Management of brain metastases: history and the present

Primary intracranial malignant melanomas: A case series with literature review

RATIONALE

There is a high chance of misdiagnosis and limited knowledge regarding therapeutic strategies owing to the rarity of primary intracranial malignant melanoma (PIMM). The objective of the present study was to evaluate the clinical features, treatment modalities, and outcomes of patients with histologically proven PIMM.

PATIENT CONCERNS

Data of 15 patients with PIMM admitted to the Chinese People's Liberation Army General Hospital in a 14-year period between January 2005 and January 2019 were collected. Clinical presentations, pathology, surgical strategies, adjuvant treatment, and prognosis were retrospectively analyzed.

DIAGNOSES

CT showed iso- or high-density lesions in 12 cases (80%). MRI revealed short T1 and slightly short T2 in 14 cases (93.3%).The tumors showed mild or no enhancement on enhanced MRI. The patients were eventually diagnosed with PIMM through pathological examination.

INTERVENTIONS

The treatment modalities included radical resection followed by conventional radiotherapy (RT, n = 12) and subtotal resection followed by stereotactic radiosurgery (n = 3).

OUTCOMES

All 15 patients had either recurrence or metastasis at an average of 14.7 months (range, 6-23 months) after surgery. In total, 14 patients (93.3%) succumbed to disease, with a mean overall survival of 22 months (range, 6-36 months). The median survival time was 23 months. The overall survival rates at 1, 2, and 3 years were 80, 47, and 13%, respectively. Radical resection with RT was associated with longer overall survival (log-rank, P < .05) than subtotal resection followed by stereotactic radiosurgery.

LESSONS

PIMM is an extremely rare tumor with a poor prognosis. Radical resection with RT may result in a longer overall survival rate. Targeted immunotherapy may be a promising treatment option for PIMM.

De novo GTP synthesis is a metabolic vulnerability for the interception of brain metastases

Patients with brain metastases (BM) face a 90% mortality rate within one year of diagnosis and the current standard of care is palliative. Targeting BM-initiating cells (BMICs) is a feasible strategy to treat BM, but druggable targets are limited. Here, we apply Connectivity Map analysis to lung-, breast-, and melanoma-pre-metastatic BMIC gene expression signatures and identify inosine monophosphate dehydrogenase (IMPDH), the rate-limiting enzyme in the de novo GTP synthesis pathway, as a target for BM. We show that pharmacological and genetic perturbation of IMPDH attenuates BMIC proliferation in vitro and the formation of BM in vivo. Metabolomic analyses and CRISPR knockout studies confirm that de novo GTP synthesis is a potent metabolic vulnerability in BM. Overall, our work employs a phenotype-guided therapeutic strategy to uncover IMPDH as a relevant target for attenuating BM outgrowth, which may provide an alternative treatment strategy for patients who are otherwise limited to palliation.

KRASG12C Inhibitors in Non-Small Cell Lung Cancer: A Review

Rat sarcoma virus (RAS) GTPase is one of the most important drivers of non-small cell lung cancer (NSCLC). RAS has three different isoforms (Harvey rat sarcoma viral oncogene homolog [HRAS], Kirsten rat sarcoma viral oncogene homolog [KRAS] and Neuroblastoma ras viral oncogene homolog [NRAS]), of which KRAS is most commonly mutated in NSCLC. The mutated KRAS protein was historically thought to be "undruggable" until the development of KRASG12C inhibitors. In this review, from the aspect of brain metastasis, we aim to provide an overview of the advances in therapies that target KRASG12C, the limitations of the current treatments, and future prospects in patients with KRAS p.G12C mutant NSCLC.

Factors associated with the local control of brain metastases: a systematic search and machine learning application

BACKGROUND

Enhancing Local Control (LC) of brain metastases is pivotal for improving overall survival, which makes the prediction of local treatment failure a crucial aspect of treatment planning. Understanding the factors that influence LC of brain metastases is imperative for optimizing treatment strategies and subsequently extending overall survival. Machine learning algorithms may help to identify factors that predict outcomes.

METHODS

This paper systematically reviews these factors associated with LC to select candidate predictor features for a practical application of predictive modeling. A systematic literature search was conducted to identify studies in which the LC of brain metastases is assessed for adult patients. EMBASE, PubMed, Web-of-Science, and the Cochrane Database were searched up to December 24, 2020. All studies investigating the LC of brain metastases as one of the endpoints were included, regardless of primary tumor type or treatment type. We first grouped studies based on primary tumor types resulting in lung, breast, and melanoma groups. Studies that did not focus on a specific primary cancer type were grouped based on treatment types resulting in surgery, SRT, and whole-brain radiotherapy groups. For each group, significant factors associated with LC were identified and discussed. As a second project, we assessed the practical importance of selected features in predicting LC after Stereotactic Radiotherapy (SRT) with a Random Forest machine learning model. Accuracy and Area Under the Curve (AUC) of the Random Forest model, trained with the list of factors that were found to be associated with LC for the SRT treatment group, were reported.

RESULTS

The systematic literature search identified 6270 unique records. After screening titles and abstracts, 410 full texts were considered, and ultimately 159 studies were included for review. Most of the studies focused on the LC of the brain metastases for a specific primary tumor type or after a specific treatment type. Higher SRT radiation dose was found to be associated with better LC in lung cancer, breast cancer, and melanoma groups. Also, a higher dose was associated with better LC in the SRT group, while higher tumor volume was associated with worse LC in this group. The Random Forest model predicted the LC of brain metastases with an accuracy of 80% and an AUC of 0.84.

CONCLUSION

This paper thoroughly examines factors associated with LC in brain metastases and highlights the translational value of our findings for selecting variables to predict LC in a sample of patients who underwent SRT. The prediction model holds great promise for clinicians, offering a valuable tool to predict personalized treatment outcomes and foresee the impact of changes in treatment characteristics such as radiation dose.

