Analysis of Prognostic Factors Affecting the Brain Metastases Free Survival and Survival After Brain Metastases in Breast Cancer

Temporal Dynamics and Clinical Predictors of Brain Metastasis in Breast Cancer: A Two-Decade Cohort Analysis Toward Tailored CNS Screening

BACKGROUND/OBJECTIVES

Breast cancer is the most common malignancy in women and the second leading cause of cancer-related deaths globally. It is also the second most frequent source of brain metastases (BMs), contributing to 5-20% of cases. Despite this, routine brain imaging for screening is not recommended and is only conducted when clinical symptoms or physical findings suggest metastasis. This study aims to identify clinical predictors associated with overall survival (OS) and the timing of BM development in breast cancer patients.

METHODS

We performed a retrospective review of medical records for 113 patients diagnosed with BMs secondary to breast cancer at our institution between 2000 and 2020. Baseline demographic data and clinical characteristics related to BMs were collected. To identify factors associated with OS and time to BM development after breast cancer diagnosis, we conducted univariate analysis using Kaplan-Meier curves, bivariate analysis with the log-rank test, and multivariate analysis via the Cox Proportional Hazard model.

RESULTS

An early diagnosis of BMs was identified as a significant predictor of prolonged OS (aHR = 0.22; 95% CI: 0.049-0.98, p = 0.05). Post-menopausal status at breast cancer diagnosis (aHR = 1.69; 95% CI: 1.13-2.53, p = 0.01), Asian ethnicity (aHR = 2.30; 95% CI: 1.03-5.16, p = 0.04), and the ER+/HER2+ subtype (aHR = 2.06; 95% CI: 1.14-3.71, p = 0.02) were significantly associated with a shorter time to BM diagnosis. A subgroup analysis of patients with ER+ breast tumors revealed that Hispanic or Arabic ethnicity (aHR = 3.63; 95% CI: 1.34-9.81, p = 0.01) and stage IV diagnosis (aHR = 2.09; 95% CI: 1.16-3.76, p = 0.01) were significantly associated with shorter intervals to BM diagnosis.

CONCLUSIONS

Breast cancer remains a significant global health burden for women, yet clear guidelines for routine BMs screening are still lacking. Early detection of BMs has been shown to notably improve long-term survival outcomes. Additionally, post-menopausal status, Hispanic or Arabic ethnicity, and the HER2+ tumor subtype are associated with shorter time to BM development, highlighting these factors as potential indicators for central nervous system screening.

Local control and toxicity after stereotactic radiotherapy in brain metastases patients and the impact of novel systemic treatments

BACKGROUND AND PURPOSE

Treatment modalities for patients with brain metastases consist of surgery, radiotherapy, and systemic treatments such as immunotherapy and targeted therapy. Although much is known about local control of brain metastases after radiotherapy and surgery alone, more understanding is needed of the additional effect of new systemic treatments. Our study presents real-world data about the combined effects of different local and systemic treatment strategies on local response of irradiated brain metastases.

MATERIALS AND METHODS

We performed a retrospective consecutive cohort study of patients that presented with brain metastases in our institution between June 2018 and May 2020, reporting the impact of radiotherapy alone versus radiotherapy combined with systemic treatment on local control of irradiated brain metastases and toxicity. Chemotherapy and targeted therapy were temporarily discontinued around irradiation.

RESULTS

262 consecutively treated patients were included in the study. Median time to local failure of irradiated brain metastases was 18 months (IQR 9-34), median overall survival was 20 months (IQR 10-36). 211 (81 %) patients received systemic treatment. Patients with breast cancer had a worse local control (HR 2.3, 95 % CI 1.0-5.0, p = 0.038), as did patients without any systemic treatment (HR 2.1, 95 % CI 1.1-4.3, p = 0.034). Symptomatic radiation necrosis occurred in 36 (14 %) patients. A diameter > 2.5 cm was associated with a higher risk of radiation necrosis. No association was found between systemic treatment in combination with local radiotherapy and symptomatic radiation necrosis.

CONCLUSION

Patients who received any form of systemic treatment had better local control after stereotactic radiosurgery for brain metastases. We did not find an association between systemic treatment and the incidence of radiation necrosis.

Brain Radiotherapy Combined with Targeted Therapy for HER2-Positive Breast Cancer Patients with Brain Metastases

Background

Research on the sequencing of brain radiotherapy and targeted chemotherapy after brain metastasis (BM) in HER2-positive breast cancer patients is limited and inconclusive. This study investigated the efficacy of sequential delivery of radiotherapy and targeted therapy in patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer with BM.

Methods

Fifty-seven patients were categorized into two groups: the targeted-radiotherapy group (receiving 2-8 cycles of anti-HER2-targeted therapy followed by radiotherapy after BM) and the radiotherapy-targeted group (undergoing radiotherapy first, followed by regular anti-HER2-targeted therapy). The study endpoints were intracranial progression-free survival (iPFS) and overall survival. Factors associated with intracranial progression and mortality were assessed by univariate and multivariate Cox proportional hazards analysis.

