Brain metastasis in breast cancer: a comprehensive literature review

Breakouts-A Radiological Sign of Poor Prognosis in Patients With Brain Metastases

Purpose

Brain metastases (BM) can present a displacing or infiltrating growth pattern, independent of the primary tumor type. Previous studies have shown that tumor cell infiltration at the macro-metastasis/brain parenchyma interface (MMPI) is correlated with poor outcome. Therefore, a pre-therapeutic, non-invasive detection tool for potential metastatic cell infiltration at the MMPI would be desirable to help identify patients who may benefit from a more aggressive local treatment strategy. The aim of this study was to identify specific magnetic resonance imaging (MRI) patterns at the MMPI in patients with BM and to correlate these patterns with patient outcome.

Patients and Methods

In this retrospective analysis of a prospective BM registry, we categorized preoperative MR images of 261 patients with BM according to a prespecified analysis system, which consisted of four MRI contrast enhancement (CE) patterns: two with apparently regularly shaped borders (termed “rim-enhancing” and “spherical”) and two with irregular delineation (termed “breakout” and “diffuse”). The primary outcome parameter was overall survival (OS). Additionally analyzed prognostic parameters were the Karnofsky Performance Index, tumor size, edema formation, extent of resection, and RPA class.

Results

OS of patients with a breakout pattern was significantly worse than OS of all other groups.

Conclusion

Our data show that BM with a breakout pattern have a highly aggressive clinical course. Patients with such a pattern potentially require a more aggressive local and systemic treatment strategy.

Adult brain tumors in Sub-Saharan Africa: A scoping review

BACKGROUND

Sub-Saharan African (SSA) neuro-oncologists report high workloads and challenges in delivering evidence-based care; however, these reports contrast with modeled estimates of adult neuro-oncology disease burden in the region. This scoping review aimed to better understand the reasons for this discrepancy by mapping out the SSA adult brain tumor landscape based on published literature.

METHODS

Systematic searches were conducted in OVID Medline, Global Index Medicus, African Journals Online, Google Scholar, and faculty of medicine libraries from database inception to May 31 st, 2021. The results were summarized quantitatively and narratively. English and French peer-reviewed articles were included (title, abstract, and full text).

RESULTS

Of the 819 records identified, 119 articles by 24 SSA countries (42.9%) were included in the final review. Odeku published the first article in 1967, and nine of the ten most prolific years were in the 21 st century. The greatest contributing region was Western Africa (n=58, 48.7%) led by Nigeria (n=37, 31.1%). Central Africa had fewer articles published later than the other SSA regions (p=0.61). Most studies were non-randomized (n=75, 63.0%) and meningiomas (n=50, 42.0%) were the most common brain tumors reported. Less than 30 studies reported on adjuvant treatment or patient outcomes.

CONCLUSIONS

Most publications were hospital-based, and there was significant heterogeneity in the quality of evidence and reporting. This study highlights the need for rapid and sustainable investments and brain tumor research capacity in SSA.

Brain Microvascular Pericytes—More than Bystanders in Breast Cancer Brain Metastasis

Brain tissue contains the highest number of perivascular pericytes compared to other organs. Pericytes are known to regulate brain perfusion and to play an important role within the neurovascular unit (NVU). The high phenotypic and functional plasticity of pericytes make this cell type a prime candidate to aid physiological adaptations but also propose pericytes as important modulators in diverse pathologies in the brain. This review highlights known phenotypes of pericytes in the brain, discusses the diverse markers for brain pericytes, and reviews current in vitro and in vivo experimental models to study pericyte function. Our current knowledge of pericyte phenotypes as it relates to metastatic growth patterns in breast cancer brain metastasis is presented as an example for the crosstalk between pericytes, endothelial cells, and metastatic cells. Future challenges lie in establishing methods for real-time monitoring of pericyte crosstalk to understand causal events in the brain metastatic process.

Surgical Management of Brain Metastasis: Challenges and Nuances

Brain metastasis is the most common type of intracranial tumor. The contemporary management of brain metastasis is a challenging issue and traditionally has carried a poor prognosis as these lesions typically occur in the setting of advanced cancer. However, improvement in systemic therapy, advances in radiation techniques and multimodal therapy tailored to the individual patient, has given hope to this patient population. Surgical resection has a well-established role in the management of brain metastasis. Here we discuss the evolving role of surgery in the treatment of this diverse patient population.

Preclinical Models of Brain Metastases in Breast Cancer

Breast cancer remains a leading cause of mortality among women worldwide. Brain metastases confer extremely poor prognosis due to a lack of understanding of their specific biology, unique physiologic and anatomic features of the brain, and limited treatment strategies. A major roadblock in advancing the treatment of breast cancer brain metastases (BCBM) is the scarcity of representative experimental preclinical models. Current models are predominantly based on the use of animal xenograft models with immortalized breast cancer cell lines that poorly capture the disease’s heterogeneity. Recent years have witnessed the development of patient-derived in vitro and in vivo breast cancer culturing systems that more closely recapitulate the biology from individual patients. These advances led to the development of modern patient-tissue-based experimental models for BCBM. The success of preclinical models is also based on the imaging technologies used to detect metastases. Advances in animal brain imaging, including cellular MRI and multimodality imaging, allow sensitive and specific detection of brain metastases and monitoring treatment responses. These imaging technologies, together with novel translational breast cancer models based on patient-derived cancer tissues, represent a unique opportunity to advance our understanding of brain metastases biology and develop novel treatment approaches. This review discusses the state-of-the-art knowledge in preclinical models of this disease.

Prediction of Short and Long Survival after Surgery for Breast Cancer Brain Metastases

Background: Brain metastases requiring surgical treatment determine the prognosis of patients with breast cancer. We aimed to develop the scores for the prediction of short (<6 months) and long (≥3 years) survival after BCBM surgery. Methods: Female patients with BCBM surgery between 2008 and 2019 were included. The new scores were constructed upon independent predictors for short and long postoperative survival. Results: In the final cohort (n = 95), 18 (18.9%) and 22 (23.2%) patients experienced short and long postoperative survival, respectively. Breast-preserving surgery, presence of multiple brain metastases and age ≥ 65 years at breast cancer diagnosis were identified as independent predictors of short postoperative survival. In turn, positive HER2 receptor status in brain metastases, time interval ≥ 3 years between breast cancer and brain metastases diagnosis and KPS ≥ 90% independently predicted long survival. The appropriate short and long survival scores showed higher diagnostic accuracy for the prediction of short (AUC = 0.773) and long (AUC = 0.775) survival than the breast Graded Prognostic Assessment score (AUC = 0.498/0.615). A cumulative survival score (total score) showed significant association with overall survival (p = 0.001). Conclusion: We identified predictors independently impacting the prognosis after BCBM surgery. After external validation, the presented scores might become useful tools for the selection of proper candidates for BCBM surgery.

A cerebellopontine angle metastatis of a male breast cancer: Case report

Male breast cancer is rare, less than 1% of men's cancers. The tumors occurring in the cerebellopontine angle remain a rare entity. Features suggestive of metastasis are acute onset, rapid progression of symptoms. We report a case of a 72-year-old man had a mastectomy and an axillary lymph node dissection for a breast cancer 22 years prior to this report. The patient was admitted with deterioration of level of consciousness with intracranial hypertension syndrome. The magnetic resonance imaging showed a cystic lesion in the left cerebellar hemisphere and the prepontine cistern. We proceeded to a large tumor resection. On the follow up, the patient presented a delayed emergence. A CT scan showed a small hematoma at the surgical site and triventricular hydrocephalus for which the patient underwent a ventriculoperitoneal shunt. This is the first described cerebellopontine angle metastasis of a male breast cancer and the first described case of a metastatic triple hormone negative breast cancer to the brain.

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A 72 years old man had a mastectomy and an axillary lymph node dissection for a breast cancer 22 years prior to this report. He was brought to our emergency for intracranial hypertension syndrome with disorders of consciousness.

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The magnetic resonance imaging showed a cystic lesion in the left cerebellar hemisphere compressing the pons, the acoustic-facial nerve bundle, with a peripheral contrast enhancement.

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This is the first described cerebellopontine angle metastasis of a male breast cancer and the first described case of a metastatic triple hormone negative breast cancer to the brain.

