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Background: This study was designed to identify common genetic susceptibility and shared genetic variants associated with acute radiation-induced toxicity across 4 cancer types (prostate, head and neck, breast, and lung)., Methods: A genome-wide association study meta-analysis was performed using 19 cohorts totaling 12 042 patients. Acute standardized total average toxicity (STATacute) was modelled using a generalized linear regression model for additive effect of genetic variants, adjusted for demographic and clinical covariates (rSTATacute). Linkage disequilibrium score regression estimated shared single-nucleotide variation (SNV-formerly SNP)-based heritability of rSTATacute in all patients and for each cancer type., Results: Shared SNV-based heritability of STATacute among all cancer types was estimated at 10% (SE = 0.02) and was higher for prostate (17%, SE = 0.07), head and neck (27%, SE = 0.09), and breast (16%, SE = 0.09) cancers. We identified 130 suggestive associated SNVs with rSTATacute (5.0 × 10‒8 < P < 1.0 × 10‒5) across 25 genomic regions. rs142667902 showed the strongest association (effect allele A; effect size ‒0.17; P = 1.7 × 10‒7), which is located near DPPA4, encoding a protein involved in pluripotency in stem cells, which are essential for repair of radiation-induced tissue injury. Gene-set enrichment analysis identified 'RNA splicing via endonucleolytic cleavage and ligation' (P = 5.1 × 10‒6, P = .079 corrected) as the top gene set associated with rSTATacute among all patients. In silico gene expression analysis showed that the genes associated with rSTATacute were statistically significantly up-regulated in skin (not sun exposed P = .004 corrected; sun exposed P = .026 corrected)., Conclusions: There is shared SNV-based heritability for acute radiation-induced toxicity across and within individual cancer sites. Future meta-genome-wide association studies among large radiation therapy patient cohorts are worthwhile to identify the common causal variants for acute radiotoxicity across cancer types., (© The Author(s) 2023. Published by Oxford University Press.)

Objective: As preservation of cognitive functioning increasingly becomes important in the light of ameliorated survival after intracranial tumor treatments, identification of eloquent brain areas would enable optimization of these treatments., Methods: This cohort study enrolled adult intracranial tumor patients who received neuropsychological assessments pre-irradiation, estimating processing speed, verbal fluency and memory. Anatomical magnetic resonance imaging scans were used for multivariate voxel-wise lesion-symptom predictions of the test scores (corrected for age, gender, educational level, histological subtype, surgery, and tumor volume). Potential effects of histological and molecular subtype and corresponding WHO grades on the risk of cognitive impairment were investigated using Chi square tests. P-values were adjusted for multiple comparisons (p < .001 and p < .05 for voxel- and cluster-level, resp.)., Results: A cohort of 179 intracranial tumor patients was included [aged 19-85 years, median age (SD) = 58.46 (14.62), 50% females]. In this cohort, test-specific impairment was detected in 20-30% of patients. Higher WHO grade was associated with lower processing speed, cognitive flexibility and delayed memory in gliomas, while no acute surgery-effects were found. No grading, nor surgery effects were found in meningiomas. The voxel-wise analyses showed that tumor locations in left temporal areas and right temporo-parietal areas were related to verbal memory and processing speed, respectively., Interpretation: Patients with intracranial tumors affecting the left temporal areas and right temporo-parietal areas might specifically be vulnerable for lower verbal memory and processing speed. These specific patients at-risk might benefit from early-stage interventions. Furthermore, based on future validation studies, imaging-informed surgical and radiotherapy planning could further be improved., (© 2022. The Author(s).)