Results

Patients in the radiotherapy-targeted group had better iPFS (P < 0.001), while there was no significant difference in overall survival between the two groups (P = 0.145). Multivariate Cox analysis showed that different sequential treatment groups were independent prognostic factors for iPFS. In patients with a modified breast graded prognostic assessment score of 3.5-4.0, the median survival time was 26 months in the radiotherapy-targeted group and 22 months in the targeted-radiotherapy group (P = 0.019).

Conclusion

Overall, radiotherapy followed by targeted therapy may improve survival in HER2-positive breast cancer patients with BM, particularly in those with a modified breast graded prognostic assessment score of 3.5-4.0.

Non-invasive Fluorescence Imaging of Breast Cancer Metastasis to the Brain in an Orthotopic Nude-mouse Model With Very-narrow-band-width Laser Excitation of Red Fluorescent Protein Resulting in an Ultra-bright Signal Without Skin Autofluorescence

BACKGROUND/AIM

Breast-cancer metastasis to the brain is an intractable disease. To discover improved therapy for this disease, we developed a precise non-invasively-imageable orthotopic nude-mouse model, using very-narrow-band-width laser fluorescence excitation.

MATERIALS AND METHODS

Female nu/nu nude mice, aged 4-8 weeks, were inoculated through the midline of the skull with triple-negative human MDA-MB-231 breast cancer cells (5×105) expressing red fluorescent protein (RFP). The mice were imaged with the Analytik Jena UVP Biospectrum Advanced at 520 nm excitation with peak emission at 605 nm.

RESULTS

Three weeks after injection of MDA-MB-231-RFP cells in the brain, non-invasive fluorescence images of the breast tumor growing on the brain were obtained. The images of the tumor were very bright, with well-defined margins with no detectable skin autofluorescence background. Images obtained at various angles showed that the extent of the tumor margins could be precisely measured. A skin flap over the skull confirmed that the tumor was growing on the surface of the brain which is a frequent occurrence in breast cancer.

CONCLUSION

A precise orthotopic model of RFP-expressing breast-cancer metastasis to the brain was developed that could be non-invasively imaged with very-narrow-band-width laser excitation, resulting in an ultra-bright, ultra-low-background signal. The model will be useful in discovering improved therapeutics for this recalcitrant disease.

Harnessing immunotherapy for brain metastases: insights into tumor-brain microenvironment interactions and emerging treatment modalities

Brain metastases signify a deleterious milestone in the progression of several advanced cancers, predominantly originating from lung, breast and melanoma malignancies, with a median survival timeframe nearing six months. Existing therapeutic regimens yield suboptimal outcomes; however, burgeoning insights into the tumor microenvironment, particularly the immunosuppressive milieu engendered by tumor-brain interplay, posit immunotherapy as a promising avenue for ameliorating brain metastases. In this review, we meticulously delineate the research advancements concerning the microenvironment of brain metastases, striving to elucidate the panorama of their onset and evolution. We encapsulate three emergent immunotherapeutic strategies, namely immune checkpoint inhibition, chimeric antigen receptor (CAR) T cell transplantation and glial cell-targeted immunoenhancement. We underscore the imperative of aligning immunotherapy development with in-depth understanding of the tumor microenvironment and engendering innovative delivery platforms. Moreover, the integration with established or avant-garde physical methodologies and localized applications warrants consideration in the prevailing therapeutic schema.

A Population-Based Research Utilized a Risk Stratification Model to Forecast the Overall Survival of Young Women With Diagnosed Stage IV Breast Cancer

BACKGROUND

The goal of this study is to develop a risk prediction model for estimating overall survival (OS) in young females diagnosed with stage IV breast cancer.

METHODS

The clinical information was retrieved from the Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2015. To identify the dependent risk factors, we utilized the Cox proportional hazards regression model in both single and multivariate analyses. We then created a new nomogram to predict the 1-, 3-, and 5-year overall survival probability for these patients based on the identified risk factors.

RESULTS

Six hundred seventy-six patients who met the eligibility requirements were stochastically partitioned into training (n = 475) and validation (n = 201) groups in a 7:3 ratio. Histology, breast subtype, T classification, brain metastasis, bone metastasis, liver metastasis, and surgery were identified as independent prognostic factors for cancer. To predict the 1-, 3-, and 5-year overall survival (OS) probabilities, all of these independent factors were incorporated into nomograms. Our nomogram demonstrated a favorable discriminatory power, as evidenced by a C-index of 0.737 (95% CI: 0.708-0.766) and 0.717 (95% CI: 0.664-0.770) for the training and validation cohorts, respectively. The calibration curves showed satisfactory consistency in both cohorts. Using this nomogram, we developed a risk stratification model that categorized patients into low-, intermediate-, and high-risk groups.

CONCLUSION

The prediction model was more precisely to predict the OS of young females with stage IV breast cancer and could enable individualized risk estimation that could be conducive to physicians exploring therapeutic strategies for effectiveness.

