Incidence, risk factors, and clinical implications of postoperative blood in or near the resection cavity after glioma surgery.

Introduction: Postoperative hematomas that require reoperation are a serious, but uncommon complication to glioma surgery. However, smaller blood volumes are frequently observed, but their clinical significance is less known. Research question: What are the incidence rates, risk factors, and patient-reported outcomes of all measurable blood in or near the resection cavity on postoperative MRI in diffuse glioma patients? Material and methods: We manually segmented intradural and extradural blood from early postoperative MRI of 292 diffuse glioma resections. Potential associations between blood volume and tumor characteristics, demographics, and perioperative factors were explored using non-parametric methods. The assessed outcomes were generic and disease-specific patient-reported HRQoL. Results: Out of the 292 MRI scans included, 184 (63%) had intradural blood, and 212 (73%) had extradural blood in or near the resection cavity. The median blood volumes were 0.4 mL and 3.0 mL, respectively. Intradural blood volume was associated with tumor volume, intraoperative blood loss, and EOR. Extradural blood volume was associated with age and tumor volume. Greater intradural blood volume was associated with less headache and cognitive improvement, but not after adjustments for tumor volume. Discussion and conclusions: Postoperative blood on early postoperative MRI is common. Intradural blood volumes tend to be larger in patients with larger tumors, more intraoperative blood loss, or undergoing subtotal resections. Extradural blood volumes tend to be larger in younger patients with larger tumors. Postoperative blood in or near the resection cavity that does not require reoperation does not seem to affect HRQoL in diffuse glioma patients.

Growth dynamics of untreated meningiomas.

Background: Knowledge about meningioma growth characteristics is needed for developing biologically rational follow-up routines. In this study of untreated meningiomas followed with repeated magnetic resonance imaging (MRI) scans, we studied growth dynamics and explored potential factors associated with tumor growth. Methods: In a single-center cohort study, we included 235 adult patients with radiologically suspected intracranial meningioma and at least 3 MRI scans during follow-up. Tumors were segmented using an automatic algorithm from contrast-enhanced T1 series, and, if needed, manually corrected. Potential meningioma growth curves were statistically compared: linear, exponential, linear radial, or Gompertzian. Factors associated with growth were explored. Results: In 235 patients, 1394 MRI scans were carried out in the median 5-year observational period. Of the models tested, a Gompertzian growth curve best described growth dynamics of meningiomas on group level. 59% of the tumors grew, 27% remained stable, and 14% shrunk. Only 13 patients (5%) underwent surgery during the observational period and were excluded after surgery. Tumor size at the time of diagnosis, multifocality, and length of follow-up were associated with tumor growth, whereas age, sex, presence of peritumoral edema, and hyperintense T2-signal were not significant factors. Conclusions: Untreated meningiomas follow a Gompertzian growth curve, indicating that increasing and potentially doubling subsequent follow-up intervals between MRIs seems biologically reasonable, instead of fixed time intervals. Tumor size at diagnosis is the strongest predictor of future growth, indicating a potential for longer follow-up intervals for smaller tumors. Although most untreated meningiomas grow, few require surgery.

Incidence, management, and outcome of incidental meningioma: what has happened in 10 years?

