Impact of breast cancer molecular subtypes on the incidence, kinetics and prognosis of central nervous system metastases in a large multicentre real-life cohort

Hormonal and neuronal interactions shaping the brain metastatic microenvironment

Metastatic progression drives the majority of cancer-related fatalities, and involvement of the central nervous system (CNS) poses especially formidable challenges to patients and clinicians. Brain metastases (BrM), commonly originate from lung, breast and melanoma cancers, and carry disproportionately poor outcomes. Although therapeutic advances have extended survival for many extracranial tumors, BrM incidence continues to climb-underscoring critical knowledge gaps in understanding the unique biology of tumor colonization in the CNS. While definitive evidence remains limited, a growing focus on cancer neuroscience-especially regarding hormone dependent cancer cells in the brain-has begun to reveal that factors normally regulated by sex steroids and neurosteroids may similarly influence the specialized metastatic microenvironment in the CNS. Steroid hormones can permeate the blood-brain barrier (BBB) or be synthesized de novo by astrocytes and other CNS-resident cells, potentially influencing processes such as inflammation, synaptic plasticity, and immune surveillance. However, how these hormonal pathways are co-opted by disseminated cancer cells remains unclear. Here, we review the complex hormonal landscape of the adult brain and examine how neuroendocrine-immune interactions, often regulated by sex hormones, may support metastatic growth. We discuss the interplay between systemic hormones, local steroidogenesis, and tumor adaptation to identify novel therapeutic opportunities.

Radiotherapy in breast cancer brain metastases: the impact of time interval and disease dynamics when breast cancer seeds to the brain

PURPOSE

The initial brain metastasis velocity (iBMV) is a prognostic metric introduced for patients receiving stereotactic radiosurgery (SRS) for brain metastases (BM), reflecting intracranial disease dynamics. This study aimed to assess the applicability of iBMV in a mixed cohort of breast cancer brain metastases (BCBM) patients treated with SRS/fractionated stereotactic radiotherapy (FSRT) and whole-brain radiotherapy (WBRT). Considering disease dynamics, we analyzed the role of biological subtypes in determining the time interval between initial diagnosis and the occurrence of BM.

METHODS

We conducted a retrospective, single center cohort study of 126 BCBM patients who received radiotherapy to the brain (SRS/FSRT and WBRT) between 01/2013 and 12/2020. Statistical endpoints included iBMV, time interval between initial diagnosis and the occurrence of BM analyzed per biological subtype, and overall survival (OS).

RESULTS

Median iBMV was 0.48 BM/year. The iBMV independently predicted for mortality in the multivariate model after accounting for WBRT (hazard ratio [HR] = 1.21; 95% confidence interval [CI] 1.04-1.41; p = 0.012). The biologic subtype significantly influenced the time interval between initial diagnosis of breast cancer and occurrence of BM. In a multivariate model, the Karnofsky performance status and HER2 status were strongest predictors of overall survival (HR = 2.60; 95% CI 1.60-4.22; p < 0.001 and HR = 2.26; 95% CI 1.34-3.84; p = 0.002, respectively).

CONCLUSION

iBMV correlates with overall survival, regardless of whether WBRT was used as part of local treatment. The biological subtype has a profound impact on prognosis and kinetics of BCBM.

Incidence of Metastasis in the Central Nervous System in Advanced Breast Cancer Treated With CDK 4/6 Inhibitors: A Multicenter, Retrospective Study

Central nervous system (CNS) metastasis remains a major cause of mortality in advanced breast cancer (ABC). While cyclin-dependent kinase 4/6 inhibitors (CDKIs) combined with endocrine therapy (ET) delay resistance in hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative ABC, their impact on CNS metastasis development has not been fully elucidated. This retrospective study analyzed 435 ABC patients without baseline CNS metastases who received first-line ET with or without CDKIs across three Chinese hospitals (August 2018-July 2022). Primary end points included CNS as the first metastatic site, CNS metastasis-free survival (CNSM-FS), and CNS metastasis incidence over time. Secondary end points were progression-free survival (PFS) and overall survival (OS). The results indicated that the addition of CDKIs to ET significantly reduced the incidence of CNS as the first site of metastasis (3.7% vs. 9.5% with ET alone; p = 0.0015) and extended CNSM-FS (71.6 months vs. 63.6 months, respectively; hazard ratio [HR], 0.53; 95% CI, 0.31-0.92). Overall, CNS metastasis incidence was lower with ET + CDKIs (7.9% vs. 15.5%, p = 0.014), and improvements were observed in both PFS and OS. These findings suggest that ET + CDKIs as first-line therapy in ABC may reduce CNS metastasis risk and extend CNSM-FS, offering a potential strategy for preventing CNS metastases.

Navigating antibody‒drug conjugates (ADCs): from metastatic to early breast cancer treatment strategies

We are currently living in the era of precision medicine, and antibody‒drug conjugates (ADCs) represent promising advancements in targeted cancer therapy. While several ADCs have been investigated over the years, only three have gained FDA approval for breast cancer (BC): ado-trastuzumab emtansine (T-DM1/Kadcyla), trastuzumab deruxtecan (T-DXd/Enhertu), and sacituzumab govitecan (SG/Trodelvy). This review focuses on the three approved ADCs for BC, reviewing the trials that led to their approval and detailing the ongoing trials testing their clinical efficacy and safety profiles. We examine ongoing trials targeting both metastatic and early-stage patients. Notably, we explore trials incorporating investigational ADCs into early management strategies, addressing the unique challenges of biomarker identification, target toxicity, and cost-effectiveness. By summarizing the current landscape of FDA-approved and investigational ADCs, this study highlights the evolving nature of BC treatment. Preliminary findings from ongoing trials suggest that early integration of ADCs can lead to significant improvements in disease-free survival, reinforcing their role in personalized medicine. As research advances, ADCs are likely to become a cornerstone of breast cancer treatment, providing new hope for better patient outcomes.

Breast Cancer Brain Metastases: A Neurosurgical Point of View From a Single-Center Experience

BACKGROUND

Brain metastases represent an important factor in breast cancer morbidity and mortality. Although various therapeutic options improved these patients' outcomes, the incidence of this disease is still rising. Several molecular subtypes of breast cancer have been studied, and human epidermal growth factor receptor 2 (HER2) positive and triple-negative breast cancer (TNBC) are more frequently associated with brain metastases. Therefore, anti-HER2 agents have been developed and studied, and they have shown promising results. Nevertheless, in patients with breast cancer brain metastases and acute neurological aggravation, neurosurgery is the primary option and the only one that can immediately reverse the symptoms. In the long run, a multimodal approach involving neurosurgical intervention can positively impact the prognosis.

MATERIAL AND METHODS

Patients with a confirmed diagnosis of brain metastases from breast cancer (BMBC) between January 2013 and December 2023 were retrospectively reviewed. All patients were newly diagnosed and treated in the 3rd Neurosurgical Department at the Clinical Emergency Hospital, "Bagdasar-Arseni" in Bucharest, Romania. Statistical analyses were carried out and interpreted accordingly.

RESULTS

The study analyzed 62 patients with BMBC. The median age at diagnosis was 57.19 years, and the most frequently encountered symptoms were represented by headaches, raised intracranial pressure syndrome, and motor deficits. More than 80% of the patients had a Karnofsky Performance Status (KPS) between 80 and 100, and the most associated comorbidities were cardiovascular and type 2 diabetes mellitus. A total of 88.70% of the patients had a single brain metastasis, and the most common localizations were the posterior fossa/cerebellum and frontal lobe. Gross-total resection was possible in 79.03% of the cases, while complications were recorded in 8.06%. Better survival rates were registered in patients of younger ages, with higher KPS, single BM, and smaller tumoral volumes, treated by gross-total resection and by a multimodal approach.

CONCLUSIONS

Notwithstanding significant advancements in the field of breast cancer, the prognosis of patients with brain metastases remains poor. However, a multimodal approach can prolong survival rates and improve outcomes, while in patients with acute clinical manifestations, neurosurgery remains the only immediate option to reverse the symptoms.

Unusual presentation of luminal breast carcinoma metastatic to the brain and coma: a case report of dramatic response to abemaciclib and literature review

Patients with luminal breast cancer (BC) may develop central nervous system metastases in 20%-40% of cases. Radiation or surgical therapy represents the cornerstone of treating central nervous system metastases. Meanwhile, the best practice for metastatic luminal BC involves using cyclin-dependent kinase 4/6 inhibitors combined with endocrine therapy. To our knowledge, this is the first case to report a dramatic response of breast metastases to abemaciclib plus endocrine therapy without radiation therapy, particularly in a patient who presented with seizures and sudden coma. She received brain surgery to control a large bleeding metastasis. Abemaciclib was crushed and diluted in water for administration via the nasogastric tube, while an upfront fulvestrant was given since aromatase inhibitors cannot be diluted. Beyond the radiological response, the clinical improvement was notable, with complete symptom recovery to the point where she is again working. Our paper supports the activity of abemaciclib in brain metastases from luminal BC and includes a review of the medical literature. Further investigation is warranted in this clinical setting.

Investigation of Prevalence, Survival, and Molecular Type of Breast Cancer Patients with Brain Metastases

Background

This study aims to investigate the factors associated with breast cancer brain metastasis (BCBM) in individuals suffering from breast cancer (BC).

Materials and Methods

This cross-sectional study conducted on 200 patients with metastatic breast cancer (MBC) including 52 brain and 148 other organ metastases. The demographic, medical, clinical, laboratory, and therapeutic approach characteristics were compared between the groups.

