Breast Cancer Brain Metastasis: The Potential Role of MRI Beyond Current Clinical Applications

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Joint EANM-SNMMI guideline on the role of 2-[18F]FDG PET/CT in no special type breast cancer : (endorsed by the ACR, ESSO, ESTRO, EUSOBI/ESR, and EUSOMA)

INTRODUCTION

There is much literature about the role of 2-[18F]FDG PET/CT in patients with breast cancer (BC). However, there exists no international guideline with involvement of the nuclear medicine societies about this subject.

PURPOSE

To provide an organized, international, state-of-the-art, and multidisciplinary guideline, led by experts of two nuclear medicine societies (EANM and SNMMI) and representation of important societies in the field of BC (ACR, ESSO, ESTRO, EUSOBI/ESR, and EUSOMA).

METHODS

Literature review and expert discussion were performed with the aim of collecting updated information regarding the role of 2-[18F]FDG PET/CT in patients with no special type (NST) BC and summarizing its indications according to scientific evidence. Recommendations were scored according to the National Institute for Health and Care Excellence (NICE) criteria.

RESULTS

Quantitative PET features (SUV, MTV, TLG) are valuable prognostic parameters. In baseline staging, 2-[18F]FDG PET/CT plays a role from stage IIB through stage IV. When assessing response to therapy, 2-[18F]FDG PET/CT should be performed on certified scanners, and reported either according to PERCIST, EORTC PET, or EANM immunotherapy response criteria, as appropriate. 2-[18F]FDG PET/CT may be useful to assess early metabolic response, particularly in non-metastatic triple-negative and HER2+ tumours. 2-[18F]FDG PET/CT is useful to detect the site and extent of recurrence when conventional imaging methods are equivocal and when there is clinical and/or laboratorial suspicion of relapse. Recent developments are promising.

CONCLUSION

2-[18F]FDG PET/CT is extremely useful in BC management, as supported by extensive evidence of its utility compared to other imaging modalities in several clinical scenarios.

Association Between 18F-FDG PET Activity and HER2 Status in Breast Cancer Brain Metastases

Purpose

The objective of this study was to evaluate whether uptake on 18F-fluorodeoxyglucose (18F-FDG) PET could help differentiate HER2-positive from HER2-negative breast cancer brain metastases.

Methods

In this retrospective, cross-sectional study of a cohort of 14 histologically proven breast cancer brain metastases, we analyzed both preoperative 18F-FDG PET/CT and HER2 status of the resected/biopsied brain specimens. The maximum standardized uptake values (SUVmax) of the lesions were normalized to contralateral normal white matter and compared using Mann-Whitney U tests.

Results

The study cohort was comprised of 12 women with breast cancer with a mean age of 59 years (range: 43-76 years) with a total of 14 distinct brain metastatic lesions. The SUVmax ratio of HER2-positive breast cancer brain metastases was significantly greater than that of HER2-negative lesions (3.98 vs 1.79, U = 38.00, p = 0.008).

Conclusion

The SUVmax ratio may help to identify the HER2 status of breast cancer brain metastases, if validated prospectively.

Evaluation of brain metastasis edema in breast cancer patients as a marker for Ki-67 and cell count-A single center analysis

BACKGROUND

Peritumoral edema is an important cause of morbidity and mortality in patients with breast cancer brain metastases (BCBM). The relationship between vasogenic edema and proliferation indices or cell density in BCBM remains poorly understood.

PURPOSE

To assess the association between tumor volume and peritumoral edema volume and histopathological and immunohistochemical parameters in BCBM.

MATERIALS AND METHODS

Patients with confirmed BCBM were retrospectively identified. The tumor volume and peritumoral edema volume of each brain metastasis (BM) were semi-automatically calculated in axial T2w and axial T2-fluid attenuated inversion recovery (FLAIR) sequences using the software MIM (Cleveland, Ohio, USA). Edema volume was correlated with histological parameters, including cell count and Ki-67. Sub-analyses were conducted for luminal B, Her2-positive, and tripe negative subgroups.

