Indeterminate pulmonary nodules in non-rhabdomyosarcoma soft tissue sarcoma: A study of the European paediatric Soft Tissue Sarcoma Study Group.

BACKGROUND: The aim of this study was to assess the clinical impact of indeterminate pulmonary nodules (no more than four pulmonary nodules of less than 5 mm or one nodule measuring between 5 and less than 10 mm by computed tomography [CT]) in children and adolescents with adult-type non-rhabdomyosarcoma soft tissue sarcoma (NRSTS) at diagnosis. METHODS: Patients with NRSTS treated in 11 centers as part of the European paediatric Soft Tissue Sarcoma Study Group (EpSSG) were retrospectively assessed. Local radiologists, blinded to clinical information except for patients' age and tumor histotype, reviewed the chest CT at diagnosis and filled out a case report form. Because patients with or without indeterminate nodules in the EpSSG NRSTS 2005 study received the same type of treatment, event-free survival (EFS) and overall survival (OS) between groups by log-rank test were compared. RESULTS: Overall, 206 patients were examined: 109 (52.9%) were without any nodules, 78 (38%) had at least one indeterminate nodule, and 19 (9.2%) had nodules meeting the definition of metastases, which were then considered to be misclassified and were excluded from further analyses. Five-year EFS was 78.5% (95% CI, 69.4%-85.1%) for patients without nodules and 69.6% (95% CI, 57.9%-78.7%) for patients with indeterminate nodules (p = .135); 5-year OS was 87.4% (95% CI, 79.3%-92.5%) and 79.0% (95% CI, 67.5%-86.8%), respectively (p = .086). CONCLUSIONS: This study suggests that survival does not differ in otherwise nonmetastatic patients with indeterminate pulmonary nodules compared to nonmetastatic patients without pulmonary nodules. PLAIN LANGUAGE SUMMARY: Radiologists should be aware of the classification of indeterminate pulmonary nodules in non-rhabdomyosarcoma soft tissue sarcomas and use it in their reports. More than a third of patients with non-rhabdomyosarcoma soft tissue sarcoma can be affected by indeterminate pulmonary nodules. Indeterminate pulmonary nodules do not significantly affect the overall survival of pediatric patients with non-rhabdomyosarcoma soft tissue sarcoma.

Correlation of gene expression with magnetic resonance imaging features of retinoblastoma: a multi-center radiogenomics validation study.

OBJECTIVES: To validate associations between MRI features and gene expression profiles in retinoblastoma, thereby evaluating the repeatability of radiogenomics in retinoblastoma. METHODS: In this retrospective multicenter cohort study, retinoblastoma patients with gene expression data and MRI were included. MRI features (scored blinded for clinical data) and matched genome-wide gene expression data were used to perform radiogenomic analysis. Expression data from each center were first separately processed and analyzed. The end product normalized expression values from different sites were subsequently merged by their Z-score to permit cross-sites validation analysis. The MRI features were non-parametrically correlated with expression of photoreceptorness (radiogenomic analysis), a gene expression signature informing on disease progression. Outcomes were compared to outcomes in a previous described cohort. RESULTS: Thirty-six retinoblastoma patients were included, 15 were female (42%), and mean age was 24 (SD 18) months. Similar to the prior evaluation, this validation study showed that low photoreceptorness gene expression was associated with advanced stage imaging features. Validated imaging features associated with low photoreceptorness were multifocality, a tumor encompassing the entire retina or entire globe, and a diffuse growth pattern (all p < 0.05). There were a number of radiogenomic associations that were also not validated. CONCLUSIONS: A part of the radiogenomic associations could not be validated, underlining the importance of validation studies. Nevertheless, cross-center validation of imaging features associated with photoreceptorness gene expression highlighted the capability radiogenomics to non-invasively inform on molecular subtypes in retinoblastoma. CLINICAL RELEVANCE STATEMENT: Radiogenomics may serve as a surrogate for molecular subtyping based on histopathology material in an era of eye-sparing retinoblastoma treatment strategies. KEY POINTS: • Since retinoblastoma is increasingly treated using eye-sparing methods, MRI features informing on molecular subtypes that do not rely on histopathology material are important. • A part of the associations between retinoblastoma MRI features and gene expression profiles (radiogenomics) were validated. • Radiogenomics could be a non-invasive technique providing information on the molecular make-up of retinoblastoma.