Purpose: Recently, it has been shown that automated treatment planning can be executed by direct fluence prediction from patient anatomy using convolutional neural networks. Proof of principle publications utilise a fixed dose prescription and fixed collimator (0°) and gantry angles. The goal of this work is to further develop these principles for the challenging lung cancer indication with variable dose prescriptions, collimator and gantry angles. First we investigate the impact of clinical applicable collimator angles and various input parameters. Then, the model is tested in a complete user independent planning workflow., Methods: The dataset consists of 152 lung cancer patients, previously treated with IMRT. The patients are treated with either a left or a right beam setup and collimator angles and dose prescriptions adjusted to their tumour shape and stage. First we compare two CNNs with standard vs. personalised, clinical collimator angles. Next, four CNNs are trained with various combinations of CT and contour inputs. Finally, a complete user free treatment planning workflow is evaluated., Results: The difference between the predicted and ground truth fluence maps for the fluence prediction CNN with all anatomical inputs in terms of the mean mean absolute error (MAE) is 4.17 × 10 -4 for a fixed collimator angle and 5.46 × 10 -4 for variable collimator angles. These differences vanish in terms of DVH metrics. Furthermore, the impact of anatomical inputs is small. The mean MAE is 5.88 × 10 -4 if no anatomical information is given to the network. The DVH differences increase when a total user free planning workflow is examined., Conclusions: Fluence prediction with personalised collimator angles performs as good as fluence prediction with a standard collimator angle of zero degrees. The impact of anatomical inputs is small. The combination of a dose prediction and fluence prediction CNN deteriorates the fluence predictions. More investigation is required., (Copyright © 2022 Associazione Italiana di Fisica Medica e Sanitaria. Published by Elsevier Ltd. All rights reserved.)

Introduction: Robust planning is essential in proton therapy for ensuring adequate treatment delivery in the presence of uncertainties. For both robust optimization and evaluation, commonly-used techniques can be overly conservative in selecting error scenarios and lack in providing quantified confidence levels. In this study, established techniques are compared to comprehensive alternatives to assess the differences in target coverage and organ at risk (OAR) dose., Method: Thirteen lung cancer patients were planned. Two robust optimization methods were used: scenario selection from marginal probabilities (SSMP) based on using maximum setup and range error values and scenario selection from joint probabilities (SSJP) that selects errors on a predefined 90% hypersurface. Two robust evaluation methods were used: conventional evaluation (CE) based on generating error scenarios from combinations of maximum errors of each uncertainty source and statistical evaluation (SE) via the Monte Carlo dose engine MCsquare which considers scenario probabilities., Results: Plans optimized using SSJP had, on average, 0.5 Gy lower dose in CTV D 98(worst-case) than SSMP-optimized plans. When evaluated using SE, 92.3% of patients passed our clinical threshold in both optimization methods. Average gains in OAR sparing were recorded when transitioning from SSMP to SSJP: esophagus (0.6 Gy D 2(nominal) , 0.9 Gy D 2(worst-case) ), spinal cord (3.9 Gy D 2(nominal) , 4.1 Gy D 2(worst-case) ) heart (1.1 Gy D mean , 1.9% V 30 ), lungs-GTV (1.0 Gy D mean , 1.9% V 30 )., Conclusion: Optimization using SSJP yielded significant OAR sparing in all recorded metrics with a target robustness within our clinical objectives, provided that a more statistically sound robustness evaluation method was used., (Copyright © 2022 Associazione Italiana di Fisica Medica e Sanitaria. Published by Elsevier Ltd. All rights reserved.)