Results

Headache (61.5%), weakness and lethargy (26.9%), dizziness (15.4%), blurred vision/blindness (15.4%), and convulsions (15.4%) were the major initial symptoms of BCBM. Radiotherapy (71.2%), injectable (34.6%), and oral chemotherapy (26.9%) were the major applied therapeutic strategies to manage brain metastasis (BM). The overall survival of the patients from cancer diagnosis to death accounted for 33 months (95%CI: 27.52-38.47), while this period after BM diagnosis was limited to 6 months (95%CI: 5.15-6.84). The rate of hormone therapy was remarkably higher among the metastasis in other organs than the brain (P value = 0.005), while targeted therapy was performed in higher rates for BM (P value = 0.001). The evaluation of BC-related tumor markers revealed that human epidermal growth factor 2 (HER2) (P value < 0.001) positivity was remarkably higher among BCBM, while positive estrogen receptor (ER) (P value = 0.004) and progesterone receptor (PR) (P value = 0.013) were statistically more in the other group.

Conclusion

Based on the findings of this study, the BC patients with BM had a remarkable short survival, had a higher rate of perineural invasion, and were mostly positive for HER2. Radiotherapy, chemotherapy, and surgery were the most common approaches to these patients.

Temporal Dynamics and Clinical Predictors of Brain Metastasis in Breast Cancer: A Two-Decade Cohort Analysis Toward Tailored CNS Screening

BACKGROUND/OBJECTIVES

Breast cancer is the most common malignancy in women and the second leading cause of cancer-related deaths globally. It is also the second most frequent source of brain metastases (BMs), contributing to 5-20% of cases. Despite this, routine brain imaging for screening is not recommended and is only conducted when clinical symptoms or physical findings suggest metastasis. This study aims to identify clinical predictors associated with overall survival (OS) and the timing of BM development in breast cancer patients.

METHODS

We performed a retrospective review of medical records for 113 patients diagnosed with BMs secondary to breast cancer at our institution between 2000 and 2020. Baseline demographic data and clinical characteristics related to BMs were collected. To identify factors associated with OS and time to BM development after breast cancer diagnosis, we conducted univariate analysis using Kaplan-Meier curves, bivariate analysis with the log-rank test, and multivariate analysis via the Cox Proportional Hazard model.

RESULTS

An early diagnosis of BMs was identified as a significant predictor of prolonged OS (aHR = 0.22; 95% CI: 0.049-0.98, p = 0.05). Post-menopausal status at breast cancer diagnosis (aHR = 1.69; 95% CI: 1.13-2.53, p = 0.01), Asian ethnicity (aHR = 2.30; 95% CI: 1.03-5.16, p = 0.04), and the ER+/HER2+ subtype (aHR = 2.06; 95% CI: 1.14-3.71, p = 0.02) were significantly associated with a shorter time to BM diagnosis. A subgroup analysis of patients with ER+ breast tumors revealed that Hispanic or Arabic ethnicity (aHR = 3.63; 95% CI: 1.34-9.81, p = 0.01) and stage IV diagnosis (aHR = 2.09; 95% CI: 1.16-3.76, p = 0.01) were significantly associated with shorter intervals to BM diagnosis.

CONCLUSIONS

Breast cancer remains a significant global health burden for women, yet clear guidelines for routine BMs screening are still lacking. Early detection of BMs has been shown to notably improve long-term survival outcomes. Additionally, post-menopausal status, Hispanic or Arabic ethnicity, and the HER2+ tumor subtype are associated with shorter time to BM development, highlighting these factors as potential indicators for central nervous system screening.

Real-World outcomes with sacituzumab govitecan among breast cancer patients with central nervous system metastases

Central nervous system (CNS) metastases are associated with poor prognosis in patients with metastatic breast cancer (MBC). In this retrospective study, we investigated the activity of sacituzumab govitecan (SG) in 33 patients with HER2-negative MBC and CNS metastases, including active, stable/treated, and leptomeningeal disease (LMD). SG demonstrated a modest CNS objective response rate of 4/30 (13%) and median CNS-progression-free survival of 2.9 months (95%CI:2.0-4.3) in a heavily pretreated population.

Local Therapy for Isolated Central Nervous System Progression Among Patients Receiving Antibody-Drug Conjugate Therapy

Purpose

Antibody drug conjugates (ADCs) are an increasingly important class of therapeutics among patients with breast, lung, urothelial, and other malignancies. Guidelines recommend local therapy and continuation of current systemic therapy among patients with isolated brain relapse. We describe the clinical outcomes of this approach among patients receiving ADCs.

Methods and Materials

We queried our institutional database for patients receiving radiation therapy (RT) in the setting of isolated brain progression on ADCs with a plan to continue same-line therapy after radiation. Patients with ≤3 brain metastases at the time of recurrence were categorized as oligoprogressive. Study endpoints included overall survival, progression-free survival (PFS), and the cumulative incidence of next therapy from the start of local therapy.

Results

We identified 17 patients receiving ADC therapy with isolated brain progression treated with radiation (stereotactic radiosurgery [SRS]: n = 13, whole brain radiation: n = 4). All patients received concurrent ADC and RT. The median follow-up from local therapy was 29.5 months (95% CI, 21.4-not reached). The median overall survival was 19 months (95% CI, 16-not reached), and the median PFS was 8.1 months (range, 6.7-19 months). One lesion treated with SRS had local failure 21 months after treatment, and the 24-month cumulative incidence of local failure across the entire cohort was 1.6% (95% CI, 0.13%-7.7%). The 6-month cumulative incidence of radiation necrosis was 12% (95% CI, 1.8%-32%). The cumulative incidence of next therapy at 6 and 12 months was 47% (95% CI, 22%-69%) and 71% (95% CI, 41%-87%), respectively, and was significantly lower among patients with oligoprogressive brain recurrence. After SRS, 2 patients were without evidence of disease, discontinued systemic therapy, and were stable on observation at last follow-up.

Conclusions

To the best of our knowledge, this is the first clinical report of outcomes using the guideline-recommended approach of local therapy for isolated brain relapse among patients receiving ADCs. Local therapy may delay the need for next line systemic therapy, particularly among patients with oligoprogressive brain relapse.

The epigenetic landscape of brain metastasis

Brain metastasis represents a significant challenge in oncology, driven by complex molecular and epigenetic mechanisms that distinguish it from primary tumors. While recent research has focused on identifying genomic mutation drivers with potential clinical utility, these strategies have not pinpointed specific genetic mutations responsible for site-specific metastasis to the brain. It is now clear that successful brain colonization by metastatic cancer cells requires intricate interactions with the brain tumor ecosystem and the acquisition of specialized molecular traits that facilitate their adaptation to this highly selective environment. This is best exemplified by widespread transcriptional adaptation during brain metastasis, resulting in aberrant gene programs that promote extravasation, seeding, and colonization of the brain. Increasing evidence suggests that epigenetic mechanisms play a significant role in shaping these pro-brain metastasis traits. This review explores dysregulated chromatin patterns driven by chromatin remodeling, histone modifications, DNA/RNA methylation, and other epigenetic regulators that underpin brain metastatic seeding, initiation, and outgrowth. We provide novel insights into how these epigenetic modifications arise within both the brain metastatic tumor and the surrounding brain metastatic tumor ecosystem. Finally, we discuss how the inherent plasticity and reversibility of the epigenomic landscape in brain metastases may offer new therapeutic opportunities.

Temporal evolution of breast cancer brain metastases treatments and outcomes

Brain metastases (BMs) are a common complication of advanced breast cancer (BC), and their management has significantly evolved. We evaluated the clinical impact of these changes dividing patients diagnosed with BCBMs at three Institutions according to year of BMs diagnosis: 2000-2007 (group A), 2008-2014 (group B) and 2015-2022 (group C). Stereotactic radiotherapy increased (p < 0.001), and WBRT decreased (p = 0.010) over time. Among HER2+ BC patients, more received anti-HER2 therapy after BM diagnosis in recent years (p < 0.011). Overall survival (OS) did not improve in the entire cohort (p = 0.260); however, OS improved in patients with HR-/HER2+ BC (median OS 8.7, 10.1, 23.7 months in group A, B, C, respectively; p = 0.002). HER2-positivity, not prognostic in group A, became prognostic in group C (p < 0.001). While therapy for patients with BCBMs significantly changed over two decades, an OS improvement was observed only in HR-/HER2+ patients, potentially due to increased availability of anti-HER2 therapies with intracranial activity.

NOX4 modulates breast cancer progression through cancer cell metabolic reprogramming and CD8+ T cell antitumor activity

Introduction

Breast cancer is the most frequently diagnosed malignancy and a leading cause of cancer-related mortality among women worldwide. Although NADPH oxidase 4 (NOX4) has been implicated in various oncogenic processes, its exact function in breast cancer progression, metabolic reprogramming, and immune modulation remains unclear.

Methods

We used murine 4T1 and EO771 breast cancer models to generate NOX4 knockout (KO) cell lines via CRISPR/Cas9. In vitro assays (cell proliferation, colony formation, wound healing, and Seahorse metabolic analyses) and in vivo orthotopic tumor studies assessed the impact of NOX4 loss. Transcriptomic changes were identified through RNA sequencing and gene set enrichment analysis. We performed MYC knockdown in NOX4 KO cells to investigate its mechanistic role. Flow cytometry characterized tumor-infiltrating immune cells. Finally, NOX4-overexpressing cells were tested for survival benefit and response to dual-checkpoint immunotherapy (anti-PD-1/anti-CTLA-4).

Results

NOX4 deletion accelerated tumor growth in vivo and enhanced proliferation, colony formation, and migratory capacity in vitro. Metabolic profiling showed that NOX4 KO cells had elevated glycolysis and fatty acid oxidation, along with increased mitochondrial mass. Transcriptomic and enrichment analyses revealed MYC pathway activation in NOX4 KO cells; suppressing MYC reversed these hyperproliferative and metabolic changes. Immunologically, NOX4 KO reduced CD8+ T cell infiltration and function, partially due to lowered CCL11/CCL5 levels, while PD-L1 expression was upregulated. In contrast, NOX4 overexpression improved survival in mice and synergized with checkpoint blockade, demonstrating a positive effect on anti-tumor immunity.

