Review of Current Principles of the Diagnosis and Management of Brain Metastases

Incidental Brain Metastases From Prostate Cancer Diagnosed With PSMA PET/CT and MRI: A Case Series and Literature Review

BACKGROUND

Brain metastases (BMETS) from prostate cancer are rare. Hence, brain imaging in neurologically asymptomatic patients with advanced prostate cancer (aPC) is not routinely performed. Prostate-specific membrane antigen (PSMA) PET/CT uses a radiotracer that binds to prostate cancer epithelial cells and is FDA-approved for initial staging for high-risk prostate cancer, detecting prostate cancer recurrence, and determining eligibility for radionuclide therapy.

METHODS

We report six patients with asymptomatic BMETS from aPC found on staging PSMA PET/CT or MRI. Along with cranial MRI, PSMA PET/CT may be useful for detecting asymptomatic intracranial metastasis in select patients with prostate cancer.

RESULTS

Brain metastases were diagnosed in four patients by staging PSMA PET/CT scan-three after systemic disease progression and one during routine surveillance. In two other patients, BMETS were detected using MRI despite negative PSMA PET/CT for brain lesions. All were neurologically asymptomatic. Three patients had undetectable serum prostate-specific antigen (PSA) concentrations; one had neuroendocrine differentiation on histology.

CONCLUSION

In patients with poorly differentiated or neuroendocrine aPC, BMETS may occur without neurologic symptoms and stable PSA. PSMA PET/CT may complement brain MRI for identifying BMETS in these patients.

Multi-institutional atlas of brain metastases informs spatial modeling for precision imaging and personalized therapy

Brain metastases are a frequent and debilitating manifestation of advanced cancer. Here, we collect and analyze neuroimaging of 3,065 cancer patients with 13,067 brain metastases, representing an extensive collection for research. We find that metastases predominantly localize to high perfusion areas near the grey-white matter junction, but also identify notable differences depending on the primary cancer histology as well as brain regions which do not conform to this relationship. Lung and breast cancers, in contrast to melanoma, frequently metastasize to the cerebellum, hinting at biological pathways of spread. Additionally, the deep brain structures are relatively spared from metastasis, regardless of primary cancer type. Leveraging this data, we propose a probabilistic brain metastasis risk model to enhance the therapeutic ratio of whole-brain radiotherapy by targeting high risk areas while preserving cortical and subcortical brain regions of functional significance and low metastasis risk, potentially reducing the cognitive side effects of therapy.

Exploring the Role of ADCs in Brain Metastases and Primary Brain Tumors: Insight and Future Directions

Primary and secondary brain tumors have always been a challenge due to their high morbidity and poor prognosis. The incidence of brain metastasis is also increasing with the advent of effective new treatments. Traditional systemic treatments have historically had limited success, partly due to poor central nervous system (CNS) penetration. However, the advent in recent decades of new therapies that have shown high encephalic response rates are challenging this paradigm. ADCs represent a new class of compounds revolutionizing cancer treatment with high systemic response rates and lower toxicities. The continuing evolution of ADCs has shown that certain structural features such as payload, linker, and drug-to-antibody ratio (DAR) are essential in determining their efficacy at the encephalic level, and some ADCs have started to exhibit promising efficacy in treating primary and secondary brain tumors. Unfortunately, most patients with untreated encephalic metastases are excluded from clinical trials, with data primarily from retrospective studies or post hoc analyses. This review describes the early signs of ADC efficacy in brain tumors, the role of complementary treatments like radiation therapy, and critical points to improve ADC efficacy in brain malignancies.

