Surgically targeted radiation therapy (STaRT) trials for brain neoplasms: A comprehensive review

Interventional Stereotactic Radiotherapy (brachytherapy) for unresected brain metastases: Systematic review of outcome and toxicity

BACKGROUND

Stereotactic brachytherapy (SBT) is an underutilized treatment for brain metastases. This systematic review evaluates SBT's clinical outcomes, toxicity, and procedural characteristics for intact brain metastases in radiation-naive and radiation-recurrent patients.

METHODS

A systematic review was conducted following PRISMA guidelines and the PICOS framework. Studies published until June 30, 2024, were identified through searches of PubMed, Scopus, Web of Science, and Cochrane databases. Retrospective studies and prospective trials were included. Key extracted data included patient characteristics, treatment protocols, local control (LC), distant-intracranial control (DIC), overall survival (OS), and procedure-related toxicity. The risk of bias was assessed using the Newcastle-Ottawa Scale.

RESULTS

Eight retrospective single-center studies involving 427 patients and 456 metastases met inclusion criteria. Median patient age ranged from 47 to 60 years, with most having a Karnofsky Performance Status ≥70. SBT mostly demonstrated high 1-year LC rates (93.3%-100%) and a 1-year DIC from 52% to 90%. Median OS for radiation-naive patients ranged from 8-17 vs. 6-28.4 months for radio-recurrent patients, with RPA class 1 showing the best outcomes. Toxicity was minimal, with no reported fatal complications or significant late toxicity. Across all studies, I-125 seeds were utilized, with temporary implantation predominating, while permanent implantation involved higher doses, up to 150Gy, and extended treatment durations. Postoperative morbidity within 30 days ranged from 0% to 6.6% across different studies. No G3/G4 acute toxicities were reported.

CONCLUSIONS

SBT is a highly effective and safe option for treating intact brain metastases, particularly in patients with large or radiation-recurrent lesions.

Cesium 131 seeds for high-grade gliomas: a systematic review and meta-analysis of gammatile as a brachytherapy innovation

High-grade gliomas (HGG) are a neuro-oncology challenge due to their aggressive nature,with conventional therapies like radiation and chemotherapy often yielding limited success. Cesium-131 (Cs-131) brachytherapy is a promising adjunct due to its short half-life (9.7 days) and high energy, enabling targeted radiation delivery with less exposure. GammaTile (GT Medical Technologies) uses Cs-131 seeds in a bioresorbable collagen matrix, enabling immediate post-surgical radiation while safeguarding healthy tissue. Therefore, this study aims to evaluate the current evidence of using Gammatile in HGG. We performed a systematic review and single-arm meta-analysis. PubMed, Web of Science, Scopus, and Embase were searched for eligible trials. A random-effects model was used to calculate the Proportions and Means, with 95% confidence intervals (CIs) and a significance level of 5%. Statistical analyses were conducted with RStudio 4.3. Twelve studies included 110 patients, 57 male (51.8%), with a mean age of 50.2 years and a follow-up of 29.47 months. Four endpoints were analyzed: Mortality (Proportion 6%; 95% CI 2% to 15%; I2 = 0%); Recurrence (Proportion 100%; 95% CI 11% to 100%; I2 = 0%); Overall Survival (OS) (Mean 27.30 months; 95% CI 17.34 to 42.96; I2 = 63.9%); Progression-Free Survival (PFS) (Mean 8.81 months; 95% CI 7.43-10.43; I2 = 0%). GammaTile shows promising outcomes for HGG, with mean OS of 27.30 months, and PFS of 8.81 months. Despite the 100% recurrence rate, the 6% mortality rate suggests contribution to prolonging patient survival.

