Metastatic breast cancer subtypes and central nervous system metastases

A phase II study of cabozantinib alone or in combination with trastuzumab in breast cancer patients with brain metastases

PURPOSE

To analyze the efficacy and tolerability of cabozantinib-a small molecule inhibitor of MET and VEGFR2-alone or with trastuzumab in patients with breast cancer brain metastases (BCBM).

METHODS

This single-arm phase II study enrolled patients with new or progressive measurable BCBM into 3 cohorts: Cohort 1 (HER2-positive), Cohort 2 (hormone receptor-positive/HER2-negative), and Cohort 3 (triple-negative). Patients received cabozantinib 60-mg daily on a 21-day cycle. Cohort 1 added trastuzumab every 3 weeks and had a primary objective of central nervous system (CNS) objective response rate (ORR) by RECIST 1.1. Secondary objectives for all cohorts were progression-free survival, overall survival, toxicity, and changes in vascular parameters and circulating biomarkers. Cohorts 2 and 3 also had CNS ORR as a secondary objective.

RESULTS

Thirty-six BCBM patients enrolled (cohort 1, n = 21; cohort 2, n = 7; cohort 3, n = 8), with a median age of 50. Patients had a median of 3 prior lines for metastatic disease (range 1-9). Treatments prior to enrollment included craniotomy (n = 4), whole brain radiation (n = 24) and stereotactic radiosurgery (n = 11). CNS ORR was 5% in cohort 1, 14% in cohort 2, and 0% in cohort 3. Most common grade 3/4 adverse events included elevations in lipase (11%), AST (8%), ALT (6%), hyponatremia (8%), and hypertension (6%). Cabozantinib increased plasma concentrations of CA-IX, soluble (s)MET, PlGF, sTIE-2, VEGF, and VEGF-D, and decreased sVEGFR2 and TNF-α and total tumor blood volume.

CONCLUSIONS

Cabozantinib had insufficient activity in heavily pretreated BCBM patients. Biomarker analysis showed that cabozantinib had antiangiogenic activity and increased tissue hypoxia.

TRIAL REGISTRATION

Clinicaltrial.gov registration: NCT02260531.

Frequency and outcomes of brain metastases in patients with HER2-mutant lung cancers

BACKGROUND

Mutations in human epidermal growth factor receptor 2 (HER2; also known as ERBB2) are found in approximately 2% of lung adenocarcinomas. The frequency and clinical course of brain metastases in this oncogenic subset are ill defined.

METHODS

Baseline and subsequent development of brain metastases was evaluated in consecutive patients with HER2-mutant (n = 98), epidermal growth factor receptor (EGFR)-mutant (n = 200), and KRAS-mutant lung cancers (n = 200).

RESULTS

At metastatic diagnosis, the odds ratio (ORs) for brain metastases was similar for patients whose tumors harbored HER2 mutations (19%) in comparison with patients with KRAS mutations (24%; OR for HER2 vs KRAS, 0.7; P = .33) but lower compared to patients with EGFR mutations (31%; OR for HER2 vs EGFR, 0.5; P = .03). Patients with lung cancer and HER2 mutations developed more brain metastases on treatment than patients with KRAS mutations (28% vs 8%; hazard ratio [HR], 5.2; P < .001) and trended more than patients with EGFR mutations (28% vs 16%; HR, 1.7; P = .06). Patients with HER2 YVMA mutations also developed more brain metastases on treatment than patients with KRAS mutations (HR, 5.9; P < .001). The median overall survival (OS) was shorter for patients with HER2-mutant (1.6 years; P < .001) or KRAS-mutant lung cancers (1.1 years; P < .001) than patients with EGFR-mutant lung cancers (3.0 years). Brain metastases occurred in 47% of patients with HER2-mutant lung cancers, which imparted shorter OS (HR, 2.7; P < .001).

CONCLUSIONS

These data provide a framework for brain imaging surveillance in patients with HER2-mutant lung cancers and underpin the need to develop HER2-targeted agents with central nervous system activity.

Identification of the key pathways and genes involved in HER2-positive breast cancer with brain metastasis

BACKGROUND

The risk of brain metastasis (BM) in HER2-positive (+) breast cancer (BC) patients is significantly higher than that in HER2-negative (-) BC patients. The high incidence and mortality rate makes it urgent to elucidate the key pathways and genes involved and identify patients who are more at risk of developing BM.

MATERIALS AND METHODS

To identify the target genes in HER2+BC patients with BM, we analyzed the microarray datasets (GSE43837) derived from the Gene Expression Omnibus (GEO) database. The GEO2R tool was used to extract the differentially expressed genes (DEGs) involved in HER2+ primary BC and BC with BM. Bioinformatics methods including Gene Ontology (GO) functional annotation analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed with the screened DEGs. The protein-protein interactions of the DEGs were analyzed using the Search Tool for the Retrieval of Interacting Genes (STRING) database and visualized using Cytoscape software. Finally, GSEA analysis was performed to identify the hub genes and the important pathways.

RESULTS

A total of 751 upregulated and 285 downregulated DEGs were identified. The GO function and KEGG pathway enrichment analyses indicated that the DEGs were all enriched in the protein binding molecular function. The top five hub nodes were screened out, included PHLPP1, UBC, ACACB, TGFB1, and ACTB. The GSEA results demonstrated that the five hub genes are mainly enriched in the ribosomal pathway.

CONCLUSION

Our study suggests that the five hub genes (PHLPP1, UBC, ACACB, TGFB1, and ACTB) are associated with HER2+BC with BM. The GSEA analysis revealed that the ribosomal pathway seems to play a very important role in the pathogenesis of HER2+BC with BM.

