Effects of systemic therapy and local therapy on outcomes of 873 breast cancer patients with metastatic breast cancer to brain: MD Anderson Cancer Center experience

Navigating the Blood-Brain Barrier: Challenges and Therapeutic Strategies in Breast Cancer Brain Metastases

Breast cancer (BC) is the most common cancer in women, with metastatic BC being responsible for the highest number of deaths. A frequent site for BC metastasis is the brain. Brain metastasis derived from BC involves the cooperation of multiple genetic, epigenetic, angiogenic, and tumor-stroma interactions. Most of these interactions provide a unique opportunity for development of new therapeutic targets. Potentially targetable signaling pathways are Notch, Wnt, and the epidermal growth factor receptors signaling pathways, all of which are linked to driving BC brain metastasis (BCBM). However, a major challenge in treating brain metastasis remains the blood-brain barrier (BBB). This barrier restricts the access of unwanted molecules, cells, and targeted therapies to the brain parenchyma. Moreover, current therapies to treat brain metastases, such as stereotactic radiosurgery and whole-brain radiotherapy, have limited efficacy. Promising new drugs like phosphatase and kinase modulators, as well as BBB disruptors and immunotherapeutic strategies, have shown the potential to ease the disease in preclinical studies, but remain limited by multiple resistance mechanisms. This review summarizes some of the current understanding of the mechanisms involved in BC brain metastasis and highlights current challenges as well as opportunities in strategic designs of potentially successful future therapies.

Systemic treatments for breast cancer brain metastasis

Breast cancer (BC) is the most common cancer in females and BC brain metastasis (BCBM) is considered as the second most frequent brain metastasis. Although the advanced treatment has significantly prolonged the survival in BC patients, the prognosis of BCBM is still poor. The management of BCBM remains challenging. Systemic treatments are important to maintain control of central nervous system disease and improve patients' survival. BCBM medical treatment is a rapidly advancing area of research. With the emergence of new targeted drugs, more options are provided for the treatment of BM. This review features currently available BCBM treatment strategies and outlines novel drugs and ongoing clinical trials that may be available in the future. These treatment strategies are discovered to be more efficacious and potent, and present a paradigm shift in the management of BCBMs.

Local and systemic therapy in breast cancer patients with central nervous system metastases

PURPOSE

As survival of patients with central nervous system (CNS) metastases from breast cancer is poor and incidence rates are increasing, there is a growing need for better treatment strategies. In the current study, the efficacy of local and systemic therapies was analyzed in breast cancer patients with CNS metastases.

METHODS

Medical records from breast cancer patients with brain and/or leptomeningeal metastases (LM) treated at a tertiary referral center and a teaching hospital between 2010 and 2020 were retrospectively studied. Main outcomes of interest were overall survival (OS) and CNS progression free survival. Analyses were performed among patients with brain metastases (BM) and patients with LM, for the different systemic and local therapies for CNS metastases, and for subgroups based on breast cancer subtypes.

RESULTS

We identified 155 patients, 97 with BM and 58 with LM. Median OS was 15.9 months for patients with BM and 1.5 months for patients with LM. Median OS was significantly longer for HER2-positive patients with BM (22.8 months) vs triple negative (8.4 months) and hormone receptor positive/HER2-negative (5.9 months) (P < 0.001). Patients with BM receiving both local and systemic therapy also had a longer median OS (21.8 months), compared to the other three subgroups (local therapy only: 9.9 months, systemic therapy only: 4.3 months, no therapy: 0.5 months, P < 0.001). No significant difference in OS was observed between different systemic treatment regimens.

CONCLUSION

Breast cancer patients with BM show longest median OS when the subtype is HER2-positive and when they are treated with both local and systemic therapy.

Clinical diagnosis and treatment of breast cancer with brain metastases and establishment of a prognostic model: a 10-year, single-center, real-world study of 559 cases

Background

This study involved a retrospective analysis of 559 metastatic breast cancer (MBC) patients with brain metastasis (BM). We aimed to establish the effectiveness of different preferred treatment methods and factors affecting overall survival following BM diagnosis (BMOS) and explore the feasibility of systemic treatment for MBC patients with BM.

Methods

Univariate and multivariate analyses were used to assess the efficacy of different preferred treatments and other factors associated with BMOS, and a nomogram was then established based on the results of the univariate analysis.

