Stereotactic radiosurgery with concurrent lapatinib is associated with improved local control for HER2-positive breast cancer brain metastases

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.

Role of radiotherapy in the management of brain oligometastases

The management of patients with brain oligometastases is complex and relies on specific reasoning compared to extracranial oligometastases. The levels of evidence are still low because patients with brain oligometastases are frequently excluded from randomized clinical trials. Stereotactic radiotherapy should be preferred in this indication over whole brain irradiation, both for patients with metastases in place and for those who have undergone surgery. The decision of local treatment and its timing must be a multidisciplinary reflection taking into account the histological and molecular characteristics of the tumor as well as the intracranial efficacy of the prescribed systemic treatments. Great caution must be observed when using stereotactic radiotherapy and concomitant systemic treatments because interactions are still poorly documented. We present the recommendations of the French society of radiation oncology on the management of brain oligometastatic patients with radiotherapy.

Advances in molecular targeted therapies to increase efficacy of (chemo)radiation therapy

Recent advances in understanding the tumor's biology in line with a constantly growing number of innovative technologies have prompted characterization of patients' individual malignancies and may display a prerequisite to treat cancer at its patient individual tumor vulnerability. In recent decades, radiation- induced signaling and tumor promoting local events for radiation sensitization were explored in detail, resulting the development of novel molecular targets. A multitude of pharmacological, genetic, and immunological principles, including small molecule- and antibody-based targeted strategies, have been developed that are suitable for combined concepts with radiation (RT) or chemoradiation therapy (CRT). Despite a plethora of promising experimental and preclinical findings, however, so far, only a very limited number of clinical trials have demonstrated a better outcome and/or patient benefit when RT or CRT are combined with targeted agents. The current review aims to summarize recent progress in molecular therapies targeting oncogenic drivers, DNA damage and cell cycle response, apoptosis signaling pathways, cell adhesion molecules, hypoxia, and the tumor microenvironment to impact therapy refractoriness and to boost radiation response. In addition, we will discuss recent advances in nanotechnology, e.g., RNA technologies and protein-degrading proteolysis-targeting chimeras (PROTACs) that may open new and innovative ways to benefit from molecular-targeted therapy approaches with improved efficacy.

Low-Dose Radiosurgery for Brain Metastases in the Era of Modern Systemic Therapy

BACKGROUND AND OBJECTIVES

Dose selection for brain metastases stereotactic radiosurgery (SRS) classically has been based on tumor diameter with a reduction of dose in the settings of prior brain irradiation, larger tumor volumes, and critical brain location. However, retrospective series have shown local control rates to be suboptimal with reduced doses. We hypothesized that lower doses could be effective for specific tumor biologies with concomitant systemic therapies. This study aims to report the local control (LC) and toxicity when using low-dose SRS in the era of modern systemic therapy.

METHODS

We reviewed 102 patients with 688 tumors managed between 2014 and 2021 who had low-margin dose radiosurgery, defined as ≤14 Gy. Tumor control was correlated with demographic, clinical, and dosimetric data.

RESULTS

The main primary cancer types were lung in 48 (47.1%), breast in 31 (30.4%), melanoma in 8 (7.8%), and others in 15 patients (11.7%). The median tumor volume was 0.037cc (0.002-26.31 cm 3 ), and the median margin dose was 14 Gy (range 10-14). The local failure (LF) cumulative incidence at 1 and 2 years was 6% and 12%, respectively. On competing risk regression analysis, larger volume, melanoma histology, and margin dose were predictors of LF. The 1-year and 2-year cumulative incidence of adverse radiation effects (ARE: an adverse imaging-defined response includes increased enhancement and peritumoral edema) was 0.8% and 2%.

CONCLUSION

It is feasible to achieve acceptable LC in BMs with low-dose SRS. Volume, melanoma histology, and margin dose seem to be predictors for LF. The value of a low-dose approach may be in the management of patients with higher numbers of small or adjacent tumors with a history of whole brain radio therapy or multiple SRS sessions and in tumors in critical locations with the aim of LC and preservation of neurological function.

Novel Mechanisms and Future Opportunities for the Management of Radiation Necrosis in Patients Treated for Brain Metastases in the Era of Immunotherapy

Radiation necrosis, also known as treatment-induced necrosis, has emerged as an important adverse effect following stereotactic radiotherapy (SRS) for brain metastases. The improved survival of patients with brain metastases and increased use of combined systemic therapy and SRS have contributed to a growing incidence of necrosis. The cyclic GMP-AMP (cGAMP) synthase (cGAS) and stimulator of interferon genes (STING) pathway (cGAS-STING) represents a key biological mechanism linking radiation-induced DNA damage to pro-inflammatory effects and innate immunity. By recognizing cytosolic double-stranded DNA, cGAS induces a signaling cascade that results in the upregulation of type 1 interferons and dendritic cell activation. This pathway could play a key role in the pathogenesis of necrosis and provides attractive targets for therapeutic development. Immunotherapy and other novel systemic agents may potentiate activation of cGAS-STING signaling following radiotherapy and increase necrosis risk. Advancements in dosimetric strategies, novel imaging modalities, artificial intelligence, and circulating biomarkers could improve the management of necrosis. This review provides new insights into the pathophysiology of necrosis and synthesizes our current understanding regarding the diagnosis, risk factors, and management options of necrosis while highlighting novel avenues for discovery.