Impact of Multileaf Collimator Width and Normal Tissue Objective on Radiation Dose Distribution in Stereotactic Radiosurgery Using HyperArc for Single Brain Lesions

This study retrospectively investigated the impact of stereotactic radiosurgery (SRS) normal tissue objective (NTO) and multileaf collimator (MLC) width on radiation dose distribution in patients with brain metastasis treated using HyperArc. In total, 21 patients who underwent SRS using the HyperArc of the TrueBeam linear accelerator from November 2022 to June 2024 were included. All patients received radiotherapy with HASH planned with SRS NTO and HD MLC. HyperArc(HAAH) combined with the auto NTO and HD MLC and HyperArc(HAAM) with auto NTO and millennium MLC were generated and compared. Monitor units (MU), conformity index (CI), radical dose homogeneity index (rDHI), moderate DHI (mDHI), and gradient index (GI) were evaluated as target factors, and V2(Gy), V10(Gy), V12(Gy), V18(Gy), V10(cc), and V12(cc) were evaluated as normal brain factors. Dosimetric comparisons were performed between HASH, HAAH, and HAAM and between target and normal brain tissues. Between HASH and HAAH, average MU was 7206 and 5798, respectively; the difference was significant (p < 0.001). The MU of HAAM was 5835. Among HASH, HAAH, and HAAM, CI and mDHI were not significantly different, but there were significant differences in rDHI, GI, and normal brain tissues. When treating a single lesion using HyperArc, SRS NTO influences MU and GI, and the MLC width influences rDHI and GI. In HyperArc for single metastatic brain lesions, SRS NTO and MLC width have a significant effect on the radiation dose delivered to the target and normal brain tissues.

Laser interstitial thermal therapy for recurrent brain metastases following stereotactic radiosurgery: a systematic review

INTRODUCTION

Laser Interstitial Thermal Therapy (LITT) has emerged as a promising minimally invasive treatment option for recurrent brain metastases, especially for patients who have previously undergone Stereotactic Radiosurgery (SRS). Despite its growing use, additional research is needed to explore its utility and safety in this population.

METHODS

This systematic review evaluates the literature on LITT for recurrent brain metastases post-SRS, including patient selection, treatment protocols, outcomes, and complications. The review was registered with PROSPERO (CRD42024577899) and followed the PRISMA 2020 guidelines.

RESULTS

Seventeen studies, encompassing 694 patients, met our inclusion criteria. The median overall survival (OS) across these studies was 14.4 months with an average 12-month OS of 60.1%. Notably, median OS was 5.9 months after LITT alone and 12.7 months when LITT was followed by adjuvant SRS. The pooled local control rate was 75.6% at 6 months and 72.2% at 12 months.

CONCLUSION

LITT is a minimally invasive treatment option that has shown potential in managing recurrent brain metastases after prior SRS, particularly when biopsy is required to differentiate between tumor recurrence and radiation necrosis. However, data on the comparative efficacy and cost-effectiveness of LITT versus alternative treatments such as repeat SRS or craniotomy remain limited.

Genomic Signature for Initial Brain Metastasis Velocity (iBMV) in Non-Small-Cell Lung Cancer Patients: The Elusive Biomarker to Predict the Development of Brain Metastases?

Background/Objectives: No prior studies have attempted to identify a biomarker for initial brain metastasis velocity (iBMV), with limited studies attempting to correlate genomic data with the development of brain metastases. Methods: Patients with non-small-cell lung cancer (NSCLC) who underwent next-generation sequencing (NGS) were identified in our departmental database. iBMV was calculated by dividing the number of BMs by the interval of time between primary cancer and BM diagnosis. Two-sample t-testing was used to identify mutations statistically associated with iBMV (p < 0.1). A value of +1 was assigned to each mutation with a positive association ("deleterious genes"), and a value of -1 to each with an inverse association ("protective genes"). The sum of these values was calculated to define iBMV risk scores of -1, 0 and 1. Pearson correlation test was used to determine the association between iBMV risk score and calculated iBMV, and a competing risk analysis assessed for death as a competing risk to the development of BMs. Results: A total of 312 patients were included in the analysis, 218 of whom (70%) developed brain metastases. "Deleterious genes" included ARID1A, BRAF, CDK4, GNAQ, MLH1, MSH6, PALB2, RAD51D, RB1 and TSC1; "protective genes" included ARAF, IDH1, MYC, and PTPN11. iBMV risk scores of 1, 0 and -1, predicted an 88%, 61% and 65% likelihood of developing a BM (p < 0.01). A competing risk analysis found a significant association between iBMV risk scores of 1 vs. 0 and 1 vs. -1, and the likelihood of developing a BM using death as a competing risk. Overall survival (OS) at 1 and 2 years for patients with iBMV risk scores of 1, 0 and -1 was 72% vs. 84% vs. 85% and 46% vs. 69% vs. 70% (p < 0.02). Conclusions: Development of a genomic signature for iBMV via non-invasive liquid biopsy appears feasible in NSCLC patients. Patients with a positive iBMV risk score were more likely to develop brain metastases. Validation of this signature could lead to a biomarker with the potential to guide treatment recommendations and surveillance schedules.