RESULTS

Thirty-eight patients were included in the study. There were 24 patients with a single BM. Mean metastasis volume was 31.40 ± 32.52 mL and mean perifocal edema volume was 72.75 ± 58.85 mL. In the overall cohort, no correlation was found between tumor volume and Ki-67 (r = 0.046, p = .782) or cellularity (r = 0.028, p = .877). Correlation between edema volume and Ki-67 was r = 0.002 (p = .989), correlation with cellularity was r = 0.137 (p = .453). No relevant correlation was identified in any subgroup analysis. There was no relevant correlation between BM volume and edema volume.

CONCLUSION

In patients with breast cancer brain metastases, we did not find linear associations between edema volumes and immunohistochemical features reflecting proliferation potential. Furthermore, there was no relevant correlation between metastasis volume and edema volume.

Brain metastases from breast cancer using magnetic resonance imaging: A systematic review

Despite improvements in imaging and treatment approaches, brain metastases (BMs) continue to be the primary cause of mortality and morbidity in about 20% of adult cancer patients. This research aimed to review the magnetic resonance imaging (MRI) and clinical characteristics of BMs resulting from breast cancer (BC). A systematic review of original research articles published from January 2000 to June 2023. We selected studies that reported MRI findings of BMs in BC patients. We excluded reviews, case reports, books/book chapters, animal studies and irrelevant records. We identified 24 studies that included 1580 BC patients with BMs. T1-weighted (T1-w) (pre- and postcontrast), T2-weighted (T2-w), fluid-attenuated inversion recovery (FLAIR) and T2*-weighted (T2*-w) was used to measure the lesion size, shape and area. In other studies, advanced structural techniques including diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI) and susceptibility-weighted imaging (SWI) were used to more precisely and sensitively evaluate the pathological area. Furthermore, functional and metabolic techniques like functional MRI (fMRI), magnetic resonance spectroscopy (MRS) and perfusion-weighted imaging (PWI) have also been utilised. The MRI findings of BMs varied depending on the MRI technique, the BC subtype, the lesion size and shape, the presence of haemorrhage or necrosis and the comparison with other brain tumours. Some MRI findings were associated with prognosis, recurrence or cognitive impairment in BC patients with BMs. MRI detects, characterises and monitors BMs from BC. Findings vary by MRI technique, BC subtype, lesion characteristics and comparison with other brain tumours. More research should validate emerging MRI techniques, determine the clinical implications of findings and explore the underlying mechanisms and biology of BMs from BC. MRI is a valuable tool for diagnosis, targeted therapy and studying BC metastasis.

Multidisciplinary management of HER2-positive breast cancer with brain metastases: An evidence-based pragmatic approach moving from pathophysiology to clinical data

INTRODUCTION

About 30-50 % of stage IV HER2+ breast cancers (BC) will present brain metastases (BMs). Their management is based on both local treatment and systemic therapy. Despite therapeutic advances, BMs still impact on survival and quality of life and the development of more effective systemic therapies represents an unmet clinical need.

MATERIALS AND METHODS

A thorough analysis of the published literature including ongoing clinical trials has been performed, investigating concepts spanning from the pathophysiology of tumor microenvironment to clinical considerations with the aim to summarize the current and future locoregional and systemic strategies.

RESULTS

Different trials have investigated monotherapies and combination treatments, highlighting how the blood-brain barrier (BBB) represents a major problem hindering diffusion and consequently efficacy of such options. Trastuzumab has long been the mainstay of systemic therapy and over the last two decades other HER2-targeted agents including lapatinib, pertuzumab, and trastuzumab emtansine, as well as more recently neratinib, tucatinib, and trastuzumab deruxtecan, have been introduced in clinical practice after showing promising results in randomized controlled trials.

CONCLUSIONS

We ultimately propose an evidence-based treatment algorithm for clinicians treating HER2 + BCs patients with BMs.