Objectives: Radiotherapy-induced toxicity may negatively impact health-related quality of life (HRQoL). This report investigates the impact of curative-intent radiotherapy on HRQoL and toxicity in early stage and locally-advanced non-small cell lung cancer patients treated with radiotherapy or chemo-radiotherapy enrolled in the observational prospective REQUITE study., Materials and Methods: HRQoL was assessed using the European Organisation for Research and Treatment of Cancer QLQ-C30 questionnaire up to 2 years post radiotherapy. Eleven toxicities were scored by clinicians using the Common Terminology Criteria for Adverse Events (CTCAE) version 4. Toxicity scores were calculated by subtracting baseline values. Mixed model analyses were applied to determine statistical significance (p ≤ 0.01). Meaningful clinical important differences (MCID) were determined for changes in HRQoL. Analysis was performed on the overall data, different radiotherapy techniques, multimodality treatments and disease stages., Results: Data of 510 patients were analysed. There was no significant change in HRQoL or its domains, except for deterioration in cognitive functioning (p = 0.01). Radiotherapy technique had no significant impact on HRQoL. The addition of chemotherapy was significantly associated with HRQoL over time (p <.001). Overall toxicity did not significantly change over time. Acute toxicities of radiation-dermatitis (p =.003), dysphagia (p =.002) and esophagitis (p <.001) peaked at 3 months and decreased thereafter. Pneumonitis initially deteriorated but improved significantly after 12 months (p =.011). A proportion of patients experienced meaningful clinically important improvements and deteriorations in overall HRQoL and its domains. In some patients, pre-treatment symptoms improved gradually., Conclusions: While overall HRQoL and toxicity did not change over time, some patients improved, whereas others experienced acute radiotherapy-induced toxicities and deteriorated HRQoL, especially physical and cognitive functioning. Patient characteristics, more so than radiotherapy technique and treatment modality, impact post-radiotherapy toxicity and HRQoL outcomes. This stresses the importance of considering the potential impact of radiotherapy on individuals' HRQoL, symptoms and toxicity in treatment decision-making., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Purpose: Treatment-related toxicity after irradiation of brain tumours has been underreported in the literature. Furthermore, there is considerable heterogeneity on how and when toxicity is evaluated. The aim of this European Particle Network (EPTN) collaborative project is to develop recommendations for uniform follow-up and toxicity scoring of adult brain tumour patients treated with radiotherapy., Methods: A Delphi method-based consensus was reached among 24 international radiation-oncology experts in the field of neuro-oncology concerning the toxicity endpoints, evaluation methods and time points., Results: In this paper, we present a basic framework for consistent toxicity scoring and follow-up, using multiple levels of recommendation. Level I includes all recommendations that are considered minimum of care, whereas level II and III are optional evaluations in the advanced clinical or research setting, respectively. Per outcome domain, the clinical endpoints and evaluation methods per level are listed. Where relevant, the organ at risk threshold doses for recommended referral to specific organ specialists are defined., Conclusion: These consensus-based recommendations for follow-up will enable the collection of uniform toxicity data of brain tumour patients treated with radiotherapy. With adoptation of this standard, collaboration will be facilitated and we can further propel the research field of radiation-induced toxicities relevant for these patients. An online tool to implement this guideline in clinical practice is provided at www.cancerdata.org., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background and Purpose: To update the digital online atlas for organs at risk (OARs) delineation in neuro-oncology based on high-quality computed tomography (CT) and magnetic resonance (MR) imaging with new OARs., Materials and Methods: In this planned update of the neurological contouring atlas published in 2018, ten new clinically relevant OARs were included, after thorough discussion between experienced neuro-radiation oncologists (RTOs) representing 30 European radiotherapy-oncology institutes. Inclusion was based on daily practice and research requirements. Consensus was reached for the delineation after critical review. Contouring was