Search

Radiotherapy for locally advanced head and neck cancer classically include large prophylactic node volume. However, the use of these large volumes can be responsible for significant toxicity. Furthermore, the disappointing results of radioimmunotherapy combinations in head and neck tumors raise concerns about radiotherapy's potential negative impact on the immune response when large lymph node volumes are treated. Besides, in other tumor locations, such as lung cancers, the volumes of elective irradiation have been considerably reduced, with the same local control as before. This opinion piece reviews the current state of radiation volumes in head and neck cancers, the rationale for these volumes, the potential impact of radiotherapy on immune response, and the volume changes that would improve the efficacy of radioimmunotherapy combinations.

We present the update of the recommendations of the French society of oncological radiotherapy on external radiotherapy of prostate cancer. External radiotherapy is intended for all localized prostate cancers, and more recently for oligometastatic prostate cancers. The irradiation techniques are detailed. Intensity-modulated radiotherapy combined with prostate image-guided radiotherapy is the recommended technique. A total dose of 74 to 80Gy is recommended in case of standard fractionation (2Gy per fraction). Moderate hypofractionation (total dose of 60Gy at a rate of 3Gy per fraction over 4 weeks) in the prostate has become a standard of therapy. Simultaneous integrated boost techniques can be used to treat lymph node areas. Extreme hypofractionation (35 to 40Gy in five fractions) using stereotactic body radiotherapy can be considered a therapeutic option to treat exclusively the prostate. The postoperative irradiation technique, indicated mainly in case of biological recurrence and lymph node involvement, is detailed.

We present the updated recommendations of the French society for oncological radiotherapy on image-guided radiotherapy (IGRT). The objective of the IGRT is to take into account the anatomical variations of the target volume occurring between or during the irradiation fractions, such as displacements and/or deformations, so that the delivered dose corresponds to the planned dose. This article presents the different IGRT devices, their use and quality control, and quantify the possible additional dose generated by each of them. The practical implementation of IGRT in various tumour locations is summarised, from the different "RecoRad™" guideline articles. Adaptive radiotherapy is then detailed, due to its complexity and its probable development in the next years. The place of radiation technologist in the practice of IGRT is then specified. Finally, a brief update is proposed on the delicate question of the additional dose linked to the in-room imaging, which must be estimated and documented at a minimum, as long as it is difficult to integrate it into the calculation of the dose distribution.

In 2021, the Ethics Commission of the SFRO has chosen the issue of the practice of palliative care in radiotherapy oncology. Radiation oncology plays a central role in the care of patients with cancer in palliative phase. But behind the broad name of palliative radiotherapy, we actually find a large variety of situations involving diverse ethical issues. Radiation oncologists have the delicate task to take into account multiple factors throughout a complex decision-making process. While the question of the therapeutic indication and the technical choice allowing it to be implemented remains central, reflection cannot be limited to these decision-making and technical aspects alone. It is also a question of being able to create the conditions for a singularity focused care and to build an authentic care relationship, beyond technicity. It is through this daily ethical work, in close collaboration with patients, and under essential conditions of multidisciplinarity and multiprofessionalism, that our fundamental role as caregiver can be deployed.

International audience; PURPOSE: The first aim was to generate and compare synthetic-CT (sCT) images using a conditional generative adversarial network (cGAN) method (Pix2Pix) for MRI-only prostate radiotherapy planning by testing several generators, loss functions, and hyper-parameters. The second aim was to compare the optimized Pix2Pix model with five other architectures (bulk-density, atlas-based, patch-based, U-Net, and GAN). METHODS: For 39 patients treated by VMAT for prostate cancer, T2-weighted MRI images were acquired in addition to CT images for treatment planning. sCT images were generated using the Pix2Pix model. The generator, loss function, and hyper-parameters were tuned to improve sCT image generation (in terms of imaging endpoints). The final evaluation was performed by 3-fold cross-validation. This method was compared to five other methods using the following imaging endpoints: the mean absolute error (MAE) and mean error (ME) between sCT and reference CT images (rCT) of the whole pelvis, bones, prostate, bladder, and rectum. For dose planning analysis, the dose-volume histogram metric differences and 3D gamma analysis (local, 1 %/1 mm) were calculated using the sCT and reference CT images. RESULTS: Compared with the other architectures, Pix2Pix with Perceptual loss function and generator ResNet 9 blocks showed the lowest MAE (29.5, 107.7, 16.0, 13.4, and 49.1 HU for the whole pelvis, bones, prostate, bladder, and rectum, respectively) and the highest gamma passing rates (99.4 %, using the 1 %/1mm and 10 % dose threshold criterion). Concerning the DVH points, the mean errors were -0.2% for the planning target volume V(95%), 0.1 % for the rectum V(70Gy), and -0.1 % for the bladder V(50Gy). CONCLUSION: The sCT images generated from MRI data with the Pix2Pix architecture had the lowest image errors and similar dose uncertainties (in term of gamma pass-rate and dose-volume histogram metric differences) than other deep learning methods.

