Utility of 68Ga-DOTATATE PET-MRI for Gamma Knife® stereotactic radiosurgery treatment planning for meningioma.

OBJECTIVES: To investigate the impact of adding 68Ga-DOTATATE PET/MRI to standard MRI for target volume delineation in Gamma Knife® stereotactic radiosurgery (GKSRS) for meningioma. METHODS: Seventeen patients with 18 lesions undergoing GKSRS for WHO grade 1 meningioma were enrolled in a prospective study. All patients underwent pre-treatment 68Ga-DOTATATE PET/MRI examination in addition to standard procedures. Five clinicians independently contoured the gross tumour volume (GTV) based on standard MRI (GTVMRI) and PET/MRI (GTVPET/MRI) on separate occasions. Interobserver agreement was evaluated using Cohen's Kappa statistic (CKS), Dice similarity coefficient (DC), and Hausdorff distance (HD). Statistical analysis was performed with paired t-test and Wilcoxon signed rank test. RESULTS: The addition of PET/MRI significantly increased GTV contour volume (mean GTVPET/MRI 3.59 cm3 versus mean GTVMRI 3.18 cm3, P = .008). Using the treating clinician's pre-treatment GTVMRI as the reference, median CKS (87.2 vs 77.5, P = .006) and DC (87.2 vs 77.4, P = .006) were significantly lower, and median HD (25.2 vs 31.0, P = .001) was significantly higher with the addition of PET/MRI. No significant difference was observed in interobserver contouring reproducibility between GTVMRI and GTVPET/MRI. CONCLUSION: The addition of 68Ga-DOTATATE PET/MRI for target volume delineation in GKSRS for meningioma is associated with an increase in GTV volume and greater interobserver variation. PET/MRI did not affect interobserver contouring reproducibility. ADVANCES IN KNOWLEDGE: This study provides novel insights into the impact of 68Ga-DOTATATE PET/MRI on GTV delineation and interobserver agreement in meningioma GKSRS, highlighting its potential for improving GKSRS treatment accuracy.

Individuals' perceptions of health and well-being in the context of stereotactic radiosurgery for benign brain tumour: A longitudinal qualitative investigation.

BACKGROUND AND OBJECTIVES: Treatment-related outcomes after Gamma Knife Stereotactic Radiosurgery (GKSRS) for benign brain tumour are well-established; yet patient reported outcomes have been largely overlooked. This study explored individuals' perspectives of their health and well-being prior to and following GKSRS. METHOD: Twenty adults (65% female) aged 24-71 years with benign brain tumour were recruited from a major metropolitan hospital and assessed approximately one week prior to, two weeks after, and at three months following GKSRS. They completed telephone-based interviews focusing on general health, symptoms, and well-being. Interviews were transcribed and analysed using thematic analysis. RESULTS: Three major themes characterized individuals' perceptions of their health and well-being. "Understanding my Illness and Treatment" reflected individuals' efforts to make sense of their illness and symptoms to reduce ambiguity and increase sense of control. "Experiencing Gamma Knife" related to expectations of the procedure, outcomes, daily impacts, and emotional reactions. "Adjusting one's Mindset and Coping" characterised how peoples' approaches to coping with their illness were altered over time. CONCLUSIONS: Coping and adjustment is highly individualistic in the context of GKSRS. Over time, most individuals were able to make sense of their illness, adjust their mindset and utilize behavioural strategies and support systems to cope with the long-term effects.

Cost-utility analysis of a telehealth psychological support intervention for people with primary brain tumor: Telehealth Making Sense of brain tumor.