Discussion

These findings show that NOX4 constrains breast cancer aggressiveness by limiting MYC-driven metabolic adaptations and supporting CD8+ T cell-mediated immunity. Loss of NOX4 promotes a more malignant phenotype and dampens T cell responses, whereas its overexpression prolongs survival and enhances checkpoint inhibitor efficacy. Therapeutically targeting the NOX4-MYC axis and leveraging NOX4's immunomodulatory capacity could offer promising strategies for breast cancer management.

Long-Term Control of Breast Cancer Brain Metastases Using Abemaciclib and Letrozole Combination Therapy: A Case Report

Breast cancer brain metastases are among the most common distant metastases and have a poor prognosis. However, the effects of subtype-specific systemic therapy on breast cancer brain metastases are unknown. This report highlights the long-term control of breast cancer brain metastases using abemaciclib and letrozole combination therapy without severe side effects. We report a case of a middle-aged premenopausal female patient who experienced convulsions and was diagnosed with hormone receptor-positive breast cancer brain metastases. After standard-of-care whole-brain radiation therapy, systemic chemotherapy was administered, and the primary tumor and multiple brain metastases were sufficiently reduced. However, treatment was discontinued because peripheral neuropathy worsened. Abemaciclib, letrozole, and luteinizing hormone-releasing hormone agonists were administered as maintenance therapy. The treatment maintained a stable disease and no new lesions were observed. Cyclin-dependent kinase 4/6 inhibitors and endocrine maintenance therapy are effective treatments for breast cancer brain metastases.

Combination strategies with PARP inhibitors in BRCA-mutated triple-negative breast cancer: overcoming resistance mechanisms

Triple-negative breast cancer (TNBC) is a particularly aggressive breast cancer subtype, characterised by a higher incidence in younger women, rapid metastasis, and a generally poor prognosis. Patients with TNBC and BRCA mutations face additional therapeutic challenges due to the cancer's intrinsic resistance to conventional therapies. Poly (ADP-ribose) polymerase inhibitors (PARPis) have emerged as a promising targeted treatment for BRCA-mutated TNBC, exploiting vulnerabilities in the homologous recombination repair (HRR) pathway. However, despite initial success, the efficacy of PARPis is often compromised by the development of resistance mechanisms, including HRR restoration, stabilisation of replication forks, reduced PARP1 trapping, and drug efflux. This review explores latest breakthroughs in overcoming PARPi resistance through combination therapies. These strategies include the integration of PARPis with chemotherapy, immunotherapy, antibody-drug conjugates, and PI3K/AKT pathway inhibitors. These combinations aim to enhance the therapeutic efficacy of PARPis by targeting multiple cancer progression pathways. The review also discusses the evolving role of PARPis within the broader treatment paradigm for BRCA-mutated TNBC, emphasising the need for ongoing research and clinical trials to optimise combination strategies. By tackling the challenges associated with PARPi resistance and exploring novel combination therapies, this review sheds light on the future possibilities for improving outcomes for patients with BRCA-mutated TNBC.

Intravenous liposomal irinotecan in metastatic triple-negative breast cancer after ≥ 2 prior lines of chemotherapy: a phase Ib study

This study (NCT04728035) aimed to explore the safety and efficacy of liposomal irinotecan (HE072) in patients with metastatic triple-negative breast cancer (mTNBC). This study consisted of two parts. In part 1, the 3 + 3 design was used to investigate three dose levels of HE072 (50, 70 and 90 mg/m2). In part 2, patients were enrolled in two cohorts (mTNBC and HER2-negative breast cancer brain metastasis [BCBM]), and received HE072 70 mg/m2 every two weeks (Q2W). The primary endpoints were maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D), and treatment emergent adverse events (TEAEs). The secondary endpoints were pharmacokinetic profiles and efficacy including objective response rate (ORR) and disease control rate (DCR) (all patients) and Central Nervous System ORR and clinical benefit rate (CBR, for patients with HER2-negative BCBM), duration of response, progression free survival (PFS), overall survival (OS). A total of 119 patients were enrolled, including 101 mTNBC and 18 HER2-negative BCBM. One dose limiting toxicity (grade 3 nausea and vomiting) occurred at 70 mg/m2, and the MTD was not reached. The most common ≥ grade 3 TEAEs related to HE072 included neutropenia (21.0%), leukopenia (18.5%), diarrhea (10.1%). Among 87 evaluable patients with mTNBC, 22 patients (25.3%) achieved overall response. The DCR was 67.8% (59/87). The median PFS and OS were 4.8 months and 14.1 months, respectively. The RP2D was 70 mg/m2 Q2W. Promising antitumor activity in heavily pre-treated patients with mTNBC was observed, which warrants further validation.

Central Nervous System Metastases in Breast Cancer

OPINION STATEMENT

Breast cancer metastasizing to the central nervous system (CNS) encompasses two distinct entities: brain metastases involving the cerebral parenchyma and infiltration of the leptomeningeal space, i.e., leptomeningeal disease. CNS metastases affect 10-15% of patients with hormone receptor-positive-status and nearly one-half of those with HER2-positive and triple-negative breast cancer with distant metastatic disease. Significant clinical morbidity and heterogeneous penetration of the blood-brain barrier by systemic therapies contribute to the poor prognosis associated with brain metastases. Recent advances in radiotherapy, including stereotactic approaches and morbidity-reducing strategies such as the use of memantine and hippocampal avoidance in whole brain radiation, coupled with the development of more effective CNS-penetrant systemic therapies, including small molecules and antibody-drug conjugates, have significantly improved patient outcomes. Consequently, patients with breast cancer CNS metastases have improved survival compared to prior decades, and longitudinal care has become increasingly complex, necessitating a multidisciplinary approach to achieve optimal outcomes for patients.

Trastuzumab Deruxtecan for HER2-Positive Breast Cancer with Central Nervous System Metastasis

Introduction

Metastasis to the central nervous system (CNS) is frequently observed in human epidermal growth factor receptor (HER2)-positive breast cancer, leading to reduced quality of life and poor prognosis. Brain metastases (BMs) are common, whereas spinal cord metastases are rare and no standardized treatment approach has been reported for their management. Herein, we report the outcomes of treatment with trastuzumab deruxtecan (T-DXd) in a patient with BMs and intramedullary spinal cord metastasis (ISCM) and another patient with BMs.

Case Presentation

The first patient was a woman in her 30s. After the surgery for HER2-positive right breast cancer, T-DXd was used as fourth-line treatment for multiple BMs and ISCM. Both the BMs and ISCM reduced, and partial response was maintained for 12 months. Grade 1 fatigue was the only adverse event observed in this patient. The second patient was a woman in her 40 s with multiple BMs after primary treatment for HER2-positive right breast cancer, as well as multiple bone and lymphoid node metastases. T-DXd was administered as second-line treatment. The multiple BMs have now shrunk, and the primary tumor and bone/lymph node metastases have not shown significant changes; the patient has maintained partial response for 6 months.

Conclusion

Metastasis to the CNS has a very poor prognosis and limited therapeutic response because it is difficult for drugs to cross the blood-brain barrier. However, T-DXd has yielded positive results for BMs in clinical trials. Additionally, a therapeutic effect of T-DXd on ISCM and BMs was observed in the reported cases.

Current Evidence in the Systemic Treatment of Brain Metastases from Breast Cancer and Future Perspectives on New Drugs, Combinations and Administration Routes: A Narrative Review

Breast cancer is the most frequently diagnosed neoplasm all over the world and the second leading cause of cancer death in women. Breast cancer prognosis has significantly improved in the last years due to the advent of novel therapeutic options, both in the early and in advanced stages. However, the spread of the disease to the brain, accounting for 15-30% of the metastatic diagnoses, is challenging, and its poor prognosis represents an unmet medical need, leading to deterioration of quality of life and causing morbidity and mortality. Generally, triple-negative and HER2-positive breast cancer subtypes more frequently spread to the brain or in the leptomeningeal space. Consequently, according to international guidelines, several systemic treatments can be offered as a first option in some subsets of patients. However, a multidisciplinary approach is recommended to offer the most appropriate strategy to patients. Antibody-drug conjugates such as trastuzumab deruxtecan or sacituzumab govitecan along with small molecules have led to important achievements in the treatment of brain metastases from HER2-positive and triple-negative breast cancer. In this narrative review, we will focus on the molecular features leading to the development of brain metastases and explore the risk and the prognostic factors involved in the development of brain metastases. Finally, we will review the major achievements in the treatment landscape of brain metastases from breast cancer and novel medical approaches.

Discovery of Thiochroman Derivatives as Potent, Oral Selective Estrogen Receptor Degraders and Antagonists for the Treatment of Endocrine-Resistant Breast Cancer

Selective estrogen receptor degraders (SERDs) deplete the ER signaling pathway via antagonism and degradation of ERα and represent a promising strategy to tackle endocrine resistance. Here, we report a new class of SERDs by pharmacological evolution of a selective estrogen receptor modulator, lasofoxifene. The structure-activity relationship study and efforts to circumvent the issue of human ether-a-go-go-related gene led to the identification of compounds 51. This bifunctional compound displayed broad activity across a vast array of cell backgrounds and was capable of effectively degrading and antagonizing wild-type ERα and clinically relevant ERα mutants. 51 exhibited favorable pharmacokinetic properties and good brain penetration, with a brain/plasma ratio of 3.05, and significantly suppressed the growth of tumor in a tamoxifen-resistant MCF-7 Tam1 xenograft model. Overall, the study demonstrates 51 as a highly potent, oral, and brain penetrant ER degrader and pure antagonist, showing a good potential in overcoming endocrine resistance.

