Advances in the management of breast cancer brain metastases

Impact of systemic disease on CNS disease control after stereotactic radiosurgery to breast cancer brain metastases (The SYBRA Study)

The objective of the study is to assess impact of systemic disease (SD) status on overall survival and brain metastasis (BM) control, adopting a novel landmark approach to categorize SD among breast cancer (BC) patients. This single institution retrospective study included BCBM patients who have received stereotactic radiosurgery (SRS) to brain. Separate endpoints [CNS failure-free survival (cFFS), overall survival (OS)] were analyzed from each Landmark (LM): LM1 (3-months), LM2 (6-months). Patients were categorized into early and non-early progression (EP, NEP) groups depending on SD status before LMs. Median survivals from LM were assessed with Kaplan Meier plots, compared with Log-Rank test. EP was associated with worse median cFFS and OS vs NEP in both LM analyses (cFFS- LM1: 3.6 vs. 9.7 months, p = 0.0016; LM2: 2.3 vs. 12.5 months, p < 0.0001; OS- LM1: 3.6 vs. 24.3 months, p < 0.0001; LM2: 5.3 vs. 30.2 months, p < 0.0001). In multivariate analyses, EP was associated with shorter cFFS [LM1: Hazard Ratio (HR) with 95% confidence interval (CI) 3.16, 1.46-6.83, p = 0.0034; LM2: 5.32, 2.33-12.15, p = <0.0001] and shorter OS (LM1: HR with 95% CI 4.28, 1.98-9.12, p = 0.0002; LM2: 7.40, 3.10-17.63, p = <0.0001) vs NEP. Early systemic disease progressions after 1st SRS to brain is associated with worse cFFS and OS in patients with BCBM.

A Case Report on Trastuzumab Emtansine (T-DM1) in a Patient With Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Metastatic Breast Cancer and Brain Metastases: Long-Term Treatment and Survival

Breast cancer remains the most common cancer in women worldwide. Among women with breast cancer, brain metastases are very prevalent among HER2-positive and affect those in the advanced stages of the disease. Various factors, including molecular subtypes, performance status, extracranial disease status, leptomeningeal metastasis, and the number of lesions, significantly influence the prognosis of patients with brain metastases from breast cancer (BCBrM). Understanding and addressing the specific risks associated with different breast cancer subtypes is crucial for developing tailored and effective medical treatments. This report presents a case of a breast cancer patient with recurrent disease and brain metastases who achieved long-term survival following a treatment regimen that included radiotherapy and a T-DM1 biosimilar.

Management of patients with advanced-stage HER2-positive breast cancer: current evidence and future perspectives

Amplification and/or overexpression of ERBB2, the gene encoding HER2, can be found in 15-20% of invasive breast cancers and is associated with an aggressive phenotype and poor clinical outcomes. Relentless research efforts in molecular biology and drug development have led to the implementation of several HER2-targeted therapies, including monoclonal antibodies, tyrosine-kinase inhibitors and antibody-drug conjugates, constituting one of the best examples of bench-to-bedside translation in oncology. Each individual drug class has improved patient outcomes and, importantly, the combinatorial and sequential use of different HER2-targeted therapies has increased cure rates in the early stage disease setting and substantially prolonged survival for patients with advanced-stage disease. In this Review, we describe key steps in the development of the modern paradigm for the treatment of HER2-positive advanced-stage breast cancer, including selecting and sequencing new-generation HER2-targeted therapies, and summarize efficacy and safety outcomes from pivotal studies. We then outline the factors that are currently known to be related to resistance to HER2-targeted therapies, such as HER2 intratumoural heterogeneity, activation of alternative signalling pathways and immune escape mechanisms, as well as potential strategies that might be used in the future to overcome this resistance and further improve patient outcomes.

Current treatment landscape of HR+/HER2- advanced breast cancer in the Nordics: a modified Delphi study

BACKGROUND

This Delphi study aimed to assess current perspectives on hormone receptor-positive/human epidermal growth factor receptor 2-negative(HR+/HER2-) advanced breast cancer (aBC) treatment strategies across the Nordics, and to establish where consensus exists across the Nordics on HR+/HER2- aBC treatment.

MATERIAL AND METHODS

A modified, three-round Delphi method was followed. A steering committee was appointed for study coordination, panellist selection, and questionnaire development. The questionnaires covered relevant topics on HR+/HER2- aBC treatment: treatment patterns in different lines of therapy (first [1L], second [2L], and third [3L]), oligometastatic disease, de novo aBC, brain metastases, age as influential factor, visceral crisis, radiotherapy, diagnostics, and clinical guidelines. Both open and closed-ended questions were included. Consensus was defined as at least 70% agreement.

RESULTS

In total, 28 experienced BC oncologists participated in the study from all five Nordic countries. Overall, topics reaching consensus included: preferred treatment approach in 1L and 2L therapy, treatment of oligometastatic disease, visceral crisis, brain metastases, and age-related treatment considerations. No consensus was reached for 3L therapy and local treatment for primary tumour in de novo aBC. Endocrine therapy (ET) combined with a cyclin-dependent kinase (CDK)4/6 inhibitor was the treatment of choice for 1L and 2L therapy. Treatment patterns in clinical practice did not always follow recommendations in current Nordic guidelines, as seen in the case of recently approved treatments.

DISCUSSION

ET in combination with a CDK4/6 inhibitor is the preferred frontline treatment for HR+/HER2- aBC in the Nordics. The observed discrepancy between current guidelines and clinical practice could be due to differences in the reimbursement of novel treatments in the Nordics. Collaborative research efforts are warranted for topics that lack consensus.