Identification of prognostic biomarkers for breast cancer brain metastases based on the bioinformatics analysis

Purpose

The prognosis of breast cancer (BC) patients who develop into brain metastases (BMs) is very poor. Thus, it is of great significance to explore the etiology of BMs in BC and identify the key genes involved in this process to improve the survival of BC patients with BMs.

Patients and methods

The gene expression data and the clinical information of BC patients were downloaded from TCGA and GEO database. Differentially expressed genes (DEGs) in TCGA-BRCA and GSE12276 were overlapped to find differentially expressed metastatic genes (DEMGs). The protein-protein interaction (PPI) network of DEMGs was constructed via STRING database. ClusterProfiler R package was applied to perform the gene ontology (GO) enrichment analysis of DEMGs. The univariate Cox regression analysis and the Kaplan-Meier (K-M) curves were plotted to screen DEMGs associated with the overall survival and the metastatic recurrence survival, which were identified as the key genes associated with the BMs in BC. The immune infiltration and the expressions of immune checkpoints for BC patients with brain relapses and BC patients with other relapses were analyzed respectively. The correlations among the expressions of key genes and the differently infiltrated immune cells or the differentially expressed immune checkpoints were calculated. The gene set enrichment analysis (GSEA) of each key gene was conducted to investigate the potential mechanisms of key genes involved in BC patients with BMs. Moreover, CTD database was used to predict the drug-gene interaction network of key genes.

Results

A total of 154 DEGs were identified in BC patients at M0 and M1 in TCGA database. A total of 667 DEGs were identified in BC patients with brain relapses and with other relapses. By overlapping these DEGs, 17 DEMGs were identified, which were enriched in the cell proliferation related biological processes and the immune related molecular functions. The univariate Cox regression analysis and the Kaplan-Meier curves revealed that CXCL9 and GPR171 were closely associated with the overall survival and the metastatic recurrence survival and were identified as key genes associated with BMs in BC. The analyses of immune infiltration and immune checkpoint expressions showed that there was a significant difference of the immune microenvironment between brain relapses and other relapses in BC. GSEA indicated that CXCL9 and GPR171 may regulate BMs in BC via the immune-related pathways.

Conclusion

Our study identified the key genes associated with BMs in BC patients and explore the underlying mechanisms involved in the etiology of BMs in BC. These findings may provide a promising approach for the treatments of BC patients with BMs.

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CXCL9 and GPR171, as the key genes, were closely associated with the prognosis of brain metastases in breast cancer.

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There was a significant difference of the immune microenvironment between brain and other metastases in breast cancer.

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We revealed candidate drugs which associated with the key genes of breast cancer patients with brain metastases.

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A series of bioinformatic analysis methods were used in this article.

Clinicopathological characteristics and prognosis of breast cancer patients with isolated central nervous system metastases in the multicentre ESME database

Background:

As a result of progress in diagnosis and treatment, there is a growing prevalence of metastatic breast cancer (MBC) with isolated CNS metastases. This study describes the largest-to-date real-life cohort of this clinical setting and compares it to other clinical presentations.

Methods:

We retrospectively analysed the French Epidemiological Strategy and Medical Economics (ESME) MBC database including patients who initiated treatment for MBC between 2008 and 2016. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan–Meier method. Descriptive statistics and multivariate Cox model were used.

Results:

Of 22,266 patients, 647 (2.9%) and 929 (4.2%) patients had isolated first-site CNS metastases or combined with extra-CNS metastases, with longer OS for the group with isolated CNS metastases (16.9 versus 13.9 months, adjusted HR = 1.69 (95% CI: 1.50–1.91), p < 0.001). Among the 541 (2.4%) patients with isolated CNS metastases and no intrathecal therapy (excluding leptomeningeal metastases), HER2+ cases were preponderant over TN or HR+ /HER2− cases (41.6% versus 26.1% versus 28.5%, respectively, p < 0.01). The treatment strategy consisted of a combination of local treatment and systemic therapy (49.2%), local treatment only (35.5%) or systemic therapy only (11.4%), or symptomatic therapy only (3.9%). Median PFS was 6.1 months (95% CI: 5.7–6.8). Median OS was 20.7 months (95% CI: 17.3–24.3), reaching 37.9 months (95% CI: 25.9–47.6) in the HR+ /HER2+ subgroup. Older age, TN subtype, MBC-free interval of 6–12 months, lower performance status, and WBRT were associated with poorer survival. Patients who received systemic therapy within 3 months from MBC diagnosis had longer OS (24.1 versus 16.1 months, p = 0.031), but this was not significant on multivariate analysis [HR = 1.0 (95% CI: 0.7–1.3), p = 0.806].

Conclusions:

Patients with isolated CNS metastases at MBC diagnosis represent a distinct population for which the role of systemic therapy needs to be further investigated in prospective studies.

Radiographic markers of breast cancer brain metastases: relation to clinical characteristics and postoperative outcome

Objective

Occurrence of brain metastases BM is associated with poor prognosis in patients with breast cancer (BC). Magnetic resonance imaging (MRI) is the standard of care in the diagnosis of BM and determines further treatment strategy. The aim of the present study was to evaluate the association between the radiographic markers of BCBM on MRI with other patients’ characteristics and overall survival (OS).

Methods

We included 88 female patients who underwent BCBM surgery in our institution from 2008 to 2019. Data on demographic, clinical, and histopathological characteristics of the patients and postoperative survival were collected from the electronic health records. Radiographic features of BM were assessed upon the preoperative MRI. Univariable and multivariable analyses were performed.

Results

The median OS was 17 months. Of all evaluated radiographic markers of BCBM, only the presence of necrosis was independently associated with OS (14.5 vs 22.5 months, p = 0.027). In turn, intra-tumoral necrosis was more often in individuals with shorter time interval between BC and BM diagnosis (< 3 years, p = 0.035) and preoperative leukocytosis (p = 0.022). Moreover, dural affection of BM was more common in individuals with positive human epidermal growth factor receptor 2 status (p = 0.015) and supratentorial BM location (p = 0.024).

Conclusion

Intra-tumoral necrosis demonstrated significant association with OS after BM surgery in patients with BC. The radiographic pattern of BM on the preoperative MRI depends on certain tumor and clinical characteristics of patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00701-021-05026-4.

Evaluating the Role of IL-1β in Transmigration of Triple Negative Breast Cancer Cells Across the Brain Endothelium

INTRODUCTION

In vivo, breast cancer cells spend on average 3-7 days adhered to the endothelial cells inside the vascular lumen before entering the brain. IL-1β is one of the highly upregulated molecules in brain-seeking triple negative breast cancer (TNBC) cells. In this study, the effect of IL-1β on the blood-brain barrier (BBB) and astrocytes and its role in transmigration of TNBC cells were evaluated.

METHODS

The effect of IL-1β on transendothelial electrical resistance, gene and protein expression of human induced pluripotent stem cell-derived brain-specific microvascular endothelial-like cells (iBMECs) was studied. Transport of IL-1β across the iBMEC layer was investigated and the effect of IL-1β treatment of astrocytes on their cytokine and chemokine secretome was evaluated with a cytokine membrane array. Using BBB-on-a-chip devices, transmigration of MDA-MB-231 cells and their brain-seeking variant (231BR) across the iBMECs was studied, and the effect of an IL-1β neutralizing antibody on TNBC cell transmigration was investigated.

RESULTS

We showed that IL-1β reduces BBB integrity and induces endothelial-to-mesenchymal transition in iBMECs. IL-1β crosses the iBMEC layer and induces secretion of multiple chemokines by astrocytes, which can enhance TNBC cell transmigration across the BBB. Transmigration assays in a BBB-on-a-chip device showed that 231BR cells have a higher rate of transmigration across the iBMECs compared to MDA-MB-231 cells, and IL-1β pretreatment of BBB-on-a-chip devices increases the number of transmigrated MDA-MB-231 cells. Finally, we demonstrated that neutralizing IL-1β reduces the rate of 231BR cell transmigration.

CONCLUSION

IL-1β plays a significant role in transmigration of brain-seeking TNBC cells across the BBB.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12195-021-00710-y.