Rosette-Forming Glioneuronal Tumor Mimicking Foramen Monro Colloid Cyst: Case Presentation and Systematic Literature Review

BACKGROUND

Rosette-forming glioneuronal tumors (RGNTs) are rare indolent and benign tumors, typically associated with the fourth ventricle. Cases in the third ventricle are less common, especially those involving only the anterior part.

METHODS

A literature review using "rosette-forming glioneuronal tumor" on PubMed yielded 176 articles from 2002 to 2024. Articles excluding third ventricle RGNTs were omitted, with titles and abstracts screened for relevance. We also present our case of an anterior third ventricle RGNT, tracking from initial presentation to follow-up.

RESULTS

Our patient, a 62-year-old woman, experienced 3 months of recurrent Hakim Triad symptoms-gait instability, urinary incontinence, and cognitive issues. Magnetic resonance imaging revealed a 1.0 × 0.7 cm mass, hypointense on T1-weighted imaging and heterogeneous on T2-weighted imaging, initially suspected as a colloid cyst. Given its high colloid cyst risk score, surgery was performed, but histopathology confirmed an RGNT diagnosis. To date, this is the first case of exclusive anterior third ventricle RGNT microsurgery reported, with 26 months of recurrence-free follow-up. Our literature review identified 20 articles detailing 23 cases of third ventricle RGNT, with only 7 achieving gross total resection, while most underwent biopsy and ventriculostomy.

CONCLUSIONS

RGNTs in the anterior third ventricle may resemble other tumor types, requiring careful monitoring. This case is significant due to the patient's clinical presentation, imaging, and extended recurrence-free follow-up.

Prognostication of Brain-Metastasized Patients Receiving Subsequent Systemic Therapy: A Single-Center Long-Term Follow-Up

BACKGROUND

Survival of patients with brain metastases (BMs) is poor. It has become clear that targeted therapy has an effect on BMs and patient' prognosis. The question remains which patients benefit from additional systemic therapy. This assumption was evaluated in a large single-center cohort.

METHODS

Patients consecutively planned to undergo local radiotherapy for their BMs in 2006-2017 were selected (n = 200). Prognosis, using CERENAL, disease-specific graded prognostic assessment (DS-GPA), and Radiation Therapy Oncology Group recursive partitioning analysis (RTOG RPA), was evaluated.

RESULTS

Ninety-three (46.5%) patients received at least one additional line of systemic therapy subsequent to the diagnosis of their BMs. The median overall survival (OS) was 6.3 months. Having received subsequent systemic therapy resulted in a more favorable OS (10.4 versus 3.9 months). Interestingly, using dichotomized scores, CERENAL showed prognostic properties in all patients for disease-specific survival on multivariate analysis, whereas RTOG RPA and DS-GPA were not withheld in the model. Lastly, only having a favorable DS-GPA resulted in prolonged progression-free survival for first systemic therapy following BM diagnosis.

CONCLUSIONS

Receiving subsequent systemic therapy has a profound influence on outcome in patients with BMs, indicating the effect of systemic therapy on BMs. Use of the CERENAL brain prognostic score shows potential for further prognostication of patients with more favorable outcomes.