ATTAIN: Phase III study of etirinotecan pegol versus treatment of physician's choice in patients with metastatic breast cancer and brain metastases

The increasing incidence of breast cancer brain metastases is a major clinical problem with its associated poor prognosis and limited treatment options. The long-acting topoisomerase-1 inhibitor, etirinotecan pegol, was designed to preferentially accumulate in tumor tissue including brain metastases, providing sustained cytotoxic SN38 levels. Motivated by improved survival findings from subgroup analyses from the Phase III BEACON trial, this ongoing randomized, Phase III trial compares etirinotecan pegol to drugs commonly used for advanced breast cancer in patients with stable, treated breast cancer brain metastases who have been previously treated with an anthracycline, taxane and capecitabine. The primary end point is overall survival. Secondary end points include objective response rate, progression-free survival and time to CNS disease progression or recurrence in patients with/without CNS lesions present at study entry. Trial registration number: NCT02915744.

A platform for artificial intelligence based identification of the extravasation potential of cancer cells into the brain metastatic niche

Brain metastases are the most lethal complication of advanced cancer; therefore, it is critical to identify when a tumor has the potential to metastasize to the brain. There are currently no interventions that shed light on the potential of primary tumors to metastasize to the brain. We constructed and tested a platform to quantitatively profile the dynamic phenotypes of cancer cells from aggressive triple negative breast cancer cell lines and patient derived xenografts (PDXs), generated from a primary tumor and brain metastases from tumors of diverse organs of origin. Combining an advanced live cell imaging algorithm and artificial intelligence, we profile cancer cell extravasation within a microfluidic blood-brain niche (μBBN) chip, to detect the minute differences between cells with brain metastatic potential and those without with a PPV of 0.91 in the context of this study. The results show remarkably sharp and reproducible distinction between cells that do and those which do not metastasize inside of the device.

Central Nervous System Metastasis in Patients with HER2-Positive Metastatic Breast Cancer: Patient Characteristics, Treatment, and Survival from SystHERs

PURPOSE

Patients with HER2-positive metastatic breast cancer (MBC) with central nervous system (CNS) metastasis have a poor prognosis. We report treatments and outcomes in patients with HER2-positive MBC and CNS metastasis from the Systemic Therapies for HER2-positive Metastatic Breast Cancer Study (SystHERs).

EXPERIMENTAL DESIGN

SystHERs (NCT01615068) was a prospective, U.S.-based, observational registry of patients with newly diagnosed HER2-positive MBC. Study endpoints included treatment patterns, clinical outcomes, and patient-reported outcomes (PRO).

RESULTS

Among 977 eligible patients enrolled (2012-2016), CNS metastasis was observed in 87 (8.9%) at initial MBC diagnosis and 212 (21.7%) after diagnosis, and was not observed in 678 (69.4%) patients. White and younger patients, and those with recurrent MBC and hormone receptor-negative disease, had higher risk of CNS metastasis. Patients with CNS metastasis at diagnosis received first-line lapatinib more commonly (23.0% vs. 2.5%), and trastuzumab less commonly (70.1% vs. 92.8%), than patients without CNS metastasis at diagnosis. Risk of death was higher with CNS metastasis observed at or after diagnosis [median overall survival (OS) 30.2 and 38.3 months from MBC diagnosis, respectively] versus no CNS metastasis [median OS not estimable: HR 2.86; 95% confidence interval (CI), 2.05-4.00 and HR 1.94; 95% CI, 1.52-2.49]. Patients with versus without CNS metastasis at diagnosis had lower quality of life at enrollment.

CONCLUSIONS

Despite advances in HER2-targeted treatments, patients with CNS metastasis continue to have a poor prognosis and impaired quality of life. Observation of CNS metastasis appears to influence HER2-targeted treatment choice.

Co-expression network analysis of gene expression profiles of HER2+ breast cancer-associated brain metastasis

Brain metastasis occurs in ~30% of patients with breast cancer, and patients with human epidermal growth factor receptor 2 (HER2)⁺ breast cancer have a particularly high frequency of brain metastasis. Weighted gene co-expression network analysis was conducted to identify the hub differentially expressed genes from patients with HER2⁺ breast cancer between brain metastases and primary tumors. The potential candidate genes were investigated in another set of patient samples to confirm their relevance. The results indicated that a number of pathways altered significantly when breast cancer metastasized to the brain. Cyclophilin A (CypA) and ribosomal protein L17 (RPL17) were overexpressed in breast cancer-associated brain metastases, whereas tumor protein 63 (TP63) and von Willebrand factor A domain-containing 8 (VWA8) were significantly downregulated in breast cancer brain metastases. Furthermore, the expression of CypA and RPL17 in brain metastases were significantly increased compared with that in primary breast tumors, and the expression of TP63 and VWA8 in brain metastases were significantly decreased. This result indicated that the significant differences in expression observed between primary breast tumors and brain metastases were derived from significantly altered systems, including gene modules rather than single genes.

The antipsychotic agent trifluoperazine hydrochloride suppresses triple-negative breast cancer tumor growth and brain metastasis by inducing G0/G1 arrest and apoptosis

Women with aggressive triple-negative breast cancer (TNBC) are at high risk of brain metastasis, which has no effective therapeutic option partially due to the poor penetration of drugs across the blood-brain barrier. Trifluoperazine (TFP) is an approved antipsychotic drug with good bioavailability in brain and had shown anticancer effect in several types of cancer. It drives us to investigate its activities to suppress TNBC, especially the brain metastasis. In this study, we chose three TNBC cell lines MDA-MB-468, MDA-MB-231, and 4T1 to assess its anticancer activities along with the possible mechanisms. In vitro, it induced G0/G1 cell cycle arrest via decreasing the expression of both cyclinD1/CDK4 and cyclinE/CDK2, and stimulated mitochondria-mediated apoptosis. In vivo, TFP suppressed the growth of subcutaneous xenograft tumor and brain metastasis without causing detectable side effects. Importantly, it prolonged the survival of mice bearing brain metastasis. Immunohistochemical analysis of Ki67 and cleaved caspase-3 indicated TFP could suppress the growth and induce apoptosis of cancer cells in vivo. Taken together, TFP might be a potential available drug for treating TNBC with brain metastasis, which urgently needs novel treatment options.