Designing Patient-Driven, Tissue-Engineered Models of Primary and Metastatic Breast Cancer

The rising survival rate for early-stage breast cancer in the United States has created an expanding population of women in remission at risk for distant recurrence, with metastatic spread to the brain demonstrating an especially poor prognosis. The current standard of care for breast cancer brain metastases is not well defined or differentiated from the treatment of brain metastases from other primary sites. Here, we present tissue-engineered models of the primary and brain metastatic breast cancer microenvironments informed by analysis of patient tumor resections. We find that metastatic resections demonstrate distinct cellular and matrix components compared with primary resections or non-cancerous controls. Using our model systems, we find that the observed deposition of collagen I after metastasis to the brain may enhance breast cancer invasion. Future optimization of these models will present a novel platform to examine tumor-stroma interactions and screen therapeutics for the management of metastatic breast cancer.

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

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

Exosomes: Breast cancer-derived extracellular vesicles; recent key findings and technologies in disease progression, diagnostics, and cancer targeting

Breast cancer is one of the most frequently diagnosed types of cancer in women. Metastasis, particularly to the lungs and brain, increases mortality in breast cancer patients. Recently, breast cancer-related exosomes have received significant attention because of their key role in breast cancer progression. As a result, numerous exosome-based therapeutic tools for diagnosis and treatment have been developed, and their biological and chemical mechanisms have been explored. This review summarizes up-to-date advanced key findings and technologies in breast cancer progression, diagnostics, and targeting. We focused on recent research on the basic biology of exosomes and disease-related exosomal genes and proteins, as well as their signal transduction in cell-to-cell communications, diagnostic markers, and exosome-based antibreast cancer technologies. We also paid special attention to technologies employing exosomes modified with functional peptides for the targeted delivery of therapeutic and diagnostic agents.

Isolated Sixth Nerve Palsy as the First Manifestation of Cavernous Sinus Metastasis From Primary Breast Cancer

Cavernous sinus metastasis is a rare clinical finding, presenting most commonly with complaints of headache, diplopia, visual field defects, facial pain, and progressive neurological deficits. Many patients present with features of III, IV, and VI nerve palsies. We hereby report an unusual case of cavernous sinus metastasis from primary breast cancer in a 40-year-old female, who presented with binocular diplopia due to left VI nerve palsy as the first presenting complaint. The patient had a history of surgery for left breast cancer which was performed at another center. Contrast-enhanced computed tomography (CECT) scan of thorax and abdomen revealed a residual neoplastic left breast mass with satellite nodules, left axillary lymphadenopathy, and hepatic, splenic, and skeletal metastasis. Contrast-enhanced magnetic resonance imaging (CE-MRI) of brain and orbit showed enhancing lesion of 20 mm x 10 mm along the lateral wall of left cavernous sinus and left petrous apex. She was referred to radiation oncology department for further management. This case report highlights the importance of ophthalmologists in such life-threatening conditions, who may first present to them.

Harnessing nanomedicine for enhanced immunotherapy for breast cancer brain metastases

Brain metastases (BMs) are the most common type of brain tumor, and the incidence among breast cancer (BC) patients has been steadily increasing over the past two decades. Indeed, ~ 30% of all patients with metastatic BC will develop BMs, and due to few effective treatments, many will succumb to the disease within a year. Historically, patients with BMs have been largely excluded from clinical trials investigating systemic therapies including immunotherapies (ITs) due to limited brain penetration of systemically administered drugs combined with previous assumptions that BMs are poorly immunogenic. It is now understood that the central nervous system (CNS) is an immunologically distinct site and there is increasing evidence that enhancing immune responses to BCBMs will improve patient outcomes and the efficacy of current treatment regimens. Progress in IT for BCBMs, however, has been slow due to several intrinsic limitations to drug delivery within the brain, substantial safety concerns, and few known targets for BCBM IT. Emerging studies demonstrate that nanomedicine may be a powerful approach to overcome such limitations, and has the potential to greatly improve IT strategies for BMs specifically. This review summarizes the evidence for IT as an effective strategy for BCBM treatment and focuses on the nanotherapeutic strategies currently being explored for BCBMs including targeting the blood-brain/tumor barrier (BBB/BTB), tumor cells, and tumor-supporting immune cells for concentrated drug release within BCBMs, as well as use of nanoparticles (NPs) for delivering immunomodulatory agents, for inducing immunogenic cell death, or for potentiating anti-tumor T cell responses.

Novel prognostic classification predicts overall survival of patients receiving salvage whole-brain radiotherapy for recurrent brain metastasis from breast cancer: A recursive partitioning analysis (KROG 16-12)

Background

To investigate outcomes of salvage whole-brain radiotherapy (WBRT) for recurrent brain metastases (BM) from breast cancer (BC), to identify prognostic factors of overall survival (OS), and to propose a novel prognostic classification for OS in these patients.

Materials and methods

We identified 54 patients who had received salvage WBRT as the second brain-focused treatment for recurrent BM from BC (2000–2014). The median follow-up duration was 4.9 months. A recursive partitioning analysis (RPA) was conducted to develop a model to predict OS at the time of salvage WBRT.

Results

The median OS was 6.8 months. OS according to BC-specific graded prognostic assessment (breast-GPA), modified breast-GPA, and updated breast-GPA did not represent our cohort. In the multivariate analysis, a long time before salvage WBRT (≥16 months), control of primary BC or extracranial metastases, systemic treatment after salvage WBRT, and administration of a biologically effective dose for an α/β of 10 Gy (BED10) of salvage WBRT >37.5 Gy showed superior OS. We proposed three RPA classes based on the control of both primary BC and extracranial metastasis and BED10 of salvage WBRT: class I, class II, and class III. In this model, patients with class I experienced the best OS (34.6 months; class II, 5.0 months; class III, 2.4 months; P < 0.001).

Conclusions

In our RPA classification according to the control of both primary BC and extracranial metastasis and the dose of salvage WBRT, significant differences in OS were observed. The subsequent use of a systemic treatment showed better OS.

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Multicenter retrospective study of salvage WBRT for recurrent brain metastasis.

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Subsequent use of systemic treatment after salvage WBRT showing better OS.

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Limitations of previous graded prognostic assessments for recurrent brain metastasis.

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Novel RPA classification consisting of four simple clinical factors predicts OS.

The presentation of brain metastases in melanoma, non-small cell lung cancer, and breast cancer and potential implications for screening brain MRIs

PURPOSE

This study assessed the presentation and institutional outcomes treating brain metastases (BM) of breast cancer (BC), non-small cell lung cancer (NSCLC), and melanoma origin.

METHODS

Patients with brain metastases treated between 2014 and 2019 with primary melanoma, NSCLC, and BC were identified. Overall survival (OS) was calculated from dates of initial BM diagnosis using the Kaplan-Meier method.

RESULTS

A total of 959 patients were identified including melanoma (31%), NSCLC (51%), and BC (18%). Patients with BC were younger at BM diagnosis (median age: 57) than NSCLC (65) and melanoma patients (62, p < 0.0001). Breast cancer patients were more likely to present with at least 5 BM (27%) than NSCLC (14%) and melanoma (13%), leptomeningeal disease (23%, 6%, and 6%, p = 0.0004) and receive whole brain radiation therapy (WBRT) (58%, 37%, and 22%, p < 0.0001). There were no differences in surgical resection (24%, 24%, and 29%, p = 0.166). Median OS was shorter for BC patients (9.9, 10.3, and 13.7 months, p = 0.0006).

CONCLUSION

Breast cancer patients were more likely to be younger, present with advanced disease, require WBRT, and have poorer OS than NSCLC and melanoma patients. Further investigation is needed to determine which BC patients are at sufficient risk for brain MRI screening.

RNA Sequence Profiling Reveals Unique Immune and Metabolic Features of Breast Cancer Brain Metastases

There is an urgent need to improve our understanding of breast cancer brain metastases (BCBMs). Thus, we obtained transcriptome data of BCBMs, primary breast cancers (BCs), and extracranial metastases (BCEMs) from the Gene Expression Omnibus (GEO) database, including GSE43837, GSE14017, and GSE14018, for immune and metabolic analysis. Firstly, we performed immune and metabolic analysis on BCBMs and primary breast cancers of GSE43837 using RNA sequence. We identified significant immunosuppression and gene signatures associated with immune infiltration in BCBMs; the lower the expression of the signatures, the worse the prognosis of breast cancer patients in the Kaplan–Meier (KM) plotter [Breast cancer] database. We also identified increased oxidative phosphorylation (OXPHOS) utilization in BCBMs compared with BCs and gene signatures associated with increased OXPHOS utilization in BCBMs; the higher the expression of the signatures, the worse the prognosis of breast cancer patients in the KM plotter [Breast cancer] database, which can predict the prognosis of breast cancer patients better, as it can also predict the prognosis of patients with different breast cancer subtypes. In addition, we performed immune and metabolic analysis on BCBMs and extracranial metastases of GSE14017 and GSE14018 using RNA sequence. Compared with extracranial metastases, we identified more significant immunosuppression but no difference in OXPHOS utilization in BCBMs, which may be because OXPHOS was also involved in extracranial metastases. We have proven that OXPHOS was functionally significant in metastasis in vitro assays. Oligomycin, an OXPHOS inhibitor, substantially attenuated the migration and invasion potential of breast cancer cells. Our study provides new insights into the pathogenesis of BCBMs.