[Clinical Practice Guidelines for the Management of Brain Metastases from Non-small Cell Lung Cancer with Actionable Gene Alterations in China (2025 Edition)]

Brain metastasis has emerged as a significant challenge in the comprehensive management of patients with non-small cell lung cancer (NSCLC), particularly in those harboring driver gene mutations. Traditional treatments such as radiotherapy and surgery offer limited clinical benefits and are often accompanied by cognitive dysfunction and a decline in quality of life. In recent years, novel small molecule tyrosine kinase inhibitors targeting epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), and other pathways have been developed, effectively penetrating the blood-brain barrier while enhancing intracranial drug concentrations and improving patient outcomes. This advancement has transformed the treatment landscape for brain metastases in NSCLC. Consequently, the Lung Cancer Medical Education Committee of the Chinese Medical Education Association and the Brain Metastasis Collaboration Group of the Lung Cancer Youth Expert Committee of the Beijing Medical Reward Foundation have jointly initiated and formulated the Clinical Practice Guidelines for the Management of Brain Metastases from Non-small Cell Lung Cancer with Actionable Gene Alterations in China (2025 Edition). This guideline integrates the latest research findings with clinical experience, adhering to multidisciplinary treatment principles, and encompasses aspects such as diagnosis, timing of intervention, and systemic and local treatment options for driver gene positive NSCLC brain metastases. Additionally, it proposes individualized treatment strategies tailored to different driver gene types, aiming to provide clinicians with a reference to enhance the overall diagnostic and therapeutic standards for NSCLC brain metastases in China.
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Divergent Crosstalk Between Microglia and T Cells in Brain Cancers: Implications for Novel Therapeutic Strategies

Background: Brain cancers represent a formidable oncological challenge characterized by their aggressive nature and resistance to conventional therapeutic interventions. The tumor microenvironment has emerged as a critical determinant of tumor progression and treatment efficacy. Within this complex ecosystem, microglia and macrophages play fundamental roles, forming intricate networks with peripheral immune cell populations, particularly T cells. The precise mechanisms underlying microglial interactions with T cells and their contributions to immunosuppression remain incompletely understood. Methods: This review comprehensively examines the complex cellular dialogue between microglia and T cells in two prominent brain malignancies: primary glioblastoma and secondary brain metastases. Results: Through a comprehensive review of the current scientific literature, we explore the nuanced mechanisms through which microglial-T cell interactions modulate tumor growth and immune responses. Conclusions: Our analysis seeks to unravel the cellular communication pathways that potentially underpin tumor progression, with the ultimate goal of illuminating novel therapeutic strategies for brain cancer intervention.

Evaluating the atherosclerosis cardiovascular disease risk score in patients with brain metastases: Associations with overall survival and high-value care outcomes

OBJECTIVE

Brain metastases (BM) constitute the most common intracranial tumor in adults. Prior literature indicates the 10-year atherosclerotic cardiovascular disease (ASCVD) risk score is associated with increased risk of cancer, potentially attributable to shared risk factors. Understanding the role of ASCVD risk scores in BM may help optimize their care and inform clinical decision-making. Our aim was to explore associations between ASCVD risk score in BM patients and their overall survival, hospital charges, and non-routine discharge disposition.

METHODS

Electronic medical records were reviewed to collect clinical data for BM patients undergoing surgery at a single institution (2017-2021). Regression analyses were performed accordingly and maximally selected rank statistics were employed to identify an optimal cutoff for ASCVD risk scores. The random survival forest (RSF) machine learning technique identified the most important variable associated with survival outcomes in BM patients.

RESULTS

A total of 139 patients were included with average age 62.93±9.29 years, 48.2 % male, 25.2 % with high hospital charges, and 23.7 % experiencing non-routine discharge. Among these patients, 32.3 % had prior history of an ASCVD event, while 67.7 % did not. Overall, this cohort had an average 10-year ASCVD risk score of 12.51±12.98, indicating intermediate risk of ASCVD among all BM patients. On multivariate logistic regression, prior history of ASCVD was associated with higher odds of high hospital charges (OR=3.670, p=0.018), and higher ASCVD risk scores were associated with greater odds of non-routine discharge (OR=1.059, p=0.012). On the multivariate Cox regression model, higher ASCVD risk scores correlated with worse overall survival (HR=1.031, p=0.014). A threshold of 25.1 was identified for high-risk ASCVD scores. Patients with ASCVD scores >25.1 exhibited reduced overall survival in Kaplan-Meier analysis (p=0.015) and multivariate Cox regression (HR: 2.811, p=0.016). Notably, ASCVD risk scores were found to be the most important variable in predicting worse survival outcomes in BM patients compared to other established frailty indices.