Survival after Stereotactic Radiosurgery in the Era of Targeted Therapy: Number of Metastases No Longer Matters

Randomised control trial data support the use of stereotactic radiosurgery (SRS) in up to 4 brain metastases (BMs), with non-randomised prospective data complementing this for up to 10 BMs. There is debate in the neuro-oncology community as to the appropriateness of SRS in patients with >10 BMs. We present data from a large single-centre cohort, reporting survival in those with >10 BMs and in a >20 BMs subgroup. A total of 1181 patients receiving SRS for BMs were included. Data were collected prospectively from the time of SRS referral. Kaplan-Meier graphs and logrank tests were used to compare survival between groups. Multivariate analysis was performed using the Cox proportional hazards model to account for differences in group characteristics. Median survival with 1 BM (n = 379), 2-4 BMs (n = 438), 5-10 BMs (n = 236), and >10 BMs (n = 128) was 12.49, 10.22, 10.68, and 10.09 months, respectively. Using 2-4 BMs as the reference group, survival was not significantly different in those with >10 BMs in either our univariable (p = 0.6882) or multivariable analysis (p = 0.0564). In our subgroup analyses, median survival for those with >20 BMs was comparable to those with 2-4 BMs (10.09 vs. 10.22 months, p = 0.3558). This study contributes a large dataset to the existing literature on SRS for those with multi-metastases and supports growing evidence that those with >10 BMs should be considered for SRS.

Radiomics for residual tumour detection and prognosis in newly diagnosed glioblastoma based on postoperative [11C] methionine PET and T1c-w MRI

Personalized treatment strategies based on non-invasive biomarkers have potential to improve patient management in patients with newly diagnosed glioblastoma (GBM). The residual tumour burden after surgery in GBM patients is a prognostic imaging biomarker. However, in clinical patient management, its assessment is a manual and time-consuming process that is at risk of inter-rater variability. Furthermore, the prediction of patient outcome prior to radiotherapy may identify patient subgroups that could benefit from escalated radiotherapy doses. Therefore, in this study, we investigate the capabilities of traditional radiomics and 3D convolutional neural networks for automatic detection of the residual tumour status and to prognosticate time-to-recurrence (TTR) and overall survival (OS) in GBM using postoperative [11C] methionine positron emission tomography (MET-PET) and gadolinium-enhanced T1-w magnetic resonance imaging (MRI). On the independent test data, the 3D-DenseNet model based on MET-PET achieved the best performance for residual tumour detection, while the logistic regression model with conventional radiomics features performed best for T1c-w MRI (AUC: MET-PET 0.95, T1c-w MRI 0.78). For the prognosis of TTR and OS, the 3D-DenseNet model based on MET-PET integrated with age and MGMT status achieved the best performance (Concordance-Index: TTR 0.68, OS 0.65). In conclusion, we showed that both deep-learning and conventional radiomics have potential value for supporting image-based assessment and prognosis in GBM. After prospective validation, these models may be considered for treatment personalization.

Neuroprotection or Sex Bias: A Protective Response to Traumatic Brain Injury in the Females

Traumatic brain injury (TBI) is a major healthcare problem and a common cause of mortality and morbidity. Clinical and preclinical research suggests sex-related differences in short- and longterm outcomes following TBI; however, males have been the main focus of TBI research. Females show a protective response against TBI. Female animals in preclinical studies and women in clinical trials have shown comparatively better outcomes against mild, moderate, or severe TBI. This reflects a favorable protective nature of the females compared to the males, primarily attributed to various protective mechanisms that provide better prognosis and recovery in the females after TBI. Understanding the sex difference in the TBI pathophysiology and the underlying mechanisms remains an elusive goal. In this review, we provide insights into various mechanisms related to the anatomical, physiological, hormonal, enzymatic, inflammatory, oxidative, genetic, or mitochondrial basis that support the protective nature of females compared to males. Furthermore, we sought to outline the evidence of multiple biomarkers that are highly potential in the investigation of TBI's prognosis, pathophysiology, and treatment and which can serve as objective measures and novel targets for individualized therapeutic interventions in TBI treatment. Implementations from this review are important for the understanding of the effect of sex on TBI outcomes and possible mechanisms behind the favorable response in females. It also emphasizes the critical need to include females as a biological variable and in sufficient numbers in future TBI studies.

Artificial Intelligence in Neuroradiology: A Review of Current Topics and Competition Challenges

There is an expanding body of literature that describes the application of deep learning and other machine learning and artificial intelligence methods with potential relevance to neuroradiology practice. In this article, we performed a literature review to identify recent developments on the topics of artificial intelligence in neuroradiology, with particular emphasis on large datasets and large-scale algorithm assessments, such as those used in imaging AI competition challenges. Numerous applications relevant to ischemic stroke, intracranial hemorrhage, brain tumors, demyelinating disease, and neurodegenerative/neurocognitive disorders were discussed. The potential applications of these methods to spinal fractures, scoliosis grading, head and neck oncology, and vascular imaging were also reviewed. The AI applications examined perform a variety of tasks, including localization, segmentation, longitudinal monitoring, diagnostic classification, and prognostication. While research on this topic is ongoing, several applications have been cleared for clinical use and have the potential to augment the accuracy or efficiency of neuroradiologists.

Comparison of 116 Radiosurgery Treatment Plans for Multi-Leaf and Cone Collimator on a Varian Edge Linac: Are Cones Superior in the Daily Routine?

Delivering focused radiation doses via linear accelerators is a crucial component of stereotactic radiosurgery (SRS) for brain metastases. The Varian Edge linear accelerator provides highly conformal radiation therapy through a high-definition multi-leaf collimator (HD120 MLC) and conical collimator (CC). HD120 MLC adapts to the shape of the target volume using movable tungsten leaves, while CC has a block of conical shape (cones). CC in SRS treatments of small brain metastases is preferred due to its mechanical stability and steeper dose fall-off, potentially sparing organs at risk (OARs) and the brain better than HD120 MLC. This study aims to determine if CC offers significant advantages over HD120 MLC for SRS treatments. For 116 metastatic lesions, CC and HD120 MLC treatment plans were created in Varian Eclipse TPS and compared based on various dose parameters, robustness tests, and QA measurements. The results indicate that CC provides no significant advantages over HD120 MLC, except for slight, clinically insignificant benefits in brain sparing and dose fall-off for the smallest lesions. HD120 MLC outperforms CC in almost every aspect, making it a better choice for irradiating brain metastases with 0.1 cm³ or higher volumes.

Imaging of brain metastasis in non-small-cell lung cancer: indications, protocols, diagnosis, post-therapy imaging, and implications regarding management

Increased survival (due to the use of targeted therapies based on genomic profiling) has resulted in the increased incidence of brain metastasis during the course of disease, and thus, made it essential to have proper imaging guidelines in place for brain metastasis from non-small-cell lung cancer (NSCLC). Brain parenchymal metastases can have varied imaging appearances, and it is pertinent to be aware of the various molecular risk factors for brain metastasis from NSCLC along with their suggestive imaging appearances, so as to identify them early. Leptomeningeal metastasis requires additional imaging of the spine and an early cerebrospinal fluid (CSF) analysis. Differentiation of post-therapy change from recurrence on imaging has a bearing on the management, hence the need for its awareness. This article will provide in-depth literature review of the epidemiology, aetiopathogenesis, screening, detection, diagnosis, post-therapy imaging, and implications regarding the management of brain metastasis from NSCLC. In addition, we will also briefly highlight the role of artificial intelligence (AI) in brain metastasis screening.

