Imaging features to distinguish posterior fossa ependymoma subgroups.

OBJECTIVES: Posterior fossa ependymoma group A (EPN_PFA) and group B (EPN_PFB) can be distinguished by their DNA methylation and give rise to different prognoses. We compared the MRI characteristics of EPN_PFA and EPN_PFB at presentation. METHODS: Preoperative imaging of 68 patients with posterior fossa ependymoma from two centers was reviewed by three independent readers, blinded for histomolecular grouping. Location, tumor extension, tumor volume, hydrocephalus, calcifications, tissue component, enhancement or diffusion signal, and histopathological data (cellular density, calcifications, necrosis, mitoses, vascularization, and microvascular proliferation) were compared between the groups. Categorical data were compared between groups using Fisher's exact tests, and quantitative data using Mann-Whitney tests. We performed a Benjamini-Hochberg correction of the p values to account for multiple tests. RESULTS: Fifty-six patients were categorized as EPN_PFA and 12 as EPN_PFB, with median ages of 2 and 20 years, respectively (p = 0.0008). The median EPN_PFA tumoral volume was larger (57 vs 29 cm3, p = 0.003), with more pronounced hydrocephalus (p = 0.002). EPN_PFA showed an exclusive central position within the 4th ventricle in 61% of patients vs 92% for EPN_PFB (p = 0.01). Intratumor calcifications were found in 93% of EPN_PFA vs 40% of EPN_PFB (p = 0.001). Invasion of the posterior fossa foramina was mostly found for EPN_PFA, particularly the foramina of Luschka (p = 0.0008). EPN_PFA showed whole and homogeneous tumor enhancement in 5% vs 75% of EPN_PFB (p = 0.0008). All mainly cystic tumors were EPN_PFB (p = 0.002). The minimal and maximal relative ADC was slightly lower in EPN_PFA (p = 0.02 and p = 0.01, respectively). CONCLUSION: Morphological characteristics from imaging differ between posterior fossa ependymoma subtypes and may help to distinguish them preoperatively. CLINICAL RELEVANCE STATEMENT: This study provides a tool to differentiate between group A and group B ependymomas, which will ultimately allow the therapeutic strategy to be adapted in the early stages of patient management. KEY POINTS: • Posterior fossa ependymoma subtypes often have different imaging characteristics. • Posterior fossa ependymomas group A are commonly median or lateral tissular calcified masses, with incomplete enhancement, affecting young children and responsible for pronounced hydrocephalus and invasion of the posterior fossa foramina. • Posterior fossa ependymomas group B are commonly median non-calcified masses of adolescents and adults, predominantly cystic, and minimally invasive, with total and homogeneous enhancement.

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.

A Longitudinal Study of Individual Radiation Responses in Pediatric Patients Treated with Proton and Photon Radiotherapy, and Interventional Cardiology: Rationale and Research Protocol of the HARMONIC Project.

The Health Effects of Cardiac Fluoroscopy and Modern Radiotherapy (photon and proton) in Pediatrics (HARMONIC) is a five-year project funded by the European Commission that aimed to improve the understanding of the long-term ionizing radiation (IR) risks for pediatric patients. In this paper, we provide a detailed overview of the rationale, design, and methods for the biological aspect of the project with objectives to provide a mechanistic understanding of the molecular pathways involved in the IR response and to identify potential predictive biomarkers of individual response involved in long-term health risks. Biological samples will be collected at three time points: before the first exposure, at the end of the exposure, and one year after the exposure. The average whole-body dose, the dose to the target organ, and the dose to some important out-of-field organs will be estimated. State-of-the-art analytical methods will be used to assess the levels of a set of known biomarkers and also explore high-resolution approaches of proteomics and miRNA transcriptomes to provide an integrated assessment. By using bioinformatics and systems biology, biological pathways and novel pathways involved in the response to IR exposure will be deciphered.

Pattern of relapse in pediatric localized extremity rhabdomyosarcomas correlated with locoregional therapies administered.