Interaction between Radiation Therapy and Targeted Therapies in HER2-Positive Breast Cancer: Literature Review, Levels of Evidence for Safety and Recommendations for Optimal Treatment Sequence

Purpose: Over the past twenty years, anti-HER2 targeted therapies have proven to be a revolution in the management of human epidermal growth receptor 2 (HER2)-positive breast cancers. Anti-HER2 therapies administered alone or in combination with chemotherapy have been specifically studied. Unfortunately, the safety of anti-HER2 therapies in combination with radiation remains largely unknown. Thus, we propose a literature review of the risks and safety of combining radiotherapy with anti-HER2 therapies. We will focus on the benefit/risk rationale and try to understand the risk of toxicity in early-stage and advanced breast cancer. Methods: Research was carried out on the following databases: PubMed, EMBASE, ClinicalTrial.gov, Medline, and Web of Science for the terms "radiotherapy", "radiation therapy", "radiosurgery", "local ablative therapy", and "stereotactic", combined with "trastuzumab", "pertuzumab", "trastuzumab emtansine", "TDM-1", "T-Dxd", "trastuzumab deruxtecan", "tucatinib", "lapatinib", "immune checkpoint inhibitors", "atezolizumab", "pembrolizumab", "nivolumab", "E75 vaccine", "interferon", "anti-IL-2", "anti-IL 12", and "ADC". Results: Association of radiation and monoclonal antibodies such as trastuzumab and pertuzumab (with limited data) seems to be safe, with no excess risk of toxicity. Preliminary data with radiation and of antibody-drug conjugate of trastuzumab combined cytotoxic (trastuzumab emtansine, trastuzumab deruxtecan), given the underlying mechanism of action, suggest that one must be particularly cautious with the association. The safety of the combination of a tyrosine kinase inhibitor (lapatinib, tucatinib) and radiation remains under-studied. The available evidence suggests that checkpoint inhibitors can be safely administrated with radiation. Conclusions: HER2-targeting monoclonal antibodies and checkpoint inhibitors can be combined with radiation, apparently with no excess toxicities. Caution is required when associating radiation with TKI and antibody drugs, considering the limited evidence.

Radiotherapeutic Strategies to Overcome Resistance of Breast Cancer Brain Metastases by Considering Immunogenic Aspects of Cancer Stem Cells

Breast cancer is the most diagnosed cancer in women, and symptomatic brain metastases (BCBMs) occur in 15-20% of metastatic breast cancer cases. Despite technological advances in radiation therapy (RT), the prognosis of patients is limited. This has been attributed to radioresistant breast cancer stem cells (BCSCs), among other factors. The aim of this review article is to summarize the evidence of cancer-stem-cell-mediated radioresistance in brain metastases of breast cancer from radiobiologic and radiation oncologic perspectives to allow for the better interpretability of preclinical and clinical evidence and to facilitate its translation into new therapeutic strategies. To this end, the etiology of brain metastasis in breast cancer, its radiotherapeutic treatment options, resistance mechanisms in BCSCs, and effects of molecularly targeted therapies in combination with radiotherapy involving immune checkpoint inhibitors are described and classified. This is considered in the context of the central nervous system (CNS) as a particular metastatic niche involving the blood-brain barrier and the CNS immune system. The compilation of this existing knowledge serves to identify possible synergistic effects between systemic molecularly targeted therapies and ionizing radiation (IR) by considering both BCSCs' relevant resistance mechanisms and effects on normal tissue of the CNS.

Update on the Management of Brain Metastasis

Brain metastases occur in almost one-third of adult patients with solid tumor malignancies and lead to considerable patient morbidity and mortality. The rising incidence of brain metastases has been ascribed to the development of better imaging and screening techniques and the formulation of better systemic therapies. Until recently, the multimodal management of brain metastases focused primarily on the utilization of neurosurgical techniques, with varying combinations of whole-brain radiation therapy and stereotactic radio-surgical procedures. Over the past 2 decades, in particular, the increment in knowledge pertaining to molecular genetics and the pathogenesis of brain metastases has led to significant developments in targeted therapies and immunotherapies. This review article highlights the recent updates in the management of brain metastases with an emphasis on novel systemic therapies.

Ways to improve breast cancer patients' management and clinical outcome: The 2020 Assisi Think Tank Meeting

We report on the third Assisi Think Tank Meeting (ATTM) on breast cancer, a brainstorming project which involved European radiation and clinical oncologists who were dedicated to breast cancer research and treatment. Held on February 2020, the ATTM aimed at identifying key clinical questions in current clinical practice and "grey" areas requiring research to improve management and outcomes. Before the meeting, three key topics were selected: 1) managing patients with frailty due to either age and/or multi-morbidity; 2) stereotactic radiation therapy and systemic therapy in the management of oligometastatic disease; 3) contralateral breast tumour prevention in BCRA-mutated patients. Clinical practice in these areas was investigated by means of an online questionnaire. In the lapse period between the survey and the meeting, the working groups reviewed data, on-going studies and the clinical challenges which were then discussed in-depth and subjected to intense brainstorming during the meeting; research protocols were also proposed. Methodology, outcome of discussions, conclusions and study proposals are summarized in the present paper. In conclusion, this report presents an in-depth analysis of the state of the art, grey areas and controversies in breast cancer radiation therapy and discusses how to confront them in the absence of evidence-based data to guide clinical decision-making.

Systemic Therapy Type and Timing Effects on Radiation Necrosis Risk in HER2+ Breast Cancer Brain Metastases Patients Treated With Stereotactic Radiosurgery

Background

There is a concern that HER2-directed systemic therapies, when administered concurrently with stereotactic radiosurgery (SRS), may increase the risk of radiation necrosis (RN). This study explores the impact of timing and type of systemic therapies on the development of RN in patients treated with SRS for HER2+ breast cancer brain metastasis (BCBrM).

Methods

This was a single-institution, retrospective study including patients >18 years of age with HER2+ BCBrM who received SRS between 2013 and 2018 and with at least 12-month post-SRS follow-up. Presence of RN was determined via imaging at one-year post-SRS, with confirmation by biopsy in some patients. Demographics, radiotherapy parameters, and timing (“during” defined as four weeks pre- to four weeks post-SRS) and type of systemic therapy (e.g., chemotherapy, HER2-directed) were evaluated.

Results

Among 46 patients with HER2+ BCBrM who received SRS, 28 (60.9%) developed RN and 18 (39.1%) did not based on imaging criteria. Of the 11 patients who underwent biopsy, 10/10 (100%) who were diagnosed with RN on imaging were confirmed to be RN positive on biopsy and 1/1 (100%) who was not diagnosed with RN was confirmed to be RN negative on biopsy. Age (mean 53.3 vs 50.4 years, respectively), radiotherapy parameters (including total dose, fractionation, CTV and size target volume, all p>0.05), and receipt of any type of systemic therapy during SRS (60.7% vs 55.6%, p=0.97) did not differ between patients who did or did not develop RN. However, there was a trend for patients who developed RN to have received more than one agent of HER2-directed therapy independent of SRS timing compared to those who did not develop RN (75.0% vs 44.4%, p=0.08). Moreover, a significantly higher proportion of those who developed RN received more than one agent of HER2-directed therapy during SRS treatment compared to those who did not develop RN (35.7% vs 5.6%, p=0.047).