A pre-operative MRI-based brain metastasis risk-prediction model for triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) patients have a high 2-year post-operative incidence of brain metastasis (BM). Currently, there is no early prediction tool to predict the risk of BM in TNBC patients.

METHODS

Data of breast cancer patients, who had been scanned, resected, and pathologically diagnosed at a local hospital from May 2012 to June 2018 were collected. Primary and radiological secondary exclusion criteria were used to determine patients' eligibility for inclusion in the study. Data for the TNBC cohort included qualified 2-year post-operative follow-up information, BM status, and pre-operative MRI data. Age-based propensity score matching (PSM) was used to build a comparable study cohort. The tumor regions of interest were segmented and used for lattice radiomics feature extraction. The filtered and normalized lattice radiomics features were then trained with BM status using the random forest (RF), support vector machine (SVM), k-nearest neighbor, least absolute shrinkage and selection operator regression, naïve Bayesian, and neural network algorithms. The generated prediction models were evaluated using 10-fold cross verification, and the areas under the curve (AUCs), accuracy, sensitivity, and specificity were reported.

RESULTS

Data from 643 breast cancer patients were collected. Among these, 84 TNBC cases (comprising 42 pairs) were included in this study after primary exclusion, radiological secondary exclusion, and PSM. We extracted 3,854 lattice radiomics features from the pre-operative MRI. Of these, 2,480 were used for model training after filtration. The 10-fold verification results showed that the BM risk-prediction model, which was based on the normalized and filtered lattice radiomics features of collected cases trained by naïve Bayesian algorithm, had a high AUC (0.878), accuracy (0.786), specificity (81.0%), and sensitivity (76.2%).

CONCLUSIONS

The pre-operative MRI data of TNBC patients can be used to predict 2-year BM risk. This application could help to achieve better early stratification, BM screening, and the overall prognosis.

Combination of cell-penetrating peptides with nanomaterials for the potential therapeutics of central nervous system disorders: a review

Although nanomedicine have greatly developed and human life span has been extended, we have witnessed the soared incidence of central nervous system (CNS) diseases including neurodegenerative diseases (Alzheimer's disease, Parkinson's disease), ischemic stroke, and brain tumors, which have severely damaged the quality of life and greatly increased the economic and social burdens. Moreover, partial small molecule drugs and almost all large molecule drugs (such as recombinant protein, therapeutic antibody, and nucleic acid) cannot cross the blood-brain barrier. Therefore, it is especially important to develop a drug delivery system that can effectively deliver therapeutic drugs to the central nervous system for the treatment of central nervous system diseases. Cell penetrating peptides (CPPs) provide a potential strategy for the transport of macromolecules through the blood-brain barrier. This study analyzed and summarized the progress of CPPs in CNS diseases from three aspects: CPPs, the conjugates of CPPs and drug, and CPPs modified nanoparticles to provide scientific basis for the application of CPPs for CNS diseases.

Is Molecular Tailored-Therapy Changing the Paradigm for CNS Metastases in Breast Cancer?

Breast cancer (BC) is the second most common tumour spreading to the central nervous system (CNS). The prognosis of patients with CNS metastases depends on several parameters including the molecular assessment of the disease. Although loco-regional treatment remains the best approach, systemic therapies are acquiring a role leading to remarkable long-lasting responses. The efficacy of these compounds diverges between tumours with different molecular assessments. Promising agents under investigation are drugs targeting the HER2 pathways such as tucatinib, neratinib, pyrotinib, trastuzumab deruxtecan. In addition, there are several promising agents under investigation for patients with triple-negative brain metastases (third-generation taxane, etirinotecan, sacituzumab, immune-checkpoint inhibitors) and hormone receptor-positive brain metastases (CDK 4/5, phosphoinositide-3-kinase-mammalian target of rapamycin [PI3K/mTOR] inhibitors). Also, the systemic treatment of leptomeningeal metastases, which represents a very negative prognostic site of metastases, is likely to change as several compounds are under investigation, some with interesting preliminary results. Here we performed a comprehensive review focusing on the current management of CNS metastases according to molecular subtypes, site of metastases (leptomeningeal vs brain), and systemic treatments under investigation.

Molecular Mechanisms Associated with Brain Metastases in HER2-Positive and Triple Negative Breast Cancers

Breast cancer (BC) is the most frequent cause of cancer-associated death for women worldwide, with deaths commonly resulting from metastatic spread to distant organs. Approximately 30% of metastatic BC patients develop brain metastases (BM), a currently incurable diagnosis. The influence of BC molecular subtype and gene expression on breast cancer brain metastasis (BCBM) development and patient prognosis is undeniable and is, therefore, an important focus point in the attempt to combat the disease. The HER2-positive and triple-negative molecular subtypes are associated with an increased risk of developing BCBM. Several genetic and molecular mechanisms linked to HER2-positive and triple-negative BC breast cancers appear to influence BCBM formation on several levels, including increased development of circulating tumor cells (CTCs), enhanced epithelial-mesenchymal transition (EMT), and migration of primary BC cells to the brain and/or through superior local invasiveness aided by cancer stem-like cells (CSCs). These specific BC characteristics, together with the ensuing developments at a clinical level, are presented in this review article, drawing a connection between research findings and related therapeutic strategies aimed at preventing BCBM formation and/or progression. Furthermore, we briefly address the critical limitations in our current understanding of this complex topic, highlighting potential focal points for future research.

Targeting the Tumor Microenvironment in Brain Metastasis

Dynamic interplay between cancer cells and the surrounding microenvironment is a feature of the metastatic process. Successful metastatic brain colonization requires complex mechanisms that ultimately allow tumor cells to adapt to the unique microenvironment of the central nervous system, evade immune destruction, survive, and grow. Accumulating evidence suggests that components of the brain tumor microenvironment (TME) play a vital role in the metastatic cascade. In this review, the authors summarize the contribution of the TME to the development and progression of brain metastasis. They also highlight opportunities for TME-directed targeted therapy.

Real world data on adjuvant treatment of older HER2-positive breast cancer patients - A single institution experience through 8 years

BACKGROUND

The large randomized trials on trastuzumab for primary breast cancer (BC) included few old patients. With exception of endocrine treatment, trials on adjuvant therapy for the old group specifically are scarce.

AIMS

To compare adjuvant treatment, recurrences and survival in old and older-old patients with primary HER2 positive BC.

MATERIAL AND METHODS

Patients ≥ 70 years with diagnose of primary HER2 positive BC from 2008 through 2015 were included in this retrospective non-randomized investigation. Standard clinical and biological data (age, surgery, tumor size, nodal status, histopathological grade, vascular invasion, expression of hormone receptors, recurrences and death) were extracted from patient's charts. Comparisons were performed according to age (old; 70-74 years vs older old; ≥ 75 years) and treatment with trastuzumab or not. Patients that initiated adjuvant trastuzumab but did not complete one year (n = 8) were included in the trastuzumab group in survival analyzes. Recurrence-free survival (RFS) and overall survival (OS) were calculated in uni- and multivariate analyses.

RESULTS

A total of 115 patients were registered, eleven patients had distant metastasis and seven were omitted from all treatment including primary surgery due to serious concomitant illness and a poor general condition leaving 97 patients for analysis. There were no differences between the groups (70-74; n = 40), (≥75; n = 57) in tumor size (p = 0.86), nodal status (p = 0.10), ER (p = 0.25), PgR (p = 1.0) or vascular invasion (p = 1.0). A lower proportion of patients ≥ 75 years received adjuvant trastuzumab (21% versus 70%, p < 0.001). Adjuvant trastuzumab improved RFS (p = 0.027) and OS (p = 0.002) in univariate analyses. The corresponding figures in multivariate analysis adjusted for tumor size, nodal status and grade were RFS (p = 0.0052) and OS (p = 0.0003) respectively. Brain was the most common site of distant metastasis (15% of patients at first recurrence).

