Late Adverse Effects after Treatment for Childhood Acute Leukemia.

The aim of this review is to raise awareness and knowledge among healthcare professionals and policymakers about late adverse effects in survivors of childhood leukemia. With contemporary treatment, over 90% of children with acute lymphoblastic leukemia (ALL) and over 60% with acute myeloid leukemia (AML) are cured. Large cohort studies demonstrate that 20% of ALL and most AML survivors have at least one chronic health condition by 20-25 years after diagnosis. These are life-changing or threatening in some survivors and contribute to increased premature mortality. We describe the frequency, causes, clinical features, and natural history of the most frequent and severe late adverse effects in childhood leukemia survivors, including subsequent malignant neoplasms, metabolic toxicity, gonadotoxicity and impaired fertility, endocrinopathy and growth disturbances, bone toxicity, central and peripheral neurotoxicity, cardiotoxicity, psychosocial late effects, accelerated ageing and late mortality. The wide range of late effects in survivors of haemopoietic stem cell transplant is highlighted. Recent developments informing the approach to long-term survivorship care are discussed, including electronic personalized patient-specific treatment summaries and care plans such as the Survivor Passport (SurPass), surveillance guidelines and models of care. The importance of ongoing vigilance is stressed given the increasing use of novel targeted drugs with limited experience of long-term outcomes. CONCLUSION: It is vital to raise awareness of the existence and severity of late effects of childhood leukemia therapy among parents, patients, health professionals, and policymakers. Structured long-term surveillance recommendations are necessary to standardize follow-up care.

Diagnostic Performance of F-18 FDG PET/CT in the Detection of Recurrent Colorectal Cancer: Correlation with Biochemical Markers and Conventional Imaging Modalities.

Background/Objectives: Although the role of PET/CT imaging is well established in oncology, its diagnostic value in routine monitoring for recurrent colorectal cancer (CRC) is still controversial. The aim was to evaluate the diagnostic value of F-18 FDG PET/CT in detecting recurrent CRC in correlation with CEA, CA 19-9 levels, and conventional imaging modalities (CIM). Methods: Between 2009 and 2023, a retrospective study was performed including 134 CRC patients referred for PET/CT imaging on the suspicion of recurrence, based on elevated CEA and/or CA 19-9 and/or equivocal CIM findings. According to our institution's Tumor Board CRC protocol, after the initial treatment, which was dependent on the TNM stage (neoadjuvant therapy, primary resection, or adjuvant treatment), patients underwent a standard 5-year surveillance including CEA and CA 19-9 measurements, CIM, and colonoscopy, every six months. The statistics, including univariate and multivariate analyses were conducted using the IBM SPSS 20.0 statistical software. p-values < 0.05 were considered statistically significant. Results: Recurrent CRC was confirmed in 54/134 (40.3%) patients with elevated tumor markers. PET/CT showed high diagnostic performance in detecting recurrent CRC with sensitivity, specificity, PPV, NPV, and accuracy of 94.4%, 82.5%, 78.5%, 95.7%, and 87.3%, respectively. The CEA showed a high sensitivity of 98.1% but both low specificity and accuracy of 15% and 48.5%, respectively. The sensitivity, specificity, and accuracy for CA 19-9 and CIM for diagnosis of CRC recurrence were 44.4%, 67.5%, 58.2%, and 51.9%, 98.8%, 79.9%, respectively. The AUC for PET/CT, elevated CEA levels, CIM, and elevated CA 19-9 levels was 0.885 (95% CI: 0.824-0.946; p < 0.001), 0.844 (95% CI: 0.772-0.916; p < 0.001), 0.753 (95% CI: 0.612-0.844; p < 0.001), and 0.547 (95% CI: 0.442-0.652; p = 0.358), respectively. Univariate analysis showed that both PET/CT and CIM positive results were highly associated with CRC recurrence (p < 0.001 and p < 0.001, respectively). At the same time, gender, mucinous tumor type, presence of initial lymph node metastasis (N+), and presence of initial distant metastasis (M+) had no significance (p = 0.211, p = 0.158, p = 0.583, and p = 0.201, respectively). Our multivariate analysis showed that independent predictors for CRC recurrence are positive PET/CT scans (p < 0.001), positive CIM results (p = 0.001), and elevated CA 19-9 levels (p = 0.023). Although CA 19-9 was not detected as a statistically significant predictor in the univariate analysis (p = 0.358), in a multivariate analysis it was recognized as a significant predicting factor in detecting the CRC recurrence (p = 0.023). Conclusions: F-18 FDG PET/CT showed high diagnostic efficacy in CRC recurrence detection, in correlation with CEA levels, CA 19-9 levels, and CIM. This imaging modality should be routinely integrated into the post-operative follow-op in patients with elevated tumor markers.