Conclusions

Patients with HER2 BCBrM who receive multiple HER2-directed therapies during SRS for BCBrM may be at higher risk of RN. Collectively, these data suggest that, in the eight-week window around SRS administration, if HER2-directed therapy is medically necessary, it is preferable that patients receive a single agent.

Improving Brain Metastases Outcomes Through Therapeutic Synergy Between Stereotactic Radiosurgery and Targeted Cancer Therapies

Brain metastases are the most common form of brain cancer. Increasing knowledge of primary tumor biology, actionable molecular targets and continued improvements in systemic and radiotherapy regimens have helped improve survival but necessitate multidisciplinary collaboration between neurosurgical, medical and radiation oncologists. In this review, we will discuss the advances of targeted therapies to date and discuss findings of studies investigating the synergy between these therapies and stereotactic radiosurgery for non-small cell lung cancer, breast cancer, melanoma, and renal cell carcinoma brain metastases.

Radiotherapy for HER 2 Positive Brain Metastases: Urgent Need for a Paradigm Shift

Brain metastases (BMs) are common among patients affected by HER2+ metastatic breast cancer (>30%). The management of BMs is usually multimodal, including surgery, radiotherapy, systemic therapy and palliative care. Standard brain radiotherapy (RT) includes the use of stereotactic radiotherapy (SRT) for limited disease and whole brain radiotherapy (WBRT) for extensive disease. The latter is an effective palliative treatment but has a reduced effect on brain local control and BM overall survival, as it is also associated with severe neurocognitive sequelae. Recent advances both in radiation therapy and systemic treatment may change the paradigm in this subset of patients who can experience long survival notwithstanding BMs. In fact, in recent studies, SRT for multiple BM sites (>4) has shown similar efficacy when compared to irradiation of a limited number of lesions (one to three) without increasing toxicity. These findings, in addition to the introduction of new drugs with recognized intracranial activity, may further limit the use of WBRT in favor of SRT, which should be employed for treatment of both multiple-site BMs and for oligo-progressive brain disease. This review summarizes the supporting literature and highlights the need for optimizing combinations of the available treatments in this setting, with a particular focus on radiation therapy.

Cerebral metastases

Brain metastases are common and deadly. Over the last 25 years GKNS has been established as an invaluable treatment. It may be used as a primary treatment or after either surgery or WBRT. Patients are assessed using one of a number of available scales. GKNS may be repeated for new metastases and for unresponsive tumors. Prescription doses are usually between 18 and 20Gy. The use of advanced MR techniques to highlight sensitive structures like the hippocampi have extended the efficacy of the treatment. More recently GKNS has been used with different target therapies with improved results. More recently frameless treatments have become more popular in this group of very sick patients. GKNS controls tumors in between 80% and over 95% of cases and may even be used for brainstem tumors.

Stereotactic Radiation and Dual Human Epidermal Growth Factor Receptor 2 Blockade with Trastuzumab and Pertuzumab in the Treatment of Breast Cancer Brain Metastases: A Single Institution Series

(1) Background: This study aims to assess the safety and efficacy of fractionated SRT (fSRT) and pertuzumab-trastuzumab (PT) in patients with breast cancer brain metastases (BCBM). (2) Methods: Patients with HER2+ BCBM who received FSRT from 2015 to 2019 were identified. Patients were included if they were treated with fSRT within 21 days of receiving PT. All lesions were treated with LINAC-based fSRT to a total dose of 27 Gy delivered in three consecutive fractions. All patients received concurrent PT. Patients were evaluated 4-6 weeks after SRS and subsequently every 2-3 months with MRI re-imaging (3) Results: A total of 49 patients with HER2+ brain metastases were identified. Of these patients, a total of 10 patients with 32 HER2+ BCBM were treated with concurrent SRT and PT and included in the analysis. No local progression was observed. Overall response rate was 68.7%. Only one patient developed asymptomatic radionecrosis. Median time to BM occurrence was 15.6 (range: 1-40.5 months). Distant intracranial failure occurred in 4/10 patients (40.0%). Overall BCBM median survival was 33.9 months (95%CI 24.1-43.6). Mean duration of PT treatment was 27.9 months (range: 10.1-53.7 months). (4) Conclusions: In our single institution experience, fSRT and PT showed to be a safe treatment for patients with BCBM with an adequate overall response rate.

Focal Radiotherapy of Brain Metastases in Combination With Immunotherapy and Targeted Drug Therapy

BACKGROUND

Advances in systemic treatment and in brain imaging have led to a higher incidence of diagnosed brain metastases. In the treatment of brain metastases, stereotactic radiotherapy and radiosurgery, systemic immunotherapy, and targeted drug therapy are important evidence-based options. In this review, we summarize the available evidence on the treatment of brain metastases of the three main types of cancer that give rise to them: non-small-cell lung cancer, breast cancer, and malignant melanoma.

METHODS

This narrative review is based on pertinent original articles, meta-analyses, and systematic reviews that were retrieved by a selective search in PubMed. These publications were evaluated and discussed by an expert panel including radiation oncologists, neurosurgeons, and oncologists.

RESULTS

There have not yet been any prospective randomized trials concerning the optimal combination of local stereotactic radiotherapy/radiosurgery and systemic immunotherapy or targeted therapy. Retrospective studies have consistently shown a benefit from early combined treatment with systemic therapy and (in particular) focal radiotherapy, compared to sequential treatment. Two metaanalyses of retrospective data from cohorts consisting mainly of patients with non-small-cell lung cancer and melanoma revealed longer overall survival after combined treatment with focal radiotherapy and checkpoint inhibitor therapy (rate of 12-month overall survival for combined versus non-combined treatment: 64.6% vs. 51.6%, p <0.001). In selected patients with small, asymptomatic brain metastases in non-critical locations, systemic therapy without focal radiotherapy can be considered, as long as follow-up with cranial magnetic resonance imaging can be performed at close intervals.

