Seizure outcomes following single-fraction versus hypofractionated radiosurgery for brain metastases: a single-center experience.

Objective: Although seizures are a relatively common phenomenon in the setting of brain metastases (BMs), there are no discrete recommendations regarding the use of antiepileptic drugs (AEDs) in this population, either in general or in the context of treatment. The authors' aim was to better understand the underlying pathological factors as well as the therapeutic techniques that may lead to seizures following the radiosurgical treatment of BMs with the goal of guiding appropriate AED prophylaxis.

Methods: Adult patients with BMs diagnosed from 2013 to 2020 at a single academic institution and treated with radiation therapy were included in this study.

Retrospective examination of pseudoprogression in mutant gliomas.

Background: Tumor surveillance of isocitrate dehydrogenase () mutant gliomas is accomplished via serial contrast MRI. When new contrast enhancement (CEnew) is detected during postsurgical surveillance, clinicians must assess whether CEnew indicates pseudoprogression (PsP) or tumor progression (TP). PsP has been better studied in wild-type glioblastoma but has not been well characterized in mutant gliomas.

Experience of Telemedicine Visits in Radiation Oncology During the COVID-19 Pandemic: A US National Survey and Lessons Learned for Incorporating Telemedicine Post-COVID-19.

Purpose: We sought to survey the attitudes and perceptions of US radiation oncologists toward the adoption of telemedicine during the COVID-19 pandemic and offer suggestions for its integration in the postpandemic era.

Methods And Materials: A 25-question, anonymous online survey was distributed nationwide to radiation oncologists.

Results: One hundred and twenty-one respondents completed the survey, with 92% from academia.

Relapse patterns and radiation dose exposure in IDH wild-type glioblastoma at first radiographic recurrence following chemoradiation.

Purpose: To quantify the radiation dose distribution and lesion morphometry (shape) at baseline, prior to chemoradiation, and at the time of radiographic recurrence in patients with glioblastoma (GBM).

Methods: The IMRT dose distribution, location of the center of mass, sphericity, and solidity of the contrast enhancing tumor at baseline and the time of tumor recurrence was quantified in 48 IDH wild-type GBM who underwent postoperative IMRT (2 Gy daily for total of 60 Gy) with concomitant and adjuvant temozolomide.

Results: Average radiation dose within enhancing tumor at baseline and recurrence was ≥ 60 Gy.

Germline biomarkers predict toxicity to anti-PD1/PDL1 checkpoint therapy.

Background: There is great interest in finding ways to identify patients who will develop toxicity to cancer therapies. This has become especially pressing in the era of immune therapy, where toxicity can be long-lasting and life-altering, and primarily comes in the form of immune-related adverse effects (irAEs). Treatment with the first drugs in this class, anti-programmed death 1 (anti-PD1)/programmed death-ligand 1 (PDL1) checkpoint therapies, results in grade 2 or higher irAEs in up to 25%-30% of patients, which occur most commonly within the first 6 months of treatment and can include arthralgias, rash, pruritus, pneumonitis, diarrhea and/or colitis, hepatitis, and endocrinopathies.

Voxelwise Prediction of Recurrent High-Grade Glioma via Proximity Estimation-Coupled Multidimensional Support Vector Machine.

Purpose: To provide early and localized glioblastoma (GBM) recurrence prediction, we introduce a novel postsurgery multiparametric magnetic resonance-based support vector machine (SVM) method coupling with stem cell niche (SCN) proximity estimation.

Methods And Materials: This study used postsurgery magnetic resonance imaging (MRI) scans from 50 patients with recurrent GBM, obtained approximately 2 months before clinically diagnosed recurrence. The main prediction pipeline consisted of a proximity-based estimator to identify regions with high risk of recurrence (HRRs) and an SVM classifier to provide voxelwise prediction in HRRs.

Linear accelerator-based radiosurgery for trigeminal neuralgia: comparative outcomes of frame-based and mask-based techniques.

Objective: Precise and accurate targeting is critical to optimize outcomes after stereotactic radiosurgery (SRS) for trigeminal neuralgia (TN). The aim of this study was to compare the outcomes after SRS for TN in which two different techniques were used: mask-based 4-mm cone versus frame-based 5-mm cone.

Methods: The authors performed a retrospective review of patients who underwent SRS for TN at their institution between 1996 and 2019.

Simultaneous radiosurgery for multiple brain metastases: technical overview of the UCLA experience.