Meningioma: Novel Diagnostic and Therapeutic Approaches

Background/Objectives: Meningiomas are the most common intracranial tumors. Surgery and radiation therapy are the cornerstones of treatment and no standard of care therapy exists for refractory meningiomas. This manuscript aims to provide a comprehensive review of novel diagnostic and therapeutic approaches against these tumors. Methods: A search for the existing literature on systemic therapies for meningiomas was performed on PubMed and a search for presently accruing clinical trials was performed on ClinicalTrials.gov. Results: Systemic treatments, including chemotherapy, somatostatin analogs, anti-hormone therapy, and anti-angiogenic therapy, have been extensively studied with marginal success. Targeted therapies are actively being studied for the treatment of meningiomas, including focal adhesion kinase (FAK), sonic hedgehog signaling pathway, phosphoinositide-3-kinase (PI3K), and cyclin-dependent kinases (CDK) inhibitors. These driver mutations are present only in a subset of meningiomas. In stark contrast, somatostatin receptor 2 (SSTR2) is ubiquitously expressed in meningiomas and was formerly targeted with somatostatin analogs with modest success. Theranostic SSTR2-targeting via [68Ga]DOTATATE for PET imaging and β-emitting [177Lu]DOTATATE for the treatment of meningiomas are currently under active investigation. Conclusions: A nuanced approach is needed for the treatment of refractory meningiomas. Targeted therapies show promise.

Hydrogels and Microgels: Driving Revolutionary Innovations in Targeted Drug Delivery, Strengthening Infection Management, and Advancing Tissue Repair and Regeneration

Hydrogels and microgels are emerging as pivotal platforms in biomedicine, with significant potential in targeted drug delivery, enhanced infection management, and tissue repair and regeneration. These gels, characterized by their high water content, unique structures, and adaptable mechanical properties, interact seamlessly with biological systems, making them invaluable for controlled and targeted drug release. In the realm of infection management, hydrogels and microgels can incorporate antimicrobial agents, offering robust defenses against bacterial infections. This capability is increasingly important in the fight against antibiotic resistance, providing innovative solutions for infection prevention in wound dressings, surgical implants, and medical devices. Additionally, the biocompatibility and customizable mechanical properties of these gels make them ideal scaffolds for tissue engineering, supporting the growth and repair of damaged tissues. Despite their promising applications, challenges such as ensuring long-term stability, enhancing therapeutic agent loading capacities, and scaling production must be addressed for widespread adoption. This review explores the current advancements, opportunities, and limitations of hydrogels and microgels, highlighting research and technological directions poised to revolutionize treatment strategies through personalized and regenerative approaches.

Repeat GammaTile Brachytherapy in the Long-Term Management of Recurrent High-Grade Glioma: A Case Report

Over the past two decades, despite the emergence of various novel therapies for glioblastoma, patient survival outcomes remain poor, particularly in the recurrent stage of the disease. Cesium-131 (Cs-131) brachytherapy presents a promising treatment option for patients with newly diagnosed and recurrent brain neoplasms, enabling the initiation of radiation therapy at the time of tumor resection. This approach eliminates the typical delay in therapy following surgery and the need for multiple return visits for fractionated external beam radiotherapy. This report describes a patient who underwent repeat Cs-131 brachytherapy implantations in the surgical cavity following the resection of a recurrent glioblastoma, achieving a good quality of life and survival of over 36 months.

Surgically targeted radiation therapy versus stereotactic radiation therapy: A dosimetric comparison for brain metastasis resection cavities

PURPOSE

Surgically targeted radiation therapy (STaRT) with Cesium-131 seeds embedded in a collagen tile is a promising treatment for recurrent brain metastasis. In this study, the biological effective doses (BED) for normal and target tissues from STaRT plans were compared with those of external beam radiotherapy (EBRT) modalities.

METHODS

Nine patients (n = 9) with 12 resection cavities (RCs) who underwent STaRT (cumulative physical dose of 60 Gy to a depth of 5 mm from the RC edge) were replanned with CyberKnifeⓇ (CK), Gamma KnifeⓇ (GK), and intensity modulated proton therapy (IMPT) using an SRT approach (30 Gy in 5 fractions). Statistical significance comparing D95% and D90% in BED10Gy (BED10Gy95% and BED10Gy90%) and to RC + 0 to + 5 mm expansion margins, and parameters associated with radiation necrosis risk (V83Gy, V103Gy, V123Gy and V243Gy) to the normal brain were evaluated by a Wilcoxon-signed rank test.