CONCLUSION

Brain metastases should be treated by a multidisciplinary team, so that the optimal sequence of local and systemic therapies can be determined for each individual patient.

Advances in the management of breast cancer brain metastases

The development of breast cancer (BC) brain metastases (BrM) is a common complication of advanced disease, occurring in up to half of the patients with advanced disease depending on the subtype. The management of BCBrM requires complex multidisciplinary care including local therapy, surgical resection and/or radiotherapy, palliative care, and carefully selected systemic therapies. Significant progress has been made in the human epidermal growth factor receptor 2-positive (HER2+) BCBrM population due to novel brain penetrable systemic therapies. Increased inclusion of patients with BCBrM in clinical trials using brain-penetrant systemic therapies recently led to the first FDA approval of a HER2-directed therapy specifically in the BCBrM population in the last year. Advances for the treatment of HR+/HER2- and TNBC BCBrM subgroups continue to evolve. In this review, we will discuss the diagnosis and multidisciplinary care of BCBrM. We focus on recent advances in neurosurgery, radiation therapy, and systemic treatment therapies with intracranial activity. We also provide an overview of the current clinical trial landscape for patients with BCBrM.

Integration of Systemic Therapy and Stereotactic Radiosurgery for Brain Metastases

Simple Summary

In the multi-modal treatment of brain metastasis (BM), the role of systemic therapy has undergone a recent revolution. Due to the development of multiple agents with modest central nervous system penetration of the blood-brain barrier, targeted therapies and immune checkpoint inhibitors are increasingly being utilized alone or in combination with radiation therapy. However, the adoption of sequential or concurrent strategies varies considerably, and treatment strategies employed in clinical practice have rapidly outpaced evidence development. Therefore, this review critically analyzes the data regarding combinatorial approaches for a variety of systemic therapeutics with stereotactic radiosurgery and provides an overview of ongoing clinical trials.

Abstract

Brain metastasis (BM) represents a common complication of cancer, and in the modern era requires multi-modal management approaches and multi-disciplinary care. Traditionally, due to the limited efficacy of cytotoxic chemotherapy, treatment strategies are focused on local treatments alone, such as whole-brain radiotherapy (WBRT), stereotactic radiosurgery (SRS), and resection. However, the increased availability of molecular-based therapies with central nervous system (CNS) penetration now permits the individualized selection of tailored systemic therapies to be used alongside local treatments. Moreover, the introduction of immune checkpoint inhibitors (ICIs), with demonstrated CNS activity has further revolutionized the management of BM patients. The rapid introduction of these cancer therapeutics into clinical practice, however, has led to a significant dearth in the published literature about the optimal timing, sequencing, and combination of these systemic therapies along with SRS. This manuscript reviews the impact of tumor biology and molecular profiles on the management paradigm for BM patients and critically analyzes the current landscape of SRS, with a specific focus on integration with systemic therapy. We also discuss emerging treatment strategies combining SRS and ICIs, the impact of timing and the sequencing of these therapies around SRS, the effect of corticosteroids, and review post-treatment imaging findings, including pseudo-progression and radiation necrosis.

Local ablative therapy in oncogenic-driven oligometastatic non-small cell lung cancer: present and ongoing strategies-a narrative review

Oligometastatic (OM) disease is defined by a low metastatic tumor spread. OM non-small cell lung cancer (NSCLC) treatment aims to improve the patient's prognosis and quality of life, in an attempt-to-cure objective. Oncogenic-driven metastatic NSCLC accounts for about 20-25% of NSCLCs, with an ever-increasing number of potentially druggable molecular alterations. Due to specific targeted therapy, the care and prognosis of mutated NSCLC is quite different from non-oncogenic-driven NSCLC. However, OM-NSCLC treatment guidelines do not specifically discuss oncogenic-driven OM-NSCLC patients. We conducted a narrative review regarding retrospective and prospective studies published from inception to May 2020 dealing with oncogenic-driven OM-NSCLC in order to: (I) describe the specific patterns of metastatic spread of oncogenic-driven NSCLC (i.e., bone and pleural tropism in EGFR mutated NSCLC and serous and brain metastases in ALK NSCLC); (II) review the low level of current evidence for local ablative therapy (LAT) strategies in patients with oncogenic-driven OM-NSCLC, focusing on the benefit/risk of tyrosine kinase inhibitors (TKI) and LATs combination and (III) present strategies to help to select the best candidate for an attempt-to-cure approach. Finally, the optimal strategy may be to introduce a targeted therapy, then treat all tumor sites with LAT, and finally continue TKI for unknown prolonged duration in an attempt to prolong progression free survival in most patients, improve overall survival for some patients, and potentially lead to a cancer cure for a few patients.

Validation of the updated renal graded prognostic assessment (GPA) for patients with renal cancer brain metastases treated with gamma knife radiosurgery

INTRODUCTION

Prognosis of patients with brain metastasis (BM) from renal cell carcinoma (RCC) is relevant for treatment decisions and can be estimated with the Renal Graded Prognostic Assessment (GPA). The aim of this study is to validate the updated version of this instrument in a cohort treated with Gamma Knife radiosurgery (GKRS) without prior local intracerebral therapy.

METHODS

Between 2007 and 2018, 106 RCC patients with BM were treated with GKRS. They were categorized according to the updated Renal GPA. Overall survival (OS), distant intracranial failure and local failure were estimated using the Kaplan-Meier method and risk factors were identified with Cox proportional hazard regressions.

RESULTS

Median OS was 8.6 months. Median OS for GPA categories 0.0-1.0 (15%), 1.5-2.0 (12%), 2.5-3.0 (35%) and 3.5-4.0 (29%) was 2.9, 5.5, 8.1 and 20.4 months, respectively. Karnofsky performance status < 90, serum hemoglobin ≤ 12.5 g/dL, age > 65 years and time from primary diagnosis to brain metastasis < 1 year were significantly related with shorter survival, while presence of extracranial disease, the volume and total number of BM had no significant impact on OS. A total count of > 4 BM was the only predictive factor for distant intracranial failure, while none of the investigated factors predicted local failure.