The duration of stereotactic body radiotherapy (SBRT) for early-stage non-small cell lung cancer (NSCLC) may affect patient outcomes. We aimed to determine the impact of a continuous versus discontinuous SBRT schedule on local control (LC) and overall survival (OS) in NSCLC patients.Consecutive NSCLC stage I patients (475) treated with SBRT in four centers were retrospectively analyzed. The delivered dose ranged from 48 to 75 Gy in 3-10 fractions. Based on the ratio between the treatment duration (TD) and number of fractions (n), patients were divided into two groups: continuous schedule (CS) (TD ≤ 1.6n; 239 patients) and discontinuous schedule (DS) (TD 1.6n; 236 patients). LC and OS were compared using Cox regression analyses after propensity score matching (216 pairs).The median follow-up period was 41 months. Multivariate analysis showed that the DS (hazard ratio (HR): 0.42; 95 % confidence interval (CI): 0.22-0.78) and number of fractions (HR: 1.24; 95 % CI: 1.07-1.43) were significantly associated with LC. The DS (HR: 0.67; 95 % CI: 0.51-0.89), age (HR: 1.02; 95 % CI: 1-1.03), WHO performance status (HR: 2.27; 95 % CI: 1.39-3.7), and T stage (HR: 1.4; 95 % CI: 1.03-1.87) were significantly associated with OS. The 3-year LC and OS were 92 % and 64 % and 81 % and 53 % for DS and CS treatments, respectively (p 0.01). Cox analysis confirmed that the discontinuous SBRT schedule significantly increased LC and OS.DS is associated with significantly improved LC and OS in early-stage NSCLC patients treated with SBRT.

Understood as a disruption of the conditions of care practice according to established protocols or procedures, crisis situations in radiation oncology departments can have multiple causes. Their seriousness can sometimes impose changes in the decision-making, organizational or technical paradigms. A possible consequence may be the need to make prioritization decisions in access to care, when there is a mismatch between the care needs of a population and the available health resources (whether technical or human). The specificities of care pathways and the wide variety of clinical situations in radiation oncology make these ethical decisions particularly difficult. Anticipation, collegial and multi-professional decision-making procedures or the integration of patient representatives in these prioritization processes are essential tools. Particular attention must be paid to the information to be provided to patients in a concern of transparency and respect. Prioritization situations are real tests for our departments. They go beyond the purely technical aspect of radiation oncology. They can lead to real ethical suffering for health professionals when their values come up against the limits imposed by crisis situations.

International audience; Image-guided radiotherapy (IGRT) has become a standard irradiation technique to improve the clinical outcome of patients in terms of toxicity and local control due to better targeting of radiation during the irradiation fraction. Positioning imaging systems, whether embedded or not, such as kV for 2 x 2D acquisitions and especially kVCBCT for 3D acquisitions are however irradiating in a large volume including the target volume but also healthy tissue, with a theoretical risk of increased toxicity and second cancer. It therefore appears very important both to optimize the absorbed dose due to IGRT practice but also to report it, especially in case of kVCBCT. The AAPM report published in 2018 (<< Image guidance doses delivered duringradiotherapy: Quantification, management, and reduction >>) proposes a management of image guidance doses delivered during radiotherapy. This report is the basis of this focus article that aims at giving orders of magnitude and proposing a management of image guidance doses delivered during radiotherapy inclinical practice. The dose delivered per kVCBCT is about 0.5 to 2 cGy at isocenter according to treatment site. As long as the calculation algorithms are not available in the treatment planning systems, it seems appropriate to use at least the published dose orders of magnitude. This estimate should ultimately allow the clinician to decide on the therapeutic strategy in the event of accumulation of positioning imaging sessions. (c) 2020 Societe francaise de radiotherapie oncologique (SFRO).; La radiothérapie guidée par l’image est devenue une technique standard d’irradiation permettant d’améliorer le devenir clinique des patients en termes de toxicité et de contrôle local du fait d’un meilleur ciblage du rayonnement lors de la séance d’irradiation. Les systèmes d’imagerie de positionnement, embarqués ou non, tels que les kV pour les acquisitions bidimensionnelles et surtout les tomographies coniques de basse énergie pour les acquisitions tridimensionnelles sont cependant irradiants dans un large volume comprenant le volume cible mais aussi du tissu sain, avec un risque théorique de majoration de toxicité et de second cancer. Il apparaît donc très important à la fois d’optimiser la dose délivrée par l’imagerie de contrôle de type tomographies coniques de basse énergie mais aussi de rapporter cette dose. Le rapport de l’AAPM (Association of Physicists in Medicine) publié en 2018 (« Image guidance doses delivered during radiotherapy : Quantification, management, and reduction ») propose une démarche d’optimisation et de gestion de ces doses. Ce rapport constitue la base de cette mise au point dont les objectifs sont de donner les ordres de grandeur des doses délivrées par l’imagerie de positionnement et de proposer une méthodologie de gestion de ces doses dans la pratique clinique. Une tomographie conique de basse énergie délivre approximativement 0,5 à 2 cGy à l’isocentre selon la localisation anatomique. Tant que les algorithmes de calcul ne sont pas disponibles dans les systèmes de planimétrie pour les faisceaux de positionnement, il semble adapté d’utiliser au moins les ordres de grandeur publiés. Cette estimation doit permettre au clinicien de décider de la stratégie thérapeutique en cas d’accumulation de sessions d’imagerie de positionnement.