Identification of Tumor-Suppressive miR-30a-3p Controlled Genes: ANLN as a Therapeutic Target in Breast Cancer

Our recently created RNA-sequence-based microRNA (miRNA) expression signature in breast cancer clinical specimens revealed that some miR-30 family members were significantly downregulated in cancer tissues. Based on TCGA database analyses, we observed that among the miR-30 family members, miR-30a-3p (the passenger strand derived from pre-miR-30a) was significantly downregulated in breast cancer (BC) clinical specimens, and its low expression predicted worse prognoses. Ectopic expression assays showed that miR-30a-3p transfected cancer cells (MDA-MB-157 and MDA-MB-231) had their aggressive phenotypes significantly suppressed, e.g., their proliferation, migration, and invasion abilities. These data indicated that miR-30a-3p acted as a tumor-suppressive miRNA in BC cells. Our subsequent search for miR-30a-3p controlled molecular networks in BC cells yielded a total of 189 genes. Notably, among those 189 genes, cell-cycle-related genes (ANLN, MKI67, CCNB1, NCAPG, ZWINT, E2F7, PDS5A, RIF1, BIRC5, MAD2L1, CACUL1, KIF23, UBE2S, EML4, SEPT10, CLTC, and PCNP) were enriched according to a GeneCodis 4 database analysis. Moreover, the overexpression of four genes (ANLN, CCNB1, BIRC5, and KIF23) significantly predicted worse prognoses for patients with BC according to TCGA analyses. Finally, our assays demonstrated that the overexpression of ANLN had cancer-promoting functions in BC cells. The involvement of miR-30a-3p (the passenger strand) in BC molecular pathogenesis is a new concept in cancer research, and the outcomes of our study strongly indicate the importance of analyzing passenger strands of miRNAs in BC cells.

Guidance for Canadian Breast Cancer Practice: National Consensus Recommendations for the Systemic Treatment of Patients with HER2+ Breast Cancer in Both the Early and Metastatic Setting

Human epidermal growth factor receptor 2-positive (HER2+) breast cancer is an aggressive subtype of breast cancer associated with a poor prognosis when sub-optimally treated. Recent advances include new and effective targeted therapies that have significantly improved outcomes for patients. Despite these advances, there are significant gaps across Canada, underscoring the need for evidence-based consensus guidance to inform treatment decisions. Addressing these gaps is crucial to ensuring that effective therapies are integrated into clinical practice, so as to improve the lives of patients affected by this aggressive form of breast cancer. The Research Excellence, Active Leadership (REAL) Canadian Breast Cancer Alliance is a standing nucleus committee of clinical-academic oncologists across Canada and Breast Cancer Canada, a patient organization. The mandate of this group is to provide evidence-based guidance on best practices in the management of patients with breast cancer. These consensus recommendations were developed using a modified Delphi process with up to three rounds of anonymous voting. Consensus was defined a priori as ≥75% of voters agreeing with the recommendation as written. There are 9 recommendations in the early setting; 7 recommendations in the metastatic setting; and 10 recommendations for patients with brain metastases.

Efficacy and safety of anlotinib for triple-negative breast cancer with brain metastases

Background

The anti-angiogenic agent anlotinib offers a new treatment option for triple-negative breast cancer (TNBC) patients with brain metastases. This study aimed to evaluate the efficacy and safety of anlotinib in the treatment of TNBC patients with brain metastases.

Methods

Between October 2019 and April 2024, 29 TNBC patients with brain metastases who had failed prior therapy and were treated with anlotinib were retrospectively analyzed. The primary endpoint was central nervous system (CNS) progression-free survival (PFS), and secondary endpoints included overall survival (OS), intracranial disease control rate (iDCR), intracranial objective response rate (iORR), and safety.

Results

The median CNS PFS of 29 patients was 7.2 months (95% confidence interval [CI], 3.5-10.9 months), and the median OS was 10.2 months (95% CI, 5.6-14.8 months). The iORR and iDCR were 31.0% and 86.2%, respectively. Five patients (17.2%) experienced grade 3-4 adverse events (AEs), with bone marrow suppression (2/29, 6.9%) being the most common. Most AEs were clinically manageable, and no treatment-related death was observed.

Conclusion

Anlotinib demonstrated encouraging efficacy and manageable toxicity in the treatment of TNBC patients with brain metastases who had failed standard treatment.

Breast Cancer Brain Metastasis: A Comprehensive Review

The mechanisms underlying breast cancer brain metastasis (BCBM) development are complex, and its clinical presentation varies depending on the number, location, and size of brain metastases. Common symptoms include headache, neurologic deficits, and seizures. Diagnosis of BCBM typically relies on neuroimaging techniques, such as magnetic resonance imaging and computed tomography scans. Local therapies, such as surgery and stereotactic radiosurgery, can be used to control tumor growth and relieve symptoms. Whole-brain radiotherapy has been a mainstay of treatment for BCBM, but its use has been associated with cognitive decline. Systemic therapy with chemotherapy and targeted agents plays an increasingly important role in the management of BCBM. Novel agents, such as human epidermal growth factor receptor 2 (HER2)-targeted therapies and tyrosine kinase inhibitors, have shown promising results in improving survival for patients with HER2-positive and triple-negative BCBM. This comprehensive review synthesizes current knowledge, clinical insights, and evolving paradigms to provide a robust understanding and roadmap for optimizing the diagnosis and management of BCBM.

Role of microsurgical tumor burden reduction in patients with breast cancer brain metastases considering molecular subtypes: a two-center volumetric survival analysis

BACKGROUND

Advancements in metastatic breast cancer (BC) treatment have enhanced overall survival (OS), leading to increased rates of brain metastases (BM). This study analyzes the association between microsurgical tumor reduction and OS in patients with BCBM, considering tumor molecular subtypes and perioperative treatment approaches.

METHODS

Retrospective analysis of surgically treated patients with BCBM from two tertiary brain tumor Swiss centers. The association of extent of resection (EOR), gross-total resection (GTR) achievement, and postoperative residual tumor volume (RV) with OS and intracranial progression-free survival (IC-PFS) was evaluated using Cox proportional hazard model.

RESULTS

101 patients were included in the final analysis, most patients (38%) exhibited HER2-/HR + BC molecular subtype, followed by HER2 + /HR + (25%), HER2-/HR- (21%), and HER2 + /HR- subtypes (13%). The majority received postoperative systemic treatment (75%) and radiotherapy (84%). Median OS and intracranial PFS were 22 and 8 months, respectively. The mean pre-surgery intracranial tumor volume was 26 cm3, reduced to 3 cm3 post-surgery. EOR, GTR achievement and RV were not significantly associated with OS or IC-PFS, but higher EOR and lower RV correlated with extended OS in patients without extracranial metastases. HER2-positive tumor status was associated with longer OS, extracranial metastases at BM diagnosis and symptomatic lesions with shorter OS and IC-PFS.

CONCLUSIONS

Our study found that BC molecular subtypes, extracranial disease status, and BM-related symptoms were associated with OS in surgically treated patients with BCBM. Additionally, while extensive resection to minimize residual tumor volume did not significantly affect OS across the entire cohort, it appeared beneficial for patients without extracranial metastases.

Role of MicroRNA-204 in Regulating the Hallmarks of Breast Cancer: An Update

microRNA-204-5p (miR-204) is a small noncoding RNA with diverse regulatory roles in breast cancer (BC) development and progression. miR-204 is implicated in the instauration of fundamental traits acquired during the multistep development of BC, known as the hallmarks of cancer. It may act as a potent tumor suppressor by inhibiting key cellular processes like angiogenesis, vasculogenic mimicry, invasion, migration, and metastasis. It achieves this by targeting multiple master genes involved in these processes, including HIF-1α, β-catenin, VEGFA, TGFBR2, FAK, FOXA1, among others. Additionally, miR-204 modulates signaling pathways like PI3K/AKT and interacts with HOTAIR and DSCAM-AS1 lncRNAs, further influencing tumor progression. Beyond its direct effects on tumor cells, miR-204 shapes the tumor microenvironment by regulating immune cell infiltration, suppressing pro-tumorigenic cytokine production, and potentially influencing immunotherapy response. Moreover, miR-204 plays a crucial role in metabolic reprogramming by directly suppressing metabolic genes within tumor cells, indirectly affecting metabolism through exosome signaling, and remodeling metabolic flux within the tumor microenvironment. This review aims to present an update on the current knowledge regarding the role of miR-204 in the hallmarks of BC. In conclusion, miR-204 is a potential therapeutic target and prognostic marker in BC, emphasizing the need for further research to fully elucidate its complex roles in orchestrating aggressive BC behavior.

"Positioning of tucatinib in the new clinical scenario of HER2-positive metastatic breast cancer: An Italian and Spanish consensus paper"

INTRODUCTION

Advancements in monoclonal antibodies, tyrosine kinase inhibitors, and antibody drug conjugates (ADCs) have notably enhanced outcomes for metastatic HER2-positive breast cancer patients. Despite the expanding treatment options and clinical complexities, determining the optimal sequence of HER2-targeted therapies remains partly uncertain, influenced by various factors.

METHODS

To refine HER2-positive metastatic breast cancer management, particularly regarding tucatinib's position, a Steering Committee of leading oncologists in breast cancer care devised a panel of statements via a Delphi approach, focusing on five key topics: general clinical management, therapeutic approaches for patients with HER2-positive breast cancer and brain metastases, treatment sequence, and tucatinib's safety and efficacy.

RESULTS

A total of 29 statements were deliberated, with strong consensus achieved for most. However, no consensus emerged regarding the management of brain progression alongside stable extracranial disease: 48 % advocated for switching to tucatinib, while 53 % favored a stereotactic brain radiotherapy (SBRT) approach if feasible.

CONCLUSION

The unanimous consensus attained in this Delphi panel, particularly regarding tucatinib's efficacy and safety, underscores oncologists' recognition of its clinical significance based on existing trial data. These findings align closely with current literature, shedding light on areas necessitating further investigation, not thoroughly explored in prior studies. Moreover, the results underscore the scarcity of data on managing brain progression alongside stable extracranial disease, emphasizing the imperative for dedicated research to address these gaps and yield definitive insights.