OBJECTIVE: To undertake an economic evaluation of a telehealth psychological support intervention for patients with primary brain tumor (PBT). METHODS: A within-trial cost-utility analysis over 6 months was performed comparing a tailored telehealth-psychological support intervention with standard care (SC) in a randomized control trial. Data were sourced from the Telehealth Making Sense of Brain Tumor (Tele-MAST) trial survey data, project records, and administrative healthcare claims. Quality-adjusted life years (QALYs) were calculated based on the EuroQol-5D-5L. Non-parametric bootstrapping with 2000 iterations was used to determine sampling uncertainty. Multiple imputation was used for handling missing data. RESULTS: The Tele-MAST trial included 82 participants and was conducted in Queensland, Australia during 2018-2021. When all healthcare claims were included, the incremental cost savings from Tele-MAST were -AU$4,327 (95% CI: -$8637, -$18) while incremental QALY gains were small at 0.03 (95% CI: -0.02, 0.08). The likelihood of Tele-MAST being cost-effective versus SC was 87% at a willingness-to-pay threshold of AU$50,000 per QALY gain. When psychological-related healthcare costs were included only, the incremental cost per QALY gain was AU$10,685 (95% CI: dominant, $24,566) and net monetary benefits were AU$534 (95% CI: $466, $602) with a 65% likelihood of the intervention being cost-effective. CONCLUSIONS: Based on this small randomized controlled trial, the Tele-MAST intervention is a cost-effective intervention for improving the quality of life of people with PBT in Australia. Patients receiving the intervention incurred significantly lower overall healthcare costs than patients in SC. There was no significant difference in costs incurred for psychological health services.

Repurposing traditional U-Net predictions for sparse SAM prompting in medical image segmentation.

Objective:Automated medical image segmentation (MIS) using deep learning has traditionally relied on models built and trained from scratch, or at least fine-tuned on a target dataset. The Segment Anything Model (SAM) by Meta challenges this paradigm by providing zero-shot generalisation capabilities. This study aims to develop and compare methods for refining traditional U-Net segmentations by repurposing them for automated SAM prompting.Approach:A 2D U-Net with EfficientNet-B4 encoder was trained using 4-fold cross-validation on an in-house brain metastases dataset. Segmentation predictions from each validation set were used for automatic sparse prompt generation via a bounding box prompting method (BBPM) and novel implementations of the point prompting method (PPM). The PPMs frequently produced poor slice predictions (PSPs) that required identification and substitution. A slice was identified as a PSP if it (1) contained multiple predicted regions per lesion or (2) possessed outlier foreground pixel counts relative to the patient's other slices. Each PSP was substituted with a corresponding initial U-Net or SAM BBPM prediction. The patients' mean volumetric dice similarity coefficient (DSC) was used to evaluate and compare the methods' performances.Main results:Relative to the initial U-Net segmentations, the BBPM improved mean patient DSC by 3.93 ± 1.48% to 0.847 ± 0.008 DSC. PSPs constituted 20.01-21.63% of PPMs' predictions and without substitution performance dropped by 82.94 ± 3.17% to 0.139 ± 0.023 DSC. Pairing the two PSP identification techniques yielded a sensitivity to PSPs of 92.95 ± 1.20%. By combining this approach with BBPM prediction substitution, the PPMs achieved segmentation accuracies on par with the BBPM, improving mean patient DSC by up to 4.17 ± 1.40% and reaching 0.849 ± 0.007 DSC.Significance:The proposed PSP identification and substitution techniques bridge the gap between PPM and BBPM performance for MIS. Additionally, the uniformity observed in our experiments' results demonstrates the robustness of SAM to variations in prompting style. These findings can assist in the design of both automatically and manually prompted pipelines.

Emergent radiotherapy for spinal cord compression/impingement-a narrative review.