Parenteral iron therapy in children with iron deficiency anemia.

Iron deficiency anemia (IDA) continues to be a global public health problem. Oral iron is the universally accepted first-line therapy, and most children have a prompt and favorable response to oral formulations. In subsets of children who fail to respond due to intolerance, poor adherence, or inadequate intestinal absorption, parenteral iron is indicated. Despite numerous studies in adults with IDA of diverse etiologies, pediatric studies on parenteral iron use are very limited. Although mostly retrospective and small, these studies have documented the efficacy and safety profile of intravenous iron formulations. In this editorial the author comments on the most important published data and underscores the need to seriously consider parenteral iron use in children unresponsive to oral therapy.

Panhypopituitarism caused by a suprasellar germinoma: A case report.

BACKGROUND: Suprasellar germinomas are rare intracranial tumors frequently associated with permanent endocrine disorders. We present the clinical picture, treatment, and complications of suprasellar germinoma at pediatric age which, besides being life-threatening, has lifelong endocrinological consequences. CASE SUMMARY: A 12-year-old female patient was presented having had intensive headaches for three weeks and visual disturbances for six months. An ophthalmological examination revealed bilateral papilledema and a marked loss of vision. Emergency brain magnetic resonance imaging (MRI) showed a suprasellar tumor, involving the infundibulum and the optic chiasm, extending to the third ventricle. Laboratory tests confirmed decreased levels of thyroxine, cortisol, gonadotropins, and insulin-like growth factor 1. Maximal tumor reduction was performed, and immunohistopathology established the diagnosis of suprasellar germinoma. MRI of the spine and cerebrospinal fluid cytology confirmed the localized disease. Adjuvant chemotherapy and radiotherapy were performed according to the SIOP CNS GCT II protocol. A post-treatment MRI showed no residual tumor, but pituitary function had not recovered. Three and a half years after the end of the treatment, the patient is in a complete remission, requiring hormonal replacement therapy, continuous education, and psychological support. CONCLUSION: This complex case highlights the importance of timely diagnosis, a multidisciplinary approach, and close follow-up in children with suprasellar germinomas.

Alterations of Nutritional Status in Children and Adolescents with Acute Lymphoblastic Leukemia.

Malnutrition is often observed in pediatric cancer patients and has been recognized as a risk factor for relapse and survival. Maintaining an appropriate nutritional status during anticancer treatment has, therefore, been more and more frequently perceived as an additional requirement for optimal therapy outcomes. The aim of our study was to establish alterations of nutritional status in 26 children and adolescents treated for acute lymphoblastic leukemia (ALL) at the Children's Hospital in Zagreb, Croatia, between 2016 and 2021, by using anthropometric measures and serum albumin levels. The majority of patients (53.8% female, median 4 years, 52.2% intermediate-risk leukemia group) had normal weight at the beginning of chemotherapy. The percentage of overweight/obese patients increased from 4.2% at diagnosis to 37.5% at the end of intensive therapy. Apart from a significant increase in body weight (BW) and body mass index (BMI) for age, a notable decline in body height/body length (BH/BL) for age in the observed period was recorded, especially in high-risk leukemia patients. The alterations in serum albumin values were not significant, nor was their correlation with BMI. Dietary consultation was offered to all patients, while children with a decline in BMI and BH/BL received additional nutritional support.