Adaptive radiotherapy (ART) is a complexe image-guided radiotherapy modality that comprises multiple planning to account for anatomical variations occurring during irradiation. Schematically, two strategies of RTA can be distinguished and combined according to tumor locations. One or more replanning can be proposed to correct systematic variations such as tumor shrinkage. A library of treatment plans with day-to-day plan selection from cone-beam CT imaging can also be proposed to correct random variations such as uterine motion or bladder/rectum volume changes. Because of strong anatomical variations occurring during irradiation, RTA appears therefore particularly justified in head and neck, lung, bladder, cervical and rectum and pancreas tumors, and to a lesser extent for prostate tumors and other digestive tumors. For these tumor locations, ART provides a fairly clear dosimetric benefit but a clinical benefit not yet formally demonstrated. ART cannot be proposed in a routine practice but must be evaluated medico-economically in the context of prospective trials. A rigorous quality control must be associated.

In 2021, the Ethics Commission of the SFRO has chosen the issue of the practice of palliative care in radiotherapy oncology. Radiation oncology plays a central role in the care of patients with cancer in palliative phase. But behind the broad name of palliative radiotherapy, we actually find a large variety of situations involving diverse ethical issues. Radiation oncologists have the delicate task to take into account multiple factors throughout a complex decision-making process. While the question of the therapeutic indication and the technical choice allowing it to be implemented remains central, reflection cannot be limited to these decision-making and technical aspects alone. It is also a question of being able to create the conditions for a singularity focused care and to build an authentic care relationship, beyond technicity. It is through this daily ethical work, in close collaboration with patients, and under essential conditions of multidisciplinarity and multiprofessionalism, that our fundamental role as caregiver can be deployed.

Background The impact of the first coronavirus disease 2019 (COVID-19) wave on cancer patient management was measured within the nationwide network of the Unicancer comprehensive cancer centers in France. Patients and methods The number of patients diagnosed and treated within 17 of the 18 Unicancer centers was collected in 2020 and compared with that during the same periods between 2016 and 2019. Unicancer centers treat close to 20% of cancer patients in France yearly. The reduction in the number of patients attending the Unicancer centers was analyzed per regions and cancer types. The impact of delayed care on cancer-related deaths was calculated based on different hypotheses. Results A 6.8% decrease in patients managed within Unicancer in the first 7 months of 2020 versus 2019 was observed. This reduction reached 21% during April and May, and was not compensated in June and July, nor later until November 2020. This reduction was observed only for newly diagnosed patients, while the clinical activity for previously diagnosed patients increased by 4% similar to previous years. The reduction was more pronounced in women, in breast and prostate cancers, and for patients without metastasis. Using an estimated hazard ratio of 1.06 per month of delay in diagnosis and treatment of new patients, we calculated that the delays observed in the 5-month period from March to July 2020 may result in an excess mortality due to cancer of 1000-6000 patients in coming years. Conclusions In this study, the delays in cancer patient management were observed only for newly diagnosed patients, more frequently in women, for breast cancer, prostate cancer, and nonmetastatic cancers. These delays may result is an excess risk of cancer-related deaths in the coming years., Highlights • A reduction of the number of cancer patients attending cancer centers was observed in France from January to July 2020. • This reduction was observed only for newly diagnosed patients. • The reduction of new diagnosis was more pronounced in women, for breast cancer, and prostate cancer, and nonmetastatic cancer. • No compensation was observed for the last months of 2020. The magnitude of delays may be larger in centers within the same country. • An estimation of the excess cancer death resulting from these delays is presented.

Introduction et but de l’etude La generation de pseudo-scanographie ou tomodensitometrie synthetique a partir d’IRM est necessaire pour le calcul de la dose dans le cadre d’une radiotherapie basee sur l’IRM. De nombreuses methodes d’apprentissage profond ont ete developpees a cet effet. L’objectif de cette etude est de generer des tomodensitometries synthetiques precises avec une methode d’apprentissage profond (Pix2Pix) pour une radiotherapie de la prostate. Materiel et methodes Trente-neuf patients ayant eu une radiotherapie conformationnelle avec modulation d’intensite (RCMI ; delivrant 78 Gy) pour un cancer de la prostate ont eu une scanographie de planification et une IRM en position de traitement. Des tomodensitometries synthetiques ont ete generees a partir de l’IRM par la methode Pix2Pix (conditional generative adversarial network), perceptual loss. Les hyper parametres du modele (momentum, learning rate) ont ete optimises afin d’obtenir la meilleure qualite de tomodensitometrie synthetique. L’evaluation a porte sur la comparaison entre la scanographie de reference et la tomodensitometrie synthetique, sur des criteres d’image et de dose. Les criteres d’image etaient la moyenne des ecarts absolus et la moyenne des ecarts en unites Hounsfield pour le contour externe, les os, la prostate, la vessie et le rectum. Les criteres dosimetriques etaient les moyennes des ecarts absolus des histogrammes dose–volume (sur tomodensitometries synthetiques contre scanographie de planification), pour le volume cible previsionnel, la vessie et le rectum. Des analyses gamma ont ete realisees (locales, 1 %/1 mm et 2 %/2 mm) ainsi que des tests de Wilcoxon. Resultats et analyse statistique Le Tableau 1 presente les resultats des metriques d’images pour le contour externe, les os, la prostate, la vessie et le rectum. En ce qui concerne les criteres dosimetriques, les differences moyennes d’histogrammes dose–volume etaient de 0,5 % pour 95 % du volume cible previsionnel, 0,4 % pour le volume recevant 70 Gy (V70 Gy) du rectum et 0,1 % pour le V50 Gy de la vessie. Les taux de passe gamma etaient de 99,4 % pour le critere 1 %/1 mm et de 100 %, pour le critere 2 %/2 mm. Les gamma moyens etaient respectivement de 0,31 et 0,17. Les doses moyennes entre la scanographie de reference et la tomodensitometrie synthetique n’etaient pas significativement differentes. L’analyse statistique a montre la complexite de l’evaluation dans le rectum due a la mobilite des gaz. En effet, le cas ayant la plus grande difference de position du gaz entre la scanographie de reference et l’IRM, a montre le gamma le plus bas et la moyenne des ecarts absolus la plus elevee et inversement. Conclusion Afin de generer une tomodensitometrie synthetique a partir de l’IRM de la prostate pour le calcul de la dose, l’architecture Pix2Pix fournit une moyenne des ecarts absolus de 29,5 HU et une difference de dose inferieure a 0,3 %. Ces resultats sont parmi les meilleurs de la litterature pour une radiotherapie de la prostate. Les faibles incertitudes de dose ouvrent la voie a une utilisation clinique de la tomodensitometrie synthetique pour la planification dosimetrique, a condition qu’un controle de qualite systematique, s’affranchissant de la scanographie de reference, puisse etre mis en place.