PURPOSE: The aim of this study was to study the use of brain scanning, and the subsequent findings of presumed incidental meningioma in two time periods, and to study differences in follow-up, treatment, and outcome. METHODS: Records of all performed CT and MRI of the brain during two time periods were retrospectively reviewed in search of patients with presumed incidental meningioma. These patients were further analyzed using medical health records, with the purpose to study clinical handling and outcome during a 3 year follow up. RESULTS: An identical number of unique patients underwent brain imaging during the two time periods (n = 22 259 vs. 22 013). In 2018-2019, 25% more incidental meningiomas were diagnosed compared to 2008-2009 (n = 161 vs. 129, p = 0.052). MRI was used more often in 2018-2019 (26.1 vs. 12.4%, p = 0.004), and the use of contrast enhancement, irrespective of modality, also increased (26.8 vs. 12.2%, p < 0.001). In the most recent cohort, patients were older (median 79 years vs. 73 years, p = 0.03). Indications showed a significant increase of cancer without known metastases among scanned patients. 29.5 and 35.4% of patients in the cohorts were deceased 3 years after diagnosis for causes unrelated to their meningioma. CONCLUSIONS: Despite the same number of unique patients undergoing brain scans in the time periods, there was a trend towards more patients diagnosed with an incidental asymptomatic meningioma in the more recent years. This difference may be attributed to more contrast enhanced scans and more scans among the elderly but needs to be further studied. Patients in the cohort from 2018 to 2019 more often had non-metastatic cancer, with their cause of scan screening for metastases. There was no significant difference in management decision at diagnosis, but within 3 years of follow up significantly more patients in the latter cohort had been re-scanned. Almost a third of all patients were deceased within 3 years after diagnosis, due to causes other than their meningioma.

Overview and recent advances in incidental meningioma.

INTRODUCTION: Meningioma has a prevalence around 1% in the population, and with the increasing use and availability of diagnostic imaging modalities, incidental meningiomas are increasingly detected. There is no clear consensus on their management, although several guidelines suggest firsthand active monitoring if no aggravating factors emerge. However, no collective guidelines on follow-up interval exist. AREAS COVERED: This narrative review covers the epidemiology, diagnosis, growth prediction, and management strategies of incidental meningioma. EXPERT OPINION: Overdiagnosis and excessive follow-up are potential pitfalls in the management of incidental meningioma. An MRI after 6-12 months could be reasonable to rule out rapid growth and differential diagnoses. Using the available prognostic models, one might later suggest more active monitoring for certain patient groups harboring specific radiological features predictive of growth. However, detecting growth may not necessarily be clinically significant as all larger non-growing meningiomas have at one point been small. Too much follow-up may place an unnecessary burden on patients and the health-care system and could be a driver toward overtreatment. It must be contemplated whether growth is an acceptable primary outcome measure or if there are other factors more relevant to consider in this often benign tumor entity.

Intraoperative risk factors for peritumoral infarctions following glioma surgery.

Background: Surgical intraoperative risk factors for peritumoral infarctions are not much studied. In the present study, we explore the possible association between intraoperative factors and infarctions diagnosed from early postoperative MRIs. Methods: We screened all adult patients operated for newly diagnosed or recurrent diffuse gliomas at out department from December 2015 to October 2020 with available postoperative MRI including DWI sequences. Patient data was prospectively collected in a local tumor registry. Immediately after surgery, the surgeon completed a questionnaire on tumor vascularization, tumor stiffness, delineation of tumor from normal brain tissue, which surgical tool(s) were used, and if they had sacrificed a functional artery or a significant vein. Results: Data from 175 operations were included for analysis. Of these, 66 cases (38%) had postoperative peritumoral infarctions. 24 (36%) were rim-shaped and 42 (64%) infarctions were sector-shaped. The median infarction volume was 2.4 â€‹cm3. Surgeon reported sacrifice of a significant vein was associated with infarctions, but we found no clear "dose-response", as "perhaps" was associated with fewer infarctions than "no". None of the other studied factors reached statistical significance. However, there was a trend for more infarctions when an ultrasonic aspirator was used for tumor resection. Subgroup analyses were done for rim-shaped and sector-shaped infarctions, and ultrasonic aspirator was associated with sector-shaped infarctions (p â€‹= â€‹0.032). Infarction rates differed across surgeons (range 15%-67%), p â€‹= â€‹0.021). Conclusion: In this single center study, no clear relationships between surgeon reported intraoperative factors and postoperative infarctions were observed. Still, risks seem to be surgeon dependent.

Is intracranial volume a risk factor for IDH-mutant low-grade glioma? A case-control study.