BACKGROUND AND OBJECTIVE: Malignant epidural spinal cord compression (MESCC), often presenting with back pain and motor/sensory deficits, is associated with poor survival, particularly when there is loss of ambulation. The purpose of this review is to evaluate the literature and discuss appropriate workup and management of MESCC, specifically in the emergent setting. METHODS: A PubMed search was conducted on "spinal cord compression" and "radiation therapy." Articles were analyzed for the purpose of this narrative review. KEY CONTENT AND FINDINGS: If MESCC is suspected, neurologic examination and complete spine imaging are recommended. Emergent treatment is indicated if there is radiographic evidence of high-grade compression and/or clinically significant motor deficits. Treatment involves a combination of medical management, surgical decompression, radiation therapy (RT), and rehabilitation. For motor deficits, emergent initiation of high dose steroids is recommended. Circumferential surgical decompression ± stabilization followed by RT provides superior clinical outcomes than RT alone. For patients whom surgery is not reasonable, RT alone may provide significant treatment response which depends on radioresponsiveness of the pathology. Systemic therapy, if indicated, is typically reserved till after primary treatment of MESCC, but patients with chemoresponsive tumors may receive primary chemotherapy. The selected RT schedule should be personalized to each patient and commonly is 30 Gy in 10 fractions (fx), 20 Gy in 5 fx, or 8 Gy in 1 fx. MESCC recurrence may be treated with additional RT, if within the spinal cord tolerance, or surgery. Stereotactic body radiation therapy (SBRT) has been used for high grade MESCC in patients with relatively intact neurologic function at a few centers with a very robust infrastructure to support rapid initiation of treatment within a short period of time, but is generally not feasible for most clinical practices. SBRT may be advantageous for low grade MESCC, recurrence, or in the post-operative setting. Detection of MESCC prior to development of high-grade compression or deterioration of neurologic function may allow patients to benefit more from advanced therapies and improve prognosis. CONCLUSIONS: MESCC is a devastating condition; optimal treatment should be personalized to each patient and approached collaboratively by a multidisciplinary team.

Outcomes for oligometastatic head and neck cancer treated with stereotactic body radiotherapy: Results from an international multi-institutional consortium.

BACKGROUND: We report the results of an international multi-institutional cohort of oligometastatic (OMD) head and neck cancer (HNC) patients treated with SBRT. METHODS: Patients with OMD HNC (≤5 metastases) treated with SBRT between 2008 and 2016 at six institutions were included. Treated metastasis control (TMC), progression-free survival (PFS), and overall survival (OS) were analyzed by multivariable analysis (MVA). RESULTS: Forty-two patients with 84 HNC oligometastases were analyzed. The TMC rate at 1 and 2 years were 80% and 66%, with a median time to recurrence of 10.1 months. The median PFS and OS were 4.7 and 23.3 months. MVA identified a PTV point maximum (BED)10 > 100 Gy as a predictor of improved TMC (HR = 0.31, p = 0.034), and a cumulative PTV > 48 cc as having worse PFS (HR = 2.99, p < 0.001). CONCLUSION: Favorable TMC and OS was observed in OMD HNCs treated with SBRT.

Emergent radiotherapy for brain and leptomeningeal metastases: a narrative review.

BACKGROUND AND OBJECTIVE: As novel systemic therapies allow patients to live longer with cancer, the risk of developing central nervous system (CNS) metastases increases and providers will more frequently encounter emergent presentation of brain metastases (BM) and leptomeningeal metastases (LM). Management of these metastases requires appropriate work-up and well-coordinated multidisciplinary care. We set out to perform a review of emergent radiotherapy (RT) for CNS metastases, specifically focusing on BM and LM. METHODS: We review the appropriate pathways for workup and initial management of BM and LM, while reviewing the literature supporting emergent treatment of these entities with surgery, systemic anti-cancer therapy, and RT. To inform this narrative review, literature searches in PubMed and Google Scholar were conducted, with preference given to articles employing modern RT techniques, when applicable. Due to the paucity of high-quality evidence for management of BM and LM in the emergent setting, discussion was supplemented by the authors' expert commentary. KEY CONTENT AND FINDINGS: This work highlights the importance of surgical evaluation, particularly for patients presenting with significant mass effect, hemorrhagic metastases, or increased intracranial pressure. We review the rare situations where emergent initiation of systemic anti-cancer therapy is indicated. When defining the role of RT, we review factors guiding selection of appropriate modality, treatment volume, and dose-fractionation. Generally, 2D- or 3D-conformal treatment techniques prescribed as 30 Gy in 10 fractions or 20 Gy in 5 fractions, should be employed in the emergent setting. CONCLUSIONS: Patients with BM and LM present from a diverse array of clinical situations, requiring well-coordinated multidisciplinary management, and there is a paucity of high-quality evidence guiding such management decisions. This narrative review aims to more thoroughly prepare providers for the challenging situation of emergent management of BM and LM.

Evaluation of the telehealth making sense of brain tumor psychological support intervention for people with primary brain tumor and their caregivers: A randomized controlled trial.

