[Ethical stakes of information in radiation oncology: Thinking the risk and building the therapeutic alliance]

Informing patients before receiving radiation therapy is a fundamental ethical imperative. As a condition of the possibility of autonomy, information allows people to make health decisions concerning themselves, which is required by French law. This information includes in particular the potential risks due to radiation therapy. It is therefore necessary to think about what risk is, and how to define and assess it, in order to finally communicate it. The practice of informing people involves many ethical issues relating to the very content of the information, the form in which it is transmitted or even the intention that leads the health professional to say (or not to say) the risk. The transmission of information also questions the way to build a relationship of trust with the patients and how to integrate their own representations about these treatments. Between the risks of paternalism or even defensive medicine, this practice is at the heart of our professional practice.

The inverse square law: A basic principle in brachytherapy

The purpose of this article is to remind the importance of the inverse square law in radiotherapy and especially in brachytherapy. Indeed, beyond the impact in radiation therapy with high energy beam, there is the use of radionuclides and low energy photons with short FSD where it is still more important. Comparisons between Iridium Brachytherapy and low energy X-rays brachytherapy show equivalent dose distributions in the first few centimeters. If the inverse square law is not the only element influencing the dose distributions calculations, it must not be forgotten. And it is playing a major role in brachytherapy with short FSD (<6cm).

Radiotherapy and pregnancy

We present the updated recommendations of the French society for radiation oncology on radiotherapy and pregnancy. The occurrence of cancer during pregnancy is a rare event (approximately 1 in 1000 pregnancies). The risks for the embryo or the foetus depend on the gestational age at the time of irradiation. The main risks are malformations with microcephaly and mental retardation. There is also a risk of radiation-induced cancer in the unborn child. In the case of only supradiaphragmatic irradiation, radiotherapy can be performed most often in pregnant women without risk to the foetus. On the other hand, in the case of an indication for subdiaphragmatic irradiation, therapeutic termination of the pregnancy should be proposed. In all cases, when radiotherapy is chosen, a phantom estimation of the dose delivered to the foetus, confirmed by in vivo measurement, is recommended. Conformational radiotherapy is the preferred technique because of the lower dose delivered to the foetus (except in tumour locations where other techniques such as IMRT are recommended).

Radiotherapy for penile cancers

Penile cancers are uncommon and should be treated in expert center. Radiotherapy indications are mainly limited to exclusive brachytherapy for early stage penile glans cancer. Brachytherapy yields to excellent outcome for disease control and organ and function preservation. Only scarce data are available for external beam radiation therapy. It could be considered as palliative setting for irradiation of the primary tumor. For lymph node irradiation, external beam radiation therapy (with or without chemotherapy) could be discussed either as neoadjuvant approach prior to surgery for massive inguinal lymph node invasion or as adjuvant approach in case of high-risk of relapse. However, these cases should be discussed on an individual basis, as the level of evidence is poor. We present the recommendations of the French Society of Oncological Radiotherapy on the indications and techniques for external beam radiotherapy and brachytherapy for penile glans cancer.

A priori quality assurance using a benchmark case of the randomized phase 2 GORTEC 2014-14 in oligometastatic head and neck cancer patients

PURPOSE

A Benchmark Case (BC) was performed as part of the quality assurance process of the randomized phase 2 GORTEC 2014-14 OMET study, testing the possibility of multisite stereotactic radiation therapy (SBRT) alone in oligometastatic head and neck squamous cell carcinoma (HNSCC) as an alternative to systemic treatment and SBRT.

MATERIAL AND METHODS

Compliance of the investigating centers with the prescription, delineation, planning and evaluation recommendations available in the research protocol was assessed. In addition, classical dosimetric analysis was supplemented by quantitative geometric analysis using conformation indices.

RESULTS

Twenty centers participated in the BC analysis. Among them, four major deviations (MaD) were reported in two centers. Two (10%) centers in MaD had omitted the satellite tumor nodule and secondarily validated after revision. Their respective DICE indexes were 0.37 and 0 and use of extracranial SBRT devices suboptimal There were significant residual heterogeneities between participating centers, including those with a similar SBRT equipment, with impact of plan quality using standard indicators and geometric indices.

CONCLUSION

A priori QA using a BC conditioning the participation of the clinical investigation centers showed deviations from good SBRT practice and led to the exclusion of one out of the twenty participating centers. The majority of centers have demonstrated rigorous compliance with the research protocol. The use of quality indexes adds a complementary approach to improve assessment of plan quality.

[Ethical stakes in palliative care in radiation oncology]

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.