Clinical outcomes in patients with brain metastases from breast cancer treated with single-session radiosurgery or whole brain radiotherapy

OBJECTIVE Gamma Knife radiosurgery (GKRS) is used to treat brain metastases from breast cancer (BMB) as the sole treatment or in conjunction with tumor resection and/or whole brain radiotherapy (WBRT). This study evaluates outcomes in BMB based on treatment techniques and tumor biological features. METHODS The authors reviewed all patients treated with BMB between 2004 and 2014. Patients were identified from a prospectively collected radiosurgery database and institutional tumor registry; 214 patients were identified. Data were collected from aforementioned sources and supplemented with chart review where needed. Independent radiological review was performed for all available brain imaging in those treated with GKRS. Survival analyses are reported using Kaplan-Meier estimates. RESULTS During the 10-year study period, 214 patients with BMB were treated; 23% underwent GKRS alone, 46% underwent a combination of GKRS and WBRT, and 31% underwent WBRT alone. Median survival after diagnosis of BMB in those treated with GKRS alone was 21 months, and in those who received WBRT alone it was 3 months. In those treated with GKRS plus WBRT, no significant difference in median survival was observed between those receiving WBRT upfront or in a salvage setting following GKRS (19 months vs 14 months, p = 0.63). The median survival of patients with total metastatic tumor volume of ≤ 7 cm³ versus > 7 cm³ was 20 months vs 7 months (p < 0.001). Human epidermal growth factor receptor-2 (Her-2) positively impacted survival after diagnosis of BMB (19 months vs 12 months, p = 0.03). Estrogen receptor status did not influence survival after diagnosis of BMB. No difference was observed in survival after diagnosis of BMB based on receptor status in those who received WBRT alone. CONCLUSIONS In this single-institution series of BMB, the addition of WBRT to GKRS did not significantly influence survival, nor did the number of lesions treated with GKRS. Survival after the diagnosis of BMB was most strongly affected by Her-2 positivity and total metastatic tumor volume.

Barriers to Effective Drug Treatment for Brain Metastases: A Multifactorial Problem in the Delivery of Precision Medicine

The treatment of metastatic lesions in the brain represents a serious unmet medical need in the field of neuro-oncology. Even though many effective compounds have demonstrated success in treating peripheral (non-CNS) tumors with targeted agents, one aspect of this lack of success in the brain may be related to poor delivery of otherwise effective compounds. Many factors can influence the brain delivery of these agents, but one key barrier is a heterogeneously "leaky" BBB that expresses efflux transporters that limit the BBB permeability for many targeted agents. Future success in therapeutics for brain metastases must take into account the adequate delivery of "active, free drug" to the target, and may include combinations of targeted drugs that are appropriate to address each individual patient's tumor type. This review discusses some issues that are pertinent to precision medicine for brain metastases, using specific examples of tumor types that have a high incidence of brain metastases.

Outcome and prognostic value of treatment for brain metastases and the primary tumor in patients with breast cancer brain metastases

OBJECTIVE

The aim of this single-institution cohort study is to describe clinical characteristics of patients with breast cancer brain metastases (BCBM), to investigate survival after diagnosis of brain metastases (BM), and to assess the aggressive treatments to BCBM.

PATIENTS AND METHODS

We identified 134 consecutive patients diagnosed with operable breast cancer and then who developed BM at the Sun Yat-sen University Cancer Center from 2000 to 2015, and analyzed the therapeutic methods for primary breast cancer and BM to evaluate whether they were associated with longer survival after the development of BM. The median age at breast cancer diagnosis was 47 years (range 21-73 years).

RESULTS

The median survival after BM was 16.2 months (range 12.1-20.3 months), and the survival rates were 62% and 37% at 1 and 2 years, respectively. Multivariate analysis showed that craniotomy (p = 0.034) and targeted therapy (p < 0.001) for BCBM were positively correlated with survival after diagnosis of BM; radiotherapy (p = 0.024) after surgery for primary breast cancer was beneficial to BM.

CONCLUSIONS

Surgical resection and targeted therapy are effective treatment for BCBM. Radiotherapy after surgery for the management of primary breast cancer is necessary in patients with brain progression later.

Anterior Clinoid Metastasis Removed Extradurally: First Case Report

Background  We report a case of isolated metastasis on the anterior clinoid process (ACP) mimicking meningioma.

Clinical Presentation  A 58-year-old male presented with headaches, right-sided visual disturbances, and blurred and double vision. The cause of double vision was partial weakness of the right III nerve, resulting from compression of the nerve by “hypertrophied” tumor-involved right anterior clinoid. Medical history revealed two primary malignant tumors—male breast cancer and prostate cancer (diagnosed 6 and 18 months prior, respectively). The patient was treated with chemotherapy and showed no signs of active disease, recurrence, or metastasis. Postcontrast head magnetic resonance imaging (MRI) showed extra-axial well-bordered enhancing mass measuring 1.6 × 1.1 × 1 × 1 cm (anteroposterior, transverse, and craniocaudal dimensions) on the ACP, resembling a clinoidal meningioma. Extradural clinoidectomy with tumor resection was performed via right orbitozygomatic pretemporal skull base approach. Visual symptoms improved. Follow-up MRI showed no signs of tumor residual or recurrence.