Impact of cyclin dependent kinase 4/6 inhibitors on breast cancer brain metastasis outcomes

BACKGROUND

Cyclin dependent kinase 4/6 inhibitors (CDK4/6i) are recommended 1st line treatments in HR+HER2- metastatic breast cancer. However, the impact of prior CDK4/6i on the natural history of brain metastases (BM) is not well described.

MATERIALS AND METHODS

We reviewed retrospective data for 363 patients with HR+HER2- BM who received a CDK4/6i (CDK-Y) between 1 Jan 2015 to 31 July 2021 and 299 patients with HR+HER2- BM who did not receive a CDK4/6i (CDK-N) between 1 Jan 2010 to 31 Dec 2014. CNS PFS and OS were assessed in patients who received CDK4/6i after BM. OS from the time of BM development was assessed between patients who received CDK4/6i before BM and the CDK-N cohort RESULTS: In the CDK-Y cohort of 363 patients, 203 (56 %) received a CDK4/6i before BM, 133 (37 %) received a CDK4/6i only after BM and 27 (7 %) received a CDK4/6i both before and after BM. Median CNS PFS was 21.4 months for patients receiving a CDK4/6i only after BM and 9.4 months for patients who received CDK4/6i both before and after BM (p = 0.006). Median OS was 24.9 months for patients receiving a CDK4/6i only after BM and 12.1 months for patients who received CDK4/6i both before and after BM (p = 0.0098). Median OS from time of BM development for patients receiving a CDK4/6i before BM versus the CDK-N cohort was 4.3 months and 7.7 months respectively (p = 0.0082).

CONCLUSIONS

CDK4/6i exposure prior to BM may lead to development of resistance mechanisms which in turn reduces CNS PFS and OS upon rechallenging with a CDK4/6i after BM development. This motivates investigation of biomarkers for patient selection.

Risk factors and prognostic factors of brain metastasis of triple-negative breast cancer: A single-center retrospective study

OBJECTIVE

This retrospective study is to explore the risk factors and prognostic factors of brain metastases of triple-negative breast cancer (TNBC) in a single center.

METHODS

Clinical data of patients with stages I-III TNBC were collected. The Kaplan-Meier method, log-rank test, and stepwise COX regression were performed.

RESULTS

The 437 patients with stages I-III TNBC were followed up for five years. Among them, 89 cases (20.4%) developed brain metastases, and they were followed up for 2 years after brain metastasis. The cumulative brain metastasis rates of TNBC patients at six months, one year, two years, three years, and five years were 1.38%, 5.75%, 12.94%, 17.63%, and 21.26%, respectively. Multivariate analysis suggested that the first diagnosis age ≤35 years old, advanced pathological stage, lymph node metastasis, and Ki-67 ≥30% represented the risk factors for brain metastasis. In contrast, the surgical method was a protective factor for brain metastasis. The median survival time after brain metastasis was 4.87 months. The survival rates at one, three, six, 12, and 24 months were 84.27%, 60.67%, 34.83%, 15.69%, and 6.64%, respectively. The age >60 years at first diagnosis, Ki-67 ≥30%, local recurrence, and distant metastasis were closely related to the poor prognosis of TNBC patients with brain metastases, while radiotherapy alone, systemic therapy, and combined chemotherapy and radiotherapy represented the prognostic protective factors.

CONCLUSIONS

Patient age, Ki-67 level, metastasis, and treatment methods are the risk factors and prognostic factors for brain metastasis of TNBC. Surgical resection of the primary lesion during the first treatment is essential to reduce the incidence of brain metastases. Close postoperative follow-up (such as brain magnetic resonance imaging [MRI]) within 2-3 years after surgery is recommended to improve the prognosis.

Density of tertiary lymphoid structures predicts clinical outcome in breast cancer brain metastasis

BACKGROUND

Patients with breast cancer brain metastases (BCBM) experience a rapid decline in their quality of life. Recently, tertiary lymphoid structures (TLSs), analogs of secondary lymphoid organs, have attracted extensive attention. However, the potential clinical implications of TLSs in BCBMs are poorly understood. In this study, we evaluated the density and composition of TLSs in BCBMs and described their prognostic value.

METHODS

Clinicopathological data were collected from 98 patients (2015-2021). TLSs were evaluated, and a TLS scoring system was constructed. Differences in progression-free survival (PFS) and overall survival (OS) between groups were calculated using the Kaplan-Meier method. Immunohistochemistry and multiplex immunofluorescence (mIF) were used to assess TLSs heterogeneity.

RESULTS

TLSs were identified in 47 patients with BCBM. High TLSs density indicated favorable survival (OS, p=0.003; PFS, p<0.001). TLS was positively associated with OS (p=0.0172) and PFS (p=0.0161) in the human epidermal growth factor receptor type 2-positive subtype, and with prolonged OS (p=0.0482) in the triple-negative breast cancer subtype. The mIF results showed significant differences in the percentages of T follicular helper (Tfh) cells, M2 macrophages, cytotoxic T lymphocytes, and CD8+TIM-3+ T lymphocytes between the groups of TLS scores 0-3 (cytotoxic T lymphocytes, p=0.044; Tfh, p=0.021; M2 macrophages, p=0.033; CD8+TIM-3+ T lymphocytes, p=0.018). Furthermore, novel nomograms incorporating the TLS scores and other clinicopathological predictors demonstrated prominent predictability of the 1-year, 3-year, and 5-year outcomes of BCBMs (area under the curve >0.800).

CONCLUSION

Our results highlight the impact of TLSs abundance on the OS and PFS of patients with BCBM. Additionally, we described the immune composition of TLSs and proposed novel nomograms to predict the prognosis of patients with BCBM.

Exploring the feasibility and implications of cranioencephalic computed tomography in HER2-positive breast cancer: A pilot study

Background

Breast cancer has several subtypes, including HER2-positive breast cancer, which is characterized by overexpression of human epidermal growth factor receptor 2 (HER2), aggressiveness, poor prognosis, and high risk of recurrence and metastasis. Brain metastases are a common complication of HER2-positive breast cancer, but brain imaging is not included in the initial staging of this disease. This prospective pilot study aimed to evaluate the usefulness of brain computed tomography (CT) in the initial staging of HER2-positive breast cancer.

Patients and methods

Fifty-eight patients were enrolled and demographic, clinical, and breast cancer-specific data were collected after the informed consent and ethical approval were obtained.

Results

A descriptive analysis was performed. The median age of the patients was 55 years, and the majority had good performance status. Brain CT scans were performed at diagnosis, and no brain metastases were detected in early-stage patients. However, brain CT identified brain metastases in one advanced-stage patient with clinical suspicion.

Conclusions

This study suggests that brain CT may have limited utility in the initial staging of early HER2-positive breast cancer, while it could be a valuable tool in advanced cases. Further research is needed, including a higher number of patients to identify those with high risk, which may benefit from brain imaging.

Loss of Kmt2c or Kmt2d drives brain metastasis via KDM6A-dependent upregulation of MMP3

KMT2C and KMT2D, encoding histone H3 lysine 4 methyltransferases, are among the most commonly mutated genes in triple-negative breast cancer (TNBC). However, how these mutations may shape epigenomic and transcriptomic landscapes to promote tumorigenesis is largely unknown. Here we describe that deletion of Kmt2c or Kmt2d in non-metastatic murine models of TNBC drives metastasis, especially to the brain. Global chromatin profiling and chromatin immunoprecipitation followed by sequencing revealed altered H3K4me1, H3K27ac and H3K27me3 chromatin marks in knockout cells and demonstrated enhanced binding of the H3K27me3 lysine demethylase KDM6A, which significantly correlated with gene expression. We identified Mmp3 as being commonly upregulated via epigenetic mechanisms in both knockout models. Consistent with these findings, samples from patients with KMT2C-mutant TNBC have higher MMP3 levels. Downregulation or pharmacological inhibition of KDM6A diminished Mmp3 upregulation induced by the loss of histone-lysine N-methyltransferase 2 (KMT2) and prevented brain metastasis similar to direct downregulation of Mmp3. Taken together, we identified the KDM6A-matrix metalloproteinase 3 axis as a key mediator of KMT2C/D loss-driven metastasis in TNBC.

Prevention of Brain Metastases: A New Frontier

This review discusses the topic of prevention of brain metastases from the most frequent solid tumor types, i.e., lung cancer, breast cancer and melanoma. Within each tumor type, the risk of brain metastasis is related to disease status and molecular subtype (i.e., EGFR-mutant non-small cell lung cancer, HER2-positive and triple-negative breast cancer, BRAF and NRAF-mutant melanoma). Prophylactic cranial irradiation is the standard of care in patients in small cell lung cancer responsive to chemotherapy but at the price of late neurocognitive decline. More recently, several molecular agents with the capability to target molecular alterations driving tumor growth have proven as effective in the prevention of secondary relapse into the brain in clinical trials. This is the case for EGFR-mutant or ALK-rearranged non-small cell lung cancer inhibitors, tucatinib and trastuzumab-deruxtecan for HER2-positive breast cancer and BRAF inhibitors for melanoma. The need for screening with an MRI in asymptomatic patients at risk of brain metastases is emphasized.