OBJECTIVE: This pragmatic randomized control trial aimed to evaluate clinical efficacy of the Making Sense of Brain Tumour program delivered via videoconferencing (Tele-MAST) for improving mental health and quality of life (QoL) relative to standard care in individuals with primary brain tumor (PBT). METHOD: Adults with PBT experiencing at least mild distress (Distress Thermometer ≥4) and caregivers were randomly allocated to the 10-session Tele-MAST program or standard care. Mental health and QoL were assessed pre-intervention, post-intervention (primary endpoint), and 6-weeks and 6-months follow-up. The primary outcome was clinician-rated depressive symptoms on the Montgomery-Asberg Depression Rating Scale. RESULTS: 82 participants with PBT (34% benign, 20% lower-grade glioma, 46% high-grade glioma) and 36 caregivers were recruited (2018-2021). Controlling for baseline functioning, Tele-MAST participants with PBT had lower depressive symptoms at post-intervention (95% CI: 10.2-14.6, vs. 15.2-19.6, p = 0.002) and 6-weeks post-intervention (95% CI: 11.5-15.8 vs. 15.6-19.9, p = 0.010) than standard care, and were almost 4 times more likely to experience clinically reduced depression (OR, 3.89; 95% CI: 1.5-9.9). Tele-MAST participants with PBT also reported significantly better global QoL, emotional QoL and lower anxiety at post-intervention and 6-weeks post-intervention than standard care. There were no significant intervention effects for caregivers. At 6-months follow-up participants with PBT who received Tele-MAST reported significantly better mental health and QoL relative to pre-intervention. CONCLUSIONS: Tele-MAST was found to be more effective for reducing depressive symptoms at post-intervention than standard care for people with PBT but not caregivers. Tailored and extended psychological support may be beneficial for people with PBT.

The impact of local control on widespread progression and survival in oligometastasis-directed SBRT: Results from a large international database.

PURPOSE: We investigated the impact of local control (LC) on widespread progression (WSP) and overall survival (OS) in patients treated to all extracranial oligometastases (OMs) at presentation to SBRT in this retrospective review across 6 international centers. MATERIALS/METHODS: Relationships between LC status of SBRT-directed OMs and OS and WSP (>5 new active/untreated lesions) were explored using Cox and Fine-Gray regression models, adjusting for radioresistant histology and pre-SBRT systemic therapy receipt. The association between LC and dosimetric predictors was analyzed with competing risk regression using death as a competing risk and across a wide range of simulated α/ßratios. RESULTS: In total, 1700 OMs in 1033 patients were analyzed, with 25.2% NSCLC, 22.7% colorectal, 12.8% prostate, and 8.1% breast histology. Patients who failed locally in any SBRT-directed OM within 6 mo were at 3.6-fold higher risk of death and 2.7-fold higher risk of WSP compared to those who remained locally-controlled (p < 0.001). Similar associations existed for each duration of LC investigated through 3 yrs post-SBRT. There was no significant difference in risk of WSP or death between patients who failed in a subset of SBRT-treated lesions vs. patients who failed in all lesions. Minimum dose (Dmin) to the GTV/ITV was most predictive of LC when compared to prescription dose, PTV Dmin, and PTV Dmax. Sensitivity analysis for achieving 1-yr LC > 95% found thresholds of 41.2 Gy and 55.2 Gy in 5 fractions for smaller (< 27.7 cc) and larger radioresistant lesions, respectively. CONCLUSION: This large multinational cohort suggests that the duration of LC following OM-directed SBRT strongly correlates with WSP and OS.

The safety, feasibility, and efficacy of an 18-week exercise intervention for adults with primary brain cancer - the BRACE study.