Image-guided core-needle or surgical biopsy for neuroblastoma diagnosis in children: A systematic review and meta-analysis from the International Society of Pediatric Surgical Oncology (IPSO).

BACKGROUND: Image-guided core-needle biopsy (IGCNB) is a widely used and valuable clinical tool for tissue diagnosis of pediatric neuroblastoma. However, open surgical biopsy remains common practice even if children undergo more invasive and painful procedures. This review aims to determine the diagnostic accuracy and safety of IGCNBs in pediatric patients with neuroblastoma. METHODS: We conducted a systematic review of peer-reviewed original articles published between 1980 and 2023, by searching "pediatric oncology," "biopsy," "interventional radiology," and "neuroblastoma." Exclusion criteria were patients older than 18 years, studies concerning non-neurogenic tumors, case reports, and language other than English. Both the systematic review and meta-analysis were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. RESULTS: A total of 533 abstracts articles were analyzed. Of these, eight retrospective studies met inclusion criteria (490 infants, 270 surgical biopsies [SB], 220 image-guided biopsies). Tissue adequacy for primary diagnosis (SB: n = 265, 98%; IGCNB: n = 199, 90%; p = .1) and biological characterization (SB: n = 186, 95%; IGCNB: n = 109, 89%; p = .15) was similar with both biopsy techniques, while intraoperative transfusion rate (SB: n = 51, 22%; IGCNB: n = 12, 6%; p = .0002) and complications (%) (SB: n = 58, 21%; IGCNB: n = 14, 6%; p = .005) were higher with surgical biopsy. Length of stay was similar in both groups; however, no additional data about concurrent diagnostic or treatment procedures were available in the analyzed studies. CONCLUSIONS: IGCNB is a safe and effective strategic approach for diagnostic workup of NB and should be considered in preferance to SB wherever possible.

MRI Features for Identifying MYCN-amplified RB1 Wild-type Retinoblastoma.

Background MYCN-amplified RB1 wild-type (MYCNARB1+/+) retinoblastoma is a rare but clinically important subtype of retinoblastoma due to its aggressive character and relative resistance to typical therapeutic approaches. Because biopsy is not indicated in retinoblastoma, specific MRI features might be valuable to identify children with this genetic subtype. Purpose To define the MRI phenotype of MYCNARB1+/+ retinoblastoma and evaluate the ability of qualitative MRI features to help identify this specific genetic subtype. Materials and Methods In this retrospective, multicenter, case-control study, MRI scans in children with MYCNARB1+/+ retinoblastoma and age-matched children with RB1-/- subtype retinoblastoma were included (case-control ratio, 1:4; scans acquired from June 2001 to February 2021; scans collected from May 2018 to October 2021). Patients with histopathologically confirmed unilateral retinoblastoma, genetic testing (RB1/MYCN status), and MRI scans were included. Associations between radiologist-scored imaging features and diagnosis were assessed with the Fisher exact test or Fisher-Freeman-Halton test, and Bonferroni-corrected P values were calculated. Results A total of 110 patients from 10 retinoblastoma referral centers were included: 22 children with MYCNARB1+/+ retinoblastoma and 88 control children with RB1-/- retinoblastoma. Children in the MYCNARB1+/+ group had a median age of 7.0 months (IQR, 5.0-9.0 months) (13 boys), while children in the RB1-/- group had a median age of 9.0 months (IQR, 4.6-13.4 months) (46 boys). MYCNARB1+/+ retinoblastomas were typically peripherally located (in 10 of 17 children; specificity, 97%; P < .001) and exhibited plaque or pleomorphic shape (in 20 of 22 children; specificity, 51%; P = .011) with irregular margins (in 16 of 22 children; specificity, 70%; P = .008) and extensive retina folding with vitreous enclosure (specificity, 94%; P < .001). MYCNARB1+/+ retinoblastomas showed peritumoral hemorrhage (in 17 of 21 children; specificity, 88%; P < .001), subretinal hemorrhage with a fluid-fluid level (in eight of 22 children; specificity, 95%; P = .005), and strong anterior chamber enhancement (in 13 of 21 children; specificity, 80%; P = .008). Conclusion MYCNARB1+/+ retinoblastomas show distinct MRI features that could enable early identification of these tumors. This may improve patient selection for tailored treatment in the future. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Rollins in this issue.

Optic nerve thickening on high-spatial-resolution MRI predicts early-stage postlaminar optic nerve invasion in retinoblastoma.