A Radiomics-Based Model for Potentially More Accurate Identification of Subtypes of Breast Cancer Brain Metastases

PURPOSE

Breast cancer brain metastases (BCBM) may involve subtypes that differ from the primary breast cancer lesion. This study aimed to develop a radiomics-based model that utilizes preoperative brain MRI for multiclass classification of BCBM subtypes and to investigate whether the model offers better prediction accuracy than the assumption that primary lesions and their BCBMs would be of the same subtype (non-conversion model) in an external validation set.

MATERIALS AND METHODS

The training and external validation sets each comprised 51 cases (102 cases total). Four machine learning classifiers combined with three feature selection methods were trained on radiomic features and primary lesion subtypes for prediction of the following four subtypes: 1) hormone receptor (HR)+/human epidermal growth factor receptor 2 (HER2)-, 2) HR+/HER2+, 3) HR-/HER2+, and 4) triple-negative. After training, the performance of the radiomics-based model was compared to that of the non-conversion model in an external validation set using accuracy and F1-macro scores.

RESULTS

The rate of discrepant subtypes between primary lesions and their respective BCBMs were 25.5% (n=13 of 51) in the training set and 23.5% (n=12 of 51) in the external validation set. In the external validation set, the accuracy and F1-macro score of the radiomics-based model were significantly higher than those of the non-conversion model (0.902 vs. 0.765, p=0.004; 0.861 vs. 0.699, p=0.002).

CONCLUSION

Our radiomics-based model represents an incremental advance in the classification of BCBM subtypes, thereby facilitating a more appropriate personalized therapy.

Radiomic Signatures for Predicting Receptor Status in Breast Cancer Brain Metastases

Backgrounds

A significant proportion of breast cancer patients showed receptor discordance between primary cancers and breast cancer brain metastases (BCBM), which significantly affected therapeutic decision-making. But it was not always feasible to obtain BCBM tissues. The aim of the present study was to analyze the receptor status of primary breast cancer and matched brain metastases and establish radiomic signatures to predict the receptor status of BCBM.

Methods

The receptor status of 80 matched primary breast cancers and resected brain metastases were retrospectively analyzed. Radiomic features were extracted using preoperative brain MRI (contrast-enhanced T1-weighted imaging, T2-weighted imaging, T2 fluid-attenuated inversion recovery, and combinations of these sequences) collected from 68 patients (45 and 23 for training and test sets, respectively) with BCBM excision. Using least absolute shrinkage selection operator and logistic regression model, the machine learning-based radiomic signatures were constructed to predict the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status of BCBM.

Results

Discordance between the primary cancer and BCBM was found in 51.3% of patients, with 27.5%, 27.5%, and 5.0% discordance for ER, PR, and HER2, respectively. Loss of receptor expression was more common (33.8%) than gain (18.8%). The radiomic signatures built using combination sequences had the best performance in the training and test sets. The combination model yielded AUCs of 0.89, 0.88, and 0.87, classification sensitivities of 71.4%, 90%, and 87.5%, specificities of 81.2%, 76.9%, and 71.4%, and accuracies of 78.3%, 82.6%, and 82.6% for ER, PR, and HER2, respectively, in the test set.

Conclusions

Receptor conversion in BCBM was common, and radiomic signatures show potential for noninvasively predicting BCBM receptor status.

Incidence, risk factors and survival of patients with brain metastases at initial metastatic breast cancer diagnosis in China

Purpose

To characterize the incidence, risk factors and survival of patients with brain metastases at initial diagnosis of metastatic breast cancer (MBC) in China.

Methods

The China National Cancer Center database was used to identify 2087 MBC patients diagnosed between 2003 and 2015. Clinicopathological features, treatment and survival information were extracted. Multivariable logistic and Cox regression were performed to determine factors predictive of brain metastases at MBC diagnosis and survival, respectively.

Results

Brain metastases occurred in ninety patients (4.3%) at MBC diagnosis, and in 27 patients (2.5%), 42 patients (7.2%) and 21 patients (5.2%) with hormone receptor positive, human epidermal growth factor receptor 2 negative (HR + HER2-), HER2-positive and triple negative breast cancer (TNBC), respectively. HER2-positive subtype (OR = 2.38; 95% CI 1.40–4.04; p < 0.0001), TNBC subtype (OR = 1.89; 95% CI 1.02–3.51; p = 0.005), and metastases to all three sites of bone, liver and lungs (OR = 3.23; 95% CI 1.52–6.87; p = 0.002) were shown to increase the risk of BM at MBC diagnosis. Median survival after BM was 23.7 months. First-line tyrosine kinase inhibitors (TKI) improved survival compared to trastuzumab-based regimen (44.9 vs 35.4 months, p = 0.09). Factors that independently decreased BM death risk were ECOG<2, brain metastases only and multidisciplinary treatment.

Conclusion

HER2-positive and TNBC subtypes have a higher incidence of BM at initial MBC diagnosis. Brain screening might be considered in patients with HER2-positive disease at MBC diagnosis, and further prospective randomized study is warranted.

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Large retrospective analysis focusing on patients with BM at initial MBC diagnosis.

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HER2-positive subtype presented with the highest incidence of BM at initial MBC diagnosis.

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Patients with brain metastases only and receiving multidisciplinary treatment have a superior OS.

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Brain screening might be considered in HER2-positive patients with BM at MBC diagnosis.