BACKGROUND: Treatment of extremity rhabdomyosarcomas (RMS) includes chemotherapy, surgery, and radiotherapy. Lymph node irradiation is recommended in the presence of regional node involvement at diagnosis. The aim of this study was to analyze the correlation between the pattern of relapse of non-metastatic extremity RMS and the initial therapies delivered. METHODS: All patients with localized extremity RMS prospectively treated in France in the MMT-95 and RMS-05 protocols were selected. Extent of disease and pattern of relapse were evaluated by clinical examination and imaging. RESULTS: We identified 59 patients with clinical characteristics corresponding to unfavorable prognostic factors. Twenty patients (34%) were considered to have lymph node involvement at diagnosis. Regional node biopsy was performed in 32 patients (54%) and modified the lymph node stage in 8 of the 59 patients (14%). Seventy-three percent of patients received radiotherapy. Fifty-two patients achieved first remission. Overall, 26 patients underwent complete tumor resection, 17 had R1 margins, and 5 were not operated due to early tumor progression. With a median follow-up of 82 months (range: 5-287), 18 relapses had occurred, at least locoregional in 12 cases. The 5­year local and nodal control rates were 73% (63-86%) and 86% (77-95%), respectively. Five-year progression-free and overall survival were 57% (95%CI [45-72%]) and 70% (95%CI [58-84%]), respectively. CONCLUSION: The main sites of extremity RMS relapse are locoregional. Nodal failures in non-irradiated fields are not uncommon. We recommend systematic biopsy of in-transit nodes, especially in alveolar RMS and/or RMS with regional positive nodes at diagnosis to ensure their negativity.

High-dose proton therapy and tomotherapy for the treatment of sacral chordoma: a retrospective monocentric study.

OBJECTIVE: Radiation therapy (RT) is used for the treatment of sacral chordoma, in combination with surgery or alone for unresected tumours, to improve local control (LC) and potentially overall survival (OS). The purpose of the present study was to evaluate efficacy and toxicity of proton therapy (PT), and/or intensity modulated radiation therapy (IMRT), particularly Tomotherapy, for sacral chordoma treatment. Material: Between November 2005 and June 2018, 41 consecutive patients who were not included in clinical trials, received sacral chordoma radiation treatment in Institut Curie with Tomotherapy alone in 13 patients, and combined PT and Tomotherapy boost (Proton - Tomo) in 28 patients. RT was delivered as the exclusive local treatment in 11 patients, and as a post-operative complementary treatment in 30 patients. RESULTS: After a median follow-up of 46 months (range, 0-125 months), eight local relapses were observed, and seven patients developed distant metastasis (particularly bone and lung). The 2- and 5- year local relapse rates were 11.4% CI (0.65-22.2%) and 29% (10.5-47.4%), respectively. Over the follow-up period, ten patients died (24.4%). The estimated 2- and 5-year OS rates were 91.4% CI (82.5-100%) and 74.5% (59.4-93.5%), respectively. Fibrosis, cauda equina syndrome, and pain were the most common late toxicities. The comparison between Tomotherapy alone and Proton - Tomo revealed that acute and late cystitis were significantly more frequent in the Tomotherapy group: SHR = 0.12 IC95% (0.01-0.90 [p = .04]), as well as late proctitis. A dosimetric comparison confirmed the interest of PT to spare rectum and bladder in this context. CONCLUSION: RT remains essential to improve local control in sacral chordoma. The combination of proton and photon seems to improve organ at risk sparing, resulting in a decreased rate of reported late toxicities.

Testicular transposition in children before scrotal external radiotherapy.

Testicular transposition (TT) before scrotal external radiotherapy (RT) is poorly reported in children with cancer, with only rare case reports published. TT surgical techniques, dosimetric parameters, and testicular functions are retrospectively reported in 12 children, median age 12.8 years, after scrotal RT for sarcomas. TT has low morbidity and allows a dramatic RT dose decrease in the healthy testicle. Endocrine functions seem preserved while more follow-up is needed to assess fertility. Though a rare situation, TT should be discussed in children and young adult cases when a scrotal high-dose RT is needed.

Management of vertebral radiotherapy dose in paediatric patients with cancer: consensus recommendations from the SIOPE radiotherapy working group.