Management of Childhood Iron Deficiency Anemia in a Developed Country-A Multi-Center Experience from Croatia.

Iron deficiency anemia (IDA) continues to be a global public health concern, mostly in the developing countries. However, precise epidemiological data on childhood IDA in Croatia are lacking. In order to establish its frequency, underlying etiologies, the rationale for tertiary care visits, diagnostic practices, and current treatment regimens of IDA, medical records of children referred to pediatric hematologists for iron deficiency in a five-year period at tertiary institutions (Zagreb, Rijeka, Split, Osijek) throughout Croatia were retrospectively analyzed. Eight hundred and sixty-four children, predominately of preschool age, were referred mainly by the primary care pediatricians, who, in general, performed basic diagnostics but failed to initiate oral iron therapy in half of the patients. Approximately one-third of patients were symptomatic, with inadequate nutrition prevailing as underlying etiology. Dextriferron was the preferred iron formulation among hematologists, with a median dose of 5 mg/kg, with acceptable compliance rates (63.5-93.2%). Hospital admission rates varied among the centers (9.4-35%), and so did transfusion policies (6.4-22.9%). The greatest difference was observed in the frequency of parenteral iron administration (0.3-21.5%). In conclusion, the burden of childhood IDA, even in a high-income country, remains substantial, necessitating consistent implementation of national guidelines and additional education of primary health care providers.

Deep convolutional neural network algorithm for the automatic segmentation of oral potentially malignant disorders and oral cancers.

This study aimed to develop an algorithm to automatically segment the oral potentially malignant diseases (OPMDs) and oral cancers (OCs) of all oral subsites with various deep convolutional neural network applications. A total of 510 intraoral images of OPMDs and OCs were collected over 3 years (2006-2009). All images were confirmed both with patient records and histopathological reports. Following the labeling of the lesions the dataset was arbitrarily split, using random sampling in Python as the study dataset, validation dataset, and test dataset. Pixels were classified as the OPMDs and OCs with the OPMD/OC label and the rest as the background. U-Net architecture was used and the model with the best validation loss was chosen for the testing among the trained 500 epochs. Dice similarity coefficient (DSC) score was noted. The intra-observer ICC was found to be 0.994 while the inter-observer reliability was 0.989. The calculated DSC and validation accuracy across all clinical images were 0.697 and 0.805, respectively. Our algorithm did not maintain an excellent DSC due to multiple reasons for the detection of both OC and OPMDs in oral cavity sites. A better standardization for both 2D and 3D imaging (such as patient positioning) and a bigger dataset are required to improve the quality of such studies. This is the first study which aimed to segment OPMDs and OCs in all subsites of oral cavity which is crucial not only for the early diagnosis but also for higher survival rates.

Melatonin Mitigates iNOS-Related Effects of HEMA and Camphorquinone in Human Dental Pulp Cells: Relevance for Postoperative Sensitivity Mechanism in Type 2 Diabetes.