Association of Relative Cerebral Blood Volume from Dynamic Susceptibility Contrast-Enhanced Perfusion MR with HER2 Status in Breast Cancer Brain Metastases

RATIONALE AND OBJECTIVES

With the development of HER2-directed therapies, identifying non-invasive imaging biomarkers of HER2 expression in breast cancer brain metastases has become increasingly important. The purpose of this study was to investigate whether relative cerebral blood volume (rCBV) from dynamic susceptibility contrast-enhanced (DSC) perfusion MR could help identify the HER2 status of breast cancer brain metastases.

MATERIALS AND METHODS

With IRB approval for this HIPAA-compliant cross-sectional study and a waiver of informed consent, we queried our institution's electronic medical record to derive a cohort of 14 histologically proven breast cancer brain metastases with preoperative DSC perfusion MR and HER2 analyses of the resected/biopsied brain specimens from 2011-2021. The rCBV of the lesions was measured and compared using Mann-Whitney tests. Receiver operating characteristic analyses were performed to evaluate the performance of rCBV in identifying HER2 status.

RESULTS

The study cohort was comprised of 14 women with a mean age of 56 years (range: 32-81 years) with a total of 14 distinct lesions. The rCBV of HER2-positive breast cancer brain metastases was significantly greater than the rCBV of HER2-negative lesions (8.02 vs 3.97, U=48.00, p=0.001). rCBV differentiated HER2-positive lesions from HER2-negative lesions with an area under the curve of 0.98 (standard error=0.032, p<0.001). The accuracy-maximizing rCBV threshold (4.8) was associated with an accuracy of 93% (13/14), a sensitivity of 100% (7/7), and a specificity of 86% (6/7).

CONCLUSION

rCBV may assist in identifying the HER2 status of breast cancer brain metastases, if validated in a large prospective trial.

Pituitary Apoplexy After Leuprolide Therapy in a Breast Cancer Patient: A Case Report

Pituitary apoplexy (PA) is a clinical syndrome resulting from sudden hemorrhage and/or infarction of the pituitary gland. Recent reports documented the development of PA secondary to treatment with gonadotropin-releasing hormone (GnRH) agonists for prostate cancer. A 52-year-old woman visited our emergency room with a severe headache, occurred 1 day prior. She underwent breast-conserving surgery for breast cancer 1 month prior. She was currently undergoing radiation and hormone therapy, consisting of leuprorelin. Brain contrast-enhanced MRI revealed a pituitary adenoma with internal hemorrhage in the sellar and suprasellar areas. Pachymeningeal enhancement was observed along the retroclival and bilateral frontal areas. The patient was diagnosed with PA and aseptic meningitis. The patient underwent total excision via transsphenoidal surgery 8 days after admission. The patient was pathologically diagnosed with a pituitary adenoma with necrosis. On immunochemical staining, the tumor was positive for follicle-stimulating hormone. The follow-up MRI revealed no evidence of residual tumor or an improved pachymeningeal enhancement. She is currently undergoing follow-up at the neurosurgery and endocrinology outpatient departments with no noted complications. In breast cancer patients receiving GnRH agonist therapy, PA may be rare complication.

Association of lesion contour and lesion composition on MR with HER2 status in breast cancer brain metastases

BACKGROUND AND PURPOSE

With the development of HER2-directed therapies, identifying non-invasive imaging biomarkers of HER2 status in breast cancer brain metastases has become increasingly important, particularly given the risks of tissue sampling within the brain and the possibility of a change in receptor expression from the primary tumor to the brain metastasis. The purpose of this study was to evaluate whether lesion contour and composition on MR could help identify the HER2 status of breast cancer brain metastases.

MATERIALS AND METHODS

We derived a cohort of 34 women with a mean age of 55 years (range: 31-81 years) with a total of 47 distinct histologically proven breast cancer brain metastases with preoperative contrast-enhanced brain MR and HER2 immunohistochemistry and/or fluorescent in-situ hybridization (FISH) of the resected/biopsied brain specimens from 2018 to 2021. Two fellowship-trained neuroradiologists evaluated the lesion contour and lesion composition of each lesion. Logistic regression analyses were performed.