PURPOSE: Risk of cancer has been associated with body or organ size in several studies. We sought to investigate the relationship between intracranial volume (ICV) (as a proxy for lifetime maximum brain size) and risk of IDH-mutant low-grade glioma. METHODS: In a multicenter case-control study based on population-based data, we included 154 patients with IDH-mutant WHO grade 2 glioma and 995 healthy controls. ICV in both groups was calculated from 3D MRI brain scans using an automated reverse brain mask method, and then compared using a binomial logistic regression model. RESULTS: We found a non-linear association between ICV and risk of glioma with increasing risk above and below a threshold of 1394 ml (p < 0.001). After adjusting for ICV, sex was not a risk factor for glioma. CONCLUSION: Intracranial volume may be a risk factor for IDH-mutant low-grade glioma, but the relationship seems to be non-linear with increased risk both above and below a threshold in intracranial volume.

Brain infarction following meningioma surgery-incidence, risk factors, and impact on function, seizure risk, and patient-reported quality of life.

In this study, we seek to explore the incidence of and potential risk factors for postoperative infarctions after meningioma surgery, in addition to the possible association with new neurological deficits, seizures, and health-related quality of life (HRQoL). A single-center cohort study was conducted, where all patients operated for an intracranial meningioma at our institution between 2007 and 2020 were screened for inclusion. Clinical data were prospectively collected in a local tumor registry, and HRQoL was assessed using both generic and disease-specific instruments. In total, 327 meningioma operations were included, and early postoperative MRIs showed peritumoral infarctions in 114 (34.9%). Median infarction volume was 4.5 ml (interquartile range 2.0-9.5) and 43 (37.7%) of the infarctions were rim-shaped, 44 (38.6%) were sector-shaped, 25 (21.9%) were a combination of rim- and sector-shaped, and two (1.8%) were remote infarctions. Permanent neurological deficits were seen in 22 patients (6.7%) and deficits were associated with infarctions (p < 0.001). There was no difference in frequency of registered postoperative epilepsy between patients with versus without infarctions. Patients with infarctions reported more future uncertainty; otherwise, there were no significant differences in disease specific HRQoL between patients with versus without infarctions. In this study, we found that peritumoral infarctions after meningioma resection are common. Most patients with permanent neurological deficits had infarctions. Yet, most infarctions were small, and although sometimes symptomatic on individual level, infarctions did not lead to significant deterioration of HRQoL on group level.

Methodological developments and practice in characterisation of unconventional and legacy waste.

Radioactive waste management requires planned and systematic actions to provide confidence that the entire system, processes and final products will satisfy given requirements for quality. The characterisation process is dependent on setting clear characterisation objectives and gathering the right information to underpin the decisions that need to be taken to manage the waste safely. This paper reviews experience of characterisation of waste generated from past nuclear activities that were not conducted in compliance consistent with current criteria, or from unexpected situations that were not planned for. This experience shows that the development of a reliable and efficient characterisation and categorisation methodology is a common challenge for such wastes, referred to here as unconventional and legacy (UL) waste. Through the activites of the Nuclear Energy Agency Expert Group on the Characterisation of Unconventional and Legacy Waste, consideration has been given to widely used waste stream characterisation procedures and methods that were originally developed primarily for application in conventional decommissioning work. Although they provide a substantial basis for characterisation, there are various additional factors that commonly need to be taken into account in the case of UL waste. By analysing the challenges and lessons learned from a variety of case studies and other international experience, it has been possible to identify opportunities for adaptations and enhancements to these characterisation methologies, and these are set out and explained. The need for integration of waste characterisation with other aspects of strategic planning for UL waste management is discussed, including characterisation to address any non-radiological hazards. The analysed case studies have also highlighted the importance of developing a robust legislative and regulatory framework in parallel with an appropriate waste infrastructure to treat, store and dispose of UL waste. Finally, the basic features of a UL waste characterisation roadmap are presented, including the interactions within a wider UL waste management programme and key areas for further consideration and possible development. It is anticipated such work can be supported by continued international cooperation.

Brain infarctions after glioma surgery: prevalence, radiological characteristics and risk factors.