Introduction et but de l’etude La radiotherapie en conditions stereotaxiques peut etre proposee comme traitement de rattrapage pour des recidives locales selectionnees de cancer de prostate apres une premiere irradiation. Si les resultats cliniques sont encourageants, l’experience est encore limitee. Une question cruciale est en particulier le choix des contraintes dose–volume appropriees lors de la planification. Le premier objectif de cette etude dosimetrique etait de quantifier la proportion de patients respectant effectivement les contraintes dose–volume definies selon l’essai du Getug-31, testant le schema de dose 36 Gy en six fractions. Le deuxieme objectif etait d’expliquer pourquoi ces contraintes ne pouvaient potentiellement pas etre respectees. Le dernier objectif etait de proposer des contraintes dose–volume plus adaptees. Materiel et methodes Les dossiers de 141 patients, pris en charge entre 2011 et 2020 dans deux centres francais experts par reirradiation stereotaxique prostatique avec CyberKnife®, ont ete analyses retrospectivement. Le schema de dose de 36 Gy en six fractions etait prescrit. Les contraintes dose–volume a respecter selon le Getug-31 etaient les suivantes : V95 % ≥ 95 % pour le volume cible previsionnel, V12Gy Resultats et analyse statistique Le pourcentage de patients respectant toutes les contraintes dose–volume n’etait que de 19 %. Ces patients avaient un volume cible previsionnel moyen de 18,5 cm3, alors qu’il etait de 40,5 cm3 dans toute la serie. Un pourcentage de 98 % des patients ayant un ratio contraintes dose–volume/prostate superieur a 0,5 ne pouvaient pas respecter les contraintes dose–volume dans les organes a risque. La couverture du volume cible et l’epargne des organes a risque diminuaient significativement avec l’augmentation du volume cible previsionnel, du volume cible anatomoclinique, du ratio volume cible anatomoclinique/prostate, des volumes d’intersection entre le volume cible previsionnel et la paroi vesicale et entre le volume cible previsionnel et la paroi rectale. Des valeurs seuils de volume cible previsionnel inferieures a 20 cm3 et 40 cm3 permettaient de respecter respectivement la couverture dans le volume cible previsionnel et les contraintes de dose dans la paroi vesicale. Afin d’ameliorer le respect des contraintes dose–volume en cas de volume cible important, les parametres suivants ont ete identifies pour les organes a risque : V12Gy Conclusion En cas de reirradiation prostatique a une dose de 36 Gy, les contraintes dose–volume du Getug-31 semblent realisables uniquement pour de petits volumes cibles (volume cible anatomoclinique inferieur a la moitie de la prostate). Dans le cas ou le volume cible est trop important, de nouvelles contraintes ont ete proposees. L’autre alternative, dans cette situation, est de s’orienter vers d’autres techniques de rattrapage.

Introduction et but de l’etude La question ethique est une thematique emergente et peu exploree dans le monde de la radiotherapie. L’objectif de notre travail etait de preciser le questionnement ethique en radiotherapie dans une approche multiprofessionnelle. Materiel et methodes Une etude multicentrique a ete realisee dans 22 departements de radiotherapie francais, a partir d’un questionnaire Google Form (dix questions) soumis aux oncologues radiotherapeutes, manipulateurs d’electroradiologie, physiciens medicaux, assistantes medicales et cadres. Le questionnaire visait a mieux comprendre la frequence et la nature du questionnement ethique dans les departements de radiotherapie, ainsi que le besoin de formation. Resultats et analyse statistique Un total de 200 personnes a repondu aux questionnaires, se repartissant en : oncologues radiotherapeutes (37 %), manipulateurs d’electroradiologie (37 %), physiciens medicaux (12,5 %), assistantes medicales (10 %) et cadres (3,5 %). Le nombre moyen d’annees d’experience en radiotherapie etait de 12 ans (extremes : 6 mois - 40 ans). En termes de frequence dans la pratique de radiotherapie, la question ethique se posait : frequemment (plus d’une fois par mois ; 52,5 %), rarement (entre trois et dix fois par an ; 35,5 %), exceptionnellement (moins de deux fois par an ; 9,5 %) et jamais (2,5 %). En termes de nature, la question ethique concernait : la comprehension et/ou l’acceptation du traitement par les patients (71 %), les objectifs attendus du traitement (65 %), la lourdeur technique et organisationnelle du traitement (62 %) et le cout du traitement (13 %). Une specificite de la question ethique en radiotherapie etait reconnue pour 64 % des personnels. Les questions ethiques etaient effectivement discutees dans les departements de radiotherapie : jamais (18,5 %), parfois (47,5 %), souvent (10,5 %) et ne se prononce pas (18,5 %). Les questions d’ethique etaient considerees comme suffisamment discutees dans ces departements : non (47,5 %), oui (14 %) et ne se prononce pas (38,5 %). Seuls 17 % des personnels ont deja eu une formation en ethique medicale. Le besoin de formation specifique etait ressenti par 83,5 % des personnels n’ayant jamais eu de formation. Conclusion La question ethique se pose effectivement assez frequemment et specifiquement en radiotherapie, avec un sentiment d’insuffisance a la fois de discussion dans les departements et de formation. Les questions principales d’ethique concernent la comprehension du traitement par les patients, ses objectifs et la lourdeur de ceux-ci.