High elution and diffusion of 2-hydroxylethyl methacrylate (HEMA) and camphorquinone (CQ) through dentinal tubules may induce pulp injury and postoperative sensitivity. We aimed to investigate the melatonin protective effect in HEMA- and CQ-treated human dental pulp cells (hDPCs) as well as its relevance in a mechanism for postoperative sensitivity in diabetic patients. hDPCs were exposed to HEMA (5 mM) and/or CQ (1 mM) in the absence and presence of melatonin (MEL) (0.1 mM and 1 mM). Heme oxygenase-1 (HMOX1), NADPH oxidase-4 (NOX4), BCL-2-associated X-protein (BAX), B-cell lymphoma-2 (BCL-2) and caspase-3 (CASP3) gene expression levels, and superoxide dismutase (SOD) activity were measured in hDPCs while inducible nitric oxide synthase (iNOS) and melatonin protein expression were measured in human dental pulp as well, by RT-PCR, by ELISA, and spectrophotometrically. Bioinformatic analyses were performed by using the ShinyGO (v.0.75) application. Type 2 diabetic patients showed a higher incidence of postoperative sensitivity and lower melatonin and higher iNOS content in dental pulp tissue compared with non-diabetic patients. Melatonin, when co-added in hDPC culture, reverses HEMA and CQ cytotoxic effects via anti-apoptotic and anti-inflammatory/antioxidant iNOS-related effects. Enrichment analyses showed that genes/proteins, altered by HEMA and CQ and normalized by melatonin, are the most prominently overrepresented in type 2 diabetes mellitus pathways and that they share subcellular localization in different oligomeric protein complexes consisting of anti- and pro-apoptotic regulators. This is the first evidence of the ability of melatonin to counteract iNOS-mediated inflammatory and stress effects in HEMA- and CQ-treated hDPCs, which could be of significance for the modulation of presently observed immediate postoperative sensitivity after composite restoration in type 2 diabetic patients.

NUT Carcinoma in Children and Adolescents: The Expert European Standard Clinical Practice Harmonized Recommendations.

BACKGROUND AND AIMS: Nuclear protein of the testis ( NUT ) carcinoma (NC) is a rare and highly aggressive tumor mainly occurring in adolescents and young adults, defined by the presence of a somatic NUTM1 rearrangement. The aim is to establish internationally harmonized consensus recommendations for the diagnosis and treatment of adolescents and young adults with NC in the framework of the European Reference Network for Paediatric Oncology. METHODS: The European Cooperative Study Group for Pediatric Rare Tumors developed recommendations according to the Consensus Conference Standard Operating procedure methodology and reviewed by external "experts." No evidence of level I to II exists. Recommendations were developed based on published prospective (level III), but more frequently retrospective series (level IV), case reports (level V), and personal expertise (level V). In addition, "strength" of recommendations were categorized by grading (grade A to E). RESULTS: Histology is mandatory for the diagnosis of NC, including immunolabeling with anti-NUT antibodies and molecular biology ( NUTM1 rearrangement) (level V; grade A). Treatment of NC usually combines aggressive approaches in multimodal regimens. Chemotherapy should be considered as first-line treatment (neoadjuvant vincristine-adriamycin-ifosfamide/cisplatin-adriamycin-ifsofamide or vincristine-doxorubicin-cyclophosphamide/ifosfamide-etoposide) for unresectable or metastatic tumor (ie, 3 courses), rapidly followed by local treatment (level IV; grade B). Referral to a specialized surgical oncology center is highly recommended (level V; grade A). In localized NC, a complete microscopic surgical resection should be attempted whenever and as soon as possible, followed by primary irradiation (60 to 70 Gy) and involved lymph nodes area (level IV; grade B). For head and neck tumors, a systematic neck dissection might be considered, even if N0 (level V; grade C). Adjuvant postirradiation chemotherapy is recommended, for a total of 9 to 12 courses (level IV; grade B). For first-line resected tumors, concomitant adjuvant chemotherapy to radiotherapy may be discussed (level IV; grade B). Targeted therapies and immunotherapeutic regimens should be delivered in the setting of prospective trials (level V; grade B). CONCLUSIONS: This project leads to a consensus strategy based on international experience with this very rare disease.

Inherited Thrombophilia and Risk of Thrombosis in Children with Cancer: a Single-center Experience.