PURPOSE: To determine the safety, feasibility, and potential effect of an 18-week exercise intervention for adults with primary brain cancer. MATERIALS AND METHODS: Eligible patients were 12-26-weeks post-radiotherapy for brain cancer. The individually-prescribed weekly exercise was ≥150-minutes of moderate-intensity exercise, including two resistance-training sessions. The intervention was deemed "safe" if exercise-related, serious adverse events (SAE) were experienced by <10% of participants, and feasible if recruitment, retention, and adherence rates were ≥75%, and ≥75% compliance rates were achieved in ≥75% of weeks. Patient-reported and objectively-measured outcomes were assessed at baseline, mid-intervention, end-intervention, and 6-month follow-up, using generalized estimating equations. RESULTS: Twelve participants enrolled (51 ± 19.5 years, 5 females). There were no exercise-related SAEs. The intervention was feasible (recruitment:80%, retention:92%, adherence:83%). Participants completed a median of 172.8 (min:77.5, max:560.8) minutes of physical activity per week. 17% met the compliance outcome threshold for ≥75% of the intervention. Improvements in quality of life (mean change (95% CI): 7.9 units (1.9, 13.8)), functional well-being (4.3 units (1.4, 7.2)), depression (-2.0 units (-3.8, -0.2)), activity (112.8 min (42.1, 183.4)), fitness (56.4 meters (20.4, 92.5)), balance (4.9 s (0.9, 9.0)), and lower-body strength (15.2 kg (9.3, 21.1)) were observed end-intervention. CONCLUSION: Preliminary evidence support that exercise is safe and beneficial to the quality of life and functional outcomes for people with brain cancer.Registration: ACTRN12617001577303.

The BRAin Cancer and Exercise (BRACE) study highlights the need for regular monitoring of disease- and treatment-related side effects which may present as barriers to exercise.Exercise prescription should be modified according to the presence and severity of disease- and treatment-related barriers.Adverse events observed, such as dizziness, highlight the importance of supervised exercise for people with brain cancer.If supervision is not possible, then exercise modes with low risk of harm from falls are recommended (e.g., walking, machine-based resistance training).

"Hey, I'm still here!": Maintaining, managing and rebuilding social connections after brain tumour.

It is well recognized that social networks can buffer the adverse effects of chronic illness on psychological wellbeing. However, the functional impairments associated with brain tumour often affect social participation, which may reduce people's capacity to draw upon their social capital for support. This qualitative phenomenological study aimed to understand how brain tumour influences people's ability to manage, maintain, and rebuild their social networks. Participants were 20 individuals (65% female) aged 22-69 years with diverse types of primary brain tumour (50% high grade or malignant) who were on average 35 months post-diagnosis. Two semi-structured interviews, conducted three months apart, comprised a Social Identity Mapping exercise and questions exploring changes in social groups since diagnosis. Two overarching and interrelated themes emerged: engaging and connecting and then versus now. An interplay of barriers, facilitators and strategies influenced people's ability to engage and connect with their social groups, which in turn influenced whether they experienced stability; maintenance and expansion; loss and rebuilding; or loss and shrinkage of their social networks over time. These novel findings highlight the need to develop interventions that specifically focus on enhancing individuals' abilities to maintain or rebuild their social networks.

Gamma Knife® stereotactic radiosurgery for intracranial cavernous malformations.

INTRODUCTION: Gamma Knife® stereotactic radiosurgery (GKSRS) is a non-invasive alternative to surgical resection for cerebral cavernous malformations (CCMs), especially in eloquent locations. METHODOLOGY: A retrospective review was performed on an Australian cohort of patients receiving GKSRS for CCMs at a single institution. All patients exhibited symptoms and/or radiological evidence of haemorrhage before therapy. The minimum follow-up was 1-year post-GKSRS. McNemar's test was used for differences in matched-pair outcomes pre- and post-GKSRS with an α = 0.05. A systematic review and meta-analysis was additionally performed to synthesise the current published evidence on the clinical efficacy of stereotactic radiosurgery in reducing haemorrhage risk in CCMs using a DerSimonian and Laird random effects model. RESULTS: Thirty-five patients (39 cavernomas) underwent GKSRS. 87.2 % of patients had evidence of at least one haemorrhage before GKSRS and the remainder exhibited seizures. The median dose was 12.5 Gy in a single fraction (IQR 12-13). The median follow-up duration from GKSRS was 809 days (IQR 536-960). There was a significant reduction in matched annual bleed rate from pre-GKSRS (52.1 %) compared to after SRS (12.3 %) (p < 0.001) [OR = 0.07, 95 % 0.008-0.283] There was no statistically significant difference in seizure incidence pre- (30.7 %) versus post-GKSRS (17.9 %) (p = 0.13) [OR = 0.167, 95 %CI 0.004-1.37]. One patient (3 %) with a brainstem lesion experienced long-term treatment-related oedema with persistent ipsilateral weakness and tremors. On meta-analysis of 25 pooled studies, radiosurgery for the treatment of CCMs was associated with a statistically significantly relative risk (RR) reduction in haemorrhage events [random effects RR 0.12 (95 % CI 0.074-0.198), p < 0.001)], with most of the proportionate risk reduction occurring in the initial 2 years following SRS. CONCLUSION: GKSRS significantly reduces the annual rate of haemorrhage for intracranial cavernomas in this cohort and on meta-analysis, particularly in the first 2 years following treatment. The overall risk of treatment-related morbidity is low.