CONCLUSIONS

We show a large difference in delivered adjuvant treatment between old and older old patients with a small proportion of patients aged 75 years or more receiving HER2 directed therapy that resulted in a worse survival. The vast majority can complete the planned treatment. Our results indicate that brain metastases is common also among older patients.

Development of next-generation tumor-homing induced neural stem cells to enhance treatment of metastatic cancers

Engineered tumor-homing neural stem cells (NSCs) have shown promise in treating cancer. Recently, we transdifferentiated skin fibroblasts into human-induced NSCs (hiNSC) as personalized NSC drug carriers. Here, using a SOX2 and spheroidal culture-based reprogramming strategy, we generated a new hiNSC variant, hiNeuroS, that was genetically distinct from fibroblasts and first-generation hiNSCs and had significantly enhanced tumor-homing and antitumor properties. In vitro, hiNeuroSs demonstrated superior migration to human triple-negative breast cancer (TNBC) cells and in vivo rapidly homed to TNBC tumor foci following intracerebroventricular (ICV) infusion. In TNBC parenchymal metastasis models, ICV infusion of hiNeuroSs secreting the proapoptotic agent TRAIL (hiNeuroS-TRAIL) significantly reduced tumor burden and extended median survival. In models of TNBC leptomeningeal carcinomatosis, ICV dosing of hiNeuroS-TRAIL therapy significantly delayed the onset of tumor formation and extended survival when administered as a prophylactic treatment, as well as reduced tumor volume while prolonging survival when delivered as established tumor therapy.

HER2 Receptor Conversion Is a strong Survival Predictor in Patients with Breast Cancer Brain Metastases

BACKGROUND

Hormone and human epidermal growth factor receptor 2 (HER2/neu) receptor status is prognostic and predictive in breast cancer (BC) and guides the choice of therapy. However, owing to receptor conversion, the receptor status can differ in metastases compared with that of the primary tumor. The aim of the present study was to analyze the prognostic value of receptor status, receptor conversion, and clinical parameters in patients with resected BC brain metastases (BMs).

METHODS

Patients with BCBMs treated at our institution from July 2007 to December 2019 were eligible for the present study. The receptor status of the BC and corresponding BMs and the occurrence of receptor conversion were separately recorded for 3 common receptors: HER2/neu, estrogen receptor, and progesterone receptor. The association between the receptor status or receptor conversion and clinical parameters was adjusted for outcome-relevant patient and tumor characteristics.

RESULTS

The final analysis included 78 patients. HER2/neu receptor status in BMs was associated with overall survival (P = 0.033). Receptor conversion was identified in 39 patients (50.0%): HER2/neu, n = 9 (11.5%); estrogen receptor, n = 22 (28.2%); and progesterone receptor, n = 25 (32.1%). In the final multivariate Cox regression analysis, HER2/neu receptor conversion (adjusted hazard ratio [aHR], 3.58; P = 0.006), Karnofsky performance status score <70% (aHR, 3.11; P = 0.048), infratentorial BM location (aHR, 2.49; P = 0.007), and age ≥55 years at BM diagnosis (aHR, 2.20; P = 0.046) were independently associated with poorer survival.

CONCLUSIONS

Of the 3 common BC receptors, only HER2/neu receptor conversion was strongly associated with the prognosis of patients with surgically treated BCBMs. The clinical relevance of the reevaluation of receptor status in BMs favors surgical treatment of patients with noneloquent BCBMs.

Economic burden of central nervous system metastases in human epidermal growth factor receptor 2-positive breast cancer

Aim: Compare healthcare resource utilization and costs among patients with HER2+ metastatic breast cancer (MBC) with and without central nervous system (CNS) metastases. Methods: Retrospective matched cohort study using IQVIA's PharMetrics^® Plus claims database. Results: Patients with CNS metastases (n = 753) experienced more outpatient, emergency room and inpatient visits versus controls (n = 753; all p < 0.05). In the post-index year, median total all-cause healthcare costs were significantly higher among patients with CNS metastases versus controls ($112,402 vs $50,835; p < 0.0001); outpatient costs primarily drove the cost differential. Conclusion: More effective therapies are needed that improve clinical outcomes and reduce economic burden associated with CNS metastases in patients with HER2+ MBC.

Multifunctional Liposomes Enable Active Targeting and Twinfilin 1 Silencing to Reverse Paclitaxel Resistance in Brain Metastatic Breast Cancer

Paclitaxel (PTX) is a first-line chemotherapeutic drug for breast cancer, but PTX resistance often occurs in metastatic breast cancer. In addition, due to the poor targeting of chemotherapeutic drugs and the presence of the blood-brain barrier (BBB), it is hard to effectively treat brain metastatic breast cancer using paclitaxel. Thus, it is urgent to develop an effective drug delivery system for the treatment of brain metastatic breast cancer. The current study found that TWF1 gene, an epithelial-mesenchymal transition-associated gene, was overexpressed in brain metastatic breast cancer (231-BR) cells and was associated with the PTX resistance of 231-BR cells. Knockdown of TWF1 by small interference RNA (siRNA) in 231-BR cells could effectively increase the sensitivity of brain metastatic breast cancer cells to paclitaxel. Then, a liposome-based drug delivery system was developed for PTX delivery across BBB, enhancing PTX sensitivity and brain metastases targeting via BRBP1 peptide modification. The results showed that BRBP1-modified liposomes could effectively cross the BBB, specifically accumulate in brain metastases, and effectively interfere TWF1 gene expression in vitro and in vivo, and thus they enhanced proliferation inhibition, cell cycle arrest, and apoptosis induction, thereby inhibiting the formation and growth of brain metastases. In summary, our results indicated that BRBP1-modified and PTX- and TWF1 siRNA-loaded liposomes have the potential for the treatment of brain metastatic breast cancer, which lays the foundation for the development of a new targeted drug delivery system.

Perspectives on the Systemic Staging in Newly Diagnosed Breast Cancer

Breast cancer is a complex disease, and accurate systemic staging is an essential aspect of the evaluation of a patient with newly diagnosed breast cancer. Considering that the chance of having metastatic disease at breast cancer diagnosis is different in each patient and depends on a variety of anatomic and biologic factors, it is crucial to understand that some populations may benefit from more intensive staging because their pretest probability of metastatic disease is higher than that of the average patient. Identifying these patients with de novo stage IV breast cancer is associated with substantial prognostic and therapeutic implications. Unfortunately, recent advances in understanding breast cancer heterogeneity and molecular biology have not been incorporated in the international guidelines and recommendations about imaging examinations for detecting de novo metastatic breast cancer. This review article discusses important issues regarding the rationale for performing systemic staging, addresses current and innovative imaging methods, and proposes an algorithm for systemic staging in patients with newly diagnosed breast cancer.

Leptomeningeal Metastasis in ER + HER2- Advanced Breast Cancer Patients: A Review of the Cases in a Single Institute Over a 15-year Period

PURPOSE

While leptomeningeal metastasis (LM) from estrogen receptor-positive, HER2-negative advanced breast cancer (ER + HER2-ABC) has a poor prognosis, the details of ER + HER2-LM are unclear. We therefore retrospectively investigated patients with LM from ER + HER2-ABC.

METHODS

ER + HER2-ABC patients who received any therapy at Shizuoka Cancer Center between October 2002 and December 2017 were retrospectively analyzed. Patients with central nervous system (CNS) metastases were divided into three groups: brain metastasis (BM) only (B group); BM with LM (BL group); and LM only (L group).