Conclusion  This is the first case report of a metastasis of any kind on ACP. Metastasis should be included as a part of the differential diagnosis of lesions of the anterior clinoid. Extradural clinoidectomy is a safe and effective method in the treatment of these tumors.

Understanding patterns of brain metastasis in breast cancer and designing rational therapeutic strategies

One of the most feared sequelae after a diagnosis of advanced breast cancer is development of metastases to the brain as this diagnosis can affect physical function, independence, relationships, quality of life, personality, and ultimately one's sense of self. The propensity to develop breast cancer brain metastases (BCBMs) varies by subtype, occurring in up to one half of those with triple negative breast cancer (TNBC), approximately a third of HER+ breast cancers and 14% in hormone positive disease. Median survival after BCBM diagnosis can be as short as 5 months in TNBC and 10-18 months in the other subtypes. Here, we review the biology of BCBMs and how it informs the rational design of new therapeutic approaches and agents. We discuss application of novel targeted and immunotherapies by breast cancer subtype. It is noteworthy that there are no U.S. Food and Drug Administration (FDA)-approved treatments specifically for BCBMs currently. Nevertheless, there are legitimate grounds for hope as patients with BCBMs are now being included in clinical trials of systemic therapies and a better understanding of the biology and genetic underpinning of BCBMs is driving an increased range of options for patients.

Current Therapies for Human Epidermal Growth Factor Receptor 2-Positive Metastatic Breast Cancer Patients

The median survival of patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) has more than doubled, since the discovery of HER2-targeted treatments: it rose from less than 2 years in 2001 (prior introduction of trastuzumab) to more than 4 years in 2017. The initial generation of HER2-targeted therapies included trastuzumab with taxanes in the first line, followed by the addition of lapatinib and by a switch to another cytotoxic agent after progression. Results of CLEOPATRA, EMILIA, and TH3RESA trials have changed this clinical practice. The current consensus includes horizontal dual blockade (trastuzumab + pertuzumab) with taxanes or vinorelbine in the first line, followed by trastuzumab-emtansine (T-DM1) in the second line, with addition of lapatinib in the later lines of treatment. However, the fast and simultaneous development of new drugs led to a relative shortage of clinical evidence to support this sequence. Triple-positive breast cancers (TPBC), which express both hormonal receptors and HER2, constitute nearly half of HER2-positive cases. For these tumors, the current consensus is to add endocrine therapy after completion of cytotoxic treatment. Again, this consensus is not fully evidence-based. In view of the recent progress in treatment of estrogen-receptor positive breast cancers, a series of trials is evaluating addition of CDK4/6 inhibitors, aromatase inhibitors or fulvestrant to HER2-targeted and cytotoxic chemotherapy in TPBC patients. Despite the remarkable progress in treatment of HER2-positive breast cancer, metastatic disease is still incurable in the majority of patients. A wide range of novel therapies are under development to prevent and overcome resistance to current HER2-targeted agents. This review discusses pivotal clinical trials that have shaped current clinical practices, the current consensus recommendations, and the new experimental treatments in metastatic HER2-positive breast cancer.

Medical management of brain metastases and leptomeningeal disease in patients with breast carcinoma

Breast cancer is the most common malignancy among women and accounts for the second highest number of cancer-related deaths. With patients surviving longer due to advances in systemic control, the incidence of CNS involvement is increasing; however, the management of CNS metastases has not undergone parallel advancements. The blood–brain barrier limits the efficacy of most systemic chemotherapies, and the utilization of surgery and radiation beyond first-line therapy is limited. We will explore the recent developments in the medical management of breast cancer brain metastasis. Beyond traditional chemotherapy, we will also discuss targeted therapies and immunotherapies which may provide a survival benefit to this population and thus, offer further treatment options and a path for future research and treatment advances.

Systemic therapy for brain metastases

Central nervous system metastases cause grave morbidity in patients with advanced malignancies. Lung cancer, breast cancer, and melanoma are the three most common causes of brain metastases. Although the exact incidence of brain metastases is unclear, there appears to be an increasing incidence which has been attributed to longer survival, better control of systemic disease, and better imaging modalities. Until recently surgical resection of solitary or symptomatic brain metastases, and radiation therapy (either whole-brain radiation therapy or stereotactic radiation) were the mainstay of treatment for patients with brain metastases. The majority of traditional chemotherapies have shown limited activity in the central nervous system, which has been attributed to the blood-brain barrier and the molecular structure of the used agents. The discovery of driver mutations and drugs targeting these mutations has changed the treatment landscape. Several of these targeted small-molecule tyrosine kinase inhibitors do cross the blood-brain barrier and/or have shown activity in the central nervous system. Another major advance in the care of brain metastases has been the advent of new immunotherapeutic agents, for which initial studies have shown intracranial activity. In this chapter, we will review the unique challenges in the treatment of brain metastases. The pertinent clinical studies of chemotherapy in brain metastases will be discussed. The currently reported clinical trials and evidence for use of targeted therapies and immunotherapeutic agents will be emphasized.