Inhomogeneities in radiotherapy dose distributions covering the vertebrae in children can produce long-term spinal problems, including kyphosis, lordosis, scoliosis, and hypoplasia. In the published literature, many often interrelated variables have been reported to affect the extent of potential radiotherapy damage to the spine. Articles published in the 2D and 3D radiotherapy era instructed radiation oncologists to avoid dose inhomogeneity over growing vertebrae. However, in the present era of highly conformal radiotherapy, steep dose gradients over at-risk structures can be generated and thus less harm is caused to patients. In this report, paediatric radiation oncologists from leading centres in 11 European countries have produced recommendations on how to approach dose coverage for target volumes that are adjacent to vertebrae to minimise the risk of long-term spinal problems. Based on available information, it is advised that homogeneous vertebral radiotherapy doses should be delivered in children who have not yet finished the pubertal growth spurt. If dose fall-off within vertebrae cannot be avoided, acceptable dose gradients for different age groups are detailed here. Vertebral delineation should include all primary ossification centres and growth plates, and therefore include at least the vertebral body and arch. For partial spinal radiotherapy, the number of irradiated vertebrae should be restricted as much as achievable, particularly at the thoracic level in young children (<6 years old). There is a need for multicentre research on vertebral radiotherapy dose distributions for children, but until more valid data become available, these recommendations can provide a basis for daily practice for radiation oncologists who have patients that require vertebral radiotherapy.

Adapted strategy to tumor response in childhood nasopharyngeal carcinoma: the French experience.

PURPOSE: The aim of this study was to retrospectively study survival and long-term morbidities of children with nasopharyngeal carcinoma (NPC) treated by induction chemotherapy and concurrent chemoradiation (CRT). The total dose of radiation was adapted to the response following neoadjuvant chemotherapy. METHODS: Children with non-metastatic NPC treated in France between 1999 and 2015 were retrospectively included in the study. The strategy combined neoadjuvant platinum-based chemotherapy, followed by adapted CRT to tumor response. RESULTS: In total, 95 patients (median age 15 years [range, 7-23 years], male-to-female ratio 1.8) with undifferentiated NPC were included; 59% of patients had TNM stage IV. Intensity-modulated radiotherapy (IMRT) was delivered to 57 patients (60%), while the other patients were treated with conformal RT (3D-RT). After a median follow-up of 4.5 years [range, 3.6-5.5 years], 13 relapses and seven deaths had occurred. The 3­year overall and relapse-free survival (RFS) were 94% [95% CI, 85-97%] and 86% [77-92%], respectively. The locoregional failure rate was 6% [95% CI, 2-14]. Long-term treatment-related sequelae of grade 2+ were reported by 37 (50%) patients; odynophagia was significantly reduced treated by IMRT vs. conventional 3D-RT (7% vs. 55%, p = 0.015). Using a reduction dose of 59.4 Gy, 54 Gy, and 45 Gy, respectively, to the primary, involved, and uninvolved neck nodes, after a favorable tumor response, was not associated with an increased locoregional failure rate. CONCLUSIONS: The survival rates for NPC have been considerably improved by means of multimodal therapy, but long-term locoregional morbidity remains common. Use of IMRT may induce less residual odynophagia. Radiation dose reduction adapted to chemotherapy response does not have a negative impact on outcome. These findings support the use of an RT protocol adapted to the tumor response to neoadjuvant chemotherapy for a long-lasting improvement in the patient's quality of life.

Childhood Nasopharyngeal Carcinoma: State-of-the-Art, and Questions for the Future.

In children, nasopharyngeal carcinoma (NPC) is a very rare tumor, mostly Epstein-Barr Virus related and quite always diagnosed at a locally advanced stage. With current protocols associating induction cisplatin-based chemotherapy and concomitant chemoradiotherapy, prognosis is excellent with overall survival higher than 85%. However, long-term toxicities are frequent. Improvement in radiation therapy modalities like intensity-modulated radiation therapy and new strategies with radiation dose adaptation to chemotherapy response have been introduced to reduce acute and long-term toxicities. Actually, 2 main questions remain: is it possible to pursue a therapeutic deescalation in children with low-risk NPC or very good response to induction chemotherapy in order to reduce the risk of late effects? Could an immunologic maintenance treatment improve prognosis of children with high-risk NPC? International collaborative groups and prospective trials including biological studies are necessary to answer these questions to improve childhood NPC treatment and knowledge.

Chordoma in children: Case-report and review of literature.