Conditional Survival of Patients With Extracranial Oligometastatic Treated With Stereotactic Body Radiation Therapy: An International Consortium Study.

PURPOSE: Prolonged survivorship is increasingly observed in patients with oligometastases (OM) treated with stereotactic body radiation therapy (SBRT). The purpose of this study was to study the conditional survival of patients with OM, which can provide more detailed prognostic information over time by considering time already survived. METHODS AND MATERIALS: A multi-institutional database consisting of 1033 patients with OM (≤5 metastases) treated with SBRT between 2006 and 2017 was analyzed. Conditional overall survival (OS) and progression-free survival (PFS) in 3 years were obtained at multiple time points for all patients and by primary cancer type. Cox regression was used to determine trends in conditional OS and PFS. Changes in the predictors of OS and PFS over time were also determined by multivariable Cox regression. RESULTS: The median follow-up was 24 months (0.3-105 months). Three-year OS and PFS at baseline were 56.7% and 23.2%, respectively. The OS in 3 years conditional on having survived for 3, 6, 12, and 24 months did not significantly change over time (56.7%, 55.4%, 55.8%, and 50.6%, respectively; P = .60). In contrast, the probability of PFS in 3 years conditional on having survived progression-free for 3, 6, 12, and 24 months significantly increased over time (23.6%, 27.3%, 35.1%, and 48.8%, respectively; P < .001). When stratified by primary site, conditional PFS significantly increased over time for patients with colorectal, breast, or kidney cancer. Conditional OS remained stable for patients with non-small cell lung cancer or kidney cancer but significantly decreased over time for patients with prostate, breast, or colorectal cancer. Changes in significant prognostic factors of OS and PFS over time were also observed. CONCLUSIONS: Analysis of conditional survival among patients with OM showed that as patients survived longer, their prognosis for further survival remained stable or decreased. However, patients who survived longer without disease progression had increased probability of PFS over time.

Stereotactic radiosurgery for melanoma brain metastases: Concurrent immune checkpoint inhibitor therapy associated with superior clinicoradiological response outcomes.

INTRODUCTION/PURPOSE: This study assessed long-term clinical and radiological outcomes following treatment with combination stereotactic radiosurgery (SRS) and immunotherapy (IT) for melanoma brain metastases (BM). METHODS: A retrospective review was performed in a contemporary cohort of patients with melanoma BM at a single tertiary institution receiving Gamma Knife® SRS for melanoma BM. Multivariate Cox proportional-hazards modelling was performed with a P <0.05 for significance. RESULTS: 101 patients (435 melanoma BM) were treated with SRS between January-2015 and June-2019. 68.3% of patients received IT within 4 weeks of SRS (concurrent) and 31.7% received SRS alone or non-concurrently with IT. Overall, BM local control rate was 87.1% after SRS. Median progression free survival was 8.7 months. Median follow-up was 29.2 months. On multivariate analysis (MVA), patients receiving concurrent SRS-IT maintained a higher chance of achieving a complete (CR) or partial response (PR) [HR 2.6 (95% CI: 1.2-5.5, P = 0.012)] and a reduced likelihood of progression of disease (PD) [HR 0.52 (95% CI: 0.16-0.60), P = 0.048]. Any increase in BM volume on the initial MRI 3 months after SRS predicted a lower likelihood of achieving long-term CR or PR on MVA accounting for concurrent IT, BRAF status and dexamethasone use [HR = 0.048 (95% CI: 0.007-0.345, P = 0.0026)]. Stratified volumetric change demonstrated a sequential relationship with outcomes on Kaplan-Meier analysis. CONCLUSION: Concurrent SRS-IT has favourable clinical and radiological outcomes with respect to CR, PR and a reduced likelihood of PD. Changes in BM volume on the initial MRI 3 months after SRS were predictive of long-term outcomes for treatment response.