CONCLUSIONS

This study confirms the updated Renal GPA in an independent cohort as a valuable instrument to estimate survival in patients with BM from RCC treated with GKRS.

Brain Metastases in HER2-Positive Breast Cancer: Current and Novel Treatment Strategies

Development of brain metastases can occur in up to 30-50% of patients with breast cancer, representing a significant impact on an individual patient in terms of survival and quality of life. Patients with HER2-positive breast cancer have an increased risk of developing brain metastases; however, screening for brain metastases is not currently recommended due to the lack of robust evidence to support survival benefit. In recent years, several novel anti-HER2 agents have led to significant improvements in the outcomes of HER2-positive metastatic breast cancer. Despite these advances, brain and leptomeningeal metastases from HER2-positive breast cancer remain a significant cause of morbidity and mortality, and their optimal management remains an unmet need. This review presents an update on the current and novel treatment strategies for patients with brain metastases from HER2-positive breast cancer and discusses the open questions in the field.

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.

Trastuzumab Emtansine (T-DM1) and stereotactic radiation in the management of HER2+ breast cancer brain metastases

Background

Due to recent concerns about the toxicity of trastuzumab emtansine (T-DM1) with stereotactic radiation, we assessed our institutional outcomes treating HER2-positive breast cancer brain metastases (BCBM) with T-DM1 and stereotactic radiation.

Methods

This is a single institution series of 16 patients with HER2-positive breast cancer who underwent 18 stereotactic sessions to 40 BCBM from 2013 to 2019 with T-DM1 delivered within 6 months. The Kaplan-Meier method was used to calculate overall survival (OS), local control (LC), distant intracranial control (DIC), and systemic progression-free survival (sPFS) from the date of SRS. A neuro-radiologist independently reviewed follow-up imaging.

Results

One patient had invasive lobular carcinoma, and 15 patients had invasive ductal carcinoma. All cases were HER2-positive, while 10 were hormone receptor (HR) positive. Twenty-four lesions were treated with stereotactic radiosurgery (SRS) to a median dose of 21 Gy (14–24 Gy). Sixteen lesions were treated with fractionated stereotactic radiation (FSRT) with a median dose of 25 Gy (20-30Gy) delivered in 3 to 5 fractions. Stereotactic radiation was delivered concurrently with T-DM1 in 19 lesions (48%). Median follow up time was 13.2 months from stereotactic radiation. The 1-year LC, DIC, sPFS, and OS were 75, 50, 30, and 67%, respectively. There was 1 case of leptomeningeal progression and 1 case (3%) of symptomatic radionecrosis.

Conclusions

We demonstrate that stereotactic radiation and T-DM1 is well-tolerated and effective for patients with HER2-positive BCBM. An increased risk for symptomatic radiation necrosis was not noted in our series.

Stereotactic radiosurgery for patients with breast cancer brain oligometastases - molecular subtypes and clinical outcomes

Background

We sought to determine the clinical outcomes of patients with breast cancer (BC) who had undergone stereotactic radiosurgery (SRS) for a limited number of brain metastases (BM) and to identify factors influencing overall survival (OS) and local control.

Materials and methods

The records of 45 patients who underwent SRS for 72 brain lesions were retrospectively evaluated. Statistics included the chi-squared test, Kaplan-Meier method, and the multivariate Cox model.

Results

The median number of treated BM was 2 (range 1-10). Median OS from BM diagnosis and post-SRS were 27.6 [95% confidence interval (CI): 14.8-40.5) and 18.5 months (95% CI: 11.1-25.8), respectively. One-year and two-year survival rates after BM diagnosis were 55% and 41%, respectively. In a univariate analysis, the Luminal-B-human-epidermal-growth-receptor-positive (HER2+) subtype had the longest median OS at 39.1 months (95% CI: 34.1-44.1, p = 0.004). In an adjusted analysis, grade 2 [hazard ratio (HR): 0.1; 95% CI: 0.1-0.6, p = 0.005), craniotomy (HR: 0.3; 95% CI: 0.1-0.7; p = 0.006), and ≥ 2 systemic therapies received (HR: 0.3; 95% CI: 0.1-0.9, p = 0.028) were associated with improved OS. One-year and two-year intracranial progression-free survival rates were 85% and 63%, respectively. Four factors for a higher risk of any intracranial recurrence remained significant in the adjusted analysis, as follows: age < 50 years (HR: 4.2; 95% CI: 1.3-36.3; p = 0.014), grade 3 (HR: 3.7; 95% CI: 1.1-13.2; p = 0.038), HER2+ (HR: 6.9; 95% CI: 1.3-36.3; p = 0.023), and whether the brain was the first metastatic site (HR: 4.7; 95% CI: 1.6-14.5; p = 0.006).

Conclusion

Intrinsic BC characteristics are important determinants for both survival and intracranial control for patients undergoing SRS for oligometastatic brain disease.

Imaging challenges of immunotherapy and targeted therapy in patients with brain metastases: response, progression, and pseudoprogression

The advent of immunotherapy using immune checkpoint inhibitors (ICIs) and targeted therapy (TT) has dramatically improved the prognosis of various cancer types. However, following ICI therapy or TT-either alone (especially ICI) or in combination with radiotherapy-imaging findings on anatomical contrast-enhanced MRI can be unpredictable and highly variable, and are often difficult to interpret regarding treatment response and outcome. This review aims at summarizing the imaging challenges related to TT and ICI monotherapy as well as combined with radiotherapy in patients with brain metastases, and to give an overview on advanced imaging techniques which potentially overcome some of these imaging challenges. Currently, major evidence suggests that imaging parameters especially derived from amino acid PET, perfusion-/diffusion-weighted MRI, or MR spectroscopy may provide valuable additional information for the differentiation of treatment-induced changes from brain metastases recurrence and the evaluation of treatment response.

Systematic review and meta-analysis of breast cancer brain metastasis and primary tumor receptor expression discordance

Background

Change in hormone receptor (estrogen [ER] and progesterone [PR]) and/or human epidermal growth factor receptor type 2 (HER2) status during the evolutionary course of metastatic breast cancer and the effect of tumor classification subtype switching remain understudied and underappreciated in brain metastasis patients.