Navigating breast cancer brain metastasis: Risk factors, prognostic indicators, and treatment perspectives

In this editorial, we comment on the article by Chen et al. We specifically focus on the risk factors, prognostic factors, and management of brain metastasis (BM) in breast cancer (BC). BC is the second most common cancer to have BM after lung cancer. Independent risk factors for BM in BC are: HER-2 positive BC, triple-negative BC, and germline BRCA mutation. Other factors associated with BM are lung metastasis, age less than 40 years, and African and American ancestry. Even though risk factors associated with BM in BC are elucidated, there is a lack of data on predictive models for BM in BC. Few studies have been made to formulate predictive models or nomograms to address this issue, where age, grade of tumor, HER-2 receptor status, and number of metastatic sites (1 vs > 1) were predictive of BM in metastatic BC. However, none have been used in clinical practice. National Comprehensive Cancer Network recommends screening of BM in advanced BC only when the patient is symptomatic or suspicious of central nervous system symptoms; routine screening for BM in BC is not recommended in the guidelines. BM decreases the quality of life and will have a significant psychological impact. Further studies are required for designing validated nomograms or predictive models for BM in BC; these models can be used in the future to develop treatment approaches to prevent BM, which improves the quality of life and overall survival.

A Review of Recent Advances in the Molecular Mechanisms Underlying Brain Metastasis in Lung Cancer

Brain metastasis from lung cancer is a prevalent mode of treatment failure associated with a poor prognosis. The incidence of brain metastasis has recently shown a dramatic increase. The early detection and risk stratification of lung cancer-related brain metastasis would be highly advantageous for patients. However, our current knowledge and comprehension of the underlying mechanisms driving brain metastasis in lung cancer pose significant challenges. This review summarizes the mechanisms underlying brain metastasis, focusing on the intricate interplay between lung cancer-derived tumor cells and the unique characteristics of the brain, recent advancements in the identification of driver genes, concomitant genes, epigenetic features, including miRNAs and long noncoding RNAs, as well as the molecular characterization of brain metastasis originating from other organs, which may further enhance risk stratification and facilitate precise treatment strategies.

The efficacy of sacituzumab govitecan and trastuzumab deruxtecan on stable and active brain metastases in metastatic breast cancer patients-a multicenter real-world analysis

BACKGROUND

Fifteen to thirty percent of all patients with metastatic breast cancer (MBC) develop brain metastases (BCBMs). Recently, the antibody-drug conjugates (ADCs) sacituzumab govitecan (SG) and trastuzumab deruxtecan (T-DXd) have shown to be highly effective in the treatment of MBC. However, there are only limited data whether these macromolecules are also effective in patients with BCBMs. We therefore aimed to examine the efficacy of SG and T-DXd in patients with stable and active BCBMs in a multicenter real-world analysis.

PATIENTS AND METHODS

Female patients with stable or active BCBMs who were treated with either SG or T-DXd at three breast centers in Germany before 30 June 2023 were included. As per local clinical praxis, chemotherapy efficacy was evaluated by whole-body computed tomography and cranial magnetic resonance imaging at baseline and at least every 3 months according to local standards. Growth dynamics of BCBMs were assessed by board-certified neuroradiologists.

RESULTS

Of 26 patients, with a median of 2.5 prior therapy lines in the metastatic setting (range 2-15), 12 (43%) and 16 (57%) patients received SG and T-DXd, respectively. Out of the 12 patients who received SG, 2 (17%) were subsequently treated with T-DXd. Five out of 12 (42%) and 5 out of 16 (31%) patients treated with SG and T-DXd, respectively, had active BCBMs at treatment initiation. The intracranial disease control rate was 42% [95% confidence interval (CI) 13% to 71%] for patients treated with SG and 88% (95% CI 72% to 100%) for patients treated with T-DXd. After a median follow-up of 12.7 months, median intracranial progression-free survival was 2.7 months (95% CI 1.6-10.5 months) for SG and 11.2 months (95% CI 7.5-23.7 months) for T-DXd.

CONCLUSIONS

SG and T-DXd showed promising clinical activity in both stable and active BCBMs. Further prospective clinical studies designed to investigate the efficacy of modern ADCs on active and stable BCBMs are urgently needed.

Incidence and outcome of brain and/or leptomeningeal metastases in HER2-low metastatic breast cancer in the French ESME cohort

BACKGROUND

Breast cancer (BC) is the second most common cancer that metastasizes to the brain. Particularly up to half of patients with human epidermal growth factor receptor 2 (HER2)-positive (HER2+) metastatic breast cancer (mBC) may develop brain metastases over the course of the disease. Nevertheless, little is known about the prevalence and the outcome of brain and leptomeningeal metastases (BLMM) in HER2-low BC. We compared the cumulative incidence of BLMM and associated outcomes among patients with HER2-low, HER2-negative (HER2-) and HER2+ mBC.

PATIENTS AND METHODS

This cohort study was conducted from the Epidemiological Strategy and Medical Economics (ESME) mBC database and included patients treated for mBC between 2012 and 2020 across 18 French comprehensive cancer centers and with known HER2 and hormone receptor (HR) status. The cumulative incidence of BLMM after metastatic diagnosis was estimated using a competing risk methodology with death defined as a competing event.

RESULTS

19 585 patients were included with 6118 (31.2%), 9943 (50.8%) and 3524 (18.0%) being HER2-low, HER2- and HER2+ mBC, respectively. After a median follow-up of 48.6 months [95% confidence interval (CI) 47.7-49.3 months], BLMM were reported in 4727 patients: 1192 (25.2%) were diagnosed with BLMM at first metastatic diagnosis and 3535 (74.8%) after metastatic diagnosis. Multivariable analysis adjusted for age, histological grade, metastases-free interval and HR status showed that the risk of BLMM at metastatic diagnosis was similar in patients with HER2- compared to HER2-low mBC [odds ratio (OR) (95% CI) 1.00 (0.86-1.17)] and higher in those with HER2+ compared to HER2-low [OR (95% CI) 2.23 (1.87-2.66)]. Similar results were found after metastatic diagnosis; the risk of BLMM was similar in HER2- compared to HER2-low [subdistribution hazard ratio (sHR) (95% CI) 1.07 (0.98-1.16)] and higher in the HER2+ group [sHR (95% CI) 1.56 (1.41-1.73)].

CONCLUSIONS

The prevalence and evolution of BLMM in HER2-low mBC are similar to those in patients with HER2- tumors. In contrast to patients with HER2+ mBC, the prognosis of BLMM remains dismal in this population.

Leptomeningeal metastasis of breast cancer during neo-adjuvant chemotherapy in a 38-year-old woman: a case report

Background

Breast cancer accounts for 5% of the population who develop central nervous system metastasis, which is only second to the lung cancer. Breast cancer metastasis to the brain including parenchymal brain metastasis (BM) and leptomeningeal metastasis (LM). Compared with BM, LM is a more rare but aggressive metastatic diagnosis with poor outcome.

Case Description

We reported a 38-year-old woman presented to the neurology department due to progressive headache for 1 month, accompanied with dizziness, nausea, vomiting and neck pain. During hospitalization, she experienced paroxysmal loss of consciousness twice. Five months prior to this visit, her first visit was diagnosed with breast cancer on the right side which was of triple-negative subtype and with homolateral axillary lymph node involvement by biopsy. After the clinician assessment she had received six cycles of TCb (docetaxel/carboplatin) neo-adjuvant chemotherapy. During the period of neo-adjuvant chemotherapy, she did not report the presence of severe neurological symptoms. Twenty days ago, she underwent right breast-conserving surgery and the postoperative evaluation was ypT1N3M0 stage and Miller-Payne grade 2. Head computed tomography (CT) scan and contrast-enhanced magnetic resonance imaging (MRI) didn't find typical brain imaging changes. No other signs of metastasis were seen in the CT examinations of the patient's chest and abdomen. Finally, lumbar puncture with cerebrospinal fluid (CSF) analysis showed the presence of malignant cells. Given the patient's clinical history and new neurologic symptoms, the diagnosis was LM from breast cancer. Various treatment modalities including intrathecal thiotepa, oral temozolomide (TMZ) and whole-brain radiation therapy (WBRT) had been used, but none of them showed significant benefit for survival.

Conclusions

Breast cancer metastasis to the brain, especially LM, should be given sufficient vigilance and attention at the beginning of the diagnosis and treatment, particularly in triple-negative breast cancer patients who are at high risk. Symptoms of LM may be masked by the chemotherapy adverse effects. The results of MRI and CT may show negative results, thus lumbar puncture with CSF should be done promptly if LM is highly suspected in clinical practice. Early prevention, early detection and timely treatment are crucial according to the poor prognosis.

O-Glycome Profiling of Breast Cancer Cell Lines to Understand Breast Cancer Brain Metastasis

Breast cancer is the second leading cause of cancer-related death among women and a major source of brain metastases. Despite the increasing incidence of brain metastasis from breast cancer, the underlying mechanisms remain poorly understood. Altered glycosylation is known to play a role in various diseases including cancer metastasis. However, profiling studies of O-glycans and their isomers in breast cancer brain metastasis (BCBM) are scarce. This study analyzed the expression of O-glycans and their isomers in human breast cancer cell lines (MDA-MB-231, MDA-MB-361, HTB131, and HTB22), a brain cancer cell line (CRL-1620), and a brain metastatic breast cancer cell line (MDA-MB-231BR) using nanoLC-MS/MS, identifying 27 O-glycan compositions. We observed significant upregulation in the expression of HexNAc1Hex1NeuAc2 and HexNAc2Hex3, whereas the expression of HexNAc1Hex1NeuAc1 was downregulated in MDA-MB-231BR compared to other cell lines. In our isomeric analysis, we observed notable alterations in the isomeric forms of the O-glycan structure HexNAc1Hex1NeuAc1 in a comparison of different cell lines. Our analysis of O-glycans and their isomers in cancer cells demonstrated that changes in their distribution can be related to the metastatic process. We believe that our investigation will contribute to an enhanced comprehension of the significance of O-glycans and their isomers in BCBM.

DEGRO guideline for personalized radiotherapy of brain metastases and leptomeningeal carcinomatosis in patients with breast cancer

PURPOSE

The aim of this review was to evaluate the existing evidence for radiotherapy for brain metastases in breast cancer patients and provide recommendations for the use of radiotherapy for brain metastases and leptomeningeal carcinomatosis.