Current status of intra-cranial stereotactic radiotherapy and stereotactic radiosurgery in Australia and New Zealand: key considerations from a workshop and surveys.

Recently, there has been increased interest worldwide in the use of conventional linear accelerator (linac)-based systems for delivery of stereotactic radiosurgery/radiotherapy (SRS/SRT) contrasting with historical delivery in specialised clinics with dedicated equipment. In order to gain an understanding and define the current status of SRS/SRT delivery in Australia and New Zealand (ANZ) we conducted surveys and provided a single-day workshop. Prior to the workshop ANZ medical physicists were invited to complete two surveys: a departmental survey regarding SRS/SRT practises and equipment; and an individual survey regarding opinions on current and future SRS/SRT practices. At the workshop conclusion, attendees completed a second opinion-based survey. Workshop discussion and survey data were utilised to identify areas of consensus, and areas where a community consensus was unclear. The workshop was held on the 8th Sept 2020 virtually due to pandemic-related travel restrictions and was attended by 238 radiation oncology medical physicists from 39 departments. The departmental survey received 32 responses; a further 89 and 142 responses were received to the pre-workshop and post-workshop surveys respectively. Workshop discussion indicated a consensus that for a department to offer an SRS/SRT service, a minimum case load should be considered depending on availability of training, peer-review, resources and equipment. It was suggested this service may be limited to brain metastases only, with less common indications reserved for departments with comprehensive SRS/SRT programs. Whilst most centres showed consensus with treatment delivery techniques and image guidance, opinions varied on the minimum target diameter and treatment margin that should be applied.

The optimal management of brain metastases from gestational trophoblastic neoplasia.

INTRODUCTION: Gestational trophoblastic diseases and neoplasias (GTDs and GTNs) comprise a spectrum of diseases arising from abnormally proliferating placental/trophoblastic tissue following an antecedent molar or non-molar pregnancy. These can spread to the brain hematogenously in about 10% of patients, mostly in high-risk disease. The optimal management of patients with brain metastases from GTN is unclear, with multiple systemic regimens under use and an uncertain role for radiotherapy. AREAS COVERED: Here, we review the epidemiology, workup, and treatment of GTN with central nervous system (CNS) involvement. Literature searches in PubMed and Google Scholar were conducted using combinations of keywords such as 'gestational trophoblastic disease,' 'gestational trophoblastic neoplasia,' 'choriocarcinoma,' and 'brain metastases.' EXPERT OPINION: Systemic therapy is the frontline treatment for GTN with brain metastases, and radiotherapy should only be considered in the context of a clinical trial or for resistant/recurrent disease. Surgery has a limited role in palliating symptoms or relieving intracranial pressure/bleeding. Given the highly specialized care these patients require, treatment at a high-volume referral center with multidisciplinary collaboration likely leads to better outcomes. Randomized trials should be conducted to determine the best systemic therapy option for GTN.

Development of a Prognostic Model for Overall Survival in Patients With Extracranial Oligometastatic Disease Treated With Stereotactic Body Radiation Therapy.