Multidisciplinary Management of Brain Metastasis from Breast Cancer

The management of patients with breast cancer and brain metastases (BMs) is exquisitely multidisciplinary. Patients presenting with a symptomatic BM may be offered neurosurgical resection, followed by radiation. Stereotactic radiosurgery (SRS) is preferred over whole-brain radiotherapy (WBRT) in most patients presenting with a limited number of BMs, whereas WBRT with hippocampal-sparing and concomitant memantine is preferred for patients with multiple BMs. There is a growing role for systemic therapy, in some cases in lieu of local therapy, particularly in patients with HER2+ breast cancer.

Stereotactic radiosurgery versus whole-brain radiotherapy after resection of solitary brain metastasis: A systematic review and meta-analysis

Objective

The standard of care in patients with solitary brain metastasis involves surgical resection and postoperative whole-brain radiotherapy (WBRT). However, WBRT is associated with adverse effects, mainly neurocognitive deterioration. Stereotactic radiosurgery (SRS) is a more targeted form of radiation therapy that could be as effective as WBRT without the detrimental neurocognitive decline.

Methods

We performed the first systematic review and meta-analysis comparing postoperative SRS versus postoperative WBRT in patients with one resected brain metastasis. PubMed, Scopus, and Cochrane library were systematically searched for studies comparing the efficacy of the two radiation modalities in terms of local and distant brain control, leptomeningeal disease control, and overall survival. Additionally, we extracted patients' neurocognitive function and quality of life after each postoperative radiation form.

Results

Four studies with 248 patients (128: WBRT, 120: SRS) were included in our analysis. There was no difference between SRS and WBRT in the risk of local recurrence (RR = 0.92, CI = 0.51-1.66, p = 0.78, I2 = 0%) and leptomeningeal disease (RR = 1.21, CI = 0.49-2.98, p = 0.67, I2 = 18%), neither in the patients' overall survival (HR = 1.06, CI = 0.61-1.85, p = 0.83, I2 = 63%). Nevertheless, SRS appeared to increase the risk of distant brain failure (RR = 2.03, CI = 0.94-4.40, p = 0.07, I2 = 61%). Neurocognitive function and quality of life in the SRS group were equal or superior to the WBRT group.

Conclusions

Although SRS may increase the risk of distant brain failure, it appears to be as effective as WBRT in terms of local control, risk of leptomeningeal disease, and overall survival while sparing the patients of the detrimental, WBRT-associated cognitive deterioration.

GammaTile® (GT) as a brachytherapy platform for rapidly growing brain metastasis

Background

A subset of brain metastasis (BM) shows rapid recurrence post-initial resection or aggressive tumor growth between interval scans. Here we provide a pilot experience in the treatment of these BM with GammaTile® (GT), a collagen tile-embedded Cesium 131 (¹³¹Cs) brachytherapy platform.

Methods

We identified ten consecutive patients (2019-2023) with BM that showed either (1) symptomatic recurrence while awaiting post-resection radiosurgery or (2) enlarged by >25% of tumor volume on serial imaging and underwent surgical resection followed by GT placement. Procedural complication, 30-day readmission, local control, and overall survival were assessed.

Results

For this cohort of ten BM patients, 3 patients suffered tumor progression while awaiting radiosurgery and 7 showed >25% tumor growth prior to surgery and GT placement. There were no procedural complications or 30-day mortality. All patients were discharged home, with a median hospital stay of 2 days (range: 1-9 days). 4/10 patients experienced symptomatic improvement while the remaining patients showed stable neurologic conditions. With a median follow-up of 186 days (6.2 months, range: 69-452 days), no local recurrence was detected. The median overall survival (mOS) for the newly diagnosed BM was 265 days from the time of GT placement. No patients suffered from adverse radiation effects.

Conclusion

Our pilot experience suggests that GT offers favorable local control and safety profile in patients suffering from brain metastases that exhibit aggressive growth patterns and support the future investigation of this treatment paradigm.

Validation and discussion of clinical practicability of the 2022 graded prognostic assessment for NSCLC adenocarcinoma patients with brain metastases in a routine clinical cohort

Introduction

The goal of this analysis is to validate the 2022 graded prognostic assessment (GPA) for patients with brain metastases from adenocarcinoma of the lung and to discuss its clinical practicability.

Methods/material

137 patients with adenocarcinoma of the lung were included in this analysis. The disease specific GPA for NSCLC, Lung-molGPA and the GPA for NSCLC adenocarcinoma were calculated. Overall survival was calculated for each GPA group. Additionally, expected and actual OS in the prognostic groups of the GPA available at the time of the patients' diagnosis was compared.

Results

Median overall survival (OS) from diagnosis of brain metastases was 15 months (95% confidence interval (CI) 9.7-20.3 months). The median OS in the three individual prognostic groups was 7 months for GPA 0-1, 16 months for GPA 1.5-2, 33 months for GPA 2.5-3 and not reached for GPA 3.5-4 (p<0.001). Median survival times for the individual groups were similar to those published in the original GPA publication. Regarding the expected and actual OS when using the available GPA at the time of diagnosis there was an underestimation of survival of more than 3 months for all except the worst prognosis group.

Conclusion

We were able to validate the 2022 GPA for NSCLC adenocarcinoma patients with brain metastases in a similar cohort from a non-academic center. However, the practical applicability regarding the expected median OS might be limited due to the constantly evolving treatment landscape and the consecutive improvement in overall survival.