We report an exceptional case of a very late local failure in a 9-year-old boy presenting with a chordoma of the cranio-cervical junction. The child was initially treated with a combination of surgical resection followed by high dose photon-proton radiation therapy. This aggressive therapy allowed a 9-year remission with minimal side-effects. Unfortunately, he subsequently presented with a local failure managed with a second full-dose course of protons. The child died one year later from local bleeding of unclear etiology.

Reprint of "Chordoma in children: Case-report and review of literature".

We report an exceptional case of a very late local failure in a 9-year-old boy presenting with a chordoma of the cranio-cervical junction. The child was initially treated with a combination of surgical resection followed by high dose photon-proton radiation therapy. This aggressive therapy allowed a 9-year remission with minimal side-effects. Unfortunately, he subsequently presented with a local failure managed with a second full-dose course of protons. The child died one year later from local bleeding of unclear etiology.

Long-term side effects of radiotherapy for pediatric localized neuroblastoma : results from clinical trials NB90 and NB94.

INTRODUCTION: Neuroblastoma (NB) is the most frequent indication for extracranial pediatric radiotherapy. As long-term survival of high-risk localized NB has greatly improved, we reviewed treatment-related late toxicities in pediatric patients who received postoperative radiotherapy (RT) for localized NB within two French prospective clinical trials: NB90 and NB94. PATIENTS AND METHODS: From 1990-2000, 610 children were enrolled. Among these, 35 were treated with induction chemotherapy, surgery, and RT. The recommended RT dose was 24 Gy at ≤ 2 years, 34 Gy at > 2 years, ± a 5 Gy boost in both age groups. RESULTS: The 22 patients still alive after 5 years were analyzed. The median follow-up time was 14 years (range 5-21 years). Late effects after therapy occurred in 73 % of patients (16/22), within the RT field for 50 % (11/22). The most frequent in-field effects were musculoskeletal abnormalities (n = 7) that occurred only with doses > 31 Gy/1.5 Gy fraction (p = 0.037). Other effects were endocrine in 3 patients and second malignancies in 2 patients. Four patients presented with multiple in-field late effects only with doses > 31 Gy. CONCLUSION: After a median follow-up of 14 years, late effects with multimodality treatment were frequent. The most frequent effects were musculoskeletal abnormalities and the threshold for their occurrence was 31 Gy.

Surface guided radiotherapy practice in paediatric oncology: a survey on behalf of the SIOPE Radiation Oncology Working Group.

INTRODUCTION: Surface guided radiotherapy (SGRT) is increasingly being implemented to track patient's surface movement and position during radiation therapy. However, limited information is available on the SGRT use in paediatrics. The aim of this double survey was to map SIOPE (European Society for Paediatric Oncology)-affiliated centres using SGRT and to gain information on potential indications, observed, or expected benefits. METHODS: A double online survey was distributed to 246 SIOPE-affiliated radiotherapy (RT) centres. Multiple choices, yes/no, and open answers were included. The first survey (41 questions) was active from February to March 2021. A shortened version (13 questions) was repeated in March 2023 to detect trends in SGRT use within the same community. RESULTS: Respectively, 76/142 (54%) and 28/142 (20%) responding centres used and planned to use SGRT clinically, including 4/34 (12%) new centres since 2021. Among the SGRT users, 33/76 (43%) already applied this technology to paediatric treatments. The main benefits of improved patient comfort, better monitoring of intrafraction motion, and more accurate initial patient set-up expected by future users did not differ from current SGRT-users (P = .893). Among non-SGRT users, the main hurdles to implement SGRT were costs and time for installation. In paediatrics, SGRT is applied to all anatomical sites. CONCLUSION: This work provides information on the practice of SGRT in paediatrics across SIOPE-affiliated RT centres which can serve as a basis for departments when considering the purchase of SGRT systems. ADVANCES IN KNOWLEDGE: Since little information is available in the literature on the use of SGRT in paediatrics, the results of this double survey can serve as a basis for departments treating children when considering the purchase of an SGRT system.

Curative high-dose reirradiation for patients with recurrent head and neck adenoid cystic carcinomas: outcomes and analysis of patterns of failure.