[Health democracy: Patient partnership]

In 2019, the scientific committee of the French society of radiation oncology (SFRO) created an ethics committee. Its mission is to provide our professional community with food for thought on ethical issues, and to identify its specificities within the radiation oncology departments. For the 2020 annual conference, the commission looked into the evolution of the patient-carer relationship, and more particularly to the strong idea of patient partnership. Indeed, the writing of the White Book of Cancer gave voice to sick people and stressed the need for new devices, such as the Caregiving Time. Patients can no longer be considered as objects of care but as people whose dignity and autonomy must be imperatively respected. The acquisition of knowledge allows a bilateral exchange, prerequisite of a dynamic collaboration. Patients can be partners in their own care, partners in training and research (expert patient), but also partners in health institutions and policies. It is this notion of partnership and involvement of the person in their path of care in radiation oncology that we will analyse here. It will be about defining it, by developing the concept of autonomy, and bringing out its complexity and ambivalence through two examples from our clinical practice: the shared decision-making process for patients with localized prostate cancer and the patient's involvement in the success of his radiotherapy.

A brief history of contact X-ray brachytherapy 50 kVp

Contact X ray brachytherapy 50 kVp was initiated in the 1930s with the Siemens unit and popularized with the Philips unit in the 1950s. A renaissance was seen in the early 2000s with the Intrabeam™ unit for breast IORT. Presently the Papillon™ systems thanks to its high dose rate (>10Gy/mn) can be used to treat breast (IORT), skin, eyelid and rectal cancers. Future developments are expected to consolidate the place of contact radiotherapy as a safe and efficient treatment for accessible early tumors.

Deterministic model for the transport of energetic particles: Application in the electron radiotherapy

A new deterministic method for calculating the dose distribution in the electron radiotherapy field is presented. The aim of this work was to validate our model by comparing it with the Monte Carlo simulation toolkit, GEANT4. A comparison of the longitudinal and transverse dose deposition profiles and electron distributions in homogeneous water phantoms showed a good accuracy of our model for electron transport, while reducing the calculation time by a factor of 50. Although the Bremsstrahlung effect is not yet implemented in our model, we propose here a method that solves the Boltzmann kinetic equation and provides a viable and efficient alternative to the expensive Monte Carlo modeling.

Évolution des pratiques de prescription des benzodiazépines et apparentés. Qu’en est-il de leur association ?

Introduction

L’utilisation prolongée et les associations de benzodiazépines (BZD) anxiolytiques et hypnotiques exposent à des risques à court et long terme (dépendance, démence, troubles psychomoteurs…). Selon la Haute Autorité de santé (HAS), il n’y a pas lieu d’associer une BZD et un apparenté (zopiclone ou zolpidem) le soir.

Objectifs

– Évaluer les habitudes de prescription des BZD et de leurs apparentés hypnotiques dans une population de patients suivis en psychiatrie hospitalière.

– Suivre sur 6 années l’évolution de ces pratiques de prescription et l’émergence d’alternatives thérapeutiques aux BZD.

– Établir un parallèle avec les recommandations et les actualités de la littérature au sujet de ces risques pendant cette même période.

Méthode

L’étude rétrospective a été réalisée au centre hospitalier Henri-Laborit (Poitiers) en sélectionnant les ordonnances informatisées comportant des BZD et/ou apparentés sur une période allant du 1er janvier 2008 au 31 décembre 2013, par tranche d’une année. Les associations de ces molécules et leurs posologies ont été répertoriées.

Résultats

L’analyse de 6511 ordonnances a notamment mis en évidence que la prescription de zolpidem ou zopiclone seuls, sans association à une benzodiazépine, est majoritaire (77,5 % des ordonnances en moyenne) jusqu’en 2010. Puis elle diminue fortement (plus que 38 % en 2013) et elle est inférieure à celle de benzodiazépine seule pendant les 3 années suivantes. Parallèlement, le nombre total d’ordonnances dans cet hôpital est en constante augmentation. L’association de benzodiazépine et d’apparentés sur une même ordonnance reste peu courante, dans 2 % des prescriptions en moyenne, mais la prise des deux se situe le soir dans 91 % des cas (69–100 %).

Conclusion

L’étude montre une diminution de prescription d’hypnotiques apparentés aux BZD, allant de pair avec les mises en garde sur leurs effets indésirables et aux actions de l’HAS. Leur association en soirée à des BZD reste présente et une étude prospective auprès des prescripteurs pour connaître leur choix d’alternative thérapeutique est nécessaire.