OBJECTIVES: To assess the diagnostic accuracy of nerve thickening on MRI to predict early-stage postlaminar optic nerve invasion (PLONI) in retinoblastoma. Furthermore, this study aimed to incorporate measurements into a multiparametric model for radiological determination of PLONI. METHODS: In this retrospective multicenter case-control study, high-spatial-resolution 3D T2-weighted MR images were used to measure the distal optic nerve. Histopathology was the reference standard for PLONI. Two neuroradiologists independently measured the optic nerve width, height, and surface at 0, 3, and 5 mm from the most distal part of the optic nerve. Subsequently, PLONI was scored on contrast-enhanced T1-weighted and 3D T2-weighted images, blinded for clinical data. Optic nerve measurements with the highest diagnostic accuracy for PLONI were incorporated into a prediction model for radiological determination of PLONI. RESULTS: One hundred twenty-four retinoblastoma patients (median age, 22 months [range, 0-113], 58 female) were included, resulting in 25 retinoblastoma eyes with histopathologically proven PLONI and 206 without PLONI. ROC analysis of axial optic nerve width measured at 0 mm yielded the best area under the curve of 0.88 (95% confidence interval: 0.79, 0.96; p < 0.001). The optimal width cutoff was ≥ 2.215 mm, with a sensitivity of 84% (95% CI: 64, 95%) and specificity of 83% (95% CI: 75, 89%) for detecting PLONI. Combining width measurements with the suspicion of PLONI on MRI sequences resulted in a prediction model with an improved sensitivity and specificity of respectively up to 88% and 92%. CONCLUSION: Postlaminar optic nerve thickening can predict early-stage postlaminar optic nerve invasion in retinoblastoma. CLINICAL RELEVANCE STATEMENT: This study provides an additional tool for clinicians to help determine postlaminar optic nerve invasion, which is a risk factor for developing metastatic disease in retinoblastoma patients. KEY POINTS: • The diagnostic accuracy of contrast-enhanced MRI for detecting postlaminar optic nerve invasion is limited in retinoblastoma patients. • Optic nerve thickening can predict postlaminar optic nerve invasion. • A prediction model combining MRI features has a high sensitivity and specificity for detecting postlaminar optic nerve invasion.

French survey of sedation practices for pediatric magnetic resonance and computed tomography imaging.

BACKGROUND: Pediatric magnetic resonance imaging (MRI) and computed tompgraphy (CT) require patient immobility and therefore often require sedation or general anesthesia of patients. Consensus on these procedures is lacking in France. OBJECTIVE: Thus, the aim of this study was to describe the current sedation practices for pediatric MRI and CT in France. MATERIAL AND METHODS: From January 2019 to December 2019, an online questionnaire was delivered by electronic mail to a representative radiologist in 60 pediatric radiology centers registered by the French-speaking pediatric and prenatal imaging society. Questions included protocols, drugs used, monitoring and side effects. RESULTS: Representatives of 40 of the 60 (67%) radiology centers responded to the survey. Among them, 31 performed sedation including 17 (55%) centers where radiologists performed sedation without anesthesiologists present during the procedure. The premedication drugs were hydroxyzine (n = 8, 80%) and melatonin (n = 2, 20%), Sedation drugs used for children ages 0 to 6 years old were pentobarbital (n = 9, 60%), midazolam (n = 2, 13%), chloral hydrate (n = 2, 13%), diazepam (n = 1, 6.5%) and chlorpromazine (n = 1, 6.5%). A written sedation protocol was available in 10/17 (59%) centers. In 6/17 (35%) centers, no monitoring was used during the procedures. Blood pressure monitoring and capnography were rarely used (< 10%) and post-sedation monitoring was heterogeneous. No life-threatening adverse effect was reported, but 6 centers reported at least one incident per year. CONCLUSION: For half of the responding radiology centers, radiologists performed sedation alone in agreement with the local anesthesiology team. Sedation procedures and monitoring were heterogenous among centers. Adjustment and harmonization of the practices according to the capacity of each center may be useful.

Magnetic Resonance Imaging Can Reliably Differentiate Optic Nerve Inflammation from Tumor Invasion in Retinoblastoma with Orbital Cellulitis.