CONCLUSION

This study indicates higher ASCVD risk scores in BM patients are associated with worse overall survival. Integrating ASCVD assessment into clinical workflow may facilitate more informed risk-based decision-making.

Lymphopenia associated with whole-brain radiotherapy and its effects on clinical outcomes of patients with brain metastases

There is increasing awareness of radiotherapy's potential side effects, such as lymphopenia. Therefore, this study aimed to establish the association between WBRT and the development of lymphopenia in patients with brain metastases undergoing brain radiotherapy (RT), along with evaluating the corresponding clinical outcomes. Including 116 patients with brain metastases undergoing brain radiotherapy, the study collected the absolute lymphocyte counts (ALC) within 2 weeks before brain radiotherapy (pre-radiotherapy, pre-RT), as well as ones at 1 and 2 months after completing RT (post-RT). Univariate and multivariate analyses were performed to identify associations between radiation modality and post-RT ALC. The relationships between post-RT ALC and overall survival were evaluated with Kaplan-Meier analysis and a multivariate Cox regression model. The median ALC definitely decreased at 1 month post-RT, but at 2 months post-RT, gradually rose but not to the pre-RT ALC. The multivariate analysis identified WBRT and lower pre-RT ALC as independent risk factors associated with the decrease in post-RT ALC at 1 month. It also revealed more than 4 brain metastases, G3-4 lymphopenia at 1 month and lower post-RT ALC at 2 months exhibited significantly worse prognosis regardless of the radiation modality. However, there was indeed an independent correlation between radiation modality and the outcome of intracranial progression-free survival (PFS). To approach the feasibility and reasonableness of treatment, clinicians should carefully consider various factors to achieve long-term survival of patients.

Performance status improvement and advances in systemic treatment after brain metastases resection: a retrospective single-center cohort study of non-small cell lung cancer patients

BACKGROUND

Brain metastasis (BrM) is prevalent among patients with NSCLC, and surgical resection of BrM constitutes a promising treatment strategy for local management and histopathological diagnosis, although it is offered for a select group of patients. Limited information exists concerning the improvement in performance status (PS) following BrM resection or the outcomes stratified by subsequent systemic therapy.

METHODS

We conducted a retrospective single-center cohort study including NSCLC patients with surgically resected BrM and focused on the improvement in PS and subsequent therapy after BrM resection.

RESULTS

71 patients were included, and the median overall survival was 18.3 months (95% confidence interval [95% CI]: 8.7, not reached). Patients with NSCLC who underwent surgical resection of BrM showed significant improvement in PS (18% and 39% showed ECOG PS of 0-1, before and after BrM resection, respectively [p = 0.006]), and patients with PS improvement were younger than those with PS unimprovement (median, 62 years versus 66 years; p = 0.041). Regarding subsequent systemic therapy after BrM resection, 21 patients (30%) received cytotoxic chemotherapy, 14 patients (20%) received tyrosine kinase inhibitors (TKIs), 3 patients (4%) received immune checkpoint inhibitors (ICIs), and 21 patients (30%) received no subsequent therapy. The survival outcomes of patients stratified by subsequent systemic treatments suggested the tendency that those who received TKI or ICI showed better survival outcomes, although a small number of patients hindered statistical comparisons.

CONCLUSIONS

We describe the outcomes of patients with NSCLC who underwent surgical resection of BrM, revealing that younger patients were more likely to anticipate improvement in PS, and patients who received TKI or ICI after BrM resection tended to exhibit a more preferable prognosis.