Impact of multidisciplinary team on the pattern of care for brain metastasis from breast cancer

Purpose

The aim of this study was to explore how a multidisciplinary team (MDT) affects patterns of local or systematic treatment.

Methods

We retrospectively reviewed the data of consecutive patients in the breast cancer with brain metastases (BCBM) database at our institution from January 2011 to April 2021. The patients were divided into an MDT group and a non-MDT group.

Results

A total of 208 patients were analyzed, including 104 each in the MDT and non-MDT groups. After MDT, 56 patients (53.8%) were found to have intracranial "diagnosis upgrade". In the matched population, patients in the MDT group recorded a higher proportion of meningeal metastases (14.4% vs. 4.8%, p = 0.02), symptomatic tumor progression (11.5% vs. 5.8%, p = 0.04), and an increased number of occurrences of brain metastases (BM) progression (p < 0.05). Attending MDT was an independent factor associated with ≥2 courses of intracranial radiotherapy (RT) [odds ratio (OR) 5.4, 95% confidence interval (CI): 2.7-10.9, p < 0.001], novel RT technique use (7.0, 95% CI 3.5-14.0, p < 0.001), and prospective clinical research (OR 5.7, 95% CI 2.4-13.4, p < 0.001).

Conclusion

Patients with complex conditions are often referred for MDT discussions. An MDT may improve the qualities of intracranial RT and systemic therapy, resulting in benefits of overall survival for BC patients after BM. This encourages the idea that treatment recommendations for patients with BMBC should be discussed within an MDT.

Pyrotinib combined with trastuzumab and chemotherapy for the treatment of human epidermal growth factor receptor 2-positive metastatic breast cancer: a single-arm exploratory phase II trial

PURPOSE

A substantial need for effective and safe treatment options is still unmet for patients with heavily pre-treated human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC). Herein, we assessed the efficacy and safety of pyrotinib plus trastuzumab and chemotherapy in patients with heavily treated HER2-positive MBC.

METHODS

In this single-arm exploratory phase II trial, patients with HER2-positive MBC previously treated with trastuzumab plus lapatinib or pertuzumab, received pyrotinib plus trastuzumab and chemotherapy. The primary end point was progression-free survival (PFS) in the total population (TP). Secondary end points included PFS in the subgroup with brain metastases (Sub-BrM), confirmed objective response rate (ORR), clinical benefit rate (CBR), disease control rate (DCR), exploration of predictive factors of PFS, and safety.

RESULTS

Between November 1, 2018, and March 31, 2021, 40 patients were eligible for this study. The median PFS reached 7.5 months (95% confidence interval [CI] 4.7 to 9.9 months) and 9.4 months (95% CI 6.6 to 12.1 months) in the TP and Sub-BrM, respectively. ORR was 50.5% (20/40). CBR was 75.5% (30/40) and DCR reached 97.5% (39/40). Cox univariate and multivariate analyses demonstrated that liver or/and lung metastases was the significant adverse prognostic factor for PFS (p = 0.018; p = 0.026; respectively). The most frequent grade 3 or 4 treatment-related adverse events were diarrhea, neutropenia and leukopenia. No new safety signals were observed.

CONCLUSION

Pyrotinib plus trastuzumab and chemotherapy offered a promising option with manageable safety profile for heavily pre-treated HER2-positive MBC, especially for those without liver or/and lung metastases.

Heterogeneity of HER2 Expression in Circulating Tumor Cells of Patients with Breast Cancer Brain Metastases and Impact on Brain Disease Control

Simple Summary

Results from a previous study suggested that the number of circulating tumor cells (CTC) might have a role as a biomarker of early distant brain failure in patients with breast cancer brain metastases (BCBM). However, it remains largely underexplored whether heterogeneous HER2 expression in CTC may have a prognostic implication. We evaluated the status of HER2 expression in CTC before and after radiotherapy/radiosurgery for BCBM and observed that the presence of HER2 expression in any moment was associated with longer distant brain failure-free survival, irrespective of the primary immunophenotype of the breast tumor. This finding suggests that the status of HER2 expression in CTC has the potential to improve the treatment selection for patients with BCBM.

Abstract

HER2 expression switching in circulating tumor cells (CTC) in breast cancer is dynamic and may have prognostic and predictive clinical implications. In this study, we evaluated the association between the expression of HER2 in the CTC of patients with breast cancer brain metastases (BCBM) and brain disease control. An exploratory analysis of a prospective assessment of CTC before (CTC1) and after (CTC2) stereotactic radiotherapy/radiosurgery (SRT) for BCBM in 39 women was performed. Distant brain failure-free survival (DBFFS), the primary endpoint, and overall survival (OS) were estimated. After a median follow-up of 16.6 months, there were 15 patients with distant brain failure and 16 deaths. The median DBFFS and OS were 15.3 and 19.5 months, respectively. The median DBFFS was 10 months in patients without HER2 expressed in CTC and was not reached in patients with HER2 in CTC (p = 0.012). The median OS was 17 months in patients without HER2 in CTC and was not reached in patients with HER2 in CTC (p = 0.104). On the multivariate analysis, DBFFS was superior in patients who were primary immunophenotype (PIP) HER2-positive (HR 0.128, 95% CI 0.025–0.534; p = 0.013). The expression of HER2 in CTC was associated with a longer DBFFS, and the switching of HER2 expression between the PIP and CTC may have an impact on prognosis and treatment selection for BCBM.

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.

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.