PURPOSE: To investigate the prevalence and magnetic resonance imaging (MRI) phenotype of retinoblastoma-associated orbital cellulitis. Additionally, this study aimed to identify postlaminar optic nerve enhancement (PLONE) patterns differentiating between inflammation and tumor invasion. DESIGN: A monocenter cohort study assessed the prevalence of orbital cellulitis features on MRI in retinoblastoma patients. A multicenter case-control study compared MRI features of the retinoblastoma-associated orbital cellulitis cases with retinoblastoma controls. PARTICIPANTS: A consecutive retinoblastoma patient cohort of 236 patients (311 eyes) was retrospectively investigated. Subsequently, 30 retinoblastoma cases with orbital cellulitis were compared with 30 matched retinoblastoma controls without cellulitis. METHODS: In the cohort study, retinoblastoma MRI scans were scored on presence of inflammatory features. In the case-control study, MRI scans were scored on intraocular features and PLONE patterns. Postlaminar enhancement patterns were compared with histopathologic assessment of postlaminar tumor invasion. Interreader agreement was assessed, and exact tests with Bonferroni correction were adopted for statistical comparisons. MAIN OUTCOME MEASURES: Prevalence of retinoblastoma-associated orbital cellulitis on MRI was calculated. Frequency of intraocular MRI features was compared between cases and controls. Sensitivity and specificity of postlaminar optic nerve patterns for detection of postlaminar tumor invasion were assessed. RESULTS: The MRI prevalence of retinoblastoma-associated orbital cellulitis was 6.8% (16/236). Retinoblastoma with orbital cellulitis showed significantly more tumor necrosis, uveal abnormalities (inflammation, hemorrhage, and necrosis), lens luxation (all P < 0.001), and a larger eye size (P = 0.012). The inflammatory pattern of optic nerve enhancement (strong enhancement similar to adjacent choroid) was solely found in orbital cellulitis cases, of which none (0/16) showed tumor invasion on histopathology. Invasive pattern enhancement was found in both cases and controls, of which 50% (5/10) showed tumor invasion on histopathology. Considering these different enhancement patterns suggestive for either inflammation or tumor invasion increased specificity for detection of postlaminar tumor invasion in orbital cellulitis cases from 32% (95% confidence interval [CI], 16-52) to 89% (95% CI, 72-98). CONCLUSIONS: Retinoblastoma cases presenting with orbital cellulitis show MRI findings of a larger eye size, extensive tumor necrosis, uveal abnormalities, and lens luxation. Magnetic resonance imaging contrast-enhancement patterns within the postlaminar optic nerve can differentiate between tumor invasion and inflammatory changes.

MRI Characteristics of Pediatric Renal Tumors: A SIOP-RTSG Radiology Panel Delphi Study.

BACKGROUND: The SIOP-Renal Tumor Study Group (RTSG) does not advocate invasive procedures to determine histology before the start of therapy. This may induce misdiagnosis-based treatment initiation, but only for a relatively small percentage of approximately 10% of non-Wilms tumors (non-WTs). MRI could be useful for reducing misdiagnosis, but there is no global consensus on differentiating characteristics. PURPOSE: To identify MRI characteristics that may be used for discrimination of newly diagnosed pediatric renal tumors. STUDY TYPE: Consensus process using a Delphi method. POPULATION: Not applicable. FIELD STRENGTH/SEQUENCE: Abdominal MRI including T1- and T2-weighted imaging, contrast-enhanced MRI, and diffusion-weighted imaging at 1.5 or 3 T. ASSESSMENT: Twenty-three radiologists from the SIOP-RTSG radiology panel with ≥5 years of experience in MRI of pediatric renal tumors and/or who had assessed ≥50 MRI scans of pediatric renal tumors in the past 5 years identified potentially discriminatory characteristics in the first questionnaire. These characteristics were scored in the subsequent second round, consisting of 5-point Likert scales, ranking- and multiple choice questions. STATISTICAL TESTS: The cut-off value for consensus and agreement among the majority was ≥75% and ≥60%, respectively, with a median of ≥4 on the Likert scale. RESULTS: Consensus on specific characteristics mainly concerned the discrimination between WTs and non-WTs, and WTs and nephrogenic rest(s) (NR)/nephroblastomatosis. The presence of bilateral lesions (75.0%) and NR/nephroblastomatosis (65.0%) were MRI characteristics indicated as specific for the diagnosis of a WT, and 91.3% of the participants agreed that MRI is useful to distinguish NR/nephroblastomatosis from WT. Furthermore, all participants agreed that age influenced their prediction in the discrimination of pediatric renal tumors. DATA CONCLUSION: Although the discrimination of pediatric renal tumors based on MRI remains challenging, this study identified some specific characteristics for tumor subtypes, based on the shared opinion of experts. These results may guide future validation studies and innovative efforts. LEVEL OF EVIDENCE: 3 Technical Efficacy Stage: 3.