PURPOSE: Patients with oligometastatic disease (OMD) can experience durable disease control with ablative therapy to all sites of disease. Stereotactic body radiation therapy (SBRT) is an important modality in the management of OMD, although a validated prognostic model for OMD treated with SBRT is currently lacking. The purpose of this study was to develop a prognostic model for overall survival (OS) in patients with OMD treated with SBRT. METHODS AND MATERIALS: A multi-institutional database of patients with extracranial OMD treated with SBRT was used for model development. The final prognostic model was generated in a training set using recursive partitioning analysis representing 75% of the population. Model performance was evaluated in the reserved test set. RESULTS: The analysis included 1033 patients. The median OS for the entire cohort was 44.2 months (95% confidence interval [CI], 39.2-48.8 months). The variables used in the regression tree, in order of importance, were primary histology, lung-only OMD on presentation, the timing of OMD presentation, and age at the start of SBRT. A full 5-category risk stratification system based on the terminal nodes possessed fair to good discriminative power with a Harrell concordance statistic of 0.683 (95% CI, 0.634-0.731) and a time-dependent area under the receiver operating characteristic curve of 0.709 (95% CI, 0.706-0.711) in the test set, with good calibration. A simplified risk stratification system consisting of 3 risk categories was also proposed for greater ease of use with comparable performance. CONCLUSIONS: A clinical prognostic model for OS in patients with extracranial OMD treated with SBRT has been developed and validated.

An analysis of a large multi-institutional database reveals important associations between treatment parameters and clinical outcomes for stereotactic body radiotherapy (SBRT) of oligometastatic colorectal cancer.

PURPOSE: In recent years, stereotactic body radiotherapy (SBRT) has emerged as an effective treatment for oligometastatic cancers. Here, we report radiation treatment parameters and clinical outcomes for patients with oligometastatic colorectal cancer (CRC) treated with SBRT using a large multi-institutional database. METHODS: Patients with extra-cranial oligometastatic CRC (≤5 lesions) treated with SBRT at six large academic cancer centers were included. The primary outcome was local recurrence while secondary outcomes included overall survival (OS) progression free survival, oligo-progression, and widespread progression. Survival outcomes were estimated using the Kaplan-Meier method. Univariable and multivariable analyses were performed to determine the relationship between patient and treatment characteristics and clinical outcomes. RESULTS: We identified 235 patients with a total of 381 oligometastatic CRC lesions. The 1- and 5-year local recurrence rate was 13.6% and 44.3% respectively. The median OS was 49 months with a 2-and 5-year OS of 76.1% and 35.9%, respectively. On multivariable analysis, a BED10 of ≥120 Gy, and lung versus liver metastases were associated with a reduction in local recurrence. Larger total PTV size (≥17.5 cc) was associated with worse overall survival, progression free survival, and widespread progression. CONCLUSION: This large multi-institutional analysis found that the use of SBRT for oligometastatic colorectal cancer resulted in favorable overall survival. However, local recurrence is higher than expected for ablative radiation treatment. An increase in BED10 should be considered if feasible and safe.

Barriers and potential solutions to international collaboration in neuro-oncology clinical trials: Challenges from the Australian perspective.

AIM: The neuro-oncology community in Australia is well positioned to collaborate internationally, with a motivated trials group, strong regulatory bodies and an attractive fiscal environment. We sought to identify gaps in the Australian neuro-oncology clinical trials landscape and describe strategies to increase international trial access in Australia. METHODS: We searched clinical trial registries to identify active adult primary brain cancer trials. We compared the participation rate and phase of these trials between tumour types and countries. A survey was distributed to the Cooperative Trials Group for Neuro-Oncology membership to identify barriers and solutions to effective international collaboration. RESULTS: Globally, 307 trials for adult primary brain cancers were identified. These included 50% pharmaceutical agents, 18% cellular therapies and 9% radiation therapy. Twelve adult primary brain cancer trials were actively recruiting in Australia at the time the survey was sent out. There were more early phase brain cancer trials (34%) compared with colorectal and breast cancer (21% and 24%, respectively). In Australia, 92% of brain cancer trials were involving pharmaceutical agents. The most commonly cited barrier was lack of funding for international trials (86%) and insufficient research time (75%). High ranking solutions included increasing the availability of funding for international trials and creating opportunities to develop personal relationships with collaborators. Accreditation of clinical research key performance indicators into practice (88%) and hospital accreditation (73%) also ranked highly. CONCLUSIONS: Participation in international research in Australia could be improved by embedding clinical research targets into institutional funding, provision of funding for early phase studies and streamlining mutual ethics schemes.