BACKGROUND: To investigate the outcomes of patients who underwent curative reirradiation (reRT), with intensity-modulated radiation therapy (IMRT) or proton therapy (PT) for unresectable recurrent or second primary head and neck adenoid cystic carcinoma (HNACC). METHODS: Ten patients, mostly KPS 90%, were reirradiated (3/10 with IMRT and 7/10 with PT) at a median maximum dose to the CTV of 64.2 Gy from July 2011 to November 2021. Locations at the time of reRT were mainly the sinus (4/10) and the salivary glands (including the parotid and submandibular gland, 3/10). CTCAEv5 was used to assess acute and late toxicities. Follow-up was the time between the end of reRT and the date of last news. RESULTS: The median time between the two irradiations was 53.5 months (IQR: 18-84). After a median follow-up of 26 months (range, 12.5-51.8 months), six patients had developed a locoregional recurrence (LR), of which four occurred within the previously irradiated volume. Two and three-year locoregional failure-free survival (LFFS) and overall survival (OS) were 55.6% [95%CI: 31-99.7%], and 41% [18.5-94%] and 66.7% [42-100%] and 44.4% [21.4-92.3%], respectively. LFFS and OS were significantly better in the subgroup of sinus tumors (p = .013) and the subgroup of patients re-irradiated more than two years after the first course of irradiation (p = .01). Seven patients had impairments before the start of reRT, including hearing impairment (3/10) and facial nerve impairment (3/10). The most severe late toxicities were brain necrosis (2/10), osteoradionecrosis (1/10) and vision decreased (1/10). CONCLUSION: Curative reRT for HNACC is possible for selected cases, but the LR rate in the irradiated field and the risk of severe toxicity remain high. Improved selection criteria and more carefully defined target volumes may improve outcome in these patients. A further study including larger cohort of patients would be useful to confirm these results.

Very long-term outcomes of pediatric patients treated for optic pathway gliomas: A longitudinal cohort study.

BACKGROUND: Optic pathway gliomas (OPGs) represent 5% of childhood brain tumors. Successive relapses lead to multiple treatments exposing to late complications. METHODS: We included patients treated at Gustave Roussy (GR) between January 1980 and December 2015 for OPG, before 18 years old and alive at 5 years from diagnosis. Mortality and physical health conditions data were extracted from medical data files and updated, thanks to the GR long-term follow-up program and French national mortality registry for patients included in the French Childhood Cancer Survivor Study. RESULTS: We included 182 5-year OPG-childhood survivors in the analysis (sex ratio M/F 0.8, 35% with neurofibromatosis type 1 [NF1]). With a median follow-up of 17.2 years (range = 5-41), we registered 82 relapses, 9 second malignancies, and 15 deaths as first events after 5 years, resulting in 20-year conditional overall survival (C-OS) and late events-free survival of 79.9% (95% confidence interval [CI] = 71-86) and 43.5% (95% CI = 36-51), respectively. Radiotherapy exposure in NF1 patients (hazard ratio [HR] = 6, 95% CI = 1.7-21.2) and hypothalamic involvement (HR = 3.2, 95% CI = 1.4-7.3) were significantly associated with C-OS in multivariable analyses. Ninety-five percent of 5-year OPG survivors suffered from any health condition, especially visual acuity "<1/10" (n = 109), pituitary deficiency (n = 106), and neurocognitive impairment (n = 89). NF1 (HR 2.1) was associated with precocious puberty. With a median time post-diagnosis of 4.2 years, 33 cerebrovascular events were observed in 21 patients. CONCLUSIONS: Late relapses, second malignancies, and cerebrovascular diseases are severe late events resulting in premature mortality. Morbidity is high and needs after-cancer care to improve quality of life. Risk factors could be considered to better stratify long-term follow-up.

Brainstem toxicity after proton or photon therapy in children and young adults with localized intracranial ependymoma: A French retrospective study.