How we approach paediatric renal tumour core needle biopsy in the setting of preoperative chemotherapy: A Review from the SIOP Renal Tumour Study Group.

The International Society of Paediatric Oncology Renal Tumour Study Group (SIOP-RTSG) advocate treating children with Wilms tumour (WT) with preoperative chemotherapy, whereas the Renal Tumor Committee of the Children's Oncology Group (COG) advocates primary nephrectomy (without biopsy) when feasible. Successive SIOP-RTSG trial protocols recommended pretreatment biopsy of children with unilateral tumours only where there were features to suggest an increased probability of a non-WT requiring a change in management. The UK experience in the SIOP WT 2001 trial showed that an alternate approach of performing biopsies on all children with renal tumour masses to determine histology at diagnosis rarely changes management, and can result in misdiagnosis (particularly patients in the age range typical for WT). Although a more selective approach to biopsy has been routine practice in all other countries participating in SIOP-RTSG trials, there was variation between national groups. To address this variation and provide evidence-based recommendations for the indications and recommended approach to renal tumour biopsy within the SIOP paradigm, an international, multidisciplinary working group of SIOP-RTSG members was convened. We describe the resulting recommendations of this group, which are to be incorporated in the ongoing SIOP-RTSG UMBRELLA study.

Clinical, pathologic, and molecular features of inflammatory myofibroblastic tumors in children and adolescents.

BACKGROUND: Inflammatory myofibroblastic tumors (IMT) are rare, intermediate malignant tumors harboring frequent somatic molecular rearrangements. The management of IMT has not been standardized. METHODS: A retrospective multicenter study was conducted on all pediatric patients treated for IMT between 2000 and 2019. RESULTS: This series included 39 cases of IMT, with a median age at diagnosis of 7 years (range 20 days to 16 years). Tumor location included pelvis-abdomen (n = 16), thorax (n = 14), head and neck (n = 7), and limbs (n = 2). One patient had metastatic disease. Immunochemistry showed 21/39 (54%) anaplastic lymphoma kinase (ALK)-positive tumors. Somatic tyrosine kinase rearrangement was present in 31/36 (86%) of the tumors analyzed: 21 ALK, five ROS1, and five NTRK. Immediate surgery was performed in 24 patients (62%), with adjuvant therapy for three patients. Delayed surgery after neoadjuvant therapy was possible in 10 cases. Exclusive systemic therapy was delivered to four patients; one patient with orbital IMT was managed by watchful waiting. After a median follow-up of 33 months (range 5-124), eight (20%) recurrences/progressions occurred after surgery (seven after primary surgery and one after delayed surgery), after a median interval of 7 months (range 2-21), all in thoracic locations. The 3-year overall and disease-free survivals were 96.8% (95% CI: 79.2%-94.0%) and 77.4% (95% CI: 59.6%-88.1%), respectively. Relapses/progressions were more common in patients with a thoracic primary (p < .001) or after incomplete surgery with no adjuvant therapy (p = .027). CONCLUSION: Surgery is effective in most cases of pediatric IMT. Systematic analysis of tyrosine kinase rearrangement is recommended. When the tumor is deemed only partially resectable to preserve organs and function, neoadjuvant therapy may be proposed to allow adequate conservative surgery.

Guidelines for magnetic resonance imaging in pediatric head and neck pathologies: a multicentre international consensus paper.

The use of standardized imaging protocols is paramount in order to facilitate comparable, reproducible images and, consequently, to optimize patient care. Standardized MR protocols are lacking when studying head and neck pathologies in the pediatric population. We propose an international, multicenter consensus paper focused on providing the best combination of acquisition time/technical requirements and image quality. Distinct protocols for different regions of the head and neck and, in some cases, for specific pathologies or clinical indications are recommended. This white paper is endorsed by several international scientific societies and it is the result of discussion, in consensus, among experts in pediatric head and neck imaging.

Nasopharyngeal carcinoma in children and adolescents: The EXPeRT/PARTNER diagnostic and therapeutic recommendations.