Methods

Using preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, a systematic review of series published prior to April 2020 obtained from the Medline database of biopsied or resected breast cancer brain metastasis (BCBM) was performed. Weighted random effects models were used to calculate pooled estimates.

Results

15 full-text articles were included with receptor expression analyses on 1373 patients who underwent biopsy or resection of at least one intracranial lesion to compare to the primary tumor. Primary tumor receptor expression immunophenotypes were 45.0% ER+, 41.0% ER−, 31.0% PR+, 51.0% PR−, 35% HER2+, and 47.0% HER2−. Corresponding BCBM immunophenotypes were 19.0% ER+, 31.0% ER−, 13.0% PR+, 40.0% PR−, 21.0% HER2+, and 26.0% HER2−. On primary/BCBM comparison, 540 patients (42.6%) exhibited discordance in any receptor with 17.0% (95% CI: 13.0%–23.0%) discordant on ER, 23.0% (95% CI: 18.0%–30.0%) discordant on PR, and 12.0% (95% CI: 8.0%–16.0%) discordant on HER2 status. The most common receptor conversions found in BCBM were ER loss 11.0% (95% CI: 8.0%–16.0%), PR loss 15.0% (95% CI: 11.0%–21.0%), and HER2 gain 9.0% (95% CI: 7.0%–11.0%).

Conclusions

BCBM exhibits significant receptor expression discordance in comparison to primary tumors in approximately 40% of patients. Classification patterns need to be analyzed to determine factors predictive of BCBM/primary tumor discordance. Overall, tumor subtype switching and its effect on clinical management remains underappreciated.

Local control and patterns of failure for "Radioresistant" spinal metastases following stereotactic body radiotherapy compared to a "Radiosensitive" reference

PURPOSE

The concept of a radioresistant (RR) phenotype has been challenged with use of stereotactic body radiotherapy (SBRT). We compared outcomes following SBRT to RR spinal metastases to a radiosensitive cohort.

METHODS

Renal cell, melanoma, sarcoma, gastro-intestinal, and thyroid spinal metastases were identified as RR and prostate cancer (PCA) as radiosensitive. The primary endpoint was MRI-based local failure (LF). Secondary endpoints included overall survival (OS) and vertebral compression fracture (VCF).

RESULTS

From a prospectively maintained database of 1394 spinal segments in 605 patients treated with spine SBRT, 173 patients/395 RR spinal segments were compared to 94 patients/185 PCA segments. Most received 24-28 Gy in 2 fractions (68.9%) and median follow-up was 15.5 months (range, 1.4-84.2 months). 1- and 2-year LF rates were 19.2% and 22.4% for RR metastases, respectively, which were significantly greater (p < 0.001) than PCA (3.2% and 8.4%, respectively). Epidural disease (HR: 2.47, 95% CI 1.65-3.71, p < 0.001) and RR histology (HR: 2.41, 95% CI 1.45-3.99, p < 0.001) predicted for greater LF. Median OS was 17.4 and 61.0 months for RR and PCA cohorts, respectively. Lung/liver metastases, polymetastatic disease and epidural disease predicted for worse OS. 2-year VCF rates were ~ 13% in both cohorts. Coverage of the CTV V90 (clinical target volume receiving 90% of prescription dose) by ≥ 87% (HR: 2.32, 95% CI 1.29-4.18, p = 0.005), no prior spine radiotherapy (HR: 1.96, 95% CI 1.09-3.55, p = 0.025), and a greater Spinal Instability Neoplasia Score (p = 0.013) predicted for VCF.

CONCLUSIONS

Higher rates of LF were observed after spine SBRT in RR metastases. Optimization strategies include dose escalation and aggressive management of epidural disease.

Safety of radiosurgery concurrent with systemic therapy (chemotherapy, targeted therapy, and/or immunotherapy) in brain metastases: a systematic review

Stereotactic radiosurgery (SRS) is a standard option for brain metastases (BM). There is lack of consensus when patients have a systemic treatment, if a washout is necessary. The aim of this review is to analyze the toxicity of SRS when it is concurrent with chemotherapies, immunotherapy, and/or targeted therapies. From Medline and Embase databases, we searched for English literature published up to April 2020 according to the PRISMA guidelines, using for key words the list of the main systemic therapies currently in use And "radiosurgery," "SRS," "GKRS," "Gamma Knife," "toxicity," "ARE," "radiation necrosis," "safety," "brain metastases." Studies reporting safety or toxicity with SRS concurrent with systemic treatment for BM were included. Of 852 abstracts recorded, 77 were included. The main cancers were melanoma, lung, breast, and renal carcinoma. These studies cumulate 6384 patients. The median SRS dose prescription was 20 Gy [12-30] .For some, they compared a concurrent arm with a non-concurrent or a SRS-alone arm. There were no skin toxicities, no clearly increased rate of bleeding, or radiation necrosis with significant clinical impact. SRS combined with systemic therapy appears to be safe, allowing the continuation of treatment when brain SRS is considered.

Hypofractionated frameless gamma knife radiosurgery for large metastatic brain tumors

Hypofractionated stereotactic radiosurgery has become an alternative for metastatic brain tumors (METs). We aimed to analyze the efficacy and safety of frameless hypofractionated Gamma Knife radiosurgery (hfGKRS) in the management of unresected, large METs. All patients who were managed with hfGKRS for unresected, large METs (> 4 cm³) between June 2017 and June 2020 at a single center were reviewed in this retrospective study. Local control (LC), progression-free survival (PFS), overall survival (OS), and toxicities were investigated. A total of 58 patients and 76 METs with regular follow-up were analyzed. LC rate was 98.5% at six months, 96.0% at one year, and 90.6% at 2 years during a median follow-up of 12 months (range, 2-37). The log-rank test indicated no difference in the distribution of LC for any clinical or treatment variable. PFS was 86.7% at 6 months, 66.6% at 1 year, and 58.5% at 2 years. OS was 81% at 6 months, 63.6% at one year, and 50.7% at 2 years. On the log-rank test, clinical parameters such as control status of primary cancer, presence of extracranial metastases, RTOG-RPA class, GPA group, and ds-GPA group were significantly associated with PFS and OS. Patients presented with grade 1 (19.0%), grade 2 (3.5%) and grade 3 (5.2%) side effects. Radiation necrosis was not observed in any patients. Our current results suggest that frameless hfGKRS for unresected, large METs is a rational alternative in selected patients with promising results.