Purpose/objective(s): To communicate our institutional experience with single isocenter radiosurgery treatments for multiple brain metastases, including challenges with determining planning target volume (PTV) margins and resulting consequences, image-guidance translational and rotational tolerances, intra-fraction patient motion, and prescription considerations with larger PTV margins.

Materials/methods: Eight patient treatments with 51 targets were planned with various margins using Elements Multiple Brain Mets SRS treatment planning software (Brainlab, Munich, Germany). Forty-eight plans with 0 mm, 1 mm and 2 mm margins were created, including plans with variable margins, where targets more than 6 cm away from the isocenter were planned with larger margins.

Practical Considerations for Single Isocenter LINAC Radiosurgery of Multiple Brain Metastases.

The purpose of this paper is to summarize treatment guidelines for the performance of single isocenter LINAC radiosurgery of multiple brain metastases developed and used by 3 experienced centers. This article is not meant to provide consensus guidelines. Rather, this is a practical, "how we do it" reference without substantial discussion.

Intra-Fraction Motion Management for Radiosurgical Treatments of Trigeminal Neuralgia: Clinical Experience, Imaging Frequency, and Motion Analysis.

Purpose The aim of this study is to evaluate the patient positioning and intra-fraction motion management performance of an image-guidance protocol established for radiosurgical treatments of trigeminal neuralgia patients. Specifically, it also aims to analyze patient motion data for the evaluation of current motion tolerance levels and imaging frequency utilized for repositioning patients. Methods A linear accelerator equipped with ExacTrac is used for patient positioning with stereoscopic imaging and treatments.

A Framework for Sharing Radiation Dose Distribution Maps in the Electronic Medical Record for Improving Multidisciplinary Patient Management.

Radiation oncology practices use a suite of dedicated software and hardware that are not common to other medical subspecialties, making radiation treatment history inaccessible to colleagues. A radiation dose distribution map is generated for each patient internally that allows for visualization of the dose given to each anatomic structure volumetrically; however, this crucial information is not shared systematically to multidisciplinary medical, surgery, and radiology colleagues. A framework was developed in which dose distribution volumes are uploaded onto the medical center's picture archiving and communication system (PACS) to rapidly retrieve and review exactly where, when, and to what dose a lesion or structure was treated.

Quantitative Characterization of Tumor Proximity to Stem Cell Niches: Implications on Recurrence and Survival in GBM Patients.

Purpose: Emerging evidence has linked glioblastoma multiforme (GBM) recurrence and survival to stem cell niches (SCNs). However, the traditional tumor-ventricle distance is insufficiently powered for an accurate prediction. We aimed to use a novel inverse distance map for improved prediction.

Treating Glioblastoma Multiforme (GBM) with super hyperfractionated radiation therapy: Implication of temporal dose fractionation optimization including cancer stem cell dynamics.

Purpose: A previously developed ordinary differential equation (ODE) that models the dynamic interaction and distinct radiosensitivity between cancer stem cells (CSC) and differentiated cancer cells (DCC) was used to explain the definitive treatment failure in Glioblastoma Multiforme (GBM) for conventionally and hypo-fractionated treatments. In this study, optimization of temporal dose modulation based on the ODE equation is performed to explore the feasibility of improving GBM treatment outcome.

Methods: A non-convex optimization problem with the objective of minimizing the total cancer cell number while maintaining the normal tissue biological effective dose (BEDnormal) at 100 Gy, equivalent to the conventional 2 Gy × 30 dosing scheme was formulated.

A Practical Guide for Navigating the Design, Build, and Clinical Integration of Electronic Patient-Reported Outcomes in the Radiation Oncology Department.

The development and integration of electronic patient-reported outcomes (ePROs) into the radiation oncology clinic workflow provide novel opportunities, accompanied by unique design considerations and implementation challenges. The processes required for implementation of ePROs are entirely distinct from standard paper-based surveys, with the majority of time devoted to conception and design before initiating questionnaire build, detailed workflow process mapping including development of new workflows, comprehensive communication of the vision between providers and the information technology team, and quality assurance. Based on our experience with implementation of ePROs in our radiation oncology department, we developed a stepwise framework for approaching ePRO conceptual design, build, workflow integration, and the electronic health record interface.

Time-Driven Activity-Based Costing Analysis of Telemedicine Services in Radiation Oncology.

Purpose: Health systems have increased telemedicine use during the SARS-CoV-2 outbreak to limit in-person contact. We used time-driven activity-based costing to evaluate the change in resource use associated with transitioning to telemedicine in a radiation oncology department.