Nasopharyngeal carcinoma (NPC) is a rare pediatric tumor. Collaborative studies performed over the last decades showed improved results compared to historical data, but standardized guidelines for diagnosis and management of pediatric NPC are still unavailable. This study presents a European consensus guideline for the diagnosis and treatment of pediatric NPC developed by the European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT). Main recommendations include induction chemotherapy with cisplatin and 5-flurouracil, concomitant chemoradiotherapy in advanced disease, and to consider maintenance treatment with interferon beta (IFN-ß) for selected high-risk patients. Dose adjustments of radiotherapy based on response to induction chemotherapy may decrease the rates of long-term treatment-related complications that affect most of the survivors.

Is surveillance imaging in pediatric patients treated for localized rhabdomyosarcoma useful? The European experience.

BACKGROUND: After the completion of therapy, patients with localized rhabdomyosarcoma (RMS) are subjected to intensive radiological tumor surveillance. However, the clinical benefit of this surveillance is unclear. This study retrospectively analyzed the value of off-therapy surveillance by comparing the survival of patients in whom relapse was detected by routine imaging (the imaging group) and patients in whom relapse was first suspected by symptoms (the symptom group). METHODS: This study included patients with relapsed RMS after the completion of therapy for localized RMS who were treated in large pediatric oncology hospitals in France, the United Kingdom, Italy, and the Netherlands and who were enrolled in the International Society of Paediatric Oncology Malignant Mesenchymal Tumor 95 (1995-2004) study, the Italian Paediatric Soft Tissue Sarcoma Committee Rhabdomyosarcoma 96 (1996-2004) study, or the European Paediatric Soft Tissue Sarcoma Study Group Rhabdomyosarcoma 2005 (2005-2013) study. The survival times after relapse were compared with a log-rank test between patients in the imaging group and patients in the symptom group. RESULTS: In total, 199 patients with relapsed RMS were included: 78 patients (39.2%) in the imaging group and 121 patients (60.8%) in the symptom group. The median follow-up time after relapse was 7.4 years (interquartile range, 3.9-11.5 years) for survivors (n = 86); the 3-year postrelapse survival rate was 50% (95% confidence interval [CI], 38%-61%) for the imaging group and 46% (95% CI, 37%-55%) for the symptom group (P = .7). CONCLUSIONS: Although systematic routine imaging is the standard of care after RMS therapy, the majority of relapses were detected as a result of clinical symptoms. This study found no survival advantage for patients whose relapse was detected before the emergence of clinical symptoms. These results show that the value of off-therapy surveillance is controversial, particularly because repeated imaging may also entail potential harm.

Multicentre survey on patient dose in paediatric imaging and proposal for updated diagnostic reference levels for France. Part 2: plain radiography and diagnostic fluoroscopy.

OBJECTIVES: To report on a dose survey conducted by the French societies of radiology and paediatric imaging (SFR and SFIPP) and the French public service expert in nuclear and radiological risks (IRSN), and to suggest new diagnostic reference levels (DRLs) for paediatric plain radiography and diagnostic fluoroscopy. METHODS: Dose reports concerning four radiography procedures and three diagnostic fluoroscopy procedures performed in 2015-2016 on children aged 0-15 years were collected from 16 imaging departments on a voluntary basis. Air kerma-area product (PKA) was recorded for at least 10 patients per procedure, per centre and per age group. New DRLs were calculated as the 3rd quartiles of the distributions of the median values. RESULTS: Results from 2249 radiography examinations and 1235 diagnostic fluoroscopy procedures were obtained. A noticeable variability in patient exposure between facilities was observed in diagnostic fluoroscopy and to a lesser extent in plain radiography. DRLs are proposed for each procedure and each age group. CONCLUSIONS: This study showed that the applicable national DRLs in plain radiography were obsolete and its results have been recently used by the French authorities to update them. In diagnostic fluoroscopy, large differences of doses were observed, even among departments accustomed to paediatric procedures. The new national DRLs will be useful for optimising diagnostic practice. KEY POINTS: • New national diagnostic reference levels (DRLs) are proposed for several paediatric procedures in plain radiography and diagnostic fluoroscopy. • Even between departments accustomed to paediatric procedures, substantial differences of practice were observed, especially in diagnostic fluoroscopy.

Multicentre survey on patient dose in paediatric imaging and proposal for updated diagnostic reference levels for France. Part 1: computed tomography.