OBJECTIVES: Thrombosis is an increasingly recognized complication of childhood malignancy and its treatment. The incidence and etiology of pediatric cancer-related thrombosis is still not well understood. The aim of this study was to evaluate the prevalence of common prothrombotic genetic conditions in children with cancer, the frequency of thrombosis, and the role of inherited thrombophilia in the development of thrombosis in a pediatric oncology population. PATIENTS AND METHODS: Forty-seven children (36 treated for hematological malignancies and 11 for solid tumors) with a median age of 8.8. years (range 0.4 - 19.3 years) were included in the study. Genetic polymorphisms of Factor V Leiden (G1691A), prothrombin G20210A, and methylenetetrahydrofolate reductase (MTHFR) C677T were determined by real-time polymerase chain reaction-based DNA analysis. RESULTS: Four (8.5%) patients were heterozygous for Factor V Leiden, 3 (6.4%) were heterozygous for prothrombin G20210A mutation, and 3 (6.4%) were homozygous for MTHFR C677T mutation. All patients had implanted central venous catheters. Four (8.5%) children had documented thrombosis, three of which were in the upper venous system. Two of the four patients with thrombosis had Factor V Leiden heterozygosity. CONCLUSIONS: Thrombosis is an important complication of childhood cancer. The risk of thrombosis may be increased in patients with Factor V Leiden. In the absence of consensus guidelines, our results support the recommendation for thrombophilia screening in children with cancer.

Acetylsalicylic-acid (ASA) regulation of osteo/odontogenic differentiation and proliferation of human dental pulp stem cells (DPSCs) in vitro.

OBJECTIVE: The study aimed to investigate acetylsalicylic acid (ASA) effects on osteo/odontogenic differentiation and proliferation of dental pulp stem cells (DPSCs) in vitro and the potential involvement of adenosine monophosphate-activated protein kinase (AMPK) pathway in these processes. DESIGN: DPSCs were isolated from third molars pulp tissues of five patients and grown in osteogenic medium alone or supplemented with ASA. Expression of DPSCs markers was tested by flow-cytometry. Cytotoxicity of ASA at concentrations of 10, 50 and 100 µg/ml was tested by MTT and NR assays. Osteo/odontogenic differentiation was analyzed via alizarin red staining and ALP activity. Quantitative PCR (qPCR) was used for osteo/odontogenic markers' (DSPP, BMP2, BMP4, BSP, OCN and RUNX2) and c-Myc expression analysis. AMPK inhibition of ASA-induced osteo/odontogenesis was tested by qPCR of selected markers (DSPP, OCN and RUNX2). RESULTS: Cytotoxicity assays showed that only the highest ASA dose decreased cell viability (89.1 %). The smallest concentration of ASA applied on DPSCs resulted in a remarkable enhancement of osteo/odontogenic differentiation, as judged by increased mineralized nodules' formation, ALP activity and gene expression of analyzed markers (increase between 2 and 30 folds), compared to untreated cells. ASA also increased DPSCs proliferation. Interestingly, AMPK inhibition per se upregulated DSPP, OCN and RUNX2; the gene upregulation was higher when ASA treatment was also included. c-Myc expression level decreased in cultures treated with ASA, indicating undergoing differentiation processes. CONCLUSIONS: Low concentrations of ASA (corresponding to the standard use in cardiovascular patients), were shown to stimulate osteo/odontogenic differentiation of dental pulp stem cells.

Primary lung carcinoma in children and adolescents: An analysis of the European Cooperative Study Group on Paediatric Rare Tumours (EXPeRT).

BACKGROUND: Primary lung carcinoma is an exceptionally rare childhood tumour, as per definition of the European Cooperative Study Group on Paediatric Rare Tumours (EXPeRT), with an incidence of 0.1-0.2/1,000,000 per year. Little is known about the clinical characteristics of children with primary lung carcinoma, a gap which this joint analysis of the EXPeRT group aimed to fill. PATIENTS AND METHODS: We performed a retrospective case series of children (aged 0-18 years) with primary lung carcinoma, as collected through the EXPeRT databases between 2000 and 2021. We recorded relevant clinical characteristics including treatment and outcome. RESULTS: Thirty-eight patients were identified with a median age of 12.8 years at diagnosis (range: 0-17). Mucoepidermoid carcinoma (MEC) was the most frequent entity (n = 20), followed by adenocarcinoma (n = 12), squamous cell carcinoma (n = 4), adenosquamous carcinoma (n = 1) and small-cell lung cancer (n = 1). Patients with MEC presented rarely with lymph node metastases (2/20 cases). Overall, 19/20 patients achieved long-lasting remission by surgical resection only. Patients with other histologies often presented in advanced stages (14/18 TNM stage IV). With multimodal treatment, 3-year overall survival was 52% ± 13%. While all patients with squamous cell carcinoma died, the 12 patients with adenocarcinoma had a 3-year overall survival of 64% ± 15%. CONCLUSIONS: Primary lung carcinomas rarely occur in children. While the outcome of children with MEC is favourable with surgery alone, patients with other histotypes have a poor prognosis, despite aggressive treatment, highlighting the need to develop new strategies for these children, such as mutation-guided treatment.