performed on registered CT with intravenous (IV) contrast (soft tissue & bone window setting) and 3 Tesla (T) MRI (T1 with gadolinium & T2 FLAIR) images of one patient (1 mm slices). For illustration purposes, delineation on a 7 T MRI without IV contrast from a healthy volunteer was added. OARs were delineated by three experienced RTOs and a neuroradiologist based on the relevant literature., Results: The presented update of the neurological contouring atlas was reviewed and approved by 28 experts in the field. The atlas is available online and includes in total 25 OARs relevant to neuro-oncology, contoured on CT and MRI T1 and FLAIR (3 T & 7 T). Three-dimensional (3D) rendered films are also available online., Conclusion: In order to further decrease inter- and intra-observer OAR delineation variability in the field of neuro-oncology, we propose the use of this contouring atlas in photon and particle therapy, in clinical practice and in the research setting. The updated atlas is freely available on www.cancerdata.org., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Introduction: To compare neurocognitive functioning in patients with SCLC who received prophylactic cranial irradiation (PCI) with or without hippocampus avoidance (HA)., Methods: In a multicenter, randomized phase 3 trial (NCT01780675), patients with SCLC were randomized to standard PCI or HA-PCI of 25 Gy in 10 fractions. Neuropsychological tests were performed at baseline and 4, 8, 12, 18, and 24 months after PCI. The primary end point was total recall on the Hopkins Verbal Learning Test-Revised at 4 months; a decline of at least five points from baseline was considered a failure. Secondary end points included other cognitive outcomes, evaluation of the incidence, location of brain metastases, and overall survival., Results: From April 2013 to March 2018, a total of 168 patients were randomized. The median follow-up time was 26.6 months. In both treatment arms, 70% of the patients had limited disease and baseline characteristics were well balanced. Decline on the Hopkins Verbal Learning Test-Revised total recall score at 4 months was not significantly different between the arms: 29% of patients on PCI and 28% of patients on HA-PCI dropped greater than or equal to five points (p = 1.000). Performance on other cognitive tests measuring memory, executive function, attention, motor function, and processing speed did not change significantly different over time between the groups. The overall survival was not significantly different (p = 0.43). The cumulative incidence of brain metastases at 2 years was 20% (95% confidence interval: 12%-29%) for the PCI arm and 16% (95% confidence interval: 7%-24%) for the HA-PCI arm., Conclusions: This randomized phase 3 trial did not find a lower probability of cognitive decline in patients with SCLC receiving HA-PCI compared with conventional PCI. No increase in brain metastases at 2 years was observed in the HA-PCI arm., (Copyright © 2021 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)

Purpose: Patients with a benign meningioma often have a long survival following the treatment of their meningioma. Since radiotherapy is frequently part of the treatment, long-term side effects are of considerable concern. A controversial long-term side effect of radiotherapy is stroke. Due to its severity, it is important to know the frequency of this side effect. The aim of this study was to assess the stroke incidence and risk factors among patients receiving radiotherapy for their benign meningioma., Methods: We performed a retrospective database study of patients who underwent primary or adjuvant radiotherapy for their benign meningioma at University Hospitals Leuven from January 2003 to December 2017., Results: We included 169 patients with a median age of 51 years (range 22-84). Every patient received fractionated radiotherapy using photons with a median dose of 56 Gy (range 54-56) in fractions of 2 Gy (range 1.8-2). The median follow-up was 5.3 years (range 0.1-14). The cumulative stroke incidence function showed an incidence of 11.6% after 9 years of follow-up, translating to a stroke incidence per year of 1.29%. We found two significant risk factors for stroke: medically treated arterial hypertension (p = 0.005) and history of previous stroke or transient ischemic attack (p < 0.001). 5-year local control and overall survival rates were respectively 97.4% and 91.2%. Other late grade III/IV toxicities occurred in 16.0% (27/169) of patients., Conclusion: Our study shows a higher incidence of stroke in patients who received radiotherapy for their benign meningioma compared to the general population.