RESULTS

In a logistic regression model, an irregular contour had an odds ratio of 170 (p = 0.007) in differentiating HER2-positive from HER2-negative lesions. In a logistic regression model, when compared to a predominantly cystic lesion composition, a solid lesion composition had an odds ratio of 17 (p = 0.016) in differentiating HER2-positive from HER2-negative lesions.

CONCLUSION

Lesion contour and lesion composition on MR were significantly associated with the HER2 status of breast cancer brain metastases. Current assessment of HER2 status requires tissue sampling and immunochemical and/or FISH analyses. A non-invasive imaging biomarker that may help predict HER2 status may be of great clinical value.

Brain metastasis screening in the molecular age

The incidence of brain metastases (BM) amongst cancer patients has been increasing due to improvements in therapeutic options and an increase in overall survival. Molecular characterization of tumors has provided insights into the biology and oncogenic drivers of BM and molecular subtype-based screening. Though there are currently some screening and surveillance guidelines for BM, they remain limited. In this comprehensive review, we review and present epidemiological data on BM, their molecular characterization, and current screening guidelines. The molecular subtypes with the highest BM incidence are epithelial growth factor receptor-mutated non-small cell lung cancer (NSCLC), BRCA1, triple-negative (TN), and HER2+ breast cancers, and BRAF-mutated melanoma. Furthermore, BMs are more likely to present asymptomatically at diagnosis in oncogene-addicted NSCLC and BRAF-mutated melanoma. European screening standards recommend more frequent screening for oncogene-addicted NSCLC patients, and clinical trials are investigating screening for BM in hormone receptor+, HER2+, and TN breast cancers. However, more work is needed to determine optimal screening guidelines for other primary cancer molecular subtypes. With the advent of personalized medicine, molecular characterization of tumors has revolutionized the landscape of cancer treatment and prognostication. Incorporating molecular characterization into BM screening guidelines may allow physicians to better identify patients at high risk for BM development and improve patient outcomes.

Molecular Mechanisms Driving the Formation of Brain Metastases

Simple Summary

Brain metastases are the most common brain tumor in adults and are associated with poor prognosis. The propensity of different solid tumors to metastasize varies greatly, with lung, breast, and melanoma primary tumors commonly leading to brain metastases, while other primaries such as prostate rarely metastasize to the brain. The molecular mechanisms that predispose and facilitate brain metastasis development are poorly understood. In this review, we present the current data on the genomic landscape of brain metastases that arise from various primary cancers and also outline potential molecular mechanisms that drive the formation of distant metastases in the brain.

Abstract

Targeted therapies for cancers have improved primary tumor response rates, but concomitantly, brain metastases (BM) have become the most common brain tumors in adults and are associated with a dismal prognosis of generally less than 6 months, irrespective of the primary cancer type. They most commonly occur in patients with primary breast, lung, or melanoma histologies; however, they also appear in patients with other primary cancers including, but not limited to, prostate cancer, colorectal cancer, and renal cell carcinoma. Historically, molecular biomarkers have normally been identified from primary tumor resections. However, clinically informative genomic alterations can occur during BM development and these potentially actionable alterations are not always detected in the primary tumor leading to missed opportunities for effective targeted therapy. The molecular mechanisms that facilitate and drive metastasis to the brain are poorly understood. Identifying the differences between the brain and other extracranial sties of metastasis, and between primary tumors and BM, is essential to improving our understanding of BM development and ultimately patient management and survival. In this review, we present the current data on the genomic landscape of BM from various primary cancers which metastasize to the brain and outline potential mechanisms which may play a role in promoting the formation of the distant metastases in the brain.