Therapeutic Options for Brain Metastases in Gynecologic Cancers

OPINION STATEMENT

Brain metastases (BM) are rare in gynecologic cancers. Overall BM confers a poor prognosis but other factors such as number of brain lesions, patient age, the presence of extracranial metastasis, the Karnofsky Performance Status (KPS) score, and the type of primary cancer also impact prognosis. Taking a patient's whole picture into perspective is crucial in deciding the appropriate management strategy. The management of BM requires an interdisciplinary approach that frequently includes oncology, neurosurgery, radiation oncology and palliative care. Treatment includes both direct targeted therapies to the lesion(s) as well as management of the neurologic side effects caused by mass effect. There is limited evidence of when screening for BM in the gynecology oncology patient is warranted but it is recommended that any cancer patient with new focal neurologic deficit or increasing headaches should be evaluated. The primary imaging modality for detection of BM is MRI, but other imaging modalities such as CT and PET scan can be used for certain scenarios. New advances in radiation techniques, improved imaging modalities, and systemic therapies are helping to discover BM earlier and provide treatments with less detrimental side effects.

Association between red blood cell distribution width and mortality in patients with metastatic brain tumors: A retrospective single-center cohort study

Metastatic brain tumor has been associated with high mortality and poor prognosis. However, information on indicators predicting surgical prognosis in patients with brain metastases is limited. This study aimed to investigate the association between preoperative red blood cell distribution width (RDW) and mortality in patients who underwent surgery for metastatic brain tumors. This study analyzed 282 patients who underwent metastatic brain tumor surgery between August 1999 and March 2020. Patients were divided into two groups based on preoperative RDW cut-off values (<13.2 and ≥13.2). The surgical outcomes were compared between the two groups. Additionally, we performed Cox regression analysis to assess the association between preoperative RDW and 1-year and overall mortality. There were significant differences in 180-day mortality (6.2% vs. 28.7%, P<0.001), 1-year mortality (23.8% vs. 46.7%, P<0.001), and overall mortality (75.0% vs. 87.7%, P=0.012) between the two groups. In the Cox regression analysis, RDW ≥ 13.2 was significantly associated with higher 1-year mortality (adjusted hazard ratio [HR], 2.14; 95% confidence interval [CI], 1.38–3.30; P<0.001) and overall mortality (HR, 1.44; 95% CI, 1.09–1.90; P=0.010). Preoperative RDW is strongly associated with high mortality in metastatic brain tumor surgery.

Comparative effectiveness of larotrectinib versus entrectinib for the treatment of metastatic NTRK gene fusion cancers

Aim: To extrapolate clinical trial results to estimate and compare expected progression-free and overall life years (LYs) and quality-adjusted LYs (QALYs) for larotrectinib and entrectinib in patients with colorectal cancer (CRC), soft tissue sarcoma (STS) and brain metastases prior to treatment with larotrectinib or entrectinib. Methods: A naive direct comparison of larotrectinib versus entrectinib was made using partitioned survival modeling methods from clinical trial data. Results: Larotrectinib resulted in an additional 1.58 LYs (1.17 QALYs), 5.81 LYs (2.02 QALYs) and 1.01 LYs in CRC, STS and baseline brain metastases, respectively, compared with entrectinib. Conclusion: Larotrectinib provided life expectancy and QALY gains compared with entrectinib. Additional studies will be beneficial as more patients are treated and survival data develop to better inform comparative effectiveness results.

Activity of Adagrasib (MRTX849) in Brain Metastases: Preclinical Models and Clinical Data from Patients with KRASG12C-Mutant Non-Small Cell Lung Cancer

PURPOSE

Patients with KRAS-mutant non-small cell lung cancer (NSCLC) with brain metastases (BM) have a poor prognosis. Adagrasib (MRTX849), a potent oral small-molecule KRASG12C inhibitor, irreversibly and selectively binds KRASG12C, locking it in its inactive state. Adagrasib has been optimized for favorable pharmacokinetic properties, including long half-life (∼24 hours), extensive tissue distribution, dose-dependent pharmacokinetics, and central nervous system penetration; however, BM-specific antitumor activity of KRASG12C inhibitors remains to be fully characterized.

EXPERIMENTAL DESIGN

A retrospective database query identified patients with KRAS-mutant NSCLC to understand their propensity to develop BM. Preclinical studies assessed physiochemical and pharmacokinetic properties of adagrasib. Mice bearing intracranial KRASG12C-mutant NSCLC xenografts (LU99-Luc/H23-Luc/LU65-Luc) were treated with clinically relevant adagrasib doses, and levels of adagrasib in plasma, cerebrospinal fluid (CSF), and brain were determined along with antitumor activity. Preliminary clinical data were collected from 2 patients with NSCLC with untreated BM who had received adagrasib 600 mg twice daily in the phase Ib cohort of the KRYSTAL-1 trial; CSF was collected, adagrasib concentrations measured, and antitumor activity in BM evaluated.

RESULTS

Patients with KRAS-mutant NSCLC demonstrated high propensity to develop BM (≥40%). Adagrasib penetrated into CSF and demonstrated tumor regression and extended survival in multiple preclinical BM models. In 2 patients with NSCLC and untreated BM, CSF concentrations of adagrasib measured above the target cellular IC50. Both patients demonstrated corresponding BM regression, supporting potential clinical activity of adagrasib in the brain.

CONCLUSIONS

These data support further development of adagrasib in patients with KRASG12C-mutant NSCLC with untreated BM. See related commentary by Kommalapati and Mansfield, p. 3179.

The influence of the blood-brain barrier in the treatment of brain tumours

Brain tumours have a poor prognosis and lack effective treatments. The blood-brain barrier (BBB) represents a major hurdle to drug delivery to brain tumours. In some locations in the tumour, the BBB may be disrupted to form the blood-brain tumour barrier (BBTB). This leaky BBTB enables diagnosis of brain tumours by contrast enhanced magnetic resonance imaging; however, this disruption is heterogeneous throughout the tumour. Thus, relying on the disrupted BBTB for achieving effective drug concentrations in brain tumours has met with little clinical success. Because of this, it would be beneficial to design drugs and drug delivery strategies to overcome the 'normal' BBB to effectively treat the brain tumours. In this review, we discuss the role of BBB/BBTB in brain tumour diagnosis and treatment highlighting the heterogeneity of the BBTB. We also discuss various strategies to improve drug delivery across the BBB/BBTB to treat both primary and metastatic brain tumours. Recognizing that the BBB represents a critical determinant of drug efficacy in central nervous system tumours will allow a more rapid translation from basic science to clinical application. A more complete understanding of the factors, such as BBB-limited drug delivery, that have hindered progress in treating both primary and metastatic brain tumours, is necessary to develop more effective therapies.