Childhood cancer survivorship care during the COVID-19 pandemic: an international report of practice implications and provider concerns.

PURPOSE: Long-term follow-up (LTFU) care is essential to optimise health outcomes in childhood cancer survivors (CCS). We aimed to assess the impact of the COVID-19 pandemic on LTFU services and providers. METHODS: A COVID-19 working group within the International Late Effects of Childhood Cancer Guideline Harmonization Group (IGHG) distributed a questionnaire to LTFU service providers in 37 countries across Europe, Asia, North America, Central/South America, and Australia. The questionnaire assessed how care delivery methods changed during the pandemic and respondents' level of worry about the pandemic's impact on LTFU care delivery, their finances, their health, and that of their family and friends. RESULTS: Among 226 institutions, providers from 178 (79%) responded. Shortly after the initial outbreak, 42% of LTFU clinics closed. Restrictions during the pandemic resulted in fewer in-person consultations and an increased use of telemedicine, telephone, and email consultations. The use of a risk assessment to prioritise the method of LTFU consultation for individual CCS increased from 12 to 47%. While respondents anticipated in-person consultations to remain the primary method for LTFU service delivery, they expected significantly increased use of telemedicine and telephone consultations after the pandemic. On average, respondents reported highest levels of worry about psychosocial well-being of survivors. CONCLUSIONS: The pandemic necessitated changes in LTFU service delivery, including greater use of virtual LTFU care and risk-stratification to identify CCS that need in-person evaluations. IMPLICATIONS FOR CANCER SURVIVORS: Increased utilisation of virtual LTFU care and risk stratification is likely to persist post-pandemic.

Childhood leukemia and non-Hodgkin's lymphoma survivors lack knowledge about their past disease and possible late effects. I-BFM ELTEC study with Chilean and Croatian participation.

PURPOSE: Late effects in childhood cancer survivors are a major cause of morbidity and mortality. The objective was to establish knowledge about the disease, late effects, self-care practices, application of health knowledge/education, sources of information, and biopsychosocial impact of cancer, and compare the results of Chile and Croatia. METHODS: One-hundred-and-seventy-one, 5-year survivors who were treated for leukemia or non-Hodgkin's lymphoma responded to a questionnaire (119 in Chile and 52 in Croatia). The questionnaire was reviewed by BFM-ELTEC. RESULTS: Health knowledge about past diagnosis and general treatment had 96% Chilean and 85% Croatian survivors. Ninety percent of Chilean and 73% of Croatian survivors were unaware of possible late effects, and half did not know which specialist to visit for follow-up. Forty-six percent of Chilean and 35% of Croatian survivors knew about healthy lifestyles, but most did not practice them. The 74% of Chileans and 87% of Croatian survivors recalled having received health education during treatment. About 50% of survivors in both groups were afraid or anguish, but it was also a growth experience for 60% of Chilean and 42% of Croatian survivors. Eighty-seven percent Chilean and 77% Croatian survivors considered themselves physically independent, while 76% and 75% felt psychologically independent, respectively. CONCLUSION: A significant lack of knowledge about the specific treatment, late effects, and future health in both countries was detected. They did not achieve significant learning with the education received. Psychological sequelae were found that are important to prevent.

Salivary VEGF and post-extraction wound healing in type 2 diabetic immediate denture wearers.