OBJECTIVES: To report on a dose survey conducted by the French societies of radiology and paediatric imaging (SFR and SFIPP) and the French public service expert in nuclear and radiological risks (IRSN), and to suggest new diagnostic reference levels (DRLs) for paediatric CT. METHODS: Dose reports concerning children aged 0-15 years and five CT procedures (brain, petrous bone, mediastinum, lung and abdomen-pelvis) performed in 2015-2016 were collected from 15 imaging departments on a voluntary basis. Volume CT dose index (CTDIvol) and dose-length product (DLP) were recorded for at least 10 patients per procedure, per centre and per age group. New DRLs were calculated as the 3rd quartiles of the distributions of the median values. RESULTS: Results from 3253 CT examinations were obtained. The exposure levels observed were much lower than for the previous surveys (2007-2008 and 2010-2013) and among the lowest values currently published. A good homogeneity between facilities was also observed. New DRLs are proposed for each procedure and age group. CONCLUSIONS: This new survey contributes to the continuing optimisation process in French paediatric CT practice. Its results have been recently used to update the national paediatric CT DRLs. KEY POINTS: • New national diagnostic reference levels (DRLs) are proposed for several paediatric CT procedures. • The DRLs proposed for brain, chest and abdomen-pelvis procedures are among the lowest published worldwide.

Pattern of loco-regional relapses and treatment in pediatric esthesioneuroblastoma: The French very rare tumors group (Fracture) contribution.

BACKGROUND: Esthesioneuroblastoma (ENB) is a rare neuroectodermal tumor that seldom occurs during childhood. Multimodal treatments are currently proposed, but the place of each therapy is still in debate. Our objective is to describe clinical evolution, especially the pattern of relapses and determine contributors to tumor progression. PROCEDURE: Medical charts of all children (≤18 years) affected by ENB treated in France from January 1990 to December 2015 were retrospectively analyzed. RESULTS: Eighteen patients were selected (10 males). Median age at diagnosis was 12.2 years (0.9-18). Tumor extension was Kadish stage A (n = 1), B (n = 3), C (n = 10), and D (n = 4). Hyams histological grades were I (n = 1), II (n = 3), III (n = 6), and IV (n = 6) (in two cases not defined). Initial cervical nodal spread was assessed by magnetic resonance imaging (n = 15), computed tomography scan (n = 16), fluorodeoxyglucose-positron emission tomography-computed tomography (n = 7), and cytological/histological analysis (n = 2). N1 stage was confirmed by imaging in two of 18 cases and one of two cases had cervical node dissection with neck irradiation (58 Gy). After a median follow-up of survivors of 7.6 years (3.8-17.9), 10 patients developed neuromeningeal progression, whereas no cervical nodal relapse occurred and only eight survived. Both 5-year overall and event-free survival rates were 44.4% (±11.7%). CONCLUSIONS: The poor prognosis is mainly related to neuromeningeal dissemination that should be considered during treatment strategy. However, cervical lymph node relapse is rare.

Craniofacial second primary tumors in patients with germline retinoblastoma previously treated with external beam radiotherapy: A retrospective institutional analysis.

BACKGROUND: The long-term survival of germline retinoblastoma patients is decreased due to the risk of second primary tumors (SPTs) that occur years after the diagnosis of retinoblastoma. This risk is related to genetic predisposition and other factors, such as the treatment of retinoblastoma by external beam radiotherapy (EBRT). PROCEDURE: We studied the incidence, risk factors, and prognosis of specific craniofacial SPTs developed within the margins of radiation field in a cohort of 209 patients with germline retinoblastoma treated with EBRT at our institution between 1977 and 2010. Clinical characteristics, survival, incidence, and histology of craniofacial SPTs were recorded. RESULTS: Fifty-three of the 209 patients developed 60 distinct craniofacial SPTs in irradiated field with a median time from EBRT of 16.9 years (4-35) and a median follow-up of 24.8 years (5.3-40). Osteosarcoma (33.3%) and undifferentiated sarcoma (23.3%) were the more prevalent histological entities. Benign tumors (16.7%) also occurred. The cumulative incidence of craniofacial SPTs reached 32.6% at 35 years after EBRT, and the median survival after diagnosis was five years. In our series, irradiation under 12 months of age, bilateral EBRT, or previous treatment of retinoblastoma with chemotherapy did not significantly increase the risk of craniofacial SPTs. CONCLUSIONS: This work presents a strong argument to avoid EBRT in the management of retinoblastoma and emphasizes the high risk and poor prognosis of specific craniofacial SPTs. This study also points to the question of the need and benefits of special programs for early detection of craniofacial SPTs in survivors of irradiated germline retinoblastoma.