Lapatinib Plus Local Radiation Therapy for Brain Metastases From HER-2 Positive Breast Cancer Patients and Role of Trastuzumab: A Systematic Review and Meta-Analysis

Background

Intracranial activity of lapatinib has been demonstrated in several studies in patients with human epidermal growth factor receptor-2 positive breast cancers (HER-2+ BC). Stereotactic radiosurgery (SRS) has been increasingly used as the local therapy for brain metastases in breast cancer patients. Increased objective response rate was observed for lapatinib plus whole brain radiotherapy (WBRT) is such patients with high toxicity.

Objective

We seek to obtain clinical evidence of synergistic efficacy of lapatinib in combination with radiation therapy, in particular, SRS.

Materials and methods

We carried out a comprehensive research using the following databases: PubMed; Medline; EMBASE; Cochrane library. These databases were searched until 10 June 2020. PRISMA guidelines were followed step by step for carrying out this systematic review and meta-analysis. Review Manager v 5.4 software was used for statistical evaluation of data.

Results

Overall 6 studies with 843 HER-2 positive breast cancer patients (442 HER-2 amplified disease, 399 luminal B disease) were included in this systematic review and meta-analysis. A total 279 patients had received lapatinib in addition to HER-2 antibody (trastuzumab) plus/minus chemoradiotherapy, while 610 patients had received trastuzumab-based management or only chemoradiotherapy. Lapatinib-based management of BM was associated with significant increase in overall survival (HR 0.63 [0.52, 0.77], p < 0.00001). Combination of the two (trastuzumab plus lapatinib) was associated with increased survival advantage compared to each agent alone (0.55 [0.32, 0.92], p = 0.02). SRS in combination with lapatinib was associated with increased local control (HR 0.47 [0.33, 0.66], p = 0.0001). Ever use of lapatinib with SRS was associated an increased survival as reported in two studies (Shireen et al.: 27.3 vs. 19.5 months, p = 0.03; Kim et al.: 33.3 vs. 23.6 months, p = 0.009). Kim et al. also revealed significant increase in intracranial activity with concurrent lapatinib reporting 57% complete response compared to 38% (p < 0.001) and lower progressive disease rate of 11 vs. 19% (p < 0.001). Risk of radiation necrosis was decreased with lapatinib use.

Conclusions

Lapatinib has shown intracranial activity and yielded better survival for HER-2+ BC patients with BMs. SRS in combination with ever use of lapatinib had better local control and were associated with better survival. Radiation necrosis risk was reduced with the use of lapatinib.

Management of brain metastases according to molecular subtypes

The incidence of brain metastases has markedly increased in the past 20 years owing to progress in the treatment of malignant solid tumours, earlier diagnosis by MRI and an ageing population. Although local therapies remain the mainstay of treatment for many patients with brain metastases, a growing number of systemic options are now available and/or are under active investigation. HER2-targeted therapies (lapatinib, neratinib, tucatinib and trastuzumab emtansine), alone or in combination, yield a number of intracranial responses in patients with HER2-positive breast cancer brain metastases. New inhibitors are being investigated in brain metastases from ER-positive or triple-negative breast cancer. Several generations of EGFR and ALK inhibitors have shown activity on brain metastases from EGFR and ALK mutant non-small-cell lung cancer. Immune-checkpoint inhibitors (ICIs) hold promise in patients with non-small-cell lung cancer without druggable mutations and in patients with triple-negative breast cancer. The survival of patients with brain metastases from melanoma has substantially improved after the advent of BRAF inhibitors and ICIs (ipilimumab, nivolumab and pembrolizumab). The combination of targeted agents or ICIs with stereotactic radiosurgery could further improve the response rates and survival but the risk of radiation necrosis should be monitored. Advanced neuroimaging and liquid biopsy will hopefully improve response evaluation.

Medical management of brain metastases

The development of brain metastases occurs in 10–20% of all patients with cancer. Brain metastases portend poor survival and contribute to increased cancer mortality and morbidity. Despite multimodal treatment options, which include surgery, radiotherapy, and chemotherapy, 5-year survival remains low. Besides, our current treatment modalities can have significant neurological comorbidities, which result in neurocognitive decline and a decrease in a patient’s quality of life. However, innovations in technology, improved understanding of tumor biology, and new therapeutic options have led to improved patient care. Novel approaches in radiotherapy are minimizing the neurocognitive decline while providing the same therapeutic benefit. In addition, advances in targeted therapies and immune checkpoint inhibitors are redefining the management of lung and melanoma brain metastases. Similar approaches to brain metastases from other primary tumors promise to lead to new and effective therapies. We are beginning to understand the appropriate combination of these novel approaches with our traditional treatment options. As advances in basic and translational science and innovative technologies enter clinical practice, the prognosis of patients with brain metastases will continue to improve.

Impact of breast cancer subtype on clinical outcomes after Gamma Knife radiosurgery for brain metastases from breast cancer: a multi-institutional retrospective study (JLGK1702)

INTRODUCTION

Brain metastasis (BM) is one of the most important issues in the management of breast cancer (BC), since BMs are associated with neurological deficits. However, the importance of BC subtypes remains unclear for BM treated with Gamma Knife radiosurgery (GKS). Thus, we conducted a multicenter retrospective study to compare clinical outcomes based on BC subtypes, with the aim of developing an optimal treatment strategy.

METHODS

We studied 439 patients with breast cancer and 1-10 BM from 16 GKS facilities in Japan. Overall survival (OS) was analyzed by the Kaplan-Meier method, and cumulative incidences of systemic death (SD), neurologic death (ND), and tumor progression were estimated by competing risk analysis.