RESULTS

Among 369 patients, 102 developed CNS metastases: 70 (68.6%), 13 (12.8%), and 19 (18.6%) in the B, BL, and L groups, respectively. The L group showed a later onset, poorer performance status, more symptoms, and more skull metastasis than the other groups. Radiotherapy as the initial treatment was introduced to 13/13 (100%) and 15/19 (78.9%) in the BL and L groups, respectively. Subsequent systemic therapy excluding best supportive care was introduced to 5/13 (38.5%) and 5/19 (26.3%) in the BL and L groups, respectively. The median overall survival from the diagnosis of CNS lesions was 295.0, 146.0, and 99.0 days in the B, BL, and L groups, respectively, and worsening of CNS lesions was the major cause of death in the BL and L groups. Multivariate analyses showed that concurrent soft tissue metastasis (hazard ratio, 4.620) and subsequent systemic therapy (hazard ratio, 0.063) were prognostic for the L group.

CONCLUSION

Management of LM from ER + HER2-ABC remains challenging, so a multimodal approach with novel systemic therapy is warranted.

The Influence of Cold Atmospheric Pressure Plasma-Treated Media on the Cell Viability, Motility, and Induction of Apoptosis in Human Non-Metastatic (MCF7) and Metastatic (MDA-MB-231) Breast Cancer Cell Lines

Breast cancer remains the most common type of cancer, occurring in middle-aged women, and often leads to patients’ death. In this work, we applied a cold atmospheric pressure plasma (CAPP)-based reaction-discharge system, one that is unique in its class, for the production of CAPP-activated media (DMEM and Opti-MEM); it is intended for further uses in breast cancer treatment. To reach this aim, different volumes of DMEM or Opti-MEM were treated by CAPP. Prepared media were exposed to the CAPP treatment at seven different time intervals and examined in respect of their impact on cell viability and motility, and the induction of the apoptosis in human non-metastatic (MCF7) and metastatic (MDA-MB-231) breast cancer cell lines. As a control, the influence of CAPP-activated media on the viability and motility, and the type of the cell death of the non-cancerous human normal MCF10A cell line, was estimated. Additionally, qualitative and quantitative analyses of the reactive oxygen and nitrogen species (RONS), generated during the CAPP operation in contact with analyzed media, were performed. Based on the conducted research, it was found that 180 s (media activation time by CAPP) should be considered as the minimal toxic dose, which significantly decreases the cell viability and the migration of MDA-MB-231 cells, and also disturbs life processes of MCF7 cells. Finally, CAPP-activated media led to the apoptosis of analyzed cell lines, especially of the metastatic MDA-MB-231 cell line. Therefore, the application of the CAPP system may be potentially applied as a therapeutic strategy for the management of highly metastatic human breast cancer.

Prognosis of patients treated in a single neurosurgical reference centre for brain metastasis caused by dormant disseminated cells

Brain metastasis (BM) is a frequent complication of systemic cancer usually associated with poor prognosis. Survival depends on numerous factors, which complicates prognosis and treatment. It has been suggested that BM growing from previously dormant disseminated tumour cells (DTCs) may exhibit a milder phenotype than BM derived from continuously progressing metastatic cells; however, to the best of our knowledge, the prognosis of patients presenting with BM from dormant DTCs is unknown. The present study retrospectively compared survival data, collected from a single neurosurgical centre, between patients presenting with BM from previously dormant DTCs and patients with non-dormant BM. A total of 262 medical records were reviewed. In the univariate Cox regression analysis, the median survival of the dormant BM group was statistically longer than that of the non-dormant group (P=0.048); a trend towards a longer survival persisted after correcting for age, presence of breast cancer and treatment options (P=0.057), which are all factors known to influence outcome. The improved outcome of these patients could be considered in models for prognostication. Moreover, the development of therapies able to eradicate dormant DTCs could provide a new promising strategy to prolong the survival of patients with a favourable prognosis.

Development of new brain metastases in triple negative breast cancer

BACKGROUND

Brain metastases are common in patients with breast cancer, and those with triple negative status have an even higher risk. Triple negative status is currently not considered when managing brain metastases.

OBJECTIVE

To determine whether triple negative breast cancer (TNBC) patients with brain metastases have a higher burden of intracranial disease and whether WBRT has a survival benefit in this cohort of patients.

METHODS

We conducted a retrospective cohort study with 85 patients meeting the inclusion criteria.

RESULTS

25% of patients had TNBC. 95% of the patients in this study received SRS and 48% received WBRT. The average number of new brain metastases from time of initial brain imaging to radiation therapy was 0.67 ± 1.1 in the non-TNBC status patients and 2.6 ± 3.7 in the triple negative status patients (p = 0.001). A cox proportional hazards model showed that WBRT does not significantly affect overall survival in patients with TNBC (HR 1.48; 95% CI 0.47-4.67; p = 0.50).

CONCLUSION

Our findings highlight the highly aggressive intracranial nature of TNBC. The rate of new brain metastasis formation is higher in TNBC patients compared to non-TNBC patients. Furthermore, there is no survival benefit for WBRT in TNBC patients. These findings are relevant for clinicians planning brain radiation for TNBC patients as they may find more brain metastases at the time of brain radiation than they anticipated based on initial brain imaging.

Breast cancer subtype predicts clinical outcomes after stereotactic radiation for brain metastases

PURPOSE

We investigated the prognostic ability of tumor subtype for patients with breast cancer brain metastases (BCBM) treated with stereotactic radiation (SRT).

METHODS

This is a retrospective review of 181 patients who underwent SRT to 664 BCBM from 2004 to 2019. Patients were stratified by subtype: hormone receptor (HR)-positive, HER2-negative (HR+/HER2-), HR-positive, HER2-positive (HR+/HER2+), HR-negative, HER2-positive (HR-/HER2+), and triple negative (TN). The Kaplan-Meier method was used to calculate overall survival (OS), local control (LC), and distant intracranial control (DIC) from the date of SRT. Multivariate analysis (MVA) was conducted using the Cox proportional hazards model.

RESULTS

Median follow up from SRT was 11.4 months. Of the 181 patients, 47 (26%) were HR+/HER2+, 30 (17%) were HR-/HER2+, 60 (33%) were HR+/HER2-, and 44 (24%) were TN. Of the 664 BCBMs, 534 (80%) received single fraction stereotactic radiosurgery (SRS) with a median dose of 21 Gy (range 12-24 Gy), and 130 (20%) received fractionated stereotactic radiation therapy (FSRT), with a median dose of 25 Gy (range 12.5-35 Gy) delivered in 3 to 5 fractions. One-year LC was 90%. Two-year DIC was 35%, 23%, 27%, and 16% (log rank, p = 0.0003) and 2-year OS was 54%, 47%, 24%, and 12% (log rank, p < 0.0001) for HR+/HER2+, HR-/HER2+, HR+/HER2-, and TN subtypes, respectively. On MVA, the TN subtype predicted for inferior DIC (HR 1.62, 95% CI 1.00-2.60, p = 0.049). The modified breast-Graded Prognostic Assessment (GPA) significantly predicted DIC and OS (both p < 0.001).

CONCLUSIONS

Subtype is prognostic for OS and DIC for patients with BCBM treated with SRT.

Inhibition of the Growth of Breast Cancer-Associated Brain Tumors by the Osteocyte-Derived Conditioned Medium

The brain is a common site of metastasis from advanced breast cancer but few effective treatments are available. We examined a therapeutic option with a conditioned medium (CM), focusing on the role of Lrp5 and β-catenin in Wnt signaling, and IL1ra in osteocytes. Osteocytes presented the innate anti-tumor effect and the overexpression of the above genes strengthened their action. In a mouse model, the injection of their CM inhibited mammary tumors and tumor-driven osteolysis. Importantly, Lrp5- and/or IL1ra-overexpressing osteocytes or the local administration of β-catenin-overexpressing CM markedly inhibited brain tumors. In the transport analysis, tumor-suppressing factors in CM were shown to diffuse through the skull. Mechanistically, the CM with overexpression of the above genes downregulated oncogenic genes such as MMP9, Runx2, TGFβ, and Snail in breast cancer cells. Also, the CM with β-catenin overexpression downregulated CXCL1 and CXCL5 and upregulated tumor suppressors such as LIMA1, DSP, p53, and TRAIL in breast cancer cells. Notably, whole-genome proteomics revealed that histone H4 was enriched in CM and acted as an atypical tumor suppressor. Lrp5-overexpressing MSCs were also shown to act as anti-tumor agents. Collectively, this study demonstrated the therapeutic role of engineered CM in brain tumors and the tumor-suppressing action of extracellular histone H4. The result sheds light on the potential CM-based therapy for breast cancer-associated brain metastases in a minimally invasive manner.