BACKGROUND AND PURPOSE: Ependymoma is the third most frequent childhood braintumor. Standard treatment is surgery followed by radiation therapy including proton therapy (PBT). Retrospective studies have reported higher rates of brainstem injury after PBT than after photon therapy (XRT). We report a national multicenter study of the incidence of brainstem injury after XRT versus PBT, and their correlations with dosimetric data. MATERIAL AND METHODS: We included all patients aged < 25 years who were treated with PBT or XRT for intracranial ependymoma at five French pediatric oncology reference centers between 2007 and 2020. We reviewed pre-irradiation MRI, follow-up MRIs over the 12 months post-treatment and clinical data. RESULTS: Of the 83 patients, 42 were treated with PBT, 37 with XRT, and 4 with both (median dose: 59.4 Gy, range: 53­60). No new or progressive symptomatic brainstem injury was found. Four patients presented asymptomatic radiographic changes (punctiform brainstem enhancement and FLAIR hypersignal), with median onset at 3.5 months (range: 3.0­9.4) after radiation therapy, and median offset at 7.6 months (range: 3.7­7.9). Two had been treated with PBT, one with XRT, and one with mixed XRT-PBT. Prescribed doses were 59.4, 55.8, 59.4 and 54 Gy. CONCLUSION: Asymptomatic radiographic changes occurred in 4.8% of patients with ependymoma in a large national series. There was no correlation with dose or technique. No symptomatic brainstem injury was identified.

Long-term weight gain in children with craniopharyngioma.

OBJECTIVE: Adamantinomatous craniopharyngioma mainly affects children. Excessive weight gain is a major long-term complication. The primary objective of this study was to assess long-term weight changes in children treated for craniopharyngioma. The secondary objectives were to identify risk factors for excessive weight gain and to look for associations with hypothalamic damage by the tumour or treatment. DESIGN: Single-centre retrospective cohort study. METHOD: Children managed for craniopharyngioma at our centre between 1990 and 2019 were included. The body mass index (BMI) standard deviation scores (SDS) at baseline and at last follow-up were compared. Univariate and multivariate analyses were performed in order to identify variables associated with the long-term BMI-SDS variation. RESULTS: The 108 patients had a mean follow-up of 10.4 years. The mean BMI-SDS increase over time was 2.11 (P < .001) overall, 1.21 (P < .001) in the group without hypothalamic involvement by the tumour, and 1.95 (P < .001) in the group managed using intended hypothalamus-sparing surgery. The absence of hypothalamic involvement by the tumour or treatment was significantly associated with less weight gain (P = .046 and P < .01, respectively). After adjustment, factors associated with a BMI-SDS change greater than 2 were female sex (P = .023), tumour involving the hypothalamus (P = .04), and higher baseline BMI (P < .001). CONCLUSION: Clinically significant weight gain occurred in nearly all children treated for craniopharyngioma, including those whose hypothalamus was spared by the tumour and intentionally by treatment. However, hypothalamus integrity was associated with less weight gain. Despite hypothalamus-sparing strategies, hypothalamic obesity remains a major concern, indicating a need for novel treatment approaches.

Radiation Doses Received by Major Organs at Risk in Children and Young Adolescents Treated for Cancer with External Beam Radiation Therapy: A Large-scale Study from 12 European Countries.

PURPOSE: Childhood cancer survivors, in particular those treated with radiation therapy, are at high risk of long-term iatrogenic events. The prediction of risk of such events is mainly based on the knowledge of the radiation dose received to healthy organs and tissues during treatment of childhood cancer diagnosed decades ago. We aimed to set up a standardized organ dose table to help former patients and clinicians in charge of long-term follow-up clinics. METHODS AND MATERIALS: We performed whole body dosimetric reconstruction for 2646 patients from 12 European countries treated between 1941 and 2006 (median, 1976). Most plannings were 2- or 3-dimensional. A total of 46% of patients were treated using Cobalt 60, and 41%, using a linear accelerator. The median prescribed dose was 27.2 Gy (IQ1-IQ3, 17.6-40.0 Gy). A patient-specific voxel-based anthropomorphic phantom with more than 200 anatomic structures or substructures delineated as a surrogate of each subject's anatomy was used. The radiation therapy was simulated with a treatment planning system based on available treatment information. The radiation dose received by any organ of the body was estimated by extending the treatment planning system dose calculation to the whole body, by type and localization of childhood cancer. RESULTS: The integral dose and normal tissue doses to most of the 23 considered organs increased between the 1950s and 1970s and decreased or plateaued thereafter. Whatever the organ considered, the type of childhood cancer explained most of the variability in organ dose. The country of treatment explained only a small part of the variability. CONCLUSIONS: The detailed dose estimates provide very useful information for former patients or clinicians who have only limited knowledge about radiation therapy protocols or techniques, but who know the type and site of childhood cancer, sex, age, and year of treatment. This will allow better prediction of the long-term risk of iatrogenic events and better referral to long-term follow-up clinics.