Double Trouble: A Case Report on the Surgical Management of Dual Intracranial Metastases

Intracranial metastasis disease (IMD) has proven to be a frequent secondary occurrence, usually for primary cancers such as lung, breast, and melanoma, which have a high possibility of metastasizing to the brain. Due to the reasons listed above, treatment and early diagnosis are incredibly challenging. In the past decade, medicine has developed much better imaging solutions and radiological and surgical approaches, increasing the postoperative survival prognosis and achieving more time-efficient results. It is still exceptionally difficult to be able to prevent what type of metastasis a patient might develop other than by using the tumor type or subtype. We present a case of a 51-year-old female patient entering the Neurosurgical Clinic at the University Hospital "St. Ivan Rilski" for operative treatment of a second metastatic lesion located on the left parietal lobe in January 2024. She had previously had an operative resection of an initial lesion located on the left temporal lobe in December 2023. Her medical history began in 2015 when her first diagnosis was a breast carcinoma, followed by operative treatment and radio-, chemo-, and targeted therapy. In 2020, due to metastases located in the bones, she had to undergo another treatment with chemotherapy as well as have a total hysterectomy done as a result of another metastasis. The patient did not provide any family history, nor did she confirm any past or current allergies to foods, drugs, etc. Under general inhalation anesthesia, the patient was placed in a park bench position to the right and had a Mayfield head holder applied. Through a left parietal craniotomy and neuronavigation, a tumor formation was revealed with the characteristic of a secondary lesion. A gross total resection was achieved through a microsurgical technique. Postoperatively, there were no further complications observed in the patient, and she was discharged on day five from the hospital with relief of her symptoms.

Advances in Mass Spectrometry of Gangliosides Expressed in Brain Cancers

Gangliosides are highly abundant in the human brain where they are involved in major biological events. In brain cancers, alterations of ganglioside pattern occur, some of which being correlated with neoplastic transformation, while others with tumor proliferation. Of all techniques, mass spectrometry (MS) has proven to be one of the most effective in gangliosidomics, due to its ability to characterize heterogeneous mixtures and discover species with biomarker value. This review highlights the most significant achievements of MS in the analysis of gangliosides in human brain cancers. The first part presents the latest state of MS development in the discovery of ganglioside markers in primary brain tumors, with a particular emphasis on the ion mobility separation (IMS) MS and its contribution to the elucidation of the gangliosidome associated with aggressive tumors. The second part is focused on MS of gangliosides in brain metastases, highlighting the ability of matrix-assisted laser desorption/ionization (MALDI)-MS, microfluidics-MS and tandem MS to decipher and structurally characterize species involved in the metastatic process. In the end, several conclusions and perspectives are presented, among which the need for development of reliable software and a user-friendly structural database as a search platform in brain tumor diagnostics.

Cerebrospinal fluid ctDNA testing shows an advantage over plasma ctDNA testing in advanced non-small cell lung cancer patients with brain metastases

Background

Brain metastases (BM), including brain parenchyma metastases (BPM) and leptomeningeal metastases (LM), are devastating metastatic complications in advanced cancer patients. Next-generation sequencing (NGS) is emerging as a new promising tool for profiling cancer mutation, which could facilitate the diagnosis of cancer. This retrospective study aimed to investigate the molecular genetic characteristics of non-small cell lung cancer (NSCLC) patients with BPM and LM using NGS.

Methods

Cerebrospinal fluid (CSF) samples and paired plasma samples were collected from 37 patients of NSCLC-BM. We profiled genetic mutation characteristics using NGS from NSCLC-BM by comparing CSF circulating tumour DNA (ctDNA) with plasma ctDNA and primary tumour tissues.

Results

Among the 37 patients with NSCLC-BM, 28 patients had LM with or without BPM, while 9 patients only had BPM. Driver and drug-resistant mutations in primary tumours with LM included: EGFR L858R (10, 35.7%), EGFR 19del (6, 21.4%), EGFR L858R+MET (1, 3.6%), EGFR L858R+S768I (1, 3.6%), ALK (2, 7.1%), ROS1 (1, 3.6%), negative (5, 17.9%), and unknown (2, 7.1%). In patients with NSCLC-LM, the detection rate and abundance of ctDNA in the CSF were significantly higher than those in paired plasma. The main driver mutations of NSCLC-LM remained highly consistent with those of the primary tumours, along with other unique mutations. Circulating tumour DNA was negative in the CSF samples of BPM patients. Patients with BMP had a higher ratio of EGFR 19del than L858R mutation (55.6% vs 11.1.%), whereas NSCLC patients with LM had a higher ratio of EGFR L858R than 19del mutation (50.0% vs 25.0%). Most patients with positive plasma ctDNA results were male (p = 0.058) and in an unstable state (p = 0.003).