Use of radiotherapy in breast cancer patients with brain metastases: a retrospective 11-year single center study

AIM

To analyse the use of radiotherapy (RT) and factors affecting overall survival (OS) after RT in breast cancer patients with brain metastases.

METHODS

Breast cancer patients treated from 2008 to 2018 with whole brain RT (WBRT) or stereotactic radiosurgery (SRS) at a large regional cancer referral center were identified from the hospital's RT register. Clinical variables were extracted from medical records. OS was calculated from date of first RT until death or last follow up. Potential factors affecting OS were analyzed.

RESULTS

255 females with WBRT (n = 206) or SRS (n = 49) as first RT were included. An increased use of initial SRS was observed in the second half of the study period. The most common WBRT fractionation regimen was 3 Gy × 10. SRS was most often single fractions; 18 or 25 Gy between 2009 and 2016, while fractionated SRS was mostly used in 2017 and 2018. Median OS in the WBRT group was 6 months (CI 1-73) relative to 23 (CI 0-78) in the SRS group. Age, performance status, initial RT technique, extracranial disease, brain metastasis surgery, number of brain metastases and DS-GPA score had significant impact on OS. Only ECOG 0 and brain metastasis surgery were associated with superior OS in multivariate analysis.

CONCLUSION

WBRT was the most frequent primary RT. An increased use of initial SRS was observed in the second half of the study period. Only ECOG 0 and brain metastasis surgery were associated with superior OS in multivariate analysis.

Relapsed breast cancer complicated by isolated brain metastasis

The most common etiology of malignant brain tumors is metastatic lesions. They usually present as multiple lesions at the gray-white matter junction. However, they can unconventionally present as a single space-occupying lesion mimicking meningioma.

Exploratory Analysis of Qualitative MR Imaging Features for the Differentiation of Glioblastoma and Brain Metastases

OBJECTIVES

To identify qualitative VASARI (Visually AcceSIble Rembrandt Images) Magnetic Resonance (MR) Imaging features for differentiation of glioblastoma (GBM) and brain metastasis (BM) of different primary tumors.

MATERIALS AND METHODS

T1-weighted pre- and post-contrast, T2-weighted, and T2-weighted, fluid attenuated inversion recovery (FLAIR) MR images of a total of 239 lesions from 109 patients with either GBM or BM (breast cancer, non-small cell (NSCLC) adenocarcinoma, NSCLC squamous cell carcinoma, small-cell lung cancer (SCLC)) were included. A set of adapted, qualitative VASARI MR features describing tumor appearance and location was scored (binary; 1 = presence of feature, 0 = absence of feature). Exploratory data analysis was performed on binary scores using a combination of descriptive statistics (proportions with 95% binomial confidence intervals), unsupervised methods and supervised methods including multivariate feature ranking using either repeated fitting or recursive feature elimination with Support Vector Machines (SVMs).

RESULTS

GBMs were found to involve all lobes of the cerebrum with a fronto-occipital gradient, often affected the corpus callosum (32.4%, 95% CI 19.1-49.2), and showed a strong preference for the right hemisphere (79.4%, 95% CI 63.2-89.7). BMs occurred most frequently in the frontal lobe (35.1%, 95% CI 28.9-41.9) and cerebellum (28.3%, 95% CI 22.6-34.8). The appearance of GBMs was characterized by preference for well-defined non-enhancing tumor margin (100%, 89.8-100), ependymal extension (52.9%, 36.7-68.5) and substantially less enhancing foci than BMs (44.1%, 28.9-60.6 vs. 75.1%, 68.8-80.5). Unsupervised and supervised analyses showed that GBMs are distinctively different from BMs and that this difference is driven by definition of non-enhancing tumor margin, ependymal extension and features describing laterality. Differentiation of histological subtypes of BMs was driven by the presence of well-defined enhancing and non-enhancing tumor margins and localization in the vision center. SVM models with optimal hyperparameters led to weighted F1-score of 0.865 for differentiation of GBMs from BMs and weighted F1-score of 0.326 for differentiation of BM subtypes.

CONCLUSION

VASARI MR imaging features related to definition of non-enhancing margin, ependymal extension, and tumor localization may serve as potential imaging biomarkers to differentiate GBMs from BMs.

Different Breast Cancer Subtypes Show Different Metastatic Patterns: A Study from A Large Public Database

BACKGROUND

Receptor status in breast cancer is known to be related to survival. However, the relationship between breast cancer subtype, preferential sites of metastasis, and overall survival is not clear.

METHODS

A total of 414,528 patients from the National Cancer Database (2010-2013) were examined. All patients received surgery and systemic treatments. Breast cancer was subtyped based on hormonal receptor (HR) and HER2 status.

RESULTS

HR-/HER2+ breast cancer patients had the highest overall rate of metastasis while HR+/HER2- had the lowest. HR+/HER2+ cancer had the most frequent metastasis to the bone, and HR-/HER2+ to brain, liver, lung and multiple sites. Generally, patients with brain or multiple metastasis had the worst overall survival (OS) across different subtypes.  Patients with bone oligometastasis tend to have better OS than patients with metastasis to other site but significantly worse OS than patients without any metastasis.

CONCLUSIONS

This large study exhibits how breast cancer subtype plays a role in the rate and site of metastasis as well as in overall survival.  Surveillance and treatment strategies should be tailored on the risk and potential site of metastases based upon receptor subtype.

Treatment strategies for breast cancer brain metastases

Brain metastases from breast cancer (BCBM) constitute the second most common cause of brain metastasis (BM), and the incidence of these frequently lethal lesions is currently increasing, following better systemic treatment. Patients with ER-negative and HER2-positive metastatic breast cancer (BC) are the most likely to develop BM, but if this diagnosis remains associated with a worse prognosis, long survival is now common for patients with HER2-positive BC. BCBM represents a therapeutic challenge that needs a coordinated treatment strategy along international guidelines. Surgery has always to be considered when feasible. It is now well established that stereotaxic radiosurgery allows for equivalent control and less-cognitive toxicities than whole-brain radiation therapy, which should be delayed as much as possible. Medical treatment for BCBM is currently a rapidly evolving field. It has been shown that the blood-brain barrier (BBB) is often impaired in macroscopic BM, and several chemotherapy regimens, antibody-drug conjugates and tyrosine-kinase inhibitors have been shown to be active on BCBM and can be part of the global treatment strategy. This paper provides an overview of the therapeutic option for BCBM that is currently available and outlines potential new approaches for tackling these deadly secondary tumours.

Phase I study of liposomal irinotecan in patients with metastatic breast cancer: findings from the expansion phase

Purpose

Metastatic breast cancer (mBC) remains incurable and is associated with low survival rates. This study assessed the efficacy and safety of liposomal irinotecan in heavily pretreated patients with mBC, with or without active brain metastases (BM).

Methods

Following the dose escalation phase and determination of recommended phase 2 dose, the expansion phase of this phase I, open-label, non-randomized study, assigned adult women to cohorts based on mBC subtype: cohort 1, hormone receptor +/human epidermal growth factor receptor 2−; cohort 2, triple-negative breast cancer; or cohort 3, any mBC subtype with active BM. Patients received liposomal irinotecan 50 or 70 mg/m² free base every 2 weeks. Here, we report secondary outcomes including best overall response (BOR), objective response rate (ORR), and treatment-emergent adverse events (TEAEs).

Results

For non-central nervous system (non-CNS) disease across all cohorts (intent-to-treat population, N = 29), the ORR was 34.5% (95% confidence interval: 17.94–54.33), with a BOR of partial response in 10 patients (34.5%), stable disease in five (17.2%), progressive disease in 10 (34.5%); four patients were unevaluable (13.8%). The ORR for the CNS cohort was 30.0% (95% confidence interval: 6.67–65.25) using modified Response Evaluation Criteria in Solid Tumors. Common grade 3 or higher TEAEs were diarrhea (27.6%), nausea (17.2%), fatigue (13.8%), asthenia (10.3%), and hypokalemia (10.3%). Serious treatment-related TEAEs were reported in six patients (20.7%). No treatment-related TEAEs resulted in death.

Conclusions

Liposomal irinotecan monotherapy demonstrated antitumor activity in heavily pretreated patients with mBC, with or without BM. The observed safety profile was consistent with that in previous studies.

Clinical trial registration: Trial registration ID NCT01770353.