Targeted therapy of brain metastases: latest evidence and clinical implications

Brain metastases (BM) occur in 20-40% of patients with cancer and 60-75% of patients with BM become symptomatic. Due to an aging population and advances in the treatment of primary cancers, patients are living longer and are more likely to experience complications from BM. The diagnosis of BM drastically worsens long-term survival rates, with multiple metastases being a poor prognostic factor. Until recently, the mainstay of treatment consisted of stereotactic radiosurgery (SRS), surgical resection, whole brain radiation therapy (WBRT), or a combination of these modalities. Systemic chemotherapy has been felt largely ineffective in the treatment of BM due to the presence of the blood-brain barrier (BBB), which includes efflux pumps on brain capillaries. Over the past decade however, researchers have identified therapeutic agents that are able to cross the BBB. These findings could make a multimodality treatment approach possible, consisting of surgery, radiation, immunotherapy, and targeted therapy, which could lead to better disease control in this patient population and prolong survival. In this review, we discuss present evidence on available targeted therapies and their role in the treatment of BM from primary tumors with the highest prevalence of central nervous system (CNS) involvement, specifically non-small cell lung cancer (NSCLC), breast cancer melanoma, and renal cell carcinoma.

JAK2-binding long noncoding RNA promotes breast cancer brain metastasis

Conventional therapies for breast cancer brain metastases (BCBMs) have been largely ineffective because of chemoresistance and impermeability of the blood-brain barrier. A comprehensive understanding of the underlying mechanism that allows breast cancer cells to infiltrate the brain is necessary to circumvent treatment resistance of BCBMs. Here, we determined that expression of a long noncoding RNA (lncRNA) that we have named lncRNA associated with BCBM (Lnc-BM) is prognostic of the progression of brain metastasis in breast cancer patients. In preclinical murine models, elevated Lnc-BM expression drove BCBM, while depletion of Lnc-BM with nanoparticle-encapsulated siRNAs effectively treated BCBM. Lnc-BM increased JAK2 kinase activity to mediate oncostatin M- and IL-6-triggered STAT3 phosphorylation. In breast cancer cells, Lnc-BM promoted STAT3-dependent expression of ICAM1 and CCL2, which mediated vascular co-option and recruitment of macrophages in the brain, respectively. Recruited macrophages in turn produced oncostatin M and IL-6, thereby further activating the Lnc-BM/JAK2/STAT3 pathway and enhancing BCBM. Collectively, our results show that Lnc-BM and JAK2 promote BCBMs by mediating communication between breast cancer cells and the brain microenvironment. Moreover, these results suggest targeting Lnc-BM as a potential strategy for fighting this difficult disease.

Brain Metastases in Newly Diagnosed Breast Cancer: A Population-Based Study

Importance

Population-based estimates of the incidence and prognosis of brain metastases at diagnosis of breast cancer are lacking.

Objective

To characterize the incidence proportions and median survivals of patients with breast cancer and brain metastases at the time of cancer diagnosis.

Design, Setting, and Participants

Patients with breast cancer and brain metastases at the time of diagnosis were identified using the Surveillance, Epidemiology, and End Results (SEER) database of the National Cancer Institute. Data were stratified by subtype, age, sex, and race. Multivariable logistic and Cox regression were performed to identify predictors of the presence of brain metastases at diagnosis and factors associated with all-cause mortality, respectively. For incidence, we identified a population-based sample of 238 726 adult patients diagnosed as having invasive breast cancer between 2010 and 2013 for whom the presence or absence of brain metastases at diagnosis was known. Patients diagnosed at autopsy or with an unknown follow-up were excluded from the survival analysis, leaving 231 684 patients in this cohort.

Main Outcomes and Measures

Incidence proportion and median survival of patients with brain metastases and newly diagnosed breast cancer.

Results

We identified 968 patients with brain metastases at the time of diagnosis of breast cancer, representing 0.41% of the entire cohort and 7.56% of the subset with metastatic disease to any site. A total of 57 were 18 to 40 years old, 423 were 41 to 60 years old, 425 were 61-80 years old, and 63 were older than 80 years. Ten were male and 958 were female. Incidence proportions were highest among patients with hormone receptor (HR)-negative human epidermal growth factor receptor 2 (HER2)-positive (1.1% among entire cohort, 11.5% among patients with metastatic disease to any distant site) and triple-negative (0.7% among entire cohort, 11.4% among patients with metastatic disease to any distant site) subtypes. Median survival among the entire cohort with brain metastases was 10.0 months. Patients with HR-positive HER2-positive subtype displayed the longest median survival (21.0 months); patients with triple-negative subtype had the shortest median survival (6.0 months).

Conclusions and Relevance

The findings of this study provides population-based estimates of the incidence and prognosis for patients with brain metastases at time of diagnosis of breast cancer. The findings lend support to consideration of screening imaging of the brain for patients with HER2-positive or triple-negative subtypes and extracranial metastases.

Tumor LDH-A expression and serum LDH status are two metabolic predictors for triple negative breast cancer brain metastasis

There are limited therapeutic methods for triple negative breast cancer in the clinic, which is easy to progress into the brain to form metastatic lesions and evolve into the terminal stage. Because both the primary cancer and the brain metastasis have high glycolysis, we hypothesize that lactate dehydrogenase (LDH), which catalyzes the final step of glycolysis, may be a predictor, as well as a treatment target, for breast cancer brain metastasis. Therefore, the expression of LDH-A was detected on 119 triple negative breast cancer tissues with immunohistochemistry, and the serum LDH levels were also measured. Our results showed that the LDH-A expression inside the tumor was significantly higher than the matched normal tissues. Tumor LDH-A expression, serum LDH status, and the slope of serum LDH status were closely associated with triple negative breast cancer brain metastasis and brain metastasis free survival. This study indicates that tumor LDH and serum LDH status are two predictors for triple negative breast cancer brain metastasis.