Introduction: The NICOLAS study is the first completed single-arm phase II trial in stage III NSCLC evaluating hierarchically first the safety and then the efficacy of adding nivolumab concurrently to standard definitive concurrent chemoradiotherapy. The safety end point was reported earlier; here, we present the efficacy results., Methods: Stage IIIA-B unresectable treatment-naive patients with NSCLC received three cycles of platinum-based chemotherapy and concurrent radiotherapy (66 Gy, 33 fractions), along with nivolumab (360 mg, 3-weekly). Nivolumab was continued as monotherapy consolidation for a maximum of 1 year (480 mg, 4-weekly). The primary end point was 1-year progression-free survival (PFS), with a target improvement compared with historical data of at least 15%, from 45% to 60%. To test this efficacy hypothesis, a sample size of 74 assessable patients provided a power of 83% with a one-sided alpha of 5%., Results: A total of 79 patients were enrolled with a median follow-up of 21.0 months (interquartile range: 15.8-25.8 mo) for the primary PFS analysis. A total of 35.4% of the patients had stage IIIA, and 63.3% had stage IIIB disease. The 1-year PFS was 53.7% (95% confidence interval [CI]: 42.0%-64.0%) and the median PFS was 12.7 months (95% CI: 10.1-22.8 mo). Because 37 PFS events occurred in the first year posttreatment among the first 74 assessable patients, a 1-year PFS rate of at least 45% could not be rejected (p = 0.23). At an extended follow-up (median 32.6 mo), 37 deaths have been recorded, with a median overall survival (OS) of 38.8 months (95% CI: 26.8 mo-not estimable) and a 2-year OS rate of 63.7% (95% CI: 51.9%-73.4%). The OS of patients with stage IIIA disease was found to be significantly higher than patients with stage IIIB disease, with a 2-year OS of 81% and 56%, respectively (p = 0.037)., Conclusions: PFS and OS are arithmetically higher in studies involving the same population. However, on the basis of the formal hierarchical efficacy analysis, we could not reject that the 1-year PFS rate is at least 45%., (Copyright © 2020. Published by Elsevier Inc.)

Purpose: To prospectively evaluate the feasibility of solid gold marker placement in oesophageal cancer patients and to quantify inter-fractional and intra-fractional (baseline shift) marker motion during radiation treatment. Radiotherapy target margins and matching strategies were investigated., Materials/methods: Thirty-four markers were implanted by echo-endoscopy in 10 patients. Patients received a planning 4D CT, daily pre-treatment cone-beam CT (CBCT) and a post-treatment CBCT for at least five fractions. For fractions with both pre- and post-treatment CBCT, marker displacement between planning CT and pre-treatment CBCT (inter-fractional) and between pre-treatment and post-treatment CBCT (intra-fractional; only for fractions without rotational treatment couch correction) were calculated in left-right (LR), cranio-caudal (CC) and anterior-posterior (AP) direction after bony-anatomy and soft-tissue matching. Systematic/random setup errors were estimated; treatment margins were calculated., Results: No serious adverse events occurred. Twenty-three (67.6%) markers were visible during radiotherapy (n = 3 middle oesophagus, n = 16 distal oesophagus, n = 4 proximal stomach). Margins for inter-fractional displacement after bony-anatomy match depended on the localisation of the primary tumour and were 11.2 mm (LR), 16.4 mm (CC) and 8.2 mm (AP) for distal markers. Soft-tissue matching reduced the CC margin for these markers (16.4 mm to 10.5 mm). The mean intra-fractional shift of 12 distal markers was 0.4 mm (LR), 2.3 mm (CC) and 0.7 mm (AP). Inclusion of this shift resulted in treatment margins for distal markers of 12.8 mm (LR), 17.3 mm (CC) and 10.4 mm (AP) after bony-anatomy matching and 12.4 mm (LR), 11.4 mm (CC) and 9.7 mm (AP) after soft-tissue matching., Conclusion: This study demonstrated that the implantation of gold markers was safe, albeit less stable compared to other marker types. Inter-fractional motion was largest cranio-caudally for markers in the distal oesophagus, which was reduced after soft-tissue compared to bony-anatomy matching. The impact of intra-fractional baseline shifts on margin calculation was rather small., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2020 The Authors. Published by Elsevier B.V. on behalf of European Society for Radiotherapy and Oncology.)