MATERIALS AND METHODS

For the current review, a PubMed search was conducted including articles from 01/1985 to 05/2023. The search was performed using the following terms: (brain metastases OR leptomeningeal carcinomatosis) AND (breast cancer OR breast) AND (radiotherapy OR ablative radiotherapy OR radiosurgery OR stereotactic OR radiation).

CONCLUSION AND RECOMMENDATIONS

Despite the fact that the biological subtype of breast cancer influences both the occurrence and relapse patterns of breast cancer brain metastases (BCBM), for most scenarios, no specific recommendations regarding radiotherapy can be made based on the existing evidence. For a limited number of BCBM (1-4), stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (SRT) is generally recommended irrespective of molecular subtype and concurrent/planned systemic therapy. In patients with 5-10 oligo-brain metastases, these techniques can also be conditionally recommended. For multiple, especially symptomatic BCBM, whole-brain radiotherapy (WBRT), if possible with hippocampal sparing, is recommended. In cases of multiple asymptomatic BCBM (≥ 5), if SRS/SRT is not feasible or in disseminated brain metastases (> 10), postponing WBRT with early reassessment and reevaluation of local treatment options (8-12 weeks) may be discussed if a HER2/Neu-targeting systemic therapy with significant response rates in the central nervous system (CNS) is being used. In symptomatic leptomeningeal carcinomatosis, local radiotherapy (WBRT or local spinal irradiation) should be performed in addition to systemic therapy. In patients with disseminated leptomeningeal carcinomatosis in good clinical condition and with only limited or stable extra-CNS disease, craniospinal irradiation (CSI) may be considered. Data regarding the toxicity of combining systemic therapies with cranial and spinal radiotherapy are sparse. Therefore, no clear recommendations can be given, and each case should be discussed individually in an interdisciplinary setting.

Palazestrant (OP-1250), A Complete Estrogen Receptor Antagonist, Inhibits Wild-type and Mutant ER-positive Breast Cancer Models as Monotherapy and in Combination

The estrogen receptor (ER) is a well-established target for the treatment of breast cancer, with the majority of patients presenting as ER-positive (ER+). Endocrine therapy is a mainstay of breast cancer treatment but the development of resistance mutations in response to aromatase inhibitors, poor pharmacokinetic properties of fulvestrant, agonist activity of tamoxifen, and limited benefit for elacestrant leave unmet needs for patients with or without resistance mutations in ESR1, the gene that encodes the ER protein. Here we describe palazestrant (OP-1250), a novel, orally bioavailable complete ER antagonist and selective ER degrader. OP-1250, like fulvestrant, has no agonist activity on the ER and completely blocks estrogen-induced transcriptional activity. In addition, OP-1250 demonstrates favorable biochemical binding affinity, ER degradation, and antiproliferative activity in ER+ breast cancer models that is comparable or superior to other agents of interest. OP-1250 has superior pharmacokinetic properties relative to fulvestrant, including oral bioavailability and brain penetrance, as well as superior performance in wild-type and ESR1-mutant breast cancer xenograft studies. OP-1250 combines well with cyclin-dependent kinase 4 and 6 inhibitors in xenograft studies of ER+ breast cancer models and effectively shrinks intracranially implanted tumors, resulting in prolonged animal survival. With demonstrated preclinical efficacy exceeding fulvestrant in wild-type models, elacestrant in ESR1-mutant models, and tamoxifen in intracranial xenografts, OP-1250 has the potential to benefit patients with ER+ breast cancer.

Whole-Brain Radiotherapy Alone vs Preceded by Bevacizumab, Etoposide, and Cisplatin for Untreated Brain Metastases From Breast Cancer: A Randomized Clinical Trial

Importance

The incidence of brain metastasis is increasing in patients with metastatic breast cancer. Treatments to extend the control of brain metastasis are urgently required.

Objective

To investigate whether the addition of an induction treatment of bevacizumab, etoposide, and cisplatin (BEEP) improves brain-specific progression-free survival (PFS) after whole-brain radiotherapy (WBRT).

Design, Setting, and Participants

This open-label, randomized, multicenter clinical trial assessed patients with brain metastases from breast cancer (BMBC) in Taiwan from September 9, 2014, to December 24, 2018, with survival follow-up until December 31, 2021. Key inclusion criteria included metastatic brain tumors not suitable for focal treatment, WBRT naivety, age 20 to 75 years, and at least 1 measurable brain metastatic lesion. The primary end point was brain-specific PFS, with an expected hazard ratio of 0.60, a 2-sided α ≤ .20, and power of 0.8.

Interventions

Eligible patients were randomly assigned at a ratio of 2:1 to the experimental arm, which involved 3 cycles of BEEP followed by WBRT, or the control arm, which involved WBRT alone.

Main Outcomes and Measures

The primary end point was the determination of brain-specific PFS by local investigators according to the Response Evaluation Criteria in Solid Tumors, version 1.1, the initiation of other brain-directed treatment after WBRT, or death. Other key end points included brain-specific objective response rate after 8 weeks of BEEP treatment or WBRT and 8-month brain-specific PFS rate, PFS, and overall survival.

Results

A total of 118 patients with BMBC were randomized, with the intention-to-treat cohort comprising 112 patients. The median age was 56 years (range, 34-71 years), and 61 patients (54.5%) had ERBB2 (formerly HER2 or HER2/neu)-positive disease. The median (range) brain-specific PFS was 8.1 (0.3-29.5) vs 6.5 (0.9-25.5) months in the experimental and control arms, respectively (hazard ratio, 0.71; 95% CI, 0.44-1.13; P = .15; significant at predefined α ≤ .20). The brain-specific objective response rate at 2 months was not significantly different (BEEP treatment vs WBRT, 41.9% vs 52.6%), but the 8-month brain-specific PFS rate was significantly higher in the experimental group (48.7% vs 26.3%; P = .03). Adverse events were generally manageable with prophylactic granulocyte colony-stimulating factor treatment.

Conclusions and Relevance

The findings show that induction BEEP before WBRT may improve the control of BMBC compared with using upfront WBRT, which could address an unmet need for an effective systemic treatment for intractable brain and extracranial metastases from metastatic breast cancer.

Trial Registration

ClinicalTrials.gov Identifier: NCT02185352.

Why does HER2-positive breast cancer metastasize to the brain and what can we do about it?

Breast cancer is the most frequent malignancy in women. However, in the middle and late stages, some people develop distant metastases, which considerably lower the quality of life and life expectancy. The brain is one of the sites where metastasis frequently happens. According to epidemiological research, brain metastases occur at a late stage in 30-50% of patients with HER2-positive breast cancer, resulting in a poor prognosis. Additionally, few treatments are available for HER2-positive brain metastatic breast cancer, and the mortality rate is remarkable owing to the complexity of the brain's anatomical structure and physiological function. In this review, we described the stages of the brain metastasis of breast cancer, the relationship between the microenvironment and metastatic cancer cells, and the unique molecular and cellular mechanisms. It involves cancer cells migrating, invading, and adhering to the brain; penetrating the blood-brain barrier; interacting with brain cells; and activating signal pathways once inside the brain. Finally, we reviewed current clinically used treatment approaches for brain metastasis in HER2-positive breast cancer; summarized the traditional treatment, targeted treatment, immunotherapy, and other treatment modalities; compared the benefits and drawbacks of each approach; discussed treatment challenges; and emphasized the importance of identifying potential targets to improve patient survival rates and comprehend brain metastasis in breast cancer.

Genomic alterations associated with postoperative nodular leptomeningeal disease after resection of brain metastases

OBJECTIVE

The relationship between brain metastasis resection and risk of nodular leptomeningeal disease (nLMD) is unclear. This study examined genomic alterations found in brain metastases with the aim of identifying alterations associated with postoperative nLMD in the context of clinical and treatment factors.

METHODS

A retrospective, single-center study was conducted on patients who underwent resection of brain metastases between 2014 and 2022 and had clinical and genomic data available. Postoperative nLMD was the primary endpoint of interest. Targeted next-generation sequencing of > 500 oncogenes was performed in brain metastases. Cox proportional hazards analyses were performed to identify clinical features and genomic alterations associated with nLMD.

RESULTS

The cohort comprised 101 patients with tumors originating from multiple cancer types. There were 15 patients with nLMD (14.9% of the cohort) with a median time from surgery to nLMD diagnosis of 8.2 months. Two supervised machine learning algorithms consistently identified CDKN2A/B codeletion and ERBB2 amplification as the top predictors associated with postoperative nLMD across all cancer types. In a multivariate Cox proportional hazards analysis including clinical factors and genomic alterations observed in the cohort, tumor volume (× 10 cm3; HR 1.2, 95% CI 1.01-1.5; p = 0.04), CDKN2A/B codeletion (HR 5.3, 95% CI 1.7-16.9; p = 0.004), and ERBB2 amplification (HR 3.9, 95% CI 1.1-14.4; p = 0.04) were associated with a decreased time to postoperative nLMD.

CONCLUSIONS

In addition to increased resected tumor volume, ERBB2 amplification and CDKN2A/B deletion were independently associated with an increased risk of postoperative nLMD across multiple cancer types. Additional work is needed to determine if targeted therapy decreases this risk in the postoperative setting.

Metastatic site patterns by intrinsic subtype and HER2DX in early HER2-positive breast cancer

BACKGROUND

Even with contemporary treatment strategies, more than 10% of HER2-positive early stage breast cancer patients may experience distant metastasis as first event during follow-up. Tools for predicting unique patterns of metastatic spread are needed to plan personalized surveillance. We evaluated how molecular heterogeneity affects the pattern of distant relapse in HER2-positive breast cancer.