Conclusion

Our study indicated that the CSF ctDNA detected by NGS may reflect the molecular characteristics and heterogeneity of NSCLC-LM. Timely screening of patients with NSCLC for CSF ctDNA, especially for patients with positive plasma ctDNA, may facilitate the early detection of LM. Furthermore, patients with the EGFR 19del may have a higher risk of developing BPM.

Immunotherapy in the context of immune-specialized environment of brain metastases

Brain metastases (BrM) develop in 20-40% of patients with advanced cancer. They mainly originate from lung cancer, melanoma, breast cancer, and renal cell carcinoma, and are associated with a poor prognosis. While patients with BrM traditionally lack effective treatment options, immunotherapy is increasingly gaining in importance in this group of patients, with clinical trials in the past decade demonstrating the efficacy and safety of immune checkpoint blockade in BrM originating from specific tumor types, foremost melanoma. The brain is an immune-specialized environment with several unique molecular, cellular, and anatomical features that affect immune responses, including those against tumors. In this review we discuss the potential role that some of these unique characteristics may play in the efficacy of immunotherapy, mainly focusing on the lymphatic drainage in the brain and the role of systemic anti-tumor immunity that develops due to the presence of concurrent extracranial disease in addition to BrM.

Heterogenous profiles between primary lung cancers and paired brain metastases reveal tumor evolution

Background

Brain metastases (BMs) are the most common central nervous system (CNS) malignant tumors, with rapid disease progression and extremely poor prognosis. The heterogeneity between primary lung cancers and BMs leads to the divergent efficacy of the adjuvant therapy response to primary tumors and BMs. However, the extent of heterogeneity between primary lung cancers and BMs, and the evolutionary process remains little known.

Methods

To deeply insight into the extent of inter-tumor heterogeneity at a single-patient level and the process of these evolutions, we retrospectively analyzed a total of 26 tumor samples from 10 patients with matched primary lung cancers and BMs. One patient underwent four times brain metastatic lesion surgery with diverse locations and one operation for the primary lesion. The genomic and immune heterogeneity between primary lung cancers and BMs were evaluated by utilizing whole-exome sequencing (WESeq) and immunohistochemical analysis.

Results

In addition to inheriting genomic phenotype and molecular phenotype from the primary lung cancers, massive unique genomic phenotype and molecular phenotype were also observed in BMs, which revealed unimaginable complexity of tumor evolution and extensive heterogeneity among lesions at a single-patient level. By analysis of a multi-metastases case (Case 3) of cancer cells' subclonal composition, we found similar multiple subclonal clusters in the four spatial and temporal isolated brain metastatic focus, with the characteristics of polyclonal dissemination. Our study also verified that the expression level of immune checkpoints-related molecule Programmed Death-Ligand 1 (PD-L1) (P = 0.0002) and the density of tumor-infiltrating lymphocytes (TILs) (P = 0.0248) in BMs were significantly lower than that in paired primary lung cancers. Additionally, tumor microvascular density (MVD) also differed between primary tumors and paired BMs, indicating that temporal and spatial diversity profoundly contributes to the evolution of BMs heterogeneity.

Conclusion

Our study revealed the significance of temporal and spatial factors to the evolution of tumor heterogeneity by multi-dimensional analysis of matched primary lung cancers and BMs, which also provided novel insight for formulating individualized treatment strategies for BMs.

Laser Interstitial Thermal Therapy for Radionecrosis

Radiotherapy is widely used for brain tumors but can cause radiation necrosis (RN). Laser interstitial thermal therapy (LITT) is a relatively new therapeutic modality for RN and its impact on patient outcome is still not well understood. Based on a systematic literature search (n=33), the authors discuss the available evidence. Most studies found a positive safety/efficacy profile, as LITT may help to lengthen survival, prevent progression, taper steroids, and improve neurological symptoms while remaining safe. Prospective studies on this subject are needed and may result in LITT becoming an essential therapeutic option for the treatment of RN.