Purpose/objectives: To develop normal tissue complication probability (NTCP) models for postoperative pulmonary and cardiac complications and one-year mortality after preoperative chemoradiotherapy and surgery in oesophageal cancer patients., Methods: 691 patients from two institutions (2002-2017) were included; 134 treated with protons. Multivariable logistic regression analyses on 601 patients studied the predictive value of clinical/treatment-related (gender, age, body mass index (BMI), smoking, cardiac comorbidity, chronic obstructive pulmonary disease, histology, cT/N) and dosimetric variables (absolute/relative lung/heart volumes receiving or spared from xGy, mean doses, planning target volume) for the presence of pulmonary complications, cardiac complications and one-year mortality. Model validation was performed using a nonrandom split-sample of 90 patients. Model performance was assessed by AUC and calibration plots., Results: Respectively 144/601 (24.0%) and 165/601 (27.5%) patients developed a pulmonary or cardiac complication. For pulmonary complications, an NTCP model with optimism-corrected AUC of 0.75 (95%CI = 0.73-0.76) was obtained. The model contained mean lung dose (OR = 1.15, 95%CI = 1.09-1.22, p < 0.001), increasing age (OR = 1.03, 95%CI = 1.01-1.06, p = 0.002), BMI (OR = 1.04, 95%CI = 0.99-1.08, p = 0.084) and squamous cell carcinoma (OR = 3.22, 95%CI = 1.97-5.24, p < 0.001) as predictors. In validation, AUC of 0.79 was obtained (calibration slope 1.26). For cardiac complications, only age (OR = 1.06, 95%CI = 1.04-1.09, p < 0.001) with optimism-corrected AUC of 0.67 (95%CI = 0.65-0.68) was selected. For one-year mortality, an NTCP model with optimism-corrected AUC of 0.63 (95%CI = 0.58-0.66) was obtained. Lung absolute V 35 (OR = 1.0016, 95%CI = 1.0007-1.0026, p = 0.001), cN (OR = 2.45, 95%CI = 1.18-5.09, p = 0.017), cT4 (OR = 2.51, 95%CI = 1.10-5.74, p = 0.029) and cardiac comorbidity (OR = 2.91, 95%CI = 1.46-5.77, p = 0.002) were selected as predictors. At validation, AUC of 0.57 was obtained (calibration slope 0.75)., Conclusion: We were able to build and validate NTCP models for the presence of a postoperative pulmonary complication and for one-year mortality after trimodality treatment in oesophageal cancer., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background and Purpose: When using highly conformal radiotherapy techniques, a stabilized breathing pattern could greatly benefit the treatment of mobile tumours. Therefore, we assessed the feasibility of Mechanically-assisted non-invasive ventilation (MANIV) on unsedated volunteers, and its ability to stabilize and modulate the breathing pattern over time., Materials and Methods: Twelve healthy volunteers underwent 2 sessions of dynamic MRI under 4 ventilation modes: spontaneous breathing (SP), volume-controlled mode (VC) that imposes regular breathing in physiologic conditions, shallow-controlled mode (SH) that intends to lower amplitudes while increasing the breathing rate, and slow-controlled mode (SL) that mimics end-inspiratory breath-holds. The last 3 modes were achieved under respirator without sedation. The motion of the diaphragm was tracked along the breathing cycles on MRI images and expressed in position, breathing amplitude, and breathing period for intra- and inter-session analyses. In addition, end-inspiratory breath-hold duration and position stability were analysed during the SL mode., Results: MANIV was well-tolerated by all volunteers, without adverse event. The MRI environment led to more discomfort than MANIV itself. Compared to SP, VC and SH modes improved the inter-session reproducibility of the amplitude (by 43% and 47% respectively) and significantly stabilized the intra- and inter-session breathing rate (p < 0.001). Compared to VC, SH mode significantly reduced the intra-session mean amplitude (36%) (p < 0.002), its variability (42%) (p < 0.001), and the intra-session baseline shift (26%) (p < 0.001). The SL mode achieved end-inspiratory plateaus lasting more than 10 s., Conclusion: MANIV offers exciting perspectives for motion management. It improves its intra- and inter-session reproducibility and should facilitate respiratory tracking, gating or margin techniques for both photon and proton treatments., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Objectives: Current guidelines recommend preoperative invasive mediastinal staging in centrally located tumours with negative mediastinum on positron emission tomography-computed tomography, based on a 20-30% prevalence of occult mediastinal disease (pN2-3). However, a uniform definition of central tumour location is lacking. Our objective was to determine the best definition in predicting occult pN2-3., Methods: A single-institution