Breast cancer subtype and stage are prognostic of time from breast cancer diagnosis to brain metastasis development

Breast cancer brain metastasis (BCBM) is associated with high morbidity and mortality. Patients with breast cancer risk factors associated with rapid development of BCBM could potentially benefit from early brain metastasis screening. We retrospectively reviewed all BCBM patients treated with brain radiotherapy at our institution from 1997 to 2015. Interval time to BCBM was defined as date of pathologic breast cancer diagnosis to date of radiographic evidence of brain metastasis. Patients were stratified by breast cancer molecular subtype and stage at diagnosis. Kaplan Meier analysis was conducted on time to development of BCBM. Breast cancer risk factors were correlated with time to BCBM on Cox proportion hazard analysis. The study cohort comprised 121 BCBM patients, with median interval time to BCBM of 46 months. Times to BCBM for Her2+/2HR+, Her2+, Her2-/HR+, and triple-negative (TNBC) subtypes were 70, 44, 42, and 28 months respectively (p = 0.002). Time to BCBM for stages I, II, III, and IV were 70, 54, 29, and 24 months, respectively (p = 0.000). BCBM patients were further stratified by both molecular subtype (TNBC vs. non-TNBC) and stage (I, II vs. III, IV). Median times to BCBM for non-TNBC/stage I-II, TNBC/stage I-II, non-TNBC stage III-IV, and TNBC/stage III-IV were 68, 47, 29, and 6 months respectively (p = 0.000). Subtype and stage were associated with shorter time to BCBM on multivariate analysis. Subtype and initial stage are independently correlated with decreased time to development of BCBM. Patients with advanced high stage and triple negative breast cancer develop brain metastases significantly earlier.

Management of breast cancer brain metastases: Focus on human epidermal growth factor receptor 2-positive breast cancer

After the introduction of trastuzumab, a monoclonal antibody that binds to human epidermal growth factor receptor 2 (HER2), the overall survival (OS) among patients with HER2-positive breast cancer has been substantially improved. However, among these patients, the incidence of brain metastases (BM) has been increasing and an increased proportion of them have died of intracranial progression, which makes HER2-positive breast cancer brain metastases (BCBM) a critical issue of concern. For local control of limited BM, stereotactic radiosurgery (SRS) and surgical resection are available modalities with different clinical indications. Postoperative or preoperative radiation is usually delivered in conjunction with surgical resection to boost local control. Adjuvant whole-brain radiotherapy (WBRT) should be deferred for limited BM because of its impairment of neurocognitive function while having no benefit for OS. Although WBRT is still the standard treatment for local control of diffuse BM, SRS is a promising treatment for diffuse BM as the technique continues to improve. Although large molecules have difficulty crossing the blood brain barrier, trastuzumab-containing regimens are critical for treating HER2-positive BCBM patients because they significantly prolong OS. Tyrosine kinase inhibitors are more capable of crossing into the brain and they have been shown to be beneficial for treating BM in HER2-positive patients, especially lapatinib combined with capecitabine. The antiangiogenic agent, bevacizumab, can be applied in the HER2-positive BCBM scenario as well. In this review, we also discuss several strategies for delivering drugs into the central nervous system and several microRNAs that have the potential to become biomarkers of BCBM.

Prognostic factors and survival according to tumour subtype in women presenting with breast cancer brain metastases at initial diagnosis

BACKGROUND

The presence of brain metastases at the time of initial breast cancer diagnosis (BMIBCD) is uncommon. Hence, the prognostic assessment and management of these patients is very challenging. The aim of this study was to analyse the influence of tumour subtype compared with other prognostic factors in the survival of patients with BMIBCD.

METHODS

We evaluated women with BMIBCD, reported to Surveillance, Epidemiology and End Results program from 2010 to 2013. Patients with other primary malignancy were excluded. Univariate and multivariate analyses were performed to determine the effects of each variable on overall survival (OS).

RESULTS

We included 740 patients. Median OS for the whole population was 10 months, and 20.7% of patients were alive at 36 months. Tumour subtype distribution was: 46.6% hormone receptor (HR)+/HER2-, 17% HR+/HER2+, 14.1% HR-/HER2+ and 22.3% triple-negative. Univariate analysis showed that the presence of liver metastases, lung metastases and triple-negative patients (median OS 6 months) had worse prognosis. The HR+/HER2+ subtype had the longest OS with a median of 22 months. In multivariate analysis, older age (hazard ratio 1.8), lobular histology (hazard ratio 2.08), triple-negative subtype (hazard ratio 2.25), liver metastases (hazard ratio 1.6) and unmarried patients (hazard ratio 1.39) had significantly shorter OS.

CONCLUSIONS

Although the prognosis of patients with BMIBCD is generally poor, 20.7% were still alive 3 years after the diagnosis. There were substantial differences in OS according to tumour subtype. In addition to tumour subtype, other independent predictors of OS are age at diagnosis, marital status, histology and liver metastases.

Pretreatment clinical prognostic factors for brain metastases from breast cancer treated with Gamma Knife radiosurgery

Background:

Brain metastases significantly affect morbidity and mortality rates for patients with metastatic breast cancer. Treatment for brain metastases lengthens survival, and options such as stereotactic radiosurgery (SRS) can increase survival to 12 months or longer. This study retrospectively analyzes the prognostic factors for overall survival (OS) for patients with one or multiple brain metastases from breast cancer treated with SRS.

Methods:

Between December 2001 and May 2015, 111 patients with brain metastases from breast cancer were grouped by potential prognostic factors including age at diagnosis, Karnofsky Performance Status (KPS) score, number of brain metastases, and whether or not they received adjuvant treatments such as whole brain radiotherapy (WBRT) or surgical resection. Survival rates were determined for all groups, and hazard ratios were calculated using univariate and multivariate analyses to compare differences in OS.