Personalized radiotherapy of brain metastases: survival prediction by means of dichotomized or differentiated blood test results?

Background and objectives

The validated LabBM score (laboratory parameters in patients with brain metastases) represents a widely applicable survival prediction model, which incorporates 5 blood test results (serum lactate dehydrogenase (LDH), C-reactive protein (CRP), albumin, platelets and hemoglobin). All tests are classified as normal or abnormal, without accounting for the wide range of abnormality observed in practice. We tested the hypothesis that improved stratification might be possible, if more granular test results are employed.

Methods

Retrospective analysis of 198 patients managed with primary whole-brain radiotherapy in one of the institutions who validated the original LabBM score.

Results

For two blood tests (albumin, CRP), discrimination was best for the original dichotomized version (normal/abnormal). For two others (LDH, hemoglobin), a three-tiered classification was best. The number of patients with low platelet count was not large enough for detailed analyses. A modified LabBM score was developed, which separates the intermediate of originally 3 prognostic groups into 2 statistically significantly different strata, resulting in a 4-tiered score.

Conclusion

This initial proof-of-principle study suggests that granular blood test results might contribute to further improvement of the score, or alternatively development of a nomogram, if additional large-scale studies confirm the encouraging results of the present analysis.

Personalized treatment of brain metastases: Evolving survival prediction models may benefit from evaluation of serum tumor markers (narrative review)

Treatment of a limited number of brain metastases (oligometastases) might include complex and sometimes invasive approaches, e.g. neurosurgical resection followed by post-operative stereotactic radiotherapy, and thus, correct identification of patients who are appropriate candidates is crucial. Both, staging procedures that visualize the true number of metastastic lesions and prognostic assessments that identify patients with limited survival, who should be managed with less complex, palliative approaches, are necessary before proceeding with local treatment that aims at eradication of all oligometastases. Some of the prognostic models, e.g. the LabBM score (laboratory parameters in patients with brain metastases), include blood biomarkers believed to represent surrogate markers of disease extent. In a recent study, patients with oligometastases and a LabBM score of 0 (no abnormal biomarkers) had an actuarial 5-year survival rate of 27% after neurosurgical resection and 39% after stereotactic radiotherapy. Other studies have tied serum tumor markers such as carcinoembryonic antigen (CEA) to survival outcomes. Even if head-to-head comparisons and large-scale definitive analyses are lacking, the available data suggest that attempts to integrate tumor marker levels in blood biomarker-based survival prediction models are warranted.

Stereotactic radiosurgery and resection for treatment of multiple brain metastases: a systematic review and analysis

OBJECTIVE

Stereotactic radiosurgery (SRS) has recently emerged as a minimally invasive alternative to resection for treating multiple brain metastases. Given the lack of consensus regarding the application of SRS versus resection for multiple brain metastases, the authors aimed to conduct a systematic literature review of all published work on the topic.

METHODS

The PubMed, OVID, Cochrane, Web of Science, and Scopus databases were used to identify studies that examined clinical outcomes after resection or SRS was performed in patients with multiple brain metastases. Radiological studies, case series with fewer than 3 patients, pediatric studies, or national database studies were excluded. Data extracted included patient demographics and mean overall survival (OS). Weighted t-tests and ANOVA were performed.

RESULTS

A total of 1300 abstracts were screened, 450 articles underwent full-text review, and 129 studies met inclusion criteria, encompassing 20,177 patients (18,852 treated with SRS and 1325 who underwent resection). The OS for the SRS group was 10.2 ± 6 months, and for the resection group it was 6.5 ± 3.8 months. A weighted ANOVA test comparing OS with covariates of age, sex, and publication year revealed that the treatment group (p = 0.045), age (p = 0.034), and publication year (0.0078) were all independently associated with OS (with SRS, younger age, and later publication year being associated with longer survival), whereas sex (p = 0.95) was not.

CONCLUSIONS

For patients with multiple brain metastases, SRS and resection are effective treatments to prolong OS, with published data suggesting that SRS may have a trend toward lengthened survival outcomes. The authors encourage additional work examining outcomes of treatments for multiple brain metastases.