Opiate dependence induces network state shifts in the limbic system

Among current theories of addiction, hedonic homeostasis dysregulation predicts that the brain reward systems, particularly the mesolimbic dopamine system, switch from a physiological state to a new "set point." In opiate addiction, evidence show that the dopamine system principal targets, prefrontal cortex (PFC), nucleus accumbens (NAC) and basolateral amygdala complex (BLA) also adapt to repeated drug stimulation. Here we investigated the impact of chronic morphine on the dynamics of the network of these three interconnected structures. For that purpose we performed simultaneous electrophysiological recordings in freely-moving rats subcutaneously implanted with continuous-release morphine pellets. Chronic morphine produced a shift in the network state underpinned by changes in Delta and Gamma oscillations in the LFP of PFC, NAC and BLA, in correlation to behavioral changes. However despite continuous stimulation by the drug, an apparent normalization of the network activity and state occurred after 2 days indicating large scale adaptations. Blockade of μ opioid receptors was nonetheless sufficient to disrupt this acquired new stability in morphine-dependent animals. In line with the homeostatic dysregulation theory of addiction, our study provides original direct evidence that the PFC-NAC-BLA network of the dependent brain is characterized by a de novo balance for which the drug of abuse becomes the main contributor.

[Multifocal Langerhans cell histiocytosis of bone: indications for radiotherapy]

Langerhans cell histiocytosis is a non-malignant proliferative disease of unknown etiology that can affect one or more organs. This is a rare disease, 1 to 2/100,000, affecting mainly children with a male predominance. The osseous lesions are the most frequent (60 to 90%). There is however no consensus treatment for the management of these sites. We report the cases of two patients successfully treated with radiotherapy after primary chemotherapy, at doses of 15 Gy in ten sessions of 1.5 Gy for one patient and 18 Gy in ten fractions of 1.8 Gy for the other. Single or multifocal bone Langerhans cell histiocytosis without visceral involvement is a benign, self-limiting affection in most cases. Some bone lesions could be treated by radiotherapy alone. But the high variability of doses currently given in the literature does not allow determining the lowest effective dose limiting the risk of secondary neoplasia or impaired growth in children, in whom lower doses of 6 to 8 Gy are recommended. The decision of radiotherapy must be weighed against the risk of the disease. Caution should be the rule in this non-malignant tumour pathology.

[Radiation therapy for glial tumors: technical aspects and clinical indications]

Radiotherapy of glial tumors is rapidly evolving with the recent technical and therapeutic progress. About technical aspects, progress in technical imaging and development of non-coplanar conformal and IMRT techniques provide new possibilities for sparing healthy tissue while increasing dose in tumoral volume. Furthermore, functional and molecular imaging are helpful for delineation and for prediction of relapse. Even modest, the actual improvement of survival with radiochemotherapy leads now to new and important developments for clinical research according to clinical data (age, general status), biological data (MGMT promotor methylation and cytogenetic modifications) and technical data (quality of surgery and radiotherapy). Understanding of molecular mechanisms allows for rational targeting or specific pathways of repair, signaling angiogenesis associated with surgery and radiotherapy in a multidisciplinary approach.

How many populations set foot through the Patagonian door? Genetic composition of the current population of Bahía Blanca (Argentina) based on data from 19 Alu polymorphisms

The city of Bahía Blanca occupies a strategic place in Argentina south of the Pampean region in the north-east corner of the Patagonia. Since 1828, this city has been the historical and political border between Amerindian lands in the south, and the lands of European colonists. Nowadays, Bahía Blanca is an urban population mainly composed by descendents of immigrants from Spain and other European countries with apparently low admixture with Amerindians. In view of the unexpectedly high Amerindian admixture levels (about 46.7%) suggested by mtDNA data, and protein markers (19.5%), we analyzed a set of 19 Alu polymorphisms (18 autosomal, 1 of Chromosome Y) in a well-documented genealogical sample from Bahía Blanca. The genotyped sample was made up of 119 unrelated healthy individuals whose birth place and grandparent origins were fully documented. According to available genealogical records, the total sample has been subdivided into two groups: Bahía Blanca Original (64 individuals with all 4 gandparents born in Argentina) and Bahía Blanca Mix (55 individuals with one to three grandparents born out of Argentina). Allele frequencies and gene diversity values in Bahía Blanca fit well into the European ranges. Population relationships have been tested for 8 Alu markers, whose variation has been described in several Amerindian and European samples. Reynolds genetic distances underline the significant genetic similarity of Bahía Blanca to Europeans (mean distance 0.044) and their differentiation from Amerindians (0.146). Interestingly enough, when the general sample is divided, Bahía Blanca Original appears slightly closer to Amerindians (0.127) in contrast to Bahía Blanca Mix (0.161). Furthermore, the genetic relationships depicted through a principal components analysis emphasize the relative similarity of Bahía Blanca Original to Amerindians. A thorough knowledge of the sample origins has allowed us to make a subtle distinction of the genetic composition of Bahía Blanca.