OBJECTIVE: Oral wound healing in healthy could be promoted by VEGF in saliva, and immediate denture wearing, but data in type 2 diabetes are lacking. Aims were to investigate the timeline of extraction wound healing in diabetic participants wearing immediate dentures and its correlation to salivary VEGF, as well as to examine the impact of the palatal plate on tissue VEGF during palatal wound healing in rat diabetic model. MATERIAL AND METHODS: Healthy (42) and type 2 diabetic (36) denture wearers, candidates for teeth extractions were included. Extraction wound healing was followed via measurements of socket closure, gingival hyperaemia, pain and presence of necrosis on 3rd, 7th, 14th and on 21st-day post-extraction. Salivary VEGF was measured before and on the 3rd and 21st day after the extraction. In streptozotocin-induced diabetic (30) as well as non-diabetic rats (30), tissue VEGF was measured in palatal wounds healing under or without a palatal plate. RESULTS: Type 2 diabetic prosthetic patients exhibit delayed socket closure, with pronounced hyperaemia, pain and necrosis. Salivary VEGF is increased in diabetes and positively correlates to socket closure while negatively with pain on 21st day after the extraction. Palatal incision induced VEGF increase in non-diabetic and diabetic, but less pronounced in diabetic rats. Wound healing under the palatal plate exhibit higher tissue VEGF. CONCLUSION: Type 2 diabetes-induced increase in salivary VEGF may mitigate diabetes-induced detrimental effects on extraction wound healing. Lack of adequate tissue VEGF response to injury may underly dysregulation of diabetic oral wound healing.

Pancreatoblastoma in children: EXPeRT/PARTNER diagnostic and therapeutic recommendations.

Pancreatoblastoma (PBL) is a rare malignant epithelial neoplasm that affects typically young children. Signs related to advanced upper-abdominal tumor accompanied by elevated serum α-fetoprotein levels in a young child suggest PBL, however histopathological confirmation is mandatory. The mainstay of the treatment is a complete surgical resection. Unresectable and/or metastatic PBL may become amenable to complete delayed surgery after neoadjuvant chemotherapy. This manuscript presents the international consensus recommendations for the diagnosis and treatment of children with PBL, established by the European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT) within the EU-funded PARTNER (Paediatric Rare Tumors Network - European Registry) project.

Facing the challenges of very rare tumors of pediatric age: The European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT) background, goals, and achievements.

It has become increasingly clear in recent years that we need to develop ad hoc strategies to combat very rare tumors (VRT) of pediatric age. In 2008, several schemes being run in different countries were pooled together to create the European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT) project: a cooperative study group that aimed to promote research in the relatively uncharted territory of rare tumors of pediatric age. EXPeRT members were able to activate different levels of cooperation to achieve their goals, and to obtain dedicated funding by participating in EU-financed projects. Their experiences emphasize the merits of networking, seeking new partnerships, joining forces, and pooling resources to extend the reach of research efforts, and ultimately improve the quality of patient care. Between 2018 and 2021, the EXPeRT has been active in establishing the Pediatric Rare Tumors Network - European Registry (PARTNER). This project had the main purposes of building a European common registry of pediatric VRT, but also the major task of developing diagnostic and treatment guidelines for VRT (or at least part of them). These clinical recommendations are the subject of a series of papers on Pediatric Blood and Cancer.

Salivary gland carcinoma in children and adolescents: The EXPeRT/PARTNER diagnosis and treatment recommendations.

Salivary gland carcinomas (SGCs) are rare during childhood and adolescence. Consequently, no standardized recommendations for the diagnosis and therapeutic management of pediatric SGC are available, and pediatric oncologists and surgeons generally follow adult guidelines. Complete surgical resection with adequate margins constitutes the cornerstone of treatment. However, the indications and modalities of adjuvant therapy remain controversial and may be challenging in view of the potential long-term toxicities in the pediatric population. This paper presents the consensus recommendations for the diagnosis and treatment of children and adolescents with SGCs, established by the European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT) within the EU-funded PARTNER project (Paediatric Rare Tumours Network - European Registry).