RESULTS

For RC + 0 mm, median BED10Gy 90% for STaRT (90.1 Gy10, range: 64.1-140.9 Gy10) was significantly higher than CK (74.3 Gy10, range:59.3-80.4 Gy10, p = 0.04), GK (69.4 Gy10, range: 59.8-77.1 Gy10, p = 0.005), and IMPT (49.3 Gy10, range: 49.0-49.7 Gy10, p = 0.003), respectively. However, for the RC + 5 mm, the median BED10Gy 90% for STaRT (34.1 Gy10, range: 22.2-59.7 Gy10) was significantly lower than CK (44.3 Gy10, range: 37.8-52.4 Gy10), and IMPT (46.6 Gy10, range: 45.1-48.5 Gy10), respectively, but not significantly different from GK (34.1 Gy10, range: 22.8-47.0 Gy10). The median V243Gy was significantly higher in CK (11.7 cc, range: 4.7-20.1 cc), GK(6.2 cc, range: 2.3-11.9 cc) and IMPT (19.9 cc, range: 11.1-36.6 cc) compared to STaRT (1.1 cc, range: 0.0-7.8 cc) (p < 0.01).

CONCLUSIONS

This comparative analysis suggests a STaRT approach may treat recurrent brain tumors effectively via delivery of higher radiation doses with equivalent or greater BED up to at least 3 mm from the RC edge as compared to EBRT approaches.

Neural Influences on Tumor Progression Within the Central Nervous System

For decades, researchers have studied how brain tumors, the immune system, and drugs interact. With the advances in cancer neuroscience, which centers on defining and therapeutically targeting nervous system-cancer interactions, both within the local tumor microenvironment (TME) and on a systemic level, the subtle relationship between neurons and tumors in the central nervous system (CNS) has been deeply studied. Neurons, as the executors of brain functional activities, have been shown to significantly influence the emergence and development of brain tumors, including both primary and metastatic tumors. They engage with tumor cells via chemical or electrical synapses, directly regulating tumors or via intricate coupling networks, and also contribute to the TME through paracrine signaling, secreting proteins that exert regulatory effects. For instance, in a study involving a mouse model of glioblastoma, the authors observed a 42% increase in tumor volume when neuronal activity was stimulated, compared to controls (p < 0.01), indicating a direct correlation between neural activity and tumor growth. These thought-provoking results offer promising new strategies for brain tumor therapies, highlighting the potential of neuronal modulation to curb tumor progression. Future strategies may focus on developing drugs to inhibit or neutralize proteins and other bioactive substances secreted by neurons, break synaptic connections and interactions between infiltrating cells and tumor cells, as well as disrupt electrical coupling within glioma cell networks. By harnessing the insights gained from this research, we aspire to usher in a new era of brain tumor therapies that are both more potent and precise.

Review of Novel Surgical, Radiation, and Systemic Therapies and Clinical Trials in Glioblastoma

Glioblastoma (GBM) is the most common malignant primary brain tumor in adults. Despite an established standard of care including surgical resection, radiation therapy, and chemotherapy, GBM unfortunately is associated with a dismal prognosis. Therefore, researchers are extensively evaluating avenues to expand GBM therapy and improve outcomes in patients with GBM. In this review, we provide a broad overview of novel GBM therapies that have recently completed or are actively undergoing study in clinical trials. These therapies expand across medical, surgical, and radiation clinical trials. We additionally review methods for improving clinical trial design in GBM.