Results:

Median OS was 16.8 ± 4.22 months. Univariate analysis of patients with a KPS ≤60 and multivariate analysis of KPS 70–80 showed significantly shorter survival than those with KPS 90–100 (5.9 ± 1.22 months, 21.3 ± 11.69 months, and 22.00 ± 12.56 months, P = 0.024 and < 0.001). Other results such as age ≥65 years and higher number of brain metastases trended toward shorter survival but were not statistically significant. No difference in survival was found for patients who had received WBRT in addition to SRS (P = 0.779).

Conclusion:

SRS has been shown to be safe and effective in treating brain metastases from breast cancer. We found our median survival to be 16.8 ± 4.22 months, an increase from other clinical reports. In addition, 38.4% of our population was alive at 2 years and 15.6% survived 5 years. Significant prognostic factors can help inform clinical treatment decisions. This study found that KPS was a significant prognostic indicator of OS in these patients.

Pattern of metastatic spread and subcategories of breast cancer

PURPOSE

The development of metastases is the most aggressive attribute of breast cancer. In this retrospective multicenter study, we evaluated if and how the different pathological breast cancer subtypes influence the spreading of tumor cells, the development of metastasis and the survival of breast cancer patients.

METHODS

This retrospective German multicenter study is based on the BRENDA collective including 9625 breast cancer patients treated in the adjuvant setting. We used the χ ² tests for the analysis of the categorical variables between groups of patients with different sites of metastasis. Survival distributions and median survival times were estimated using the Kaplan-Meier product-limit method. The log-rank test was applied to compare survival rates. The Cox proportional hazards model was used to estimate the hazard ratio and confidence intervals.

RESULTS

886 women developed metastases during a time interval of 53 months after primary diagnosis. Luminal A tumor patients were more likely to get bone metastases than lung, liver or CNS metastases. Patients with a triple-negative subtype were, however, the least affected by metastasis in the skeleton. They were most likely to develop visceral metastases. Location, numbers of metastases herein and the subtype influenced the overall survival (OAS). Altogether, the best OAS was found in patients with the luminal A subtype, the worst in patients with the triple-negative subtype.

CONCLUSIONS

Knowledge of the typical metastatic pattern of the subtypes of breast cancer will help to personalize therapeutic options and follow-up examinations of cancer patients.

Mcl-1 confers protection of Her2-positive breast cancer cells to hypoxia: therapeutic implications

BACKGROUND

Molecular mechanisms leading to the adaptation of breast cancer (BC) cells to hypoxia are largely unknown. The anti-apoptotic Bcl-2 family member myeloid cell leukemia-1 (Mcl-1) is frequently amplified in BC; and elevated Mcl-1 levels have been correlated with poor prognosis. Here we investigated the pathophysiologic role of Mcl-1 in Her2-positive BC cells under hypoxic conditions.

METHODS

RNA interference and a novel small molecule inhibitor, EU-5346, were used to examine the role of Mcl-1 in Her2-positive BC cell lines and primary BC cells (sensitive or intrinsically resistant to Her2 inhibitors) under hypoxic conditions (using a hypoxic incubation chamber). Mechanisms-of-action were investigated by RT-PCR, mitochondrial isolation, as well as immunoprecipitation/blotting analysis, and microscopy. The specificity against Mcl-1 of the novel small molecule inhibitor EU5346 was verified in Mcl-1(Δ/null) versus Mcl-1(wt/wt) Murine Embryonic Fibroblasts (MEFs). Proliferation, survival, and spheroid formation were assessed in response to Mcl-1 and Her2 inhibition.

RESULTS

We demonstrate for a strong correlation between high Mcl-1 protein levels and hypoxia, predominantly in Her2-positive BC cells. Surprisingly, genetic depletion of Mcl-1 decreased Her2 and Hif-1α levels followed by inhibition of BC cell survival. In contrast, Mcl-1 protein levels were not downregulated after genetic depletion of Her2 indicating a regulatory role of Mcl-1 upstream of Her2. Indeed, Mcl-1 and Her2 co-localize within the mitochondrial fraction and form a Mcl-1/Her2- protein complex. Similar to genetically targeting Mcl-1 the novel small molecule Mcl-1 inhibitor EU-5346 induced cell death and decreased spheroid formation in Her2-positive BC cells. Of interest, EU-5346 induced ubiquitination of Mcl-1- bound Her2 demonstrating a previously unknown role for Mcl-1 to stabilize Her2 protein levels. Importantly, targeting Mcl-1 was also active in Her2-positive BC cells resistant to Her2 inhibitors, including a brain-primed Her2-positive cell line.

CONCLUSION

Our data demonstrate a critical role of Mcl-1 in Her2-positive BC cell survival under hypoxic conditions and provide the preclinical framework for the therapeutic use of novel Mcl-1- targeting agents to improve patient outcome in BC.

Changing molecular profile of brain metastases compared with matched breast primary cancers and impact on clinical outcomes

Background:

Breast cancer commonly metastasises to the brain, but little is known about changes in the molecular profile of the brain secondaries and impact on clinical outcomes.

Methods:

Patients with samples from brain metastases and matched breast cancers were included. Immunohistochemical analysis for oestrogen receptor, progesterone receptor, p27kip1, cyclin D1, epidermal growth factor receptor, insulin like growth factor 1, insulin like growth factor 1 receptor, vascular endothelial growth factor A, transforming growth factor-β and HER2 receptor was performed. Borderline HER2 results were analysed by fluorescent in situ hybridisation. Levels of expression were compared, with review of effect on clinical outcomes.

Results:

A total of 41 patients were included. Of the patients, 20% had a change in oestrogen receptor or HER2 in their brain metastasis that could affect therapeutic decisions. There were statistically significant rises in brain metastases for p27kip1 (P=0.023) and cyclin D1 (P=0.030) and a fall in vascular endothelial growth factor A (P=0.012). Overall survival from the time of metastasis increased significantly with oestrogen receptor-positive (P=0.005) and progesterone receptor-positive (P=0.013) brain lesions and with a longer duration from diagnosis of the breast primary (P<0.001).