BACKGROUND: Prevalence, radiological characteristics, and risk factors for peritumoral infarctions after glioma surgery are not much studied. In this study, we assessed shape, volume, and prevalence of peritumoral infarctions and investigated possible associated factors. METHODS: In a prospective single-center cohort study, we included all adult patients operated for diffuse gliomas from January 2007 to December 2018. Postoperative infarctions were segmented using early postoperative MRI images, and volume, shape, and location of postoperative infarctions were assessed. Heatmaps of the distribution of tumors and infarctions were created. RESULTS: MRIs from 238 (44%) of 539 operations showed restricted diffusion in relation to the operation cavity, interpreted as postoperative infarctions. Of these, 86 (36%) were rim-shaped, 103 (43%) were sector-shaped, 40 (17%) were a combination of rim- and sector-shaped, and six (3%) were remote infarctions. Median infarction volume was 1.7 cm3 (IQR 0.7-4.3, range 0.1-67.1). Infarctions were more common if the tumor was in the temporal lobe, and the map shows more infarctions in the periventricular watershed areas. Sector-shaped infarctions were more often seen in patients with known cerebrovascular disease (47.6% vs. 25.5%, p = 0.024). There was a positive correlation between infarction volume and tumor volume (r = 0.267, p < 0.001) and infarction volume and perioperative bleeding (r = 0.176, p = 0.014). Moreover, there was a significant positive association between age and larger infarction volumes (r = 0.193, p = 0.003). Infarction rates and infarction volumes varied across individual surgeons, p = 0.037 (range 32-72%) and p = 0.026. CONCLUSIONS: In the present study, peritumoral infarctions occurred in 44% after diffuse glioma operations. Infarctions were more common in patients operated for tumors in the temporal lobe but were not more common following recurrent surgeries. Sector-shaped infarctions were more common in patients with known cerebrovascular disease. Increasing age, larger tumors, and more perioperative bleeding were factors associated with infarction volumes. The risk of infarctions and infarction volumes may also be surgeon-dependent.

Building optimization into the process for decommissioning, remediation of legacy sites and facilities, and management of the wastes arising: results of an international workshop.

The coordinated organisation of decommissioning, remediation of legacy sites and facilities and management of the resultant waste materials has long been recognized as complex, involving technical challenges, safety and security issues, and a wide range of stakeholder interests. To help address these matters, an international workshop was held in November 2019 in Tromsø, jointly organized by the Norwegian Radiation and Nuclear Safety Authority and the Nuclear Energy Agency, in cooperation with the International Commission on Radiological Protection and the International Atomic Energy Agency. The workshop was the third in series hosted by DSA. The first, in 2015, considered regulatory supervision of legacy sites from recognition to resolution; the second, in 2017, considered the need for an overall process, recognising the links between legacies and the decommissioning of major nuclear installations, the management of contaminated areas and the management of the corresponding radioactive waste. The focus of the Tromsø workshop was on incorporating optimization into that overall process. Attendance included 66 participants from 17 countries, as well as representatives from international organizations. The 29 presentations and associated discussion resulted in a set of recommendations supporting the development of a coherent and practical framework for optimization of decommissioning, legacy site management, and related waste management activities. This paper provides an overview of the presented material and discussion, and provides further information and suggestions for taking forward the recommendations. It is hoped that these ideas, along with the many further inputs from other international organisations and forums, will support the completion of work to implement these recommendations, leading to international guidance on the construction of an overall process for decommissioning and legacy management from a multidisciplinary perspective. That guidance should support holistically optimised management of current projects and help to avoid the future creation of new legacies.

The impact of authors' medical specialty on publication patterns and published results of adjuvant radiotherapy for WHO grade 2 meningiomas-a systematic review.