Local therapy in glioma: An evolving paradigm from history to horizons (Review)

Despite the implementation of multimodal treatments after surgery, glioblastoma (GBM) remains an incurable disease, posing a significant challenge in neuro-oncology. In this clinical setting, local therapy (LT), a developing paradigm, has received significant interest over time due to its potential to overcome the drawbacks of conventional therapy options for GBM. The present review aimed to trace the historical development, highlight contemporary advances and provide insights into the future horizons of LT in GBM management. In compliance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols criteria, a systematic review of the literature on the role of LT in GBM management was conducted. A total of 2,467 potentially relevant articles were found and, after removal of duplicates, 2,007 studies were screened by title and abstract (Cohen's κ coefficient=0.92). Overall, it emerged that 15, 10 and 6 clinical studies explored the clinical efficiency of intraoperative local treatment modalities, local radiotherapy and local immunotherapy, respectively. GBM recurrences occur within 2 cm of the radiation field in 80% of cases, emphasizing the significant influence of local factors on recurrence. This highlights the urgent requirement for LT strategies. In total, three primary reasons have thus led to the development of numerous LT solutions in recent decades: i) Intratumoral implants allow the blood-brain barrier to be bypassed, resulting in limited systemic toxicity; ii) LT facilitates bridging therapy between surgery and standard treatments; and iii) given the complexity of GBM, targeting multiple components of the tumor microenvironment through ligands specific to various elements could have a synergistic effect in treatments. Considering the spatial and temporal heterogeneity of GBM, the disease prognosis could be significantly improved by a combination of therapeutic strategies in the era of precision medicine.

Exploring a novel seven-gene marker and mitochondrial gene TMEM38A for predicting cervical cancer radiotherapy sensitivity using machine learning algorithms

Background

Radiotherapy plays a crucial role in the management of Cervical cancer (CC), as the development of resistance by cancer cells to radiotherapeutic interventions is a significant factor contributing to treatment failure in patients. However, the specific mechanisms that contribute to this resistance remain unclear. Currently, molecular targeted therapy, including mitochondrial genes, has emerged as a new approach in treating different types of cancers, gaining significant attention as an area of research in addressing the challenge of radiotherapy resistance in cancer.

Methods

The present study employed a rigorous screening methodology within the TCGA database to identify a cohort of patients diagnosed with CC who had received radiotherapy treatment. The control group consisted of individuals who demonstrated disease stability or progression after undergoing radiotherapy. In contrast, the treatment group consisted of patients who experienced complete or partial remission following radiotherapy. Following this, we identified and examined the differentially expressed genes (DEGs) in the two cohorts. Subsequently, we conducted additional analyses to refine the set of excluded DEGs by employing the least absolute shrinkage and selection operator regression and random forest techniques. Additionally, a comprehensive analysis was conducted in order to evaluate the potential correlation between the expression of core genes and the extent of immune cell infiltration in patients diagnosed with CC. The mitochondrial-associated genes were obtained from the MITOCARTA 3.0. Finally, the verification of increased expression of the mitochondrial gene TMEM38A in individuals with CC exhibiting sensitivity to radiotherapy was conducted using reverse transcription quantitative polymerase chain reaction and immunohistochemistry assays.

Results

This process ultimately led to the identification of 7 crucial genes, viz., GJA3, TMEM38A, ID4, CDHR1, SLC10A4, KCNG1, and HMGCS2, which were strongly associated with radiotherapy sensitivity. The enrichment analysis has unveiled a significant association between these 7 crucial genes and prominent signaling pathways, such as the p53 signaling pathway, KRAS signaling pathway, and PI3K/AKT/MTOR pathway. By utilizing these 7 core genes, an unsupervised clustering analysis was conducted on patients with CC, resulting in the categorization of patients into three distinct molecular subtypes. In addition, a predictive model for the sensitivity of CC radiotherapy was developed using a neural network approach, utilizing the expression levels of these 7 core genes. Moreover, the CellMiner database was utilized to predict drugs that are closely linked to these 7 core genes, which could potentially act as crucial agents in overcoming radiotherapy resistance in CC.