International audience; PURPOSE: In radiotherapy, MRI is used for target volume and organs-at-risk delineation for its superior soft-tissue contrast as compared to CT imaging. However, MRI does not provide the electron density of tissue necessary for dose calculation. Several methods of synthetic-CT (sCT) generation from MRI data have been developed for radiotherapy dose calculation. This work reviewed deep learning (DL) sCT generation methods and their associated image and dose evaluation, in the context of MRI-based dose calculation. METHODS: We searched the PubMed and ScienceDirect electronic databases from January 2010 to March 2021. For each paper, several items were screened and compiled in figures and tables. RESULTS: This review included 57 studies. The DL methods were either generator-only based (45% of the reviewed studies), or generative adversarial network (GAN) architecture and its variants (55% of the reviewed studies). The brain and pelvis were the most commonly investigated anatomical localizations (39% and 28% of the reviewed studies, respectively), and more rarely, the head-and-neck (HandN) (15%), abdomen (10%), liver (5%) or breast (3%). All the studies performed an image evaluation of sCTs with a diversity of metrics, with only 36 studies performing dosimetric evaluations of sCT. CONCLUSIONS: The median mean absolute errors were around 76 HU for the brain and HandN sCTs and 40 HU for the pelvis sCTs. For the brain, the mean dose difference between the sCT and the reference CT was

International audience; Adaptive radiotherapy (ART) corresponds to various replanning strategies aiming to correct for anatomical variations occurring during the course of radiotherapy. The goal of the article was to report the rational, feasibility and benefit of using PET and/or MRI to guide this ART strategy in various tumor localizations. The anatomical modifications defined by scanner taking into account tumour mobility and volume variation are not always sufficient to optimise treatment. The contribution of functional imaging by PET or the precision of soft tissue by MRI makes it possible to consider optimized ART. Today, the most important data for both PET and MRI are for lung, head and neck, cervical and prostate cancers. PET and MRI guided ART appears feasible and safe, however in a very limited clinical experience. Phase I/II studies should be therefore performed, before proposing cost-effectiveness comparisons in randomized trials and before using the approach in routine practice.

International audience; Multicenter studies are needed to demonstrate the clinical potential value of radiomics as a prognostic tool. However, variability in scanner models, acquisition protocols and reconstruction settings are unavoidable and radiomic features are notoriously sensitive to these factors, which hinders pooling them in a statistical analysis. A statistical harmonization method called ComBat was developed to deal with the "batch effect" in gene expression microarray data and was used in radiomics studies to deal with the "center-effect". Our goal was to evaluate modifications in ComBat allowing for more flexibility in choosing a reference and improving robustness of the estimation. Two modified ComBat versions were evaluated M-ComBat allows to transform all features distributions to a chosen reference, instead of the overall mean, providing more flexibility. B-ComBat adds bootstrap and Monte Carlo for improved robustness in the estimation. BM-ComBat combines both modifications. The four versions were compared regarding their ability to harmonize features in a multicenter context in two different clinical datasets. The first contains 119 locally advanced cervical cancer patients from 3 centers, with magnetic resonance imaging and positron emission tomography imaging. In that case ComBat was applied with 3 labels corresponding to each center. The second one contains 98 locally advanced laryngeal cancer patients from 5 centers with contrast-enhanced computed tomography. In that specific case, because imaging settings were highly heterogeneous even within each of the five centers, unsupervised clustering was used to determine two labels for applying ComBat. The impact of each harmonization was evaluated through three different machine learning pipelines for the modelling step in predicting the clinical outcomes, across two performance metrics (balanced accuracy and Matthews correlation coefficient). Before harmonization, almost all radiomic features had significantly different distributions between labels. These differences were successfully removed with all ComBat versions. The predictive ability of the radiomic models was always improved with harmonization and the improved ComBat provided the best results. This was observed consistently in both datasets, through all machine learning pipelines and performance metrics. The proposed modifications allow for more flexibility and robustness in the estimation. They also slightly but consistently improve the predictive power of resulting radiomic models.