RESULTS

OS differed among subtypes. The median OS time (months) after GKS was 10.4 in triple-negative (TN), 13.7 in Luminal, 31.4 in HER2, and 35.8 in Luminal-HER2 subtype BC (p < 0.0001). On multivariate analysis, poor control of the primary disease (hazard ratio [HR] = 1.84, p < 0.0001), active extracranial disease (HR = 2.76, p < 0.0001), neurological symptoms (HR 1.44, p = 0.01), and HER2 negativity (HR = 2.66, p < 0.0001) were significantly associated with worse OS. HER2 positivity was an independent risk factor for local recurrence (p = 0.03) but associated with lower rates of ND (p = 0.03). TN histology was associated with higher rates of distant brain failure (p = 0.03).

CONCLUSIONS

HER2 positivity is related to the longer OS after SRS; however, we should pay attention to preventing recurrence in Luminal-HER2 patients. Also, TN patients require meticulous follow-up observation to detect distant metastases and/or LMD.

Tumor Primary Site and Histology Subtypes Role in Radiotherapeutic Management of Brain Metastases

Randomized controlled trials have failed to report any survival advantage for WBRT combined with SRS in the management of brain metastases, despite the enhanced local and distant control in comparison to each treatment alone. Literature review have revealed important role of primary histology of the tumor when dealing with brain metastases. NSCLC responds better to combined approach even when there was only single brain metastasis present while breast cancer has registered better survival with SRS alone probably due to better response of primary tumor to advancement in surgical and chemotherapeutic agents. Furthermore, mutation status (EGFR/ALK) in lung cancer and receptor status (ER/PR/HER2) in breast cancer also exhibit diversity in their response to radiotherapy. Radioresistant tumors like renal cell carcinoma and melanoma brain metastases have achieved better results when treated with SRS alone. Secondly, single brain metastasis may benefit from local and distant brain control achieved with combined treatment. These diverse outcomes suggest a primary histology-based analysis of the radiotherapy regimens (WBRT, SRS, or their combination) would more ideally establish the role of radiotherapy in the management of brain metastases. Molecularly targeted therapeutic and immunotherapeutic agents have revealed synergism with radiation therapy particularly SRS in treating cancer patients with brain metastases. Clinical updates in this regard have also been reviewed.

Repeated courses of radiation treatment in an HER2-positive breast cancer patient with diffuse brain metastases: A case report

In human epidermal growth factor receptor 2 (HER2+) expressing breast cancer subtype, the incidence of brain metastases is common and patients often die due to uncontrolled cranial disease. This is a case report of a HER2+ breast cancer woman with diffuse brain metastases that experienced long survival and clinical benefit from multiple radiotherapy treatments and combined systemic therapy, without increased toxicity.

Stereotactic radiosurgery in the treatment of adults with metastatic brain tumors

Brain metastasis is the most common type of intracranial tumor affecting a significant proportion of advanced cancer patients. In recent years, stereotactic radiosurgery (SRS) has become commonly utilized. It has contributed significantly to decreased toxicity, prolonged quality of life and general improvement in outcomes of patients with brain metastases. Frequent imaging and advanced treatment techniques have allowed for the treatment of more patients with large and numerous metastases extending their overall survival. The addition of targeted therapy and immunotherapy to SRS has introduced novel treatment paradigms and has further improved our ability to effectively treat brain lesions. In this review, we examined in detail the available evidence for the use of SRS alone or in combination with surgery and systemic therapies. Given our developing understanding of the importance of primary tumor histology, the use of different treatment strategies for different metastasis is evolving. Combining SRS with immunotherapy and targeted therapy in breast cancer, lung cancer and melanoma as well as the use of preoperative SRS have shown significant promise in recent years and are investigated in multiple ongoing prospective trials. Further research is needed to guide the optimal sequence of therapies and to identify specific patient subgroups that may benefit the most from aggressive, combined treatment approaches.

HER2-targeted therapy prolongs survival in patients with HER2-positive breast cancer and intracranial metastatic disease: a systematic review and meta-analysis

BACKGROUND

Intracranial metastatic disease (IMD) is a serious and known complication of human epidermal growth factor receptor 2 (HER2)-positive breast cancer. The role of targeted therapy for patients with HER2-positive breast cancer and IMD remains unclear. In this study, we sought to evaluate the effect of HER2-targeted therapy on IMD from HER2-positive breast cancer.

METHODS

We searched MEDLINE, EMBASE, CENTRAL, and gray literature sources for interventional and observational studies reporting survival, response, and safety outcomes for patients with IMD receiving HER2-targeted therapy. We pooled outcomes through meta-analysis and examined confounder effects through forest plot stratification and meta-regression. Evidence quality was evaluated using GRADE (PROSPERO CRD42020161209).

RESULTS

A total of 97 studies (37 interventional and 60 observational) were included. HER2-targeted therapy was associated with prolonged overall survival (hazard ratio [HR] 0.47; 95% confidence interval [CI], 0.39-0.56) without significantly prolonged progression-free survival (HR 0.52; 95% CI, 0.27-1.02) versus non-targeted therapy; the intracranial objective response rate was 19% (95% CI, 12-27%), intracranial disease control rate 62% (95% CI, 55-69%), intracranial complete response rate 0% (95% CI, 0-0.01%), and grade 3+ adverse event rate 26% (95% CI, 11-45%). Risk of bias was high in 40% (39/97) of studies.

CONCLUSION

These findings support a potential role for systemic HER2-targeted therapy in the treatment of patients with IMD from HER2-positive metastatic breast cancer.

A Brief Overview of Neurosurgical Management for Breast Cancer Metastasis

Despite advances in chemotherapy and radiation, stage IV breast cancer presents a serious challenge to clinicians in light of the continued poor outcomes for patients. Stage IV breast cancer frequently metastasizes to the brain often necessitating neurosurgical intervention. The goals of the neurosurgeon are to adequately address metastatic disease to the central nervous system, limit morbidity for the patients, while preserving as much neurologic function as possible, and to help guide next steps regarding need for radiation and immunotherapy. In this review, we provide a background overview of the role of neurosurgery in managing stage IV metastatic breast cancer involving the brain, discuss what is known about brain metastasis, and highlight avenues for future study and investigation.