Cytokine Landscape in Central Nervous System Metastases

The central nervous system is the location of metastases in more than 40% of patients with lung cancer, breast cancer and melanoma. These metastases are associated with one of the poorest prognoses in advanced cancer patients, mainly due to the lack of effective treatments. In this review, we explore the involvement of cytokines, including interleukins and chemokines, during the development of brain and leptomeningeal metastases from the epithelial-to-mesenchymal cell transition and blood–brain barrier extravasation to the interaction between cancer cells and cells from the brain microenvironment, including astrocytes and microglia. Furthermore, the role of the gut–brain axis on cytokine release during this process will also be addressed.

Brain Vascular Microenvironments in Cancer Metastasis

Primary tumours, particularly from major solid organs, are able to disseminate into the blood and lymphatic system and spread to distant sites. These secondary metastases to other major organs are the most lethal aspect of cancer, accounting for the majority of cancer deaths. The brain is a frequent site of metastasis, and brain metastases are often fatal due to the critical role of the nervous system and the limited options for treatment, including surgery. This creates a need to further understand the complex cell and molecular biology associated with the establishment of brain metastasis, including the changes to the environment of the brain to enable the arrival and growth of tumour cells. Local changes in the vascular network, immune system and stromal components all have the potential to recruit and foster metastatic tumour cells. This review summarises our current understanding of brain vascular microenvironments, fluid circulation and drainage in the context of brain metastases, as well as commenting on current cutting-edge experimental approaches used to investigate changes in vascular environments and alterations in specialised subsets of blood and lymphatic vessel cells during cancer spread to the brain.

Transfontanelle photoacoustic imaging: ultrasound transducer selection analysis

Transfontanelle ultrasound imaging (TFUI) is the conventional approach for diagnosing brain injury in neonates. Despite being the first stage imaging modality, TFUI lacks accuracy in determining the injury at an early stage due to degraded sensitivity and specificity. Therefore, a modality like photoacoustic imaging that combines the advantages of both acoustic and optical imaging can overcome the existing TFUI limitations. Even though a variety of transducers have been used in TFUI, it is essential to identify the transducer specification that is optimal for transfontanelle imaging using the photoacoustic technique. In this study, we evaluated the performance of 6 commercially available ultrasound transducer arrays to identify the optimal characteristics for transfontanelle photoacoustic imaging. We focused on commercially available linear and phased array transducer probes with center frequencies ranging from 2.5MHz to 8.5MHz which covers the entire spectrum of the transducer arrays used for brain imaging. The probes were tested on both in vitro and ex vivo brain tissue, and their performance in terms of transducer resolution, size, penetration depth, sensitivity, signal to noise ratio, signal amplification and reconstructed image quality were evaluated. The analysis of selected transducers in these areas allowed us to determine the optimal transducer for transfontanelle imaging, based on vasculature depth and blood density in tissue using ex vivo sheep brain. The outcome of this evaluation identified the two most suitable ultrasound transducer probes for transfontanelle photoacoustic imaging.

Glial activation positron emission tomography imaging in radiation treatment of breast cancer brain metastases

Brain metastases affect more breast cancer patients than ever before due to increased overall patient survival with improved molecularly targeted treatments. Approximately 25–34% of breast cancer patients develop brain metastases in their lifetime. Due to the blood–brain barrier (BBB), the standard treatment for breast cancer brain metastases (BCBM) is surgery, stereotactic radiosurgery (SRS) and/or whole brain radiation therapy (WBRT). At the cost of cognitive side effects, WBRT has proven efficacy in treating brain metastases when used with local therapies such as SRS and surgery. This review investigated the potential use of glial activation positron emission tomography (PET) imaging for radiation treatment of BCBM. In order to put these studies into context, we provided background on current radiation treatment approaches for BCBM, our current understanding of the brain microenvironment, its interaction with the peripheral immune system, and alterations in the brain microenvironment by BCBM and radiation. We summarized preclinical literature on the interactions between glial activation and cognition and clinical studies using translocator protein (TSPO) PET to image glial activation in the context of neurological diseases. TSPO-PET is not employed clinically in assessing and guiding cancer therapies. However, it has gained traction in preclinical studies where glial activation was investigated from primary brain cancer, metastases and radiation treatments. Novel glial activation PET imaging and its applications in preclinical studies using breast cancer models and glial immunohistochemistry are highlighted. Lastly, we discuss the potential clinical application of glial activation imaging to improve the therapeutic ratio of radiation treatments for BCBM.

Interrupted Time-Series Analysis of Stereotactic Radiosurgery for Brain Metastases Before and After the Affordable Care Act

The 2010 Patient Protection and Affordable Care Act was aimed at reducing healthcare costs, improving healthcare quality, and expanding health insurance coverage among uninsured individuals in the United States. We examined trends in the utilization of radiation therapies and stereotactic radiosurgery before and after its implementation among U.S. adults hospitalized with brain metastasis. Interrupted time-series analyses of data on 383,934 Nationwide Inpatient Sample hospitalizations (2005-2010 and 2011-2013) were performed, whereby yearly and quarterly cross-sectional data were evaluated and Affordable Care Act implementation was considered the main exposure variable, stratifying by patient and hospital characteristics. Overall, we observed a declining trend in radiation therapy over time, with an upward shift post-Affordable Care Act. A downward shift in radiation therapy post-Affordable Care Act was observed among Northeastern and rural hospitals, whereas an upward shift was noted among specific patient (females, 18-39 or ≥ 65 years of age, Charlson Comorbidity Index (CCI) ≥10, non-elective admissions, Medicare, self-pay, no pay or other insurance) and hospital (Midwestern, Western, non-teaching urban) subgroups. Stereotactic radiosurgery utilization among recipients of radiation therapy increased over time among Hispanics, elective admissions, and rural hospitals, whereas post-Affordable Care Act was associated with increased stereotactic radiosurgery among African-Americans and non-elective admissions and decreased stereotactic radiosurgery among elective admissions, and rural hospitals. Whereas hospitalized adults in the United States utilized less radiation therapy over the nine-year period, utilization of radiation therapy, in general, and stereotactic radiosurgery, in particular, were not consistent among distinct subgroups defined by patient and hospital characteristics, with some traditionally underserved populations more likely to receive healthcare services post-Affordable Care Act. The Affordable Care Act may be helpful at closing the gap in access to technological advances such as stereotactic radiosurgery for treating brain metastases.