Myocardial scar-related ventricular tachycardia is a serious and potentially life-threatening arrhythmia. The prevention of sudden rhythmic death and ventricular tachycardia recurrence relies on implantable cardioverter defibrillator (ICD), anti-arrhythmic drugs and more recently on radiofrequency catheter ablation. Nevertheless, these approaches have their own risk of adverse events and complications, with a recurrence rate up to 50 % at 2 years. Stereotactic body radiotherapy, delivered in a single dose of 25Gy, has emerged as a new therapeutic tool in the management of highly refractory ventricular tachycardia. In 2017, the very first prospective 5-patient cohort suffering from recurrent ventricular tachycardia on structural heart disease (40 % of ischemic cardiomyopathy) who benefited from cardiac stereotactic body radiotherapy was published. After stereotactic body radiotherapy, the authors observed a strong ventricular tachycardia burden reduction at 12 months, with no major side effects. Since then, around 100 cases have been described in the literature, particularly in the prospective ENCORE-VT study, with positive short- and medium-term outcomes in terms of safety and ventricular tachycardia burden reduction. Recently, another American prospective 5-patient series, published in March 2020, mitigated these results since all patients presented a ventricular tachycardia recurrence at 12 months despite an initial reduction in ventricular tachycardia burden. This article describes the use of stereotactic body radiotherapy in refractory VT, the rationale of the technique, its implementation, preliminary results and potential acute and long-term consequences.

Resume Objectif de l’etude Pour faciliter la formation a la delineation, la Societe francaise de radiotherapie oncologique (SFRO) et l’association de formation continue en oncologie radiotherapie (Afcor) ont cree en 2008 un site Internet de radioanatomie et d’aide a la delineation. Materiel et methodes Entre 2015 et 2017, une mise a jour du site a ete entreprise, necessitant la mise en place de deux parties : des cours theoriques d’une part, et des ateliers de delineation en ligne d’autre part. Resultats Un nouveau site exploitant l’ensemble des nouvelles technologies numeriques a ete mis en ligne. Les cours ont ete realises sous forme de videos commentees et consultables a tout moment. La partie pratique offre une interface de delineation en ligne qui genere a la fin de l’exercice un rapport permettant de quantifier la qualite de sa delineation. Conclusion Siriade 2.0 est un outil numerique innovant qui s’inscrit en complement des formations initiales et continues deja disponibles.

Resume Le developpement de la radiotherapie stereotaxique ces dix dernieres annees oblige les services de radiotherapie a redoubler d’effort dans le domaine de la qualite et de la gestion des risques. Des controles de plus en plus complexes et rigoureux des machines de traitement, mais aussi une formation solide des equipes doivent ainsi etre mis en place. L’hypofractionnement extreme necessite a la fois une vigilance accrue au pupitre et des procedures bien definies connues de tous. Les organisations mises en place contribuent a la maitrise de ces risques eleves. La presence medicale au debut des traitements est precisee de facon reglementaire depuis janvier 2017. Celle-ci permet non seulement d’assurer une securite, mais egalement une transmission d’informations vers les manipulateurs en electroradiologie. Au centre Eugene-Marquis, il a ete decide de definir des competences specifiques pour les manipulateurs en electroradiologie concernant les radiotherapies stereotaxiques sur les machines dediees a cette technique (Cyberknife® et Versa HD® type Novalis®). Une habilitation, formalisee apres un temps de formation, est reevaluee annuellement. La communication entre et dans les metiers de la radiotherapie joue aussi un role important pour maintenir un haut niveau d’echanges et un partage d’informations. Les moyens mis en œuvre au centre Eugene-Marquis permettent ainsi de mieux maitriser le risque de la radiotherapie stereotaxique, en accordant une part importante a la gestion des competences au poste de traitement.

Resume La radiotherapie conformationnelle avec modulation d’intensite (RCMI) permet une epargne significative en termes de dose aux organes a risque chez les patientes prises en charge pour un cancer gynecologique. Compte tenu des forts gradients de dose autour du volume cible previsionnel, les variations anatomiques interne des organes pendant le traitement peuvent cependant entrainer un « sous-dosage » du volume cible anatomoclinique et un surdosage des organes a risque. Il est donc important de prendre en compte le mouvement et les deformations des organes pelviens et d’etudier les solutions potentielles apportees par la radiotherapie guidee par l’image. Une revue de la litterature a ete effectuee en utilisant les bases de donnees suivantes : Medline, Embase, la bibliotheque Cochrane, Web of Science, Cinahl et Pubmed. Des strategies de recherche appropriees aux bases de donnees ont ete elaborees en fonction des termes relatifs a « uterine neoplasms, image-guided radiotherapy, adaptative radiotherapy, organ motion and target volume ». Ces etudes montrent que le mouvement uterin est principalement influence par la repletion vesicale, le mouvement cervical et de la voute vaginale par la repletion rectale. Les marges entre le volume cible anatomoclinique et le volume cible previsionnel basees sur la population sont importantes, entrainant une inclusion inutile des organes a risque dans le volume cible previsionnel, reduisant les avantages de la RCMI. Cependant, le mouvement des organes pelviens etant specifique a chaque patiente, des marges de volume cible previsionnel individualisees et des strategies de radiotherapie adaptative semblent pouvoir assurer une couverture adequate du volume cible tout en augmentant l’epargne des organes a risque. Dans cette etude, nous faisons une revue des differentes techniques de radiotherapie guidee par l’image utilisees et les perspectives concernant la radiotherapie adaptative.