Conclusion

To summarize, the genes GJA3, TMEM38A, ID4, CDHR1, SLC10A4, KCNG1, and HMGCS2 were found to be closely correlated with the sensitivity of CC to radiotherapy. Notably, TMEM38A, a mitochondrial gene, exhibited the highest degree of correlation, indicating its potential as a crucial biomarker for the modulation of radiotherapy sensitivity in CC.

The role of GammaTile in the treatment of brain tumors: a technical and clinical overview

Malignant and benign brain tumors with a propensity to recur continue to be a clinical challenge despite decades-long efforts to develop systemic and more advanced local therapies. GammaTile (GT Medical Technologies Inc., Tempe AZ) has emerged as a novel brain brachytherapy device placed during surgery, which starts adjuvant radiotherapy immediately after resection. GammaTile received FDA clearance in 2018 for any recurrent brain tumor and expanded clearance in 2020 to include upfront use in any malignant brain tumor. More than 1,000 patients have been treated with GammaTile to date, and several publications have described technical aspects of the device, workflow, and clinical outcome data. Herein, we review the technical aspects of this brachytherapy treatment, including practical physics principles, discuss the available literature with an emphasis on clinical outcome data in the setting of brain metastases, glioblastoma, and meningioma, and provide an overview of the open and pending clinical trials that are further defining the efficacy and safety of GammaTile.

The surgical management of diffuse gliomas: Current state of neurosurgical management and future directions

After recent updates to the World Health Organization pathological criteria for diagnosing and grading diffuse gliomas, all major North American and European neuro-oncology societies recommend a maximal safe resection as the initial management of a diffuse glioma. For neurosurgeons to achieve this goal, the surgical plan for both low- and high-grade gliomas should be to perform a supramaximal resection when feasible based on preoperative imaging and the patient's performance status, utilizing every intraoperative adjunct to minimize postoperative neurological deficits. While the surgical approach and technique can vary, every effort must be taken to identify and preserve functional cortical and subcortical regions. In this summary statement on the current state of the field, we describe the tools and technologies that facilitate the safe removal of diffuse gliomas and highlight intraoperative and postoperative management strategies to minimize complications for these patients. Moreover, we discuss how surgical resections can go beyond cytoreduction by facilitating biological discoveries and improving the local delivery of adjuvant chemo- and radiotherapies.

Novel combination of GammaTile cesium-131 brachytherapy with 5-aminolevulinic acid fluorescence-guided resection in the re-irradiation of pediatric recurrent high-grade glioma: illustrative case

BACKGROUND

Herein, the authors describe the successful utilization of 5-aminolevulinic acid (5-ALA) and the first case of GammaTile cesium-131 therapy in a pediatric patient with recurrent high-grade glioma. 5-ALA was utilized to optimize gross-total resection prior to GammaTile implantation. After conversion to an equivalent dose in 2-Gy fractions (EQD2), a composite was made of the GammaTile dose with the initial external beam radiotherapy. Two hypothetical plans consisting of a standard hypofractionated strategy for glioma reirradiation and a CyberKnife plan using GammaTile's planning target volume were developed and likewise underwent EQD2 conversion and composite plan generation with the initial radiotherapy.

OBSERVATIONS

5-ALA was useful in achieving gross-total resection with no acute toxicity from the surgery or GammaTile irradiation. When compared with the hypothetical composite doses, GammaTile's composite, axium point dose (D0.03cc) to the brainstem was 32.9 Gy less than the hypofractionated and the CyberKnife composite plans at 38.7 Gy and 40.2 Gy, respectively. The right hippocampus demonstrated a substantially reduced composite plan dose with GammaTile with a D0.03cc of 62.4 Gy versus 71.7 and 80.7 Gy for the hypofractionated and CyberKnife composite plans, respectively.

LESSONS

Utilization of 5-ALA and GammaTile therapy yielded clinically superior tumor debulking and effective radiotherapy dose localization with sparing of organs at risk, respectively.