Conclusions:

In this cohort there were phenotypic differences in metastatic brain tumours compared with matched primary breast tumours. These could be relevant for aetiology, and have an impact on prognostication, current and future therapies.

Metastatic breast cancer: the potential of miRNA for diagnosis and treatment monitoring

Breast cancer affects approximately 12 % women worldwide and results in 14 % of all cancer-related fatalities. Breast cancer is commonly categorized into one of four main subtypes (luminal A, luminal B, human epidermal growth factor receptor 2 (HER2) positive and basal), indicating molecular characteristics and informing treatment regimes. The most severe form of breast cancer is metastasis, when the tumour spreads from the breast tissue to other parts of the body. Significantly, the primary tumour subtype affects rates and sites of metastasis. Currently, up to 5 % of patients present with incurable metastasis, with an additional 10–15 % of patients going on to develop metastasis within 3 years of diagnosis. MicroRNAs (miRNAs) are short 21–25 long nucleotides that have been shown to significantly affect gene expression. Currently, >2000 miRNAs have been identified and significantly, specific miRNAs have been found associated with diseases states. Importantly, miRNAs are found circulating in the blood, presenting an opportunity to use these circulating disease-related miRNAs as biomarkers. Clearly, the identification of circulating miRNA specific to metastatic breast cancer presents a unique opportunity for early disease identification and for monitoring disease burden. Currently however, few groups have identified miRNA associated with metastatic breast cancer. Here, we review the literature surrounding the identification of metastatic miRNA in breast cancer patients, highlighting key areas where miRNA biomarker discovery could be beneficial, identifying key concepts, recognizing critical areas requiring further research and discussing potential problems.

Breast cancer brain metastases: the last frontier

Breast cancer is a common cause of brain metastases, with metastases occurring in at least 10–16 % of patients. Longer survival of patients with metastatic breast cancer and the use of better imaging techniques are associated with an increased incidence of brain metastases. Unfortunately, patients who develop brain metastases tend to have poor prognosis with short overall survival. In addition, brain metastases are a major cause of morbidity, associated with progressive neurologic deficits that result in a reduced quality of life. Tumor subtypes play a key role in prognosis and treatment selection. Current therapies include surgery, whole-brain radiation therapy, stereotactic radiosurgery, chemotherapy and targeted therapies. However, the timing and appropriate use of these therapies is controversial and careful patient selection by using available prognostic tools is extremely important. This review will focus on current treatment options, novel therapies, future approaches and ongoing clinical trials for patients with breast cancer brain metastases.

The challenge of durable brain control in patients with brain-only metastases from breast cancer

The vast majority of patients with brain metastases from breast cancer have extracranial metastases, e.g., in the liver, lungs or bones, with serious impact on prognosis. Limited research has been performed on patients with brain-only disease. We analyzed patterns of treatment, brain control and survival in uni- and multivariate analyses. All 25 patients with brain-only disease were treated with radiotherapy (whole-brain radiotherapy (WBRT) with or without stereotactic radiotherapy/radiosurgery (SRS) or surgical resection) and most patients with systemic treatment later during the disease trajectory. Only a minority of patients remained free from brain progression at 1 year after their initial therapy, regardless of initial treatment approach (median brain progression-free survival 6.2 months). However, overall survival was significantly better after initial surgical resection/SRS as compared to upfront WBRT (median 24.1 and 5.2 months, respectively). For all patients combined, median survival was 11.7 months (2-year survival rate 28 %). Several prognostic factors for shorter survival were identified in multivariate regression analysis: lower KPS, triple-negative tumor, coordination deficit, older age, lack of upfront surgical resection or SRS, and lack of endocrine or HER2-directed therapy after brain metastases treatment. Although durable brain control and long-term survival beyond 5 years could be achieved in a subset of patients (largely after successful salvage), progression of brain metastases during the first year after diagnosis was common. Prognosis was influenced by patient-, disease- and treatment-related factors.

Clinical and molecular complexity of breast cancer metastases

Clinical oncology is advancing toward a more personalized treatment orientation, making the need to understand the biology of metastasis increasingly acute. Dissecting the complex molecular, genetic and clinical phenotypes underlying the processes involved in the development of metastatic disease, which remains the principal cause of cancer-related deaths, could lead to the identification of more effective prognostication and targeted approaches to prevent and treat metastases. The past decade has witnessed significant progress in the field of cancer metastasis research. Clinical and technological milestones have been reached which have tremendously enriched our understanding of the complex pathways undertaken by primary tumors to progress into lethal metastases and how some of these processes might be amenable to therapy. The aim of this review article is to highlight the recent advances toward unraveling the clinical and molecular complexity of breast cancer metastases. We focus on genes mediating breast cancer metastases and organ-specific tropism, and discuss gene signatures for prediction of metastatic disease. The challenges of translating this information into clinically applicable tools for improving the prognostication of the metastatic potential of a primary breast tumor, as well as for therapeutic interventions against latent and active metastatic disease are addressed.

Emerging strategies for treating brain metastases from breast cancer

Brain metastasis is an end stage in breast cancer progression. Traditional treatment options have minimal efficacy, and overall survival is on the order of months. The incidence of brain metastatic disease is increasing with the improved management of systemic disease and prolongation of survival. Unfortunately, the targeted therapies that control systemic disease have diminished efficacy against brain lesions. There are reasons to be optimistic, however, as emerging therapies have shown promise in preclinical and early clinical settings. This review discusses recent advances in breast cancer brain metastasis therapy and potential approaches for successful treatment.