Management of advanced uni- or bilateral retinoblastoma with macroscopic optic nerve invasion.

BACKGROUND: Retinoblastoma with macroscopic optic nerve (ON) invasion depicted by imaging at diagnosis remains a major problem and carries a poor prognosis. We sought to describe the treatment and outcome of these high-risk patients. METHODS: Retrospective mono-institutional clinical, radiological, and histological review of patients with uni- or bilateral retinoblastoma with obvious ON invasion, defined by radiological optic nerve enlargement (RONE) depicted by computed tomography scan or magnetic resonance imaging (MRI), was performed. RESULTS: Between 1997 and 2014, among the 936 patients with retinoblastoma treated at Institut Curie, 11 had detectable RONE. Retinoblastoma was unilateral in 10 and bilateral in one. Median age at diagnosis was 28 months (range, 11-96). ON enlargement extended to the orbital portion in three patients, to the optic canal in five, to the prechiasmatic portion in two, and to the optic chiasm in one. Nine patients received neoadjuvant chemotherapy and partial response was obtained in all. Enucleation was performed in 10/11 patients-by an anterior approach in three and by anterior and subfrontal approaches in seven. Three patients had a positive ON resection margin (2/3 after primary enucleation). All enucleated patients received adjuvant treatment (conventional chemotherapy: 10, high-dose chemotherapy: seven, radiotherapy: five). Leptomeningeal progression occurred in four patients. Seven are in first complete remission (median follow up: 8 years [3.5-19.4]). CONCLUSION: Neoadjuvant chemotherapy and microscopic complete resection have a pivotal role in the management of retinoblastoma with RONE. MRI is recommended for initial and pre-operative accurate staging. Surgery should be performed by neurosurgeons in case of posterior nerve invasion. Radiotherapy is required in case of incomplete resection.

Exploring heterogeneity of adrenal cortical tumors in children: The French pediatric rare tumor group (Fracture) experience.

INTRODUCTION: Pediatric adrenal cortical tumors are characterized by a wide spectrum of behavior. Questions remain regarding intermediate disease stages with isolated tumor rupture or relapse. OBJECTIVES: To describe clinical characteristics, treatment strategy, and outcome of patients depending on disease stage, tumor rupture, or in case of a refractory tumor, to discuss optimal management. MATERIAL AND METHODS: Pediatric patients with histological material reviewed and treated between 2000 and 2018 in 23 French oncology centers were included. RESULTS: Among 95 cases, 59% of patients had stage I tumors (n = 55), 16% had stage II tumors (n = 16), 19% had stage III tumors (n = 17), and 5% had stage IV tumors (n = 5) (missing data: 2). Overall, 27% of patients (n = 25) had an unfavorable histology. Initial tumor resection was performed for 90% of patients (n = 86). Systemic therapies included mitotane in 20 cases and chemotherapy in 13 cases. Among 17 stage III patients, 12 had microscopic residual tumor due to an initial biopsy (n = 5), intraoperative rupture (n = 8), or surgical resection with microscopic residue or tumor spillage surgery (n = 1) (two patients with two modalities). After a median follow-up of 96 months (25-119), four early progressions and two relapses occurred. A total of seven patients died, including five of disease. Stage III diseases due to microscopic residual disease correlated with a worse prognosis: 5-year progression-free survival 44% (95% CI, 22-87%) versus 82% (95% CI, 73-91%) for the whole cohort (P < .0001). Among the 14 patients with refractory disease, only 3 were alive and free of disease after multimodal second-line therapy. CONCLUSIONS: Stage III diseases due to a microscopic residual tumor have a dismal prognosis, arguing for the systematic use of adjuvant therapy. Patients with a relapsed disease should be included in experimental studies.

From Wilms to kidney tumors: which ones require a biopsy?

Ninety percent of childhood renal tumors are Wilms tumors (nephroblastoma). While the Children's Oncology Group (COG) recommends primary surgery, the International Society of Paediatric Oncology (SIOP) recommends neoadjuvant chemotherapy, which can be initiated without histological confirmation if the presentation is typical for Wilms tumor. This review article describes the clinical, biological and radiologic criteria used by the SIOP community to consider diagnostic biopsy, i.e. when the renal origin is doubtful, when a pseudotumor is suspected or when a non-Wilms histology may be anticipated.