Radiation therapy technique and schedules could be adapted to patient's age because of a natural history of prostate cancer perceived as different, taking into account the comorbidities of patients but also a particular tolerance of elderly subjects. Thus, in localized prostate cancer, evaluation of associated diseases is essential before considering a treatment that will be of interest only if the life expectancy is greater than 10 years. When a curative approach is decided, radiotherapy holds a place of choice. Due to the recent results of randomized studies evaluating moderate hypofractionnated radiotherapy, showing a carcinological equivalence compared to a standard fractionation, this reduction in the duration of treatment appears particularly indicated in this elderly population. This approach permits to maintain the quality of life of patients, potentially with lower costs for society. The purpose of this article is to present the results of randomized trials of moderate hypofractionnation and discuss their application in the population of elderly patients with localized prostate cancer.

In external beam radiotherapy, the dose planning is currently based on computed tomography (CT) images. A relation between Hounsfield numbers and electron densities (or mass densities) is necessary for dose calculation taking heterogeneities into account. In image-guided radiotherapy process, the cone beam CT is classically used for tissue visualization and registration. Cone beam CT for dose calculation is also attractive in dose reporting/monitoring perspectives and particularly in a context of dose-guided adaptive radiotherapy. The accuracy of cone beam CT-based dose calculation is limited by image characteristics such as quality, Hounsfield numbers consistency and restrictive sizes of volume acquisition. The analysis of the literature identifies three kinds of strategies for cone beam CT-based dose calculation: establishment of Hounsfield numbers versus densities curves, density override to regions of interest, and deformable registration between CT and cone beam CT images. Literature results show that discrepancies between the reference CT-based dose calculation and the cone beam CT-based dose calculation are often lower than 3%, regardless of the method. However, they can also reach 10% with unsuitable method. Even if the accuracy of the cone beam CT-based dose calculation is independent of the method, some strategies are promising but need improvements in the automating process for a routine implementation.

Quality of life is a major issue for good prognostic prostate cancer, for which brachytherapy is one of the reference treatments. Stereotactic Body Radiotherapy (SBRT) is a recent alternative however not yet validated as a standard treatment. This review of the literature reports and compares the toxicities and the quality of life, either after exclusive brachytherapy with iodine 125 or after SBRT. The comparison is made with the limitations of the absence of randomized trial comparing the two treatment techniques. Acute toxicity appears to be lower after SBRT compared to brachytherapy (from 10 to 40 % versus 30 to 40 %, respectively). Conversely, acute and late gastrointestinal toxicity (from 0 to 21 % and from 0 to 10 % of grade 2, respectively) appears more frequent with SBRT. Late urinary toxicity seems identical between both techniques (from 20 to 30 % of grade 2), with a possible urinary flare syndrome. Both treatments have an impact on erectile dysfunction, although it is not possible to conclude that a technique is superior because of the limited data on SBRT. SBRT has better bowel and urinary (irritation or obstruction) quality of life scores than brachytherapy; while sexual and urinary incontinence remain the same. The absence of randomized trial comparing SBRT with brachytherapy for prostate cancers does not allow to conclude on the superiority of one technique over another, thus justifying a phase III medicoeconomic evaluation.

Bladder dose constraints in case of conformational radiotherapy/intensity-modulated radiotherapy and stereotactic radiotherapy are reported from the literature, in particular from the French radiotherapy society RECORAD recommendations, according to the treated pelvic tumor sites. The dose-volume effect on urinary toxicity is not clearly demonstrated, making difficult to establish absolute dose constraints for the bladder. In case of high-dose prostate cancer radiotherapy, the bladder dose constraints are: V60Gy

International audience; Purpose In the context of locally advanced oropharyngeal cancer (LAOC) treated with definitive radiotherapy (RT) (combined with chemotherapy or cetuximab), the aims of this study were: (1) to identify PET-FDG parameters correlated with overall survival (OS) from a first cohort of patients; then (2) to compute a prognostic score; and (3) finally to validate this scoring system in a second independent cohort of patients. Materials and methods A total of 76 consecutive patients (training cohort from Rennes) treated with chemoradiotherapy or RT with cetuximab for LAOC were used to build a predictive model of locoregional control (LRC) and OS based on PET-FDG parameters. After internal calibration and validation of this model, a nomogram and a scoring system were developed and tested in a validation cohort of 46 consecutive patients treated with definitive RT for LAOC in Lausanne. Results In multivariate analysis, the metabolic tumour volume (MTV) of the primary tumour and the lymph nodes were independent predictive factors for LRC and OS. Internal calibration showed a very good adjustment between the predicted OS and the observed OS at 24 months. Using the predictive score, two risk groups were identified (median OS 42 versus 14 months, p

Prostate cancer is a sensitive adenocarcinoma, in more than 80% of cases, to chemical castration, due to its hormone dependence. Locally advanced and/or high-risk cancer is defined based on clinical stage, initial prostate specific antigen serum concentration value or high Gleason score. Hormone therapy associated with radiation therapy is the standard of management and improves local control, reduces the risk of distant metastasis and improves specific and overall survival. Duration of hormone therapy, dose level of radiation therapy alone or associated with brachytherapy are controversial data in the literature. The therapeutic choice, multidisciplinary, depends on the age and comorbidity of the patient, the prognostic criteria of the pathology and the urinary function of the patient. Current research focuses on optimizing local and distant control of these aggressive forms and incorporates neoadjuvant or adjuvant chemotherapy and also new hormone therapies.