database was queried for patients with (suspected) non-small-cell lung cancer staged cN0 after positron emission tomography-computed tomography and referred to invasive staging and/or primary surgery. We evaluated 5 definitions: inner 1/3, inner 2/3, contact with bronchovascular structures, ≤2 cm from bronchus or endobronchial visualization., Results: Between 2005 and 2015, 813 patients were eligible (cT1: 42%, cT2: 28%, cT3: 17% and cT4: 11%). Invasive mediastinal staging and resection were performed in 30% and 97% of patients, respectively. Any nodal upstaging (pN+) was found in 21% of patients, of whom pN2-3 was found in 8%. Central tumour location demonstrated 4 times higher odds for any pN+ [for inner 1/3 vs outer 2/3, odds ratio 3.90 (95% confidence interval 2.24-6.77), P < 0.001], whereas no significantly different odds was observed for pN2-3. The discriminative ability for pN+ was not significantly different between the several definitions., Conclusions: The prevalence of occult pN2-3 was only 8% when modern fusion positron emission tomography-computed tomography imaging pointed at clinical N0 non-small-cell lung cancer. None of the 5 verified definitions of centrality was predictive for occult pN2-3. However, each definition of centrality was related to any pN+ at a prevalence of 21%, without significant differences in discriminative ability between definitions. These data question whether indication for preoperative invasive mediastinal staging should be based on centrality alone.

Purpose: For unbiased comparison of different radiation modalities and techniques, consensus on delineation of radiation sensitive organs at risk (OARs) and on their dose constraints is warranted. Following the publication of a digital, online atlas for OAR delineation in neuro-oncology by the same group, we assessed the brain OAR-dose constraints in a follow-up study., Methods: We performed a comprehensive search to identify the current papers on OAR dose constraints for normofractionated photon and particle therapy in PubMed, Ovid Medline, Cochrane Library, Embase and Web of Science. Moreover, the included articles' reference lists were cross-checked for potential studies that met the inclusion criteria. Consensus was reached among 20 radiation oncology experts in the field of neuro-oncology., Results: For the OARs published in the neuro-oncology literature, we summarized the available literature and recommended dose constraints associated with certain levels of normal tissue complication probability (NTCP) according to the recent ICRU recommendations. For those OARs with lacking or insufficient NTCP data, a proposal for effective and efficient data collection is given., Conclusion: The use of the European Particle Therapy Network-consensus OAR dose constraints summarized in this article is recommended for the model-based approach comparing photon and proton beam irradiation as well as for prospective clinical trials including novel radiation techniques and/or modalities., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Purpose: To create a digital, online atlas for organs at risk (OAR) delineation in neuro-oncology based on high-quality computed tomography (CT) and magnetic resonance (MR) imaging., Methods: CT and 3 Tesla (3T) MR images (slice thickness 1 mm with intravenous contrast agent) were obtained from the same patient and subsequently fused. In addition, a 7T MR without intravenous contrast agent was obtained from a healthy volunteer. Based on discussion between experienced radiation oncologists, the clinically relevant organs at risk (OARs) to be included in the atlas for neuro-oncology were determined, excluding typical head and neck OARs previously published. The draft atlas was delineated by a senior radiation oncologist, 2 residents in radiation oncology, and a senior neuro-radiologist incorporating relevant available literature. The proposed atlas was then critically reviewed and discussed by European radiation oncologists until consensus was reached., Results: The online atlas includes one CT-scan at two different window settings and one MR scan (3T) showing the OARs in axial, coronal and sagittal view. This manuscript presents the three-dimensional descriptions of the fifteen consensus OARs for neuro-oncology. Among these is a new OAR relevant for neuro-cognition, the posterior cerebellum (illustrated on 7T MR images)., Conclusion: In order to decrease inter- and intra-observer variability in delineating OARs relevant for neuro-oncology and thus derive consistent dosimetric data, we propose this atlas to be used in photon and particle therapy. The atlas is available online at www.cancerdata.org and will be updated whenever required., (Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.)