METHODS

A total of 677 HER2-positive stage I-III breast cancer patients from ShortHER trial, Cher-LOB trial, and 2 institutional cohorts were included. PAM50 molecular subtypes and research-based HER2DX scores were evaluated. The cumulative incidence of distant relapse as the first event (any site and site specific) was evaluated using competing risk analysis. Median follow-up was 8.4 years. Tests of statistical significance are 2-sided.

RESULTS

Stage III and high HER2DX risk score identified patients at the highest risk of distant relapse as first event (10-year incidence 24.5% and 19.7%, respectively). Intrinsic molecular subtypes were associated with specific patterns of metastatic spread: compared with other subtypes, HER2-enriched tumors were more prone to develop brain metastases (10-year incidence 3.8% vs 0.6%, P = .005), basal-like tumors were associated with an increased risk of lung metastases (10-year incidence 11.1% vs 2.6%, P = .001), and luminal tumors developed more frequently bone-only metastases (10-year incidence 5.1% vs 2.0%, P = .042). When added to stage or HER2DX risk score in competing risk regression models, intrinsic subtype maintained an independent association with site-specific metastases.

CONCLUSIONS

The integration of intrinsic molecular subtypes with stage or HER2DX risk score predicts site-specific metastatic risk in HER2-positive breast cancer, with potential implications for personalized surveillance and clinical trials aimed at preventing site-specific recurrence.

BRCAness of brain lesions reflects a worse outcome for patients with metastatic breast cancer

PURPOSE

Breast cancer often metastasizes to the central nervous system. Although the prognosis of brain metastases from breast cancer has been considered poor, and systemic therapy has not contributed to an improved prognosis, newer agents are expected to be more effective. BRCAness is defined as the status of homologous recombination deficiency (HRD) in tumor tissue, regardless of the presence of pathogenic germline BRCA1/2 variants. A study employing next-generation sequencing analysis showed that HRD was found relatively frequently in brain metastases of breast cancer patients. However, there have been no studies evaluating BRCAness in brain metastases of breast cancer with more efficient, rapid, and cost-effective methods.

METHODS

We retrospectively investigated 17 brain metastases of breast cancer that were surgically resected at our hospital from January 2007 to December 2022. Of these, samples from 15 patients were evaluable for BRCAness by employing multiplex ligation-dependent probe amplification (MLPA) assay.

RESULTS

Of the 15 patients, five patients (33%) had tumors with BRCAness. Clinicopathological factors of patients with brain metastases with BRCAness were not statistically different from those of patients who possessed tumors without BRCAness. Patients with brain metastases with BRCAness had shorter overall survival compared to those without BRCAness (BRCAness, median 15 months (95% CI 2-30) vs. non-BRCAness, median 28.5 months (95% CI 10-60); P = 0.013).

CONCLUSION

In this study, we evaluated BRCAness in brain metastases of breast cancer with the MLPA method, and found that about one-third of patients had BRCAness-positive tumors. The analysis of BRCAness using MLPA has the potential for practical clinical use.

Stereotactic Radiosurgery for Women Older than 65 with Breast Cancer Brain Metastases

BACKGROUND

Breast cancer is the second most common cause of brain metastases (BM). Despite increasing incidence of BM in older women, there are limited data on the optimal management of BM in this age group. In this study, we assessed the survival outcomes and treatment patterns of older breast cancer patients ≥65 years old with BM compared to younger patients at our institution.

METHODS

An IRB-approved single-institutional retrospective review of biopsy-proven breast cancer patients with BM treated with 1- to 5-fraction stereotactic radiation therapy (SRS) from 2015 to 2020 was performed. Primary endpoint was intracranial progression-free survival (PFS) defined as the time interval between the end of SRS to the date of the first CNS progression. Secondary endpoints were overall survival (OS) from the end of SRS and radiation treatment patterns. Kaplan-Meier estimates and Cox proportional hazard regression method were used for survival analyses.

RESULTS

A total of 112 metastatic breast cancer patients with BMs were included of which 24 were ≥65 years old and 88 were <65 years old. Median age at RT was 72 years (range 65-84) compared to 52 years (31-64) in younger patients. There were significantly higher number of older women with ER/PR positive disease (75% vs. 49%, p = 0.036), while younger patients were more frequently triple negative (32% vs. 12%, p = 0.074) and HER2 positive (42% vs. 29%, p = 0.3). Treatment-related adverse events were similar in both groups. Overall, 14.3% patients had any grade radiation necrosis (RN) (older vs. young: 8.3% vs. 16%, p = 0.5) while 5.4% had grade 3 or higher RN (0% vs. 6.8%, p = 0.7). Median OS after RT was poorer in older patients compared to younger patients (9.5 months vs. 14.5 months, p = 0.037), while intracranial PFS from RT was similar between the two groups (9.7 months vs. 7.1 months, p = 0.580). On univariate analysis, significant predictors of OS were age ≥65 years old (hazard risk, HR = 1.70, p = 0.048), KPS ≤ 80 (HR = 2.24, p < 0.001), HER2 positive disease (HR = 0.46, p < 0.001), isolated CNS metastatic disease (HR = 0.29, p < 0.001), number of brain metastases treated with RT (HR = 1.06, p = 0.028), and fractionated SRS (HR = 0.53, p = 0.013). On multivariable analysis, KPS ≤ 80, HER2 negativity and higher number of brain metastases predicted for poorer survival, while age was not a significant factor for OS after adjusting for other variables. Patients who received systemic therapy after SRS had a significantly improved OS on univariate and multivariable analysis (HR = 0.32, p < 0.001). Number of brain metastases treated was the only factor predictive of worse PFS (HR = 1.06, p = 0.041), which implies a 6% additive risk of progression for every additional metastasis treated.

CONCLUSIONS

Although older women had poorer OS than younger women, OS was similar after adjusting for KPS, extracranial progression, and systemic therapy; and there was no difference in rates of intracranial PFS, neurological deaths, and LMD in the different age groups. This study suggests that age alone may not play an independent role in treatment-selection and that outcomes for breast cancer patients with BMs and personalized decision-making including other clinical factors should be considered. Future studies are warranted to assess neurocognitive outcomes and other radiation treatment toxicities in older patients.

Extracellular vesicles in the breast cancer brain metastasis: physiological functions and clinical applications

Breast cancer, which exhibits an increasing incidence and high mortality rate among cancers, is predominantly attributed to metastatic malignancies. Brain metastasis, in particular, significantly contributes to the elevated mortality in breast cancer patients. Extracellular vesicles (EVs) are small lipid bilayer vesicles secreted by various cells that contain biomolecules such as nucleic acids and proteins. They deliver these bioactive molecules to recipient cells, thereby regulating signal transduction and protein expression levels. The relationship between breast cancer metastasis and EVs has been extensively investigated. In this review, we focus on the molecular mechanisms by which EVs promote brain metastasis in breast cancer. Additionally, we discuss the potential of EV-associated molecules as therapeutic targets and their relevance as early diagnostic markers for breast cancer brain metastasis.

A comparison of the efficacy of trastuzumab deruxtecan in advanced HER2-positive breast cancer: active brain metastasis versus progressive extracranial disease alone

BACKGROUND

Trastuzumab deruxtecan (T-DXd) has demonstrated efficacy in patients with brain metastasis (BM), a group historically with poor outcomes. The prevalence of BMs in patients commencing T-DXd is currently unknown. No direct comparisons have been made of the activity of T-DXd in patients with active BM versus those with extracranial progression alone. This real-world study explored the prevalence of BMs in patients commencing T-DXd, the efficacy of T-DXd in active BM versus extracranial progression alone and the safety of T-DXd.

PATIENTS AND METHODS

Patients with human epidermal growth factor receptor 2-positive advanced breast cancer treated with T-DXd between June 2021 and February 2023 at our specialist cancer hospital were identified and notes reviewed. Clinicopathological information, prior treatment, the presence or absence of central nervous system (CNS) disease, outcomes and treatment-emergent adverse events (TEAEs) were recorded.

RESULTS

Twenty-nine female patients, with a median age of 52 years (interquartile range 44-62 years), were identified; the prevalence of BM was 41%. Median number of lines of prior therapy was 2 (range 2-6). At a median follow-up of 13.8 months, median progression-free survival (PFS) for the overall population was 13.9 months [95% confidence interval (CI) 12.4 months-not estimable (NE)], 16.1 months (95% CI 15.1 months-NE) for active BMs and 12.4 months (95% CI 8.3 months-NE) for progressive extracranial disease alone. The 12-month overall survival (OS) rate was 74% (95% CI 59% to 95%) in the overall population, and 83% (95% CI 58% to 100%) and 66% (95% CI 45% to 96%) for active BMs and extracranial disease only, respectively. Most common TEAEs were fatigue, alopecia, and constipation. In nine patients (31%, including two deaths), pneumonitis occurred.

CONCLUSION

In this real-world population, we demonstrate T-DXd to be effective in patients with active BMs and those with progressive extracranial disease alone. PFS and OS were numerically longer in those with active BMs. These data demonstrate that patients with active BM treated with T-DXd have at least comparable outcomes to those with extracranial disease alone. The high rate of pneumonitis warrants further consideration.

Systemic Treatment for Brain Metastasis and Leptomeningeal Disease in Breast Cancer Patients

PURPOSE OF REVIEW

Breast cancer with brain metastasis (BCBM) and leptomeningeal disease (LMD) are important clinical problems. Traditionally, patients with metastases to the brain and meninges were excluded from clinical trials; hence, robust, evidence-based treatment recommendations are lacking. In this review, we outline the systemic treatment options and ongoing clinical trials.

RECENT FINDINGS

Several recent studies have added to the systemic treatment options available. Antibody-drug conjugates have changed the therapeutic landscape. Combination treatment modalities that target multiple mechanisms including disruption of the blood brain barrier are increasingly being studied. Breast cancer with brain metastases and LMD is a heterogenous disease. While the prognosis remains grim, with more systemic treatment options, patients with BCBM are now living longer. Many ongoing clinical trials hold promise to further improve outcomes.