BACKGROUND: The role of adjuvant radiotherapy after gross total resection (GTR) of WHO grade 2 meningioma remains unclear, and conflicting results have been published. We hypothesized that authors' medical specialties could be associated with reported findings on the role of adjuvant radiotherapy after GTR of WHO grade 2 meningiomas. METHOD: A systematic review was conducted in Embase and Medline databases, in addition to screening of all relevant bibliographies. Articles including patients aged 18 years or older, with histologically confirmed WHO grade 2 meningioma, were included. We extracted data on medical subspecialties using the author list. We registered study design, median follow-up, number of included patients, WHO classification in use, and years of study inclusion. RESULTS: Thirty-seven relevant studies were identified, where 34 (92%) were retrospective cohort studies, two studies (5%) were systematic reviews, and one study (3%) was a meta-analysis. If the last author was a radiation-oncologist, the study was more likely to favor adjuvant radiotherapy, and if a neurosurgeon was last author, the study was more likely to not advocate adjuvant radiotherapy (p=0.009). There was no significant association between study result and whether the study was published in a neurosurgical or oncological journal (p=0.802). There was no significant difference in follow-up time, years of inclusion, or number of included patients between studies favoring or not favoring adjuvant radiotherapy. CONCLUSIONS: In this systematic review of the literature, we found that if a radiation-oncologist was the last author of the study, the study was more likely to favor adjuvant radiotherapy after gross total resection of WHO grade 2 meningioma. Clinicians and researchers should be aware of a possible genealogy bias in the neuro-oncological literature.

Prenatal exposure to Chernobyl fallout in Norway: neurological and developmental outcomes in a 25-year follow-up.

Ionizing radiation at high doses early in life may cause neurodevelopmental problems. Possible effects of lower doses are, however, controversial. We use carefully collected exposure data for Norway following the Chernobyl accident in April 1986 combined with population-based registries to assess long-term effects of fetal exposure on neurodevelopmental outcomes. Radiation doses were estimated for each Norwegian municipality for each calendar month from May 1986 to April 1989. We established a cohort of all Norwegian pregnancies during the three-year period of radiation measurement and compared them with appropriate unexposed groups. All cohorts were followed into adulthood. Risks of cerebral palsy, mental retardation, schizophrenia, epilepsy, vision or hearing problems, school dropout, and low income were estimated. We also conducted an analysis of mathematics and language grades using siblings born after the exposure period as comparison. There was little evidence of associations between radiation exposure and cerebral palsy, mental retardation, schizophrenia, epilepsy, or hearing or vision problems associated with radiation exposure. (p-values for trend with exposure dose were 0.27, 0.14, 0.83, 0.35 and 0.42.) Slightly more of the exposed failed to complete high school (p = 0.05), but there was no increase in the proportion with low income (p = 0.38). The natural advantage of older siblings over younger siblings in mathematics grades was diminished with exposure of older siblings (p = 0.003), but there was no association of exposure with Norwegian language grades (p = 0.37). There is scant evidence that the low-dose fallout from Chernobyl in Norway increased the risk for serious neurodevelopmental problems. We cannot exclude the possibility of lower mathematics grades with exposure, similar to a report from Sweden.

Addressing ecological effects of radiation on populations and ecosystems to improve protection of the environment against radiation: Agreed statements from a Consensus Symposium.

This paper reports the output of a consensus symposium organized by the International Union of Radioecology in November 2015. The symposium gathered an academically diverse group of 30 scientists to consider the still debated ecological impact of radiation on populations and ecosystems. Stimulated by the Chernobyl and Fukushima disasters' accidental contamination of the environment, there is increasing interest in developing environmental radiation protection frameworks. Scientific research conducted in a variety of laboratory and field settings has improved our knowledge of the effects of ionizing radiation on the environment. However, the results from such studies sometimes appear contradictory and there is disagreement about the implications for risk assessment. The Symposium discussions therefore focused on issues that might lead to different interpretations of the results, such as laboratory versus field approaches, organism versus population and ecosystemic inference strategies, dose estimation approaches and their significance under chronic exposure conditions. The participating scientists, from across the spectrum of disciplines and research areas, extending also beyond the traditional radioecology community, successfully developed a constructive spirit directed at understanding discrepancies. From the discussions, the group has derived seven consensus statements related to environmental protection against radiation, which are supplemented with some recommendations. Each of these statements is contextualized and discussed in view of contributing to the orientation and integration of future research, the results of which should yield better consensus on the ecological impact of radiation and consolidate suitable approaches for efficient radiological protection of the environment.