A pragmatic diagnostic approach to primary intracranial germ cell tumors and their treatment outcomes

Background: Primary intracranial germ cell tumors (ICGCT) are often diagnosed with tumor markers and imaging, which may avoid the need for a biopsy. An intracranial germ cell tumor with mild elevation of markers is seldom stratified as a distinct entity. Methods: Fifty-nine patients were stratified into three groups: pure germinoma (PG), secreting germinoma (SG) and non-germinomatous germ cell tumors (NGGCTs). Results: At 5 years, progression-free survival and overall survival of the three groups (PG vs SG vs NGGCT) were 91% versus 81% versus 59%, and 100% versus 82% versus 68%, respectively. There was no statistically significant difference in outcome among histologically and clinically diagnosed germinomas. Conclusion: A criterion for clinical diagnosis when a biopsy is not feasible is elucidated, and comparable outcomes were demonstrated with histologically diagnosed germinomas.

Safety and efficacy of nivolumab plus ipilimumab in patients with advanced renal cell carcinoma with brain metastases: CheckMate 920

Background

Nivolumab plus ipilimumab (NIVO + IPI) has demonstrated long‐term efficacy and safety in patients with previously untreated, advanced renal cell carcinoma (aRCC). Although most phase 3 clinical trials exclude patients with brain metastases, the ongoing, multicohort phase 3b/4 CheckMate 920 trial (ClincalTrials.gov identifier NCT02982954) evaluated the safety and efficacy of NIVO + IPI in a cohort that included patients with aRCC and brain metastases, as reported here.

Methods

Patients with previously untreated aRCC and asymptomatic brain metastases received NIVO 3 mg/kg plus IPI 1 mg/kg every 3 weeks × 4 followed by NIVO 480 mg every 4 weeks. The primary end point was the incidence of grade ≥3 immune‐mediated adverse events (imAEs) within 100 days of the last dose of study drug. Key secondary end points were progression‐free survival and the objective response rate according to Response Evaluation Criteria in Solid Tumors, version 1.1 (both determined by the investigator). Exploratory end points included overall survival, among others.

Results

After a minimum follow‐up of 24.5 months (N = 28), no grade 5 imAEs occurred. The most common grade 3 and 4 imAEs were diarrhea/colitis (n = 2; 7%) and hypophysitis, rash, hepatitis, and diabetes mellitus (n = 1 each; 4%). The objective response rate was 32% (95% CI, 14.9%‐53.5%) with a median duration of response of 24.0 months; 4 of 8 responders remained without reported progression. Seven patients (25%) had intracranial progression. The median progression‐free survival was 9.0 months (95% CI, 2.9‐12.0 months), and the median overall survival was not reached (95% CI, 14.1 months to not estimable).

Conclusions

In patients who had previously untreated aRCC and brain metastases—a population with a high unmet medical need that often is underrepresented in clinical trials—the approved regimen of NIVO + IPI followed by NIVO showed encouraging antitumor activity and no new safety signals.

CheckMate 920 is the first prospective, multicohort study of nivolumab plus ipilimumab as first‐line therapy for advanced renal cell carcinoma in patients who have a poor prognosis and a high unmet medical need. In cohort 3 (advanced renal cell carcinoma and brain metastases), nivolumab plus ipilimumab has a safety profile consistent with previous reports of this dosing regimen with encouraging antitumor activity.

Nkx3-1 and Fech genes might be switch genes involved in pituitary non-functioning adenoma invasiveness

Non-functioning pituitary adenomas (NFPAs) are typical pituitary macroadenomas in adults associated with increased mortality and morbidity. Although pituitary adenomas are commonly considered slow-growing benign brain tumors, numerous of them possess an invasive nature. Such tumors destroy sella turcica and invade the adjacent tissues such as the cavernous sinus and sphenoid sinus. In these cases, the most critical obstacle for complete surgical removal is the high risk of damaging adjacent vital structures. Therefore, the development of novel therapeutic strategies for either early diagnosis through biomarkers or medical therapies to reduce the recurrence rate of NFPAs is imperative. Identification of gene interactions has paved the way for decoding complex molecular mechanisms, including disease-related pathways, and identifying the most momentous genes involved in a specific disease. Currently, our knowledge of the invasion of the pituitary adenoma at the molecular level is not sufficient. The current study aimed to identify critical biomarkers and biological pathways associated with invasiveness in the NFPAs using a three-way interaction model for the first time. In the current study, the Liquid association method was applied to capture the statistically significant triplets involved in NFPAs invasiveness. Subsequently, Random Forest analysis was applied to select the most important switch genes. Finally, gene set enrichment (GSE) and gene regulatory network (GRN) analyses were applied to trace the biological relevance of the statistically significant triplets. The results of this study suggest that "mRNA processing" and "spindle organization" biological processes are important in NFAPs invasiveness. Specifically, our results suggest Nkx3-1 and Fech as two switch genes in NFAPs invasiveness that may be potential biomarkers or target genes in this pathology.

Prospective Longitudinal Assessment of Health-related Quality of Life in Patients With Brain Metastases Undergoing Radiation Therapy

OBJECTIVE

We conducted a prospective clinical trial of patients receiving radiation (RT) for brain metastases to identify clinical predictors of pre-RT and post-RT health-related quality of life (hrQoL).

MATERIALS AND METHODS

Patients with brain metastases completed overall (European Organisation for Research and Treatment of Cancer QLQ C15-PAL) and brain tumor-specific (QLQ-BN20) hrQoL assessments pre-RT (n=127) and 1 (n=56) and 3 (n=45) months post-RT. Linear and proportional-odds models analyzed patient, disease, and treatment predictors of baseline, 1-, and 3-month hrQoL scores. Generalized estimating equations and repeated measures proportional-odds models assessed predictors of longitudinal hrQoL scores.

RESULTS

Most patients underwent stereotactic radiosurgery (SRS) (69.3%) and had non-small-cell lung (36.0%) metastases. Compared with SRS, receipt of whole brain RT was associated with a higher odds of appetite loss (baseline P=0.04, 1 mo P=0.02) and greater motor dysfunction (baseline P=0.01, 1 mo P=0.003, 3 mo P=0.02). Receipt of systemic therapy was associated with better emotional functioning after RT (1 mo P=0.03, 3 mo P=0.01). Compared with patients with breast cancer, patients with melanoma had higher odds of better global hrQoL (P=0.01) and less pain (P=0.048), while patients with lung cancer reported lower physical function (P=0.048) 3 months post-RT. Nonmarried patients had greater odds of higher global hrQoL (1 mo P=0.01), while male patients had lower odds of reporting more hair loss (baseline P=0.03, 3 mo P=0.045). Patients 60 years and above had lower odds of more drowsiness (P=0.04) and pain (P=0.049) over time.