First application of GammaTile cesium-131 brachytherapy with maximal safe resection of a glioma in a patient with limited scleroderma

The purpose of this report is to present the first documented application of GammaTile to an intra-cranial tumor of a patient with a symptomatic radiosensitive connective tissue disorder, a case where there were significant concerns with standard oncologic strategies. We hypothesized that GammaTile® (GT Medical Technologies, Tempe, Arizona, USA) would also be advantageous in the application of intra-cranial tumors in patients with conditions of increased radiosensitivity. We generated a standard external beam radiation therapy (EBRT) plan consisting of an overall 1.5 cm expansion to 59.4 Gy in 1.8 Gy fractions. Also, we developed a CyberKnife (Accuray, Sunnyvale, CA, USA) plan with a 5 mm expansion on the surgical cavity prescribed to 60 Gy in 30 fractions, to make an EBRT comparison using the same prescription volume as GammaTile. We report the first published application of GammaTile® brachytherapy to an intra-cranial malignancy in a patient with limited scleroderma. The dose delivered by GammaTile was compared to the dose that would be delivered with both typical volumes and small volumes of EBRT. The maximum dose delivered to the scar and scalp by GammaTile was reduced to half of that from other external beam techniques (~25 Gy vs. ~55 Gy). MRI imaging at 6 months and 12 months post-resection demonstrated no evidence of disease recurrence nor radiation necrosis. At the 12-month follow-up visit, the surgical scar was well-healed with no skin changes to the surrounding scalp. Dosimetrically and clinically, this report highlights the successful application of GammaTile to an intra-cranial tumor bed in a patient with scleroderma.

Systematic Review of WHO Grade 4 Astrocytoma in the Cerebellopontine Angle: The Impact of Anatomic Corridor on Treatment Options and Outcomes

Background  Despite advances in multimodal oncologic therapies and molecular genetics, overall survival (OS) in patients with high-grade astrocytomas remains poor. We present an illustrative case and systematic review of rare, predominantly extra-axial World Health Organization (WHO) grade 4 astrocytomas located within the cerebellopontine angle (CPA) and explore the impact of anatomic location on diagnosis, management, and outcomes. Methods  A systematic review of adult patients with predominantly extra-axial WHO grade 4 CPA astrocytomas was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines through December 2022. Results  Eighteen articles were included comprising 21 astrocytomas: 13 exophytic tumors arising from the cerebellopontine parenchyma and 8 tumors originating from a cranial nerve root entry zone. The median OS was 15 months with one-third of cases demonstrating delayed diagnosis. Gross total resection, molecular genetic profiling, and use of ancillary treatment were low. We report the only patient with an integrated isocitrate dehydrogenase 1 (IDH-1) mutant diagnosis, who, after subtotal resection and chemoradiation, remains alive at 40 months without progression. Conclusion  The deep conical-shaped corridor and abundance of eloquent tissue of the CPA significantly limits both surgical resection and utility of device-based therapies in this region. Prompt diagnosis, molecular characterization, and systemic therapeutic advances serve as the predominant means to optimize survival for patients with rare skull base astrocytomas.

Hydrogel systems for targeted cancer therapy

When hydrogel materials with excellent biocompatibility and biodegradability are used as excellent new drug carriers in the treatment of cancer, they confer the following three advantages. First, hydrogel materials can be used as a precise and controlled drug release systems, which can continuously and sequentially release chemotherapeutic drugs, radionuclides, immunosuppressants, hyperthermia agents, phototherapy agents and other substances and are widely used in the treatment of cancer through radiotherapy, chemotherapy, immunotherapy, hyperthermia, photodynamic therapy and photothermal therapy. Second, hydrogel materials have multiple sizes and multiple delivery routes, which can be targeted to different locations and types of cancer. This greatly improves the targeting of drugs, thereby reducing the dose of drugs and improving treatment effectiveness. Finally, hydrogel can intelligently respond to environmental changes according to internal and external environmental stimuli so that anti-cancer active substances can be remotely controlled and released on demand. Combining the abovementioned advantages, hydrogel materials have transformed into a hit in the field of cancer treatment, bringing hope to further increase the survival rate and quality of life of patients with cancer.