Methods And Materials: Using a patient undergoing 28-fraction treatment as an example, process maps for traditional in-person and telemedicine-based workflows consisting of discrete steps were created.

Targeted Radiation Therapy Can Treat Myxomatous Cerebral Aneurysms.

Background: Neoplastic cerebral aneurysms are rare presentations of cardiac myxomas. The natural history of such aneurysms is not well understood, and the optimal treatment strategy remains unclear. Clipping and coiling are effective, although can carry significant morbidity.

Time-Driven Activity-Based Costing Comparison of Stereotactic Radiosurgery to Multiple Brain Lesions Using Single-Isocenter Versus Multiple-Isocenter Technique.

Purpose: Stereotactic radiosurgery (SRS) historically has been used to treat multiple brain lesions using a multiple-isocenter technique-frequently associated with significant complexity in treatment planning and long treatment times. Recently, given innovations in planning algorithms, patients with multiple brain lesions may now be treated with a single-isocenter technique using fewer total arcs and less time spent during image guidance (though with stricter image guided radiation therapy tolerances). This study used time-driven activity-based costing to determine the difference in cost to a provider for delivering SRS to multiple brain lesions using single-isocenter versus multiple-isocenter techniques.

Diffusion MRI changes in the anterior subventricular zone following chemoradiation in glioblastoma with posterior ventricular involvement.

Introduction: There is growing evidence that the subventricular zone (SVZ) plays a key role in glioblastoma (GBM) tumorigenesis. However, little is known regarding how the SVZ, which is a harbor for adult neural stem cells, may be influenced by chemoradiation. The current diffusion-weighted imaging (DWI) study explored ipsilateral and contralateral alterations in the anterior SVZ in GBM patients with posterior enhancing lesions following chemoradiation.

Comparison of Clinical Outcomes Stratified by Target Delineation for Patients Undergoing Stereotactic Body Radiotherapy for Spinal Metastases.

Objective: Stereotactic body radiotherapy (SBRT) is an effective treatment of spinal metastases in the vertebral body. However, variation has existed between practitioners regarding the appropriate target delineation. As such, we compared the tumor control, rates of compression fractures, and pain control for patients who had undergone SBRT for spinal metastases to either the lesion only (LO) or the full vertebral body (FVB).

Increased cochlear radiation dose predicts delayed hearing loss following both stereotactic radiosurgery and fractionated stereotactic radiotherapy for vestibular schwannoma.

Purpose: Stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (fSRT) are noninvasive therapies for vestibular schwannomas providing excellent tumor control. However, delayed hearing loss after radiation therapy remains an issue. One potential target to for improving hearing rates is limiting radiation exposure to the cochlea.

Timing of adjuvant radiation therapy and survival outcomes after surgical resection of intracranial non-small cell lung cancer metastases.

Objective: To investigate if delay of adjuvant radiotherapy (ART) beyond 6 post-operative weeks affects survival outcomes in patients undergoing craniotomy or craniectomy for resection of non-small cell lung cancer (NSCLC) intracranial metastases.

Patients And Methods: We performed a retrospective analysis of 28 patients undergoing resection of intracranial metastases and ART at our institution from 2001 to 2016. We assessed survival outcomes for patients who received delayed versus non-delayed ART, as well as associated risk factors.

Hearing Preservation for Vestibular Schwannomas Treated with Stereotactic Radiosurgery or Fractionated Stereotactic Radiotherapy.

Background: Vestibular schwannomas (VS) are benign intracranial neoplasms arising from the eighth cranial nerve for which targeted radiation therapy (RT) has proved increasingly successful. However, long-term hearing and related cranial nerve outcomes have been disputed for the 3 current RT modalities.

Objective: To determine differences in hearing preservation for patients treated with stereotactic radiosurgery (SRS), fractionated stereotactic radiotherapy (FSRT), or hypofractionated stereotactic radiotherapy (hypoFSRT) for VS.

Assessing the volume of large cerebral arteriovenous malformations: Can the ABC/2 formula reliably predict true volume?

Background: Outcomes of stereotactic radiosurgery in the treatment of cerebral arteriovenous malformations (AVMs) are volume-dependent. The ability to estimate AVM volume has significant value in guiding AVM management.

Objective: To determine whether AVM volume measurement calculated from the ABC/2 formula is accurate compared to volume calculated by a computer-assisted planimetric method for large AVMs.