The impact of the Fukushima nuclear accident on marine biota: retrospective assessment of the first year and perspectives.

An international study under the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) was performed to assess radiological impact of the nuclear accident at the Fukushima-Daiichi Nuclear Power Station (FDNPS) on the marine environment. This work constitutes the first international assessment of this type, drawing upon methodologies that incorporate the most up-to-date radioecological models and knowledge. To quantify the radiological impact on marine wildlife, a suite of state-of-the-art approaches to assess exposures to Fukushima derived radionuclides of marine biota, including predictive dynamic transfer modelling, was applied to a comprehensive dataset consisting of over 500 sediment, 6000 seawater and 5000 biota data points representative of the geographically relevant area during the first year after the accident. The dataset covers the period from May 2011 to August 2012. The method used to evaluate the ecological impact consists of comparing dose (rates) to which living species of interest are exposed during a defined period to critical effects values arising from the literature. The assessed doses follow a highly variable pattern and generally do not seem to indicate the potential for effects. A possible exception of a transient nature is the relatively contaminated area in the vicinity of the discharge point, where effects on sensitive endpoints in individual plants and animals might have occurred in the weeks directly following the accident. However, impacts on population integrity would have been unlikely due to the short duration and the limited space area of the initially high exposures. Our understanding of the biological impact of radiation on chronically exposed plants and animals continues to evolve, and still needs to be improved through future studies in the FDNPS marine environment.

Application of an environmental impact assessment methodology to a site discharging low levels of radioactivity to a freshwater environment in Norway.

Significant shifts in opinion regarding environmental protection from ionising radiation have resulted in the development and availability of bespoke approaches for the assessment of impacts on wildlife from radioactive contaminants. The application of such assessment methodologies to actual situations, however, remains relatively limited. This paper describes the implementation of the ERICA Integrated Approach and associated tools within the context of routine discharges of radioactive materials to a freshwater environment. The article follows the implementation through its relevant stages and discusses strengths and weaknesses of the approach in relation to the case study. For current discharge levels, 137Cs and 60Co constitute the main dose contributors to the majority of reference organisms studied, although 241Am and 3H are the main contributors for the phyto- and zooplankton categories. Patterns are observed depending on whether the reference organism is sediment-associated or not. At current discharge levels, none of the reference organisms exceeded or approached the selected screening level, and impacts on biota could be regarded as negligible.

On the potential for climate change impacts on marine anthropogenic radioactivity in the Arctic regions.

Current predictions as to the impacts of climate change in general and Arctic climate change in particular are such that a wide range of processes relevant to Arctic contaminants are potentially vulnerable. Of these, radioactive contaminants and the processes that govern their transport and fate may be particularly susceptible to the effects of a changing Arctic climate. This paper explores the potential changes in the physical system of the Arctic climate system as they are deducible from present day knowledge and model projections. As a contribution to a better preparedness regarding Arctic marine contamination with radioactivity we present and discuss how a changing marine physical environment may play a role in altering the current understanding pertaining to behavior of contaminant radionuclides in the marine environment of the Arctic region.

Overview of dose assessment developments and the health of riverside residents close to the "Mayak" PA facilities, Russia.

The Norwegian Radiation Protection Authority (NRPA) has been involved in studies related to the Mayak PA and the consequences of activities undertaken at the site for a number of years. This paper strives to present an overview of past and present activities at the Mayak PA and subsequent developments in the quantification of health effects on local populations caused by discharges of radioactive waste into the Techa River. Assessments of doses to affected populations have relied on the development of dose reconstruction techniques for both external and internal doses. Contamination levels are typically inhomogeneous and decrease with increasing distance from the discharge point. Citations made in this paper give a comprehensive, though not exhaustive, basis for further reading about this topic.