Electronic supplementary material

The online version of this article (10.1007/s10549-020-05995-7) contains supplementary material, which is available to authorized users.

Identification of the origin of brain metastases based on the relative methylation orderings of CpG sites

Accurate diagnosis of the origin of brain metastases (BMs) is crucial for tailoring an effective therapy to improve patients' prognosis. BMs of unknown origin account for approximately 2-14% of patients with BMs. Hence, the aim of this study was to identify the original cancer type of BMs based on their DNA methylation profiles. The DNA methylation profiles of glioma (GM), BM, and seven other types of primary cancers were collected. In comparison with GM, the reversal CpG site pairs were identified for each of the seven other types of primary cancers based on the within-sample relative methylation orderings (RMOs) of the CpG sites. Then, using the reversal CpG site pairs, GMs were distinguished from BMs and the seven other types of primary cancers. All 61 of the GM samples were correctly identified as GM. The cancer type was also identified for the non-GM samples. For the seven other types of primary cancers, greater than 93% of samples of each cancer type were correctly identified as their corresponding cancer type, except for breast cancer, which had an 88% accuracy. For 133 BM samples, 132 BM samples were identified as non-GM, and 95% of the 133 BM samples were correctly classified into their corresponding original cancer types. The RMO-based method can accurately identify the origin of BMs, which is important for precision treatment.

Breast Cancer Brain Metastasis: The Potential Role of MRI Beyond Current Clinical Applications

PURPOSE

Breast cancer brain metastasis (BCBM) represents a major clinical challenge. Can MRI help in advancements in the management of BCBM? This review discusses MRI developments and the corresponding potential advancements in BCBM management.

METHODS

An exhaustive literature search was undertaken to identify studies which look into the potential of MRI in BCBM management. Seven hundred and eighty-four studies published from September 1984 to May 2020 were identified. Three topics are covered where MRI is not clinically established yet: 1) the prognosis of BCBM; 2) the screening of BC patients for BCBM development, and 3) the assessment of imaging features correlated to BC subtype.

RESULTS

Thirty-six studies were considered eligible for the purposes of this review. On-going progress is made with the identification of different BCBM characteristics and MRI metrics that might be related to prognosis. Progress has been made with the identification of different BCBM characteristics, including BCBM location, degree of edema, white matter disruption, tumor edge sharpness, and temporal muscle thickness. A more accurate prediction of prognosis could lead to more suitable patient management and treatment. The use of MRI in BCBM screening of the high-risk breast cancer population remains a controversial subject. To date, there are no results from clinical trials; however, there is a rising number of relatively small studies that show concern on this subject and support BCBM screening. It is important to oncologists to be able to assess the tumor subtype non-invasively. MRI features, which have shown some correlation with subtype, include the number of tumors, location, and their distribution in the brain. Advanced tools and metrics have been produced to carry out radiological characteristics analysis on MRI images. Assessing MRI features in more detail could provide a more personalized management of patients.

CONCLUSION

Developments in the use of MRI have the potential to improve BCBM management.

Pre-Treatment Seizures in Patients With 1-3 Cerebral Metastases Receiving Local Therapies Plus Whole-brain Radiotherapy

BACKGROUND/AIM

Seizures impair patients' quality of life. The prognostic role of pre-treatment seizures in patients with 1-3 cerebral metastases receiving local therapies plus whole-brain radiotherapy (WBRT) was investigated.

PATIENTS AND METHODS

In 249 patients, prevalence, risk factors and associations of pre-treatment seizures with survival were retrospectively evaluated. Age, gender, performance score, tumor type, number of lesions, extra-cerebral metastases, and time from tumor diagnosis to treatment of cerebral metastasis were analyzed for associations with seizures. These characteristics and pre-treatment seizures were also analyzed for associations with survival.

RESULTS

The prevalence of pre-treatment seizures was 24.1%. Trends for associations were found between seizures and gender or performance score. On multivariate analysis, age (p=0.008), performance score (p=0.004), tumor type (p<0.001) and extra-cerebral metastasis (p<0.001) were significantly associated with survival.

CONCLUSION

Seizures were comparably common prior to local therapies plus WBRT for cerebral metastases. No factor was found to be significantly associated with seizures, and seizures were not associated with survival.

Pre-operative Seizures in Patients With Single Brain Metastasis Treated With Resection Plus Whole-Brain Irradiation and a Boost

BACKGROUND/AIM

Seizures can be the initial symptom of brain metastases. This study investigated pre-treatment seizures in patients with a single lesion.

PATIENTS AND METHODS

Pre-operative seizures were analyzed in 104 patients with a single brain metastasis receiving resection plus whole-brain irradiation and a boost. Prevalence of seizures, risk factors and associations with survival (OS) were evaluated.

RESULTS

Thirty patients (34.6%) had seizures prior to neurosurgery. Significant associations between seizures and investigated characteristics were not found. However, age ≤61 years showed a trend (p=0.117) for increased incidence of seizures. Time from diagnosis of malignancy until neurosurgery >12 months was significantly associated with improved OS on univariate analysis (p=0.003). Trends for a positive association with OS were found for no seizures (p=0.054), female gender (p=0.066) and breast cancer (p=0.098). On multivariate analysis, time until neurosurgery >12 months was independently associated (p=0.019) with better OS, and seizures showed a trend (p=0.119) for improved OS.

CONCLUSIONS

Considering the high prevalence of seizures in this cohort, regular screening and monitoring of these patients appears reasonable. This applies particularly to patients aged ≤61 years.

Genomic landscape of the immune microenvironments of brain metastases in breast cancer

Background

This study was intended to investigate the genomic landscape of the immune microenvironments of brain metastases in breast cancer.

Methods

Three gene expression profile datasets (GSE76714, GSE125989 and GSE43837) of breast cancer with brain metastases were downloaded from Gene Expression Omnibus (GEO) database. After differential expression analysis, the tumor immune microenvironment and immune cell infiltration were analyzed. Then immune-related genes were identified, followed by function analysis, transcription factor (TF)-miRNA–mRNA co-regulatory network analysis, and survival analysis of metastatic recurrence.

Results

The present results showed that the tumor immune microenvironment in brain metastases was immunosuppressed compared with primary caner. Compared with primary cancer samples, the infiltration ratio of plasma cells in brain metastases samples was significantly higher, while the infiltration ratio of macrophages M2 cells in brain metastases samples was significantly lower. Total 42 immune-related genes were identified, such as THY1 and NEU2. CD1B, THY1 and DOCK2 were found to be implicated in the metastatic recurrence of breast cancer.

Conclusions

Targeting macrophages or plasma cells may be new strategies for immunotherapy of breast cancer with brain metastases. THY1 and NEU2 may be potential therapeutic targets for breast cancer with brain metastases, and THY1, CD1B and DOCK2 may serve as potential prognostic markers for improvement of brain metastases survival.

Evaluating the natural growth rate of metastatic cancer to the brain

BACKGROUND

Brain metastases are becoming increasingly more prevalent as cancer patients survive longer with both improved local and systemic therapy. Little is known, however, of the natural growth rates of brain metastases. This investigation aims to ascertain this growth rate of these lesions before the initiation of any CNS- directed therapy.

METHODS

A total of 700 patients were screened, identifying 18 cancer patients (13 breast and 5 lung) with 29 brain metastases that were serially imaged from 2011 to 2017 before treatment for their intracranial metastases. Growth rates were measured by contouring lesions serially across at least two MRI studies in iPlan software by independent raters. These values were then compared between primary (breast and lung) cancer cohorts.

RESULTS

The mean age at diagnosis was 53 and 95% were female. The interval between primary cancer diagnosis and brain metastases was 4.6 years and 1.2 years in the breast and lung cancer groups, respectively. Of the breast and lung cancer patients, 23% and 40% were deceased, with respective 5.08 cm3 and 2.44 cm3 initial tumor volumes. The average growth rate of lung and breast tumors was 0.018 and 0.040 cm3/day, respectively, with deceased patients having larger and faster growing tumors. Breast and lung metastases grew 2.39% and 1.14% of their total volumes daily and doubling times were 86 and 139 days, respectively.

CONCLUSION

This investigation provides a unique perspective into the biological growth of metastatic brain lesions. It is our hope that this study guides timing of treatment and informs both clinicians and patients of tumor growth kinetics before initiating treatment for intracranial metastases.