CONCLUSIONS

Patients receiving SRS versus whole brain RT and systemic therapy reported better posttreatment hrQoL. In addition, melanoma metastases, nonmarried, male, and older patients with reported better hrQoL in various as well as domains after intracranial RT.

Hospitalization outcomes among brain metastasis patients receiving radiation therapy with or without stereotactic radiosurgery from the 2005-2014 Nationwide Inpatient Sample

The purpose of this study was to compare hospitalization outcomes among US inpatients with brain metastases who received stereotactic radiosurgery (SRS) and/or non-SRS radiation therapies without neurosurgical intervention. A cross-sectional study was conducted whereby existing data on 35,199 hospitalization records (non-SRS alone: 32,981; SRS alone: 1035; SRS + non-SRS: 1183) from 2005 to 2014 Nationwide Inpatient Sample were analyzed. Targeted maximum likelihood estimation and Super Learner algorithms were applied to estimate average treatment effects (ATE), marginal odds ratios (MOR) and causal risk ratio (CRR) for three distinct types of radiation therapy in relation to hospitalization outcomes, including length of stay (' ≥ 7 days' vs. ' < 7 days') and discharge destination ('non-routine' vs. 'routine'), controlling for patient and hospital characteristics. Recipients of SRS alone (ATE = - 0.071, CRR = 0.88, MOR = 0.75) or SRS + non-SRS (ATE = - 0.17, CRR = 0.70, MOR = 0.50) had shorter hospitalizations as compared to recipients of non-SRS alone. Recipients of SRS alone (ATE = - 0.13, CRR = 0.78, MOR = 0.59) or SRS + non-SRS (ATE = - 0.17, CRR = 0.72, MOR = 0.51) had reduced risks of non-routine discharge as compared to recipients of non-SRS alone. Similar analyses suggested recipients of SRS alone had shorter hospitalizations and similar risk of non-routine discharge when compared to recipients of SRS + non-SRS radiation therapies. SRS alone or in combination with non-SRS therapies may reduce the risks of prolonged hospitalization and non-routine discharge among hospitalized US patients with brain metastases who underwent radiation therapy without neurosurgical intervention.

Stereotactic Radiosurgery (SRS) experience on brain metastases: A 3-year retrospective study at King Abdulaziz University Hospital

Objectives

Stereotactic radiosurgery (SRS), a non-invasive surgical procedure had been utilized for treatment of patients with brain metastases. This study aims to determine the survival, local control of brain metastases and treatment outcome to SRS-treated patients based on radiological imaging.

Methods

The MRI scans of SRS-treated patients with brain metastases (n = 24) from the Radiology Department of King Abdulaziz University from January 2016 to September 2019 were examined. The data was analyzed using descriptive statistics and Chi-square test.

Results

Out of 24 patients, most had brain metastases (95.8%, n = 23) with mean interval development (after primary site) of 21.88 ± 25.2 months. Radiological imaging revealed tumor characteristics of smallest (n = 11) and biggest lesions (n = 24) of patients to be 0.98 ± 0.7 and 2.23 ± 0.9, respectively and number of lesion to be 4-5 lesions (n = 3), 3 lesions (n = 6), 2 lesions (n = 4) and 1 lesion (n = 11). After SRS treatment, findings showed 17.6% (n = 3) no recurrence among the patients. Those with recurrences have decrease in lesion enhancement (11.8%, n = 2), decrease in size (29.4%, n = 5) and decrease in both enhancement and size (29.4%). Overall survival obtained was 16.7% (n = 2) at 313.83 ± 376.0 days (n = 23) survival period. Chi-square test showed that radiological findings were significantly associated with tumor recurrence (p = 0.010), having SRS-treated patients with recurrences (n = 12) to experience significant decrease (p = 0.010) in tumor enhancement, size, and both enhancement and size.

Conclusion

A significant decrease in tumor size and enhancement was observed in SRS-treated patients, suggesting SRS treatment to have associated benefit with prolonged survival duration.

The clinical relevance of laboratory prognostic scores for patients with radiosurgically treated brain metastases of non-pulmonary primary tumor

Purpose

To investigate the clinical value of the inflammation based prognostic scores for patients with radiosurgically treated brain metastases (BM) originating from non-pulmonary primary tumor (PT).

Methods

A retrospective analysis of 340 BM patients of different PT origin (melanoma, breast, gastrointestinal, or genitourinary cancer) was performed. Pre-radiosurgical laboratory prognostic scores, such as the Neutrophil-to-Lymphocyte Ratio (NLR), the Platelet-to-Lymphocyte Ratio (PLR), Lymphocyte-to-Monocyte Ratio (LMR), and the modified Glasgow Prognostic Score (mGPS), were investigated within 14 days before the first Gamma Knife radiosurgical treatment (GKRS1).

Results

In our study cohort, the estimated survival was significantly longer in patients with NLR < 5 (p < 0.001), LMR > 4 (p = 0.001) and in patients with a mGPS score of 0 (p < 0.001). Furthermore, univariate and multivariate Cox regression models revealed NLR ≥ 5, LMR < 4 and mGPS score ≥ 1 as independent prognostic factors for an increased risk of death even after adjusting for age, sex, KPS, extracranial metastases status, presence of neurological symptoms and treatment with immunotherapy (IT) or targeted therapy (TT).

Conclusions

Summarizing previously published and present data, pre-radiosurgical mGPS and NLR groups seem to be the most effective and simple independent prognostic factors to predict clinical outcome in radiosurgically treated BM patients.

Emerging principles of brain immunology and immune checkpoint blockade in brain metastases

Brain metastases are the most common type of brain tumours, harbouring an immune microenvironment that can in principle be targeted via immunotherapy. Elucidating some of the immunological intricacies of brain metastases has opened a therapeutic window to explore the potential of immune checkpoint inhibitors in this globally lethal disease. Multiple lines of evidence suggest that tumour cells hijack the immune regulatory mechanisms in the brain for the benefit of their own survival and progression. Nonetheless, the role of the immune checkpoint in the complex interplays between cancers cells and T cells and in conferring resistance to therapy remains under investigation. Meanwhile, early phase trials with immune checkpoint inhibitors have reported clinical benefit in patients with brain metastases from melanoma and non-small cell lung cancer. In this review, we explore the workings of the immune system in the brain, the immunology of brain metastases, and the current status of immune checkpoint inhibitors in the treatment of brain metastases.