Results

Patients that initially received systemic drug therapy exhibited a clinical benefit rate (CBR) of 43.9% and an intracranial disease control rate (DCR) of 80.6%. The median time between BM diagnosis and the requirement for local intracranial treatment due to worsening disease status was 10.0 months for these patients (95% CI: 7.811–12.189 months). The median follow-up was 28.0 months, and the median BMOS was 16.0 months. Following BM diagnosis, the systemic drug treatment group had a better outcome than the local brain treatment group, with a respective median BMOS of 22.0 and 16.0 months (χ²=7.743, P=0.005). At the time of BM diagnosis, the median BMOS for patients without neurological symptoms diagnosed by regular screen was significantly longer than that of patients with neurological symptoms (18.0 vs. 13.0 months, respectively; χ²=11.371, P=0.001). Based on these analyses, a nomogram was constructed that incorporated disease-free survival (DFS), Karnofsky performance status (KPS), molecular subtype, number of extracranial metastases, BM location, number of BMs, neurological symptoms, and the preferred treatment approach, with a prediction probability (c-index) value of 0.76.

Conclusions

Systemic drug treatment has a beneficial effect on brain lesions, and effective treatment delays the need for local intracranial treatment. Cranial magnetic resonance imaging (MRI) screening can detect asymptomatic BM in MBC patients (particularly those with HER2−positive or triple-negative disease), offering these patients an opportunity to undergo systemic drug therapy, thereby prolonging their survival. To our knowledge, this is a well-fitted nomogram including current treatment and medical examination strategies to predict BMOS probability that offers value as an adjunct for the prognostic evaluation of MBC-BM patients.

Histone citrullination by PADI4 is required for HIF-dependent transcriptional responses to hypoxia and tumor vascularization

Hypoxia-inducible factors (HIFs) activate transcription of target genes by recruiting coactivators and chromatin-modifying enzymes. Peptidylarginine deiminase 4 (PADI4) catalyzes the deimination of histone arginine residues to citrulline. Here, we demonstrate that PADI4 expression is induced by hypoxia in a HIF-dependent manner in breast cancer and hepatocellular carcinoma cells. PADI4, in turn, is recruited by HIFs to hypoxia response elements (HREs) and is required for HIF target gene transcription. Hypoxia induces histone citrullination at HREs that is PADI4 and HIF dependent. RNA sequencing revealed that almost all HIF target genes in breast cancer cells are PADI4 dependent. PADI4 is required for breast and liver tumor growth and angiogenesis in mice. PADI4 expression is correlated with HIF-1α expression and vascularization in human breast cancer biopsies. Thus, HIF-dependent recruitment of PADI4 to target genes and local histone citrullination are required for transcriptional responses to hypoxia.

"Triple-Negative Breast Cancer Central Nervous System Metastases From the Laboratory to the Clinic"

ABSTRACT

Triple-negative breast cancer (TNBC) accounts for 15% to 20% of breast cancers and has an incidence as high as 50% of brain metastases once patients develop advanced disease. The lack of targeted and effective therapies, characteristic of this subtype of breast cancer, is especially evident once central nervous system (CNS) metastases occur. Compared with other subtypes of breast cancer, TNBC patients have the shorter interval from diagnosis to development of brain metastases and the shorter overall survival once they occur, a median of 4 to 6 months. Preclinical studies of TNBC and CNS microenvironment are actively ongoing, clarifying mechanisms and orienting more effective approaches to therapy. While the first drugs have been specifically approved for use in metastatic TNBC, data on their CNS effect are still awaited.

Recursive Partitioning Analysis of Systemic Therapy after Radiotherapy in Patients with Brain Metastases

PURPOSE

The purpose of this study was to identify factors associated with the initiation or continuation of systemic treatment after brain irradiation. The outcome of interest was a utilization rate of at least 75%, given that active extracranial disease is common in patients with brain metastases. If left untreated, extracranial disease limits survival, regardless of successful local treatment of the brain metastases. In this context, systemic therapy has been shown to improve survival, e.g., after whole-brain radiotherapy.

PATIENTS AND METHODS

The study included 185 patients with active extracranial disease, 60% of whom received systemic therapy.

RESULTS

Survival from the start of brain irradiation was longest in patients who received additional immune checkpoint inhibitors, endocrine treatment, or anti-HER-2 drugs. After uni- and multivariate analyses, Eastern Cooperative Oncology Group performance status (PS) was selected as the first prediction criterion in the recursive partitioning analysis (RPA) decision tree analysis. RPA was successful for patients with PS 0-1, but patients with PS 2 had lower treatment utilization rates (maximum 60-70%, with a disease-dependent impact of age and LabBM score [blood test results]). The highest utilization rates were observed in (1) patients with PS 0 and (2) those with breast cancer, small-cell lung cancer, or lung adenocarcinoma with PS 1.

CONCLUSIONS

These results inform the multidisciplinary discussion and treatment planning for the common scenario of simultaneous intra- and extracranial metastases.