem tumors with K27M-H3.3 mutation.

Diffuse intrinsic pontine glioma (DIPG) is characterized by a short history of brainstem symptoms and well-known magnetic resonance imaging features with a fatal outcome. However, we report three unusual cases of brainstem tumors with an initial indolent and protracted course, which subsequently developed the classical imaging and clinical features of DIPG. Our findings support this notion that K27M is an early event in development and suggest that the emergence of additional events resulted in rapid progression after a long period of latency. Identification of such markers of aggressive behavior in the context of an indolent course is needed for better characterization and treatment management.

Tumor risk and surveillance for children with hereditary disorders affecting growth.

PURPOSE OF REVIEW: Hereditary disorders affecting growth (both overgrowth and growth retardation) are frequently associated with heightened risk of neoplastic disease. This review summarizes the tumor spectra associated with these conditions and identifies disease-specific screening approaches. RECENT FINDINGS: An understanding of the molecular events underlying many of these growth disorders has evolved significantly over the past several years. Recognition of genotype-phenotype associations, in many cases, informs the cancer risk profile. Additionally, accumulating data suggest a benefit of rational presymptomatic surveillance for at-risk individuals, with a reduction in tumor-associated morbidity. Recent clinical practice recommendations have established risk-driven paradigms for tumor surveillance in the context of hereditary tumor predisposition syndromes, including those affecting growth. SUMMARY: Clinicians caring for children with growth disorders should be aware of syndromic associations and the associated cancer risks. Knowledge of tumor spectra and recommended surveillance strategies may facilitate tumor diagnosis at an early stage and reduce morbidity of the disease and associated treatments.

Pediatric High Grade Gliomas in the Context of Cancer Predisposition Syndromes.

Germline mutations in cancer causing genes result in high risk of developing cancer throughout life. These cancer predisposition syndromes (CPS) are especially prevalent in childhood brain tumors and impact both the patient's and other family members' survival. Knowledge of specific CPS may alter the management of the cancer, offer novel targeted therapies which may improve survival for these patients, and enables early detection of other malignancies. This review focuses on the role of CPS in pediatric high grade gliomas (PHGG), the deadliest group of childhood brain tumors. Genetic aspects and clinical features are depicted, allowing clinicians to identify and diagnose these syndromes. Challenges in the management of PHGG in the context of each CPS and the promise of innovative options of treatment and surveillance guidelines are discussed with the hope of improving outcome for individuals with these devastating syndromes.

Calcineurin inhibitor-free strategies for prophylaxis and treatment of GVHD in children with posterior reversible encephalopathy syndrome after stem cell transplantation.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) is a distinct clinico-radiologic entity that can occur following allogeneic hematopoietic stem cell transplantation, often in the context of treatment with calcineurin inhibitors (CNIs). PROCEDURE: We describe the results of CNI-free management of 14 children with PRES and review the clinical and radiologic manifestations of their presentation. RESULTS: Discontinuation of CNIs usually resulted in remission of PRES, but patients with established graft versus host disease (GVHD) at the time when treatment was changed often experienced progressive GVHD despite administration of immune suppressive and modulating treatments. All but three patients experienced full neurologic recovery. Nine children died as a result of either GVHD, disease relapse, or severe infection. CONCLUSIONS: Discontinuation of CNIs results in neurologic improvement in most cases, but superior alternative immune modulatory treatment is needed to prevent progression of established GVHD.

Long-term motor, cognitive and behavioral outcome of acute disseminated encephalomyelitis.

OBJECTIVE: The purpose of this study was to evaluate the long-term motor and neurocognitive outcome of children with acute disseminated encephalomyelitis and to identify prognostic risk factors. METHODS: The study included 43 children who were hospitalized due to acute disseminated encephalomyelitis during the years 2002-2012. The children underwent full neurological examinations, along with comprehensive neurocognitive and behavioral assessments. RESULTS: Twenty-six (61%) children had different degrees of neurological sequelae after a mean follow-up of 5.5 ± 3.5 years. The most common residual impairment included attention-deficit hyperactivity disorder (44%), behavioral problems (32%), and learning disabilities (21%). Five (12%) children had a full-scale IQ of 70 or less, compared to 2.2% in the general population. CONCLUSIONS: Neurocognitive sequelae were found even in children who were considered as fully recovered at the time of discharge. Risk factors for severe neurological sequelae were older age at diagnosis and male gender. We suggest neuropsychological testing and long-term follow-up for all children with acute disseminated encephalomyelitis, even in the absence of neurological deficits at discharge.

Long-term motor and cognitive outcome of acute encephalitis.

OBJECTIVES: To examine the long-term motor and neurocognitive outcome of children with acute encephalitis and to look at possible prognostic factors. METHODS: Children who were treated for acute encephalitis in 2000-2010 were reevaluated. All children and their parents were interviewed by using structured questionnaires, and the children underwent full neurologic examinations, along with comprehensive neurocognitive, attention, and behavioral assessments. RESULTS: Of the 47 children enrolled, 1 died and 29 had neurologic sequelae, including motor impairment, mental retardation, epilepsy, and attention and learning disorders. Children with encephalitis had a significantly higher prevalence of attention-deficit/hyperactivity disorder (50%) and learning disabilities (20%) compared with the reported rate (5%-10%) in the general population of Israel (P < .05) and lower IQ scores. Lower intelligence scores and significantly impaired attention and learning were found even in children who were considered fully recovered at the time of discharge. Risk factors for long-term severe neurologic sequelae were focal signs in the neurologic examination and abnormal neuroimaging on admission, confirmed infectious cause, and long hospital stay. CONCLUSIONS: Encephalitis in children may be associated with significant long-term neurologic sequelae. Significant cognitive impairment, attention-deficit/hyperactivity disorder, and learning disabilities are common, and even children who were considered fully recovered at discharge may be significantly affected. Neuropsychological testing should be recommended for survivors of childhood encephalitis.