Quantum dots: The cutting-edge nanotheranostics in brain cancer management

Quantum dots (QDs) are semiconductor nanocrystals possessing unique optoelectrical properties in that they can emit light energy of specific tunable wavelengths when excited by photons. They are gaining attention nowadays owing to their all-around ability to allow high-quality bio-imaging along with targeted drug delivery. The most lethal central nervous system (CNS) disorders are brain cancers or malignant brain tumors. CNS is guarded by the blood-brain barrier which poses a selective blockade toward drug delivery into the brain. QDs have displayed strong potential to deliver therapeutic agents into the brain successfully. Their bio-imaging capability due to photoluminescence and specific targeting ability through the attachment of ligand biomolecules make them preferable clinical tools for coming times. Biocompatible QDs are emerging as nanotheranostic tools to identify/diagnose and selectively kill cancer cells. The current review focuses on QDs and associated nanoformulations as potential futuristic clinical aids in the continuous battle against brain cancer.

Analysis of microRNAs in Exosomes of Breast Cancer Patients in Search of Molecular Prognostic Factors in Brain Metastases

Brain metastases are the most severe tumorous spread during breast cancer disease. They are associated with a limited quality of life and a very poor overall survival. A subtype of extracellular vesicles, exosomes, are sequestered by all kinds of cells, including tumor cells, and play a role in cell-cell communication. Exosomes contain, among others, microRNAs (miRs). Exosomes can be taken up by other cells in the body, and their active molecules can affect the cellular process in target cells. Tumor-secreted exosomes can affect the integrity of the blood-brain barrier (BBB) and have an impact on brain metastases forming. Serum samples from healthy donors, breast cancer patients with primary tumors, or with brain, bone, or visceral metastases were used to isolate exosomes and exosomal miRs. Exosomes expressed exosomal markers CD63 and CD9, and their amount did not vary significantly between groups, as shown by Western blot and ELISA. The selected 48 miRs were detected using real-time PCR. Area under the receiver-operating characteristic curve (AUC) was used to evaluate the diagnostic accuracy. We identified two miRs with the potential to serve as prognostic markers for brain metastases. Hsa-miR-576-3p was significantly upregulated, and hsa-miR-130a-3p was significantly downregulated in exosomes from breast cancer patients with cerebral metastases with AUC: 0.705 and 0.699, respectively. Furthermore, correlation of miR levels with tumor markers revealed that hsa-miR-340-5p levels were significantly correlated with the percentage of Ki67-positive tumor cells, while hsa-miR-342-3p levels were inversely correlated with tumor staging. Analysis of the expression levels of miRs in serum exosomes from breast cancer patients has the potential to identify new, non-invasive, blood-borne prognostic molecular markers to predict the potential for brain metastasis in breast cancer. Additional functional analyzes and careful validation of the identified markers are required before their potential future diagnostic use.

Brain metastases: An update on the multi-disciplinary approach of clinical management

IMPORTANCE

Brain metastasis (BM) is the most common malignant intracranial neoplasm in adults with over 100,000 new cases annually in the United States and outnumbering primary brain tumors 10:1.

OBSERVATIONS

The incidence of BM in adult cancer patients ranges from 10-40%, and is increasing with improved surveillance, effective systemic therapy, and an aging population. The overall prognosis of cancer patients is largely dependent on the presence or absence of brain metastasis, and therefore, a timely and accurate diagnosis is crucial for improving long-term outcomes, especially in the current era of significantly improved systemic therapy for many common cancers. BM should be suspected in any cancer patient who develops new neurological deficits or behavioral abnormalities. Gadolinium enhanced MRI is the preferred imaging technique and BM must be distinguished from other pathologies. Large, symptomatic lesion(s) in patients with good functional status are best treated with surgery and stereotactic radiosurgery (SRS). Due to neurocognitive side effects and improved overall survival of cancer patients, whole brain radiotherapy (WBRT) is reserved as salvage therapy for patients with multiple lesions or as palliation. Newer approaches including multi-lesion stereotactic surgery, targeted therapy, and immunotherapy are also being investigated to improve outcomes while preserving quality of life.

CONCLUSION

With the significant advancements in the systemic treatment for cancer patients, addressing BM effectively is critical for overall survival. In addition to patient's performance status, therapeutic approach should be based on the type of primary tumor and associated molecular profile as well as the size, number, and location of metastatic lesion(s).