International audience; Purpose - To guide parotid gland (PG) sparing at the dose planning step, a specific model based on overlap between PTV and organ at risk (Moore et al.) was developed and evaluated for VMAT in head-and-neck (H&N) cancer radiotherapy. Materials and methods - One hundred and sixty patients treated for locally advanced H&N cancer were included. A model optimization was first performed (20 patients) before a model evaluation (110 patients). Thirty cases were planned with and without the model to quantify the PG dose sparing. The inter-operator variability was evaluated on one case, planned by 12 operators with and without the model. The endpoints were PG mean dose (D), PTV homogeneity and number of monitor units (MU). Results - The PG D predicted by the model was reached in 89% of cases. Using the model significantly reduced the PG D: -6.1±4.3Gy. Plans with the model showed lower PTV dose homogeneity and more MUs (+10.5% on average). For the inter-operator variability, PG dose volume histograms without the optimized model were significantly different compared to those with the model; the D standard deviation for the ipsilateral PG decreased from 2.2Gy to 1.2Gy. For the contralateral PG, this value decreased from 2.9Gy to 0.8Gy. Conclusion - During the H&N inverse planning, the optimized model guides to the lowest PG achievable mean dose, allowing a significant PG mean dose reduction of -6.1Gy. Integrating this method at the treatment-planning step significantly reduced the inter-patient and inter-operator variabilities.

Purpose In context of head-and-neck radiotherapy, this study aims to compare MR image quality according to diagnostic (DIAG) and radiotherapy (RT) setups; and to optimise an MRI-protocol (including 3D T1 and T2-weighted sequences) for dose-planning (based on pseudo-CT generation). Materials and methods To compare DIAG and RT setups, signal-to-noise-ratio (SNR) and percentage-image-uniformity (PIU) were computed on T1 images of phantoms and volunteers. Influence of the sample conductivity on SNR was quantified using homemade phantoms. To obtain reliable T1 and T2 images for RT-planning, an experimental design was performed on volunteers by using SNR, contrast-to-noise-ratio (CNR) and mean-opinion-score (MOS). Further, pseudo-CTs were generated from 8 patients T2 images with a state-of-art deep-learning method. These pseudo-CTs were evaluated by mean-absolute-error (MAE) and mean-error (ME). Results SNR was higher for DIAG-setup compared to RT-setup (SNR-ratio = 1.3). A clear influence of the conductivity on SNR was observed. PIU was higher for DIAG-setup (38.8%) compared to RT-setup (33.5%). Regarding the protocol optimisation, SNR, CNR, and MOS were 20.6, 6.16, and 3.91 for the optimal T1 sequence. For the optimal T2 sequence, SNR, CNR and MOS were 25.6, 44.46 and 4.0. In the whole head-and-neck area, the mean MAE and ME of the pseudo-CTs were 82.8 and -3.9 HU. Conclusion We quantified the image quality decrease induces by using an RT-setup for head-and-neck radiotherapy. To compensate this decrease, an MRI protocol was optimised by using an experimental design. This protocol of 15 minutes provides accurate images which could be used for MRI-dose-planning in clinical practice.

Resume Les tachycardies ventriculaires secondaires a la presence de zones cicatricielles heterogenes au sein du myocarde representent une forme d’arythmie grave degradant la qualite de vie et pouvant engager le pronostic vital a court terme. La prevention de la mort subite rythmique et des recidives repose sur le defibrillateur automatique implantable, les medicaments antiarythmiques et plus recemment sur l’ablation par radiofrequence. Neanmoins ces approches presentent des risques d’effets indesirables et de complications, avec un taux de recidive qui reste eleve, pouvant atteindre 50 % a 2 ans. La radiotherapie stereotaxique corporelle en dose unique de 25 Gy est apparue comme un nouvel outil non invasif de prise en charge complementaire des tachycardies ventriculaires hautement refractaires, qui peuvent concerner plusieurs dizaines de patients par an en France. Ainsi, en 2017 la toute premiere serie prospective de cinq patients atteints de tachycardies ventriculaires recidivantes sur cardiopathie structurelle (dont 40 % de cardiopathies ischemiques) ayant beneficie d’une radiotherapie stereotaxique corporelle cardiaque a ete publiee. Apres la radiotherapie stereotaxique corporelle, les auteurs ont pu observer une reduction marquee de la charge en tachycardies ventriculaires a 12 mois, sans effet indesirable majeur a court terme. Depuis, une centaine de cas de patients traites ont ete decrits dans la litterature, notamment dans l’etude prospective ENCORE-VT avec des resultats a court et moyen termes plutot positifs en termes de securite et de reduction de la charge en tachycardies ventriculaires. Recemment, une autre serie prospective americaine parue en mars 2020 menee chez cinq patients nuancait ces resultats avec une recidive rythmique chez la totalite des patients a 12 mois, malgre une reduction initiale observee. Cet article decrit l’utilisation de la radiotherapie stereotaxique corporelle pour les tachycardies ventriculaires refractaires, son rationnel d’utilisation, sa mise en œuvre, ses resultats preliminaires et ses potentielles consequences a court, moyen et long termes.