18F-FACBC PET/MRI in the evaluation of human brain metastases: a case report

Background

Patients with metastatic cancer to the brain have a poor prognosis. In clinical practice, MRI is used to delineate, diagnose and plan treatment of brain metastases. However, MRI alone is limited in detecting micro-metastases, delineating lesions and discriminating progression from pseudo-progression. Combined PET/MRI utilises superior soft tissue images from MRI and metabolic data from PET to evaluate tumour structure and function. The amino acid PET tracer ¹⁸F-FACBC has shown promising results in discriminating high- and low-grade gliomas, but there are currently no reports on its use on brain metastases. This is the first study to evaluate the use of ¹⁸F-FACBC on brain metastases.

Case presentation

A middle-aged female patient with brain metastases was evaluated using hybrid PET/MRI with ¹⁸F-FACBC before and after stereotactic radiotherapy, and at suspicion of recurrence. Static/dynamic PET and contrast-enhanced T1 MRI data were acquired and analysed. This case report includes the analysis of four ¹⁸F-FACBC PET/MRI examinations, investigating their utility in evaluating functional and structural metastasis properties.

Conclusion

Analysis showed high tumour-to-background ratios in brain metastases compared to other amino acid PET tracers, including high uptake in a very small cerebellar metastasis, suggesting that ¹⁸F-FACBC PET can provide early detection of otherwise overlooked metastases. Further studies to determine a threshold for ¹⁸F-FACBC brain tumour boundaries and explore its utility in clinical practice should be performed.

A real-world study in advanced non-small cell lung cancer with de novo brain metastasis

Brain metastases are the major cause of life-expectancy shortened for patients with lung cancer. The prognostic value of EGFR mutation subtypes and survival benefit of EGFR-tyrosine kinase inhibitors (TKIs) in advanced non-small cell lung cancer (NSCLC) patients with de novo brain metastasis is still not clear. Here, we present a real-world study nation-wide focusing on the prognostic value of genomic and therapeutic factors in overall survival (OS) of those patients. We enrolled a total of 233 patients diagnosed with advanced NSCLC and de novo BM from multi-medical centers across China. The enrolled patients were divided into 4 groups, including EGFR 19del, EGFR L858R, EGFR wild-type, and EGFR unknown groups. The median OS of patients with EGFR mutations and all patients were 29.0 and 25.0 months, respectively. There was significant difference in OS of patients among EGFR 19del (n=76), EGFR L858R (n=94), EGFR wild-type (n=46) and EGFR unknown (n=17) groups (30.5 vs 27.5 vs 16.0 vs 25.0, P=0.025). Patients treated by icotinib showed better OS than gefitinib and erlotinib (31.0 vs 25.5 vs 26.5, P=0.02). There was a difference in OS of patients received the whole-brain radiotherapy (WBRT), stereotactic radiosurgery (SRS), or WBRT+SRS (20.0 vs 31.0 vs 30.0 months, P<0.001), respectively. In multivariate analysis, patients treated with icotinib had superior iPFS benefit than gefitinib and erlotinib (HR=0.86[95%CI (0.74-1.0)], P=0.04). Besides, the histology of non-adenocarcinomas, the number of BM (>3), and extracranial metastases status could have an independent negative impact on the OS of all patients (P<0.001). EGFR mutant NSCLC patients with de novo BM had a better OS than patients with EGFR wild type. Patients treated with icotinib had longer iPFS than gefitinib and erlotinib but not in OS. Non-adenocarcinomas, number of BM (>3) and extracranial metastases were independent negative prognostic factors in iPFS and OS of all patients. Prospective clinical trials are warranted to explore more effective multimodality in this population.

Role of radiotherapy in the management of brain metastases of NSCLC - Decision criteria in clinical routine

BACKGROUND

Whole brain radiotherapy (WBRT) is a common treatment option for brain metastases secondary to non-small cell lung cancer (NSCLC). Data from the QUARTZ trial suggest that WBRT can be omitted in selected patients and treated with optimal supportive care alone. Nevertheless, WBRT is still widely used to treat brain metastases secondary to NSCLC. We analysed decision criteria influencing the selection for WBRT among European radiation oncology experts.

METHODS

Twenty-two European radiation oncology experts in lung cancer as selected by the European Society for Therapeutic Radiation Oncology (ESTRO) for previous projects and by the Advisory Committee on Radiation Oncology Practice (ACROP) for lung cancer were asked to describe their strategies in the management of brain metastases of NSCLC. Treatment strategies were subsequently converted into decision trees and analysed for agreement and discrepancies.

RESULTS

Eight decision criteria (suitability for SRS, performance status, symptoms, eligibility for targeted therapy, extra-cranial tumour control, age, prognostic scores and "Zugzwang" (the compulsion to treat)) were identified. WBRT was recommended by a majority of the European experts for symptomatic patients not suitable for radiosurgery or fractionated stereotactic radiotherapy. There was also a tendency to use WBRT in the ALK/EGFR/ROS1 negative NSCLC setting.

CONCLUSION

Despite the results of the QUARTZ trial WBRT is still widely used among European radiation oncology experts.

Radiotherapeutic management of brain tumours during the COVID-19 pandemic

Aim:

The coronavirus disease (COVID-19) pandemic is bound to put tremendous pressure on the existing healthcare system. This aim of this technical note is to help in triaging patients with brain tumours who are sent for radiotherapy during this pandemic and to provide safe and evidence-based care.

Materials and Methods:

Published data for this review were identified by systematically searching PubMed database from November 2007 onwards with the following Medical Subject Heading (Mesh) terms ‘Brain tumours’, ‘COVID-19’, ‘coronavirus’, ‘SARS-nCoV-2’, ‘Radiotherapy’, ‘Guidelines’ ‘hypofractionation’ using Boolean search algorithm. Articles in English language were reviewed.

Results:

We tried to apply the as low as reasonable achievable (ALARA) principle in triaging and management of patients for radiotherapy. We identified protocols which have hypofractionated regimens (reducing patient visits to hospital, time spent in treatment console) with similar outcomes when compared to conventional fractionated regimens and not overburdening the healthcare facility. We also identified the tumours for which we could safely avoid or delay the initiation of radiotherapy.

Conclusion:

Treatment decisions made during the COVID-19 pandemic rely on the safety first/do no harm principle and evidence-based prioritisation of cases for triage. This article is a tool to aid in triaging and prioritising brain tumour patient management. This is for consideration during the pandemic only and certainly not as a strategy for permanent practice change.