Development Of Brain Metastases Research Articles

A tissue-engineered model of the blood-tumor barrier during metastatic breast cancer

Metastatic brain cancer has poor prognosis due to challenges in both detection and treatment. One contributor to poor prognosis is the blood–brain barrier (BBB), which severely limits the transport of therapeutic agents to intracranial tumors. During the development of brain metastases from primary breast cancer, the BBB is modified and is termed the ‘blood-tumor barrier’ (BTB). A better understanding of the differences between the BBB and BTB across cancer types and stages may assist in identifying new therapeutic targets. Here, we utilize a tissue-engineered microvessel model with induced pluripotent stem cell (iPSC)-derived brain microvascular endothelial-like cells (iBMECs) and surrounded by human breast metastatic cancer spheroids with brain tropism. We directly compare BBB and BTB in vitro microvessels to unravel both physical and chemical interactions occurring during perivascular cancer growth. We determine the dynamics of vascular co-option by cancer cells, modes of vascular degeneration, and quantify the endothelial barrier to antibody transport. Additionally, using bulk RNA sequencing, ELISA of microvessel perfusates, and related functional assays, we probe early brain endothelial changes in the presence of cancer cells. We find that immune cell adhesion and endothelial turnover are elevated within the metastatic BTB, and that macrophages exert a unique influence on BTB identity. Our model provides a novel three-dimensional system to study mechanisms of cancer-vascular-immune interactions and drug delivery occurring within the BTB.

Analysis of risk factors and prognostic factors of brain metastasis in gastric cancer: a surveillance, epidemiology and end-results database study

Brain metastasis in gastric cancer (GC) patients is a rare phenomenon that is associated with adverse clinical outcomes and poor survival rates. We conducted a retrospective cohort study to investigate the incidence, risk factors and prognostic factors of brain metastasis in GC patients. Data on sociodemographic and tumor characteristics of GC patients from 2010 to 2019 was extracted from the Surveillance, Epidemiology and End-Results (SEER) database. Descriptive statistics, multivariable logistic and Cox regression were applied on SPSS. Kaplan–Meier-Survival curves and ROC curves were constructed. A total of 59,231 GC patients, aged 66.65 ± 13.410 years were included. Brain metastasis was reported in 368 (0.62%) patients. On logistic regression, the risk of brain metastasis was significantly greater in males, patients aged < 60 years and patients having concurrent bone and lung metastasis. High grade and high N stage were significant risk factors for development of brain metastasis. Patients who had undergone surgery for the primary tumor were at reduced risk for brain metastasis (adjusted odds ratio 0.210, 95% CI 0.131–0.337). The median OS was 3 months in patients with brain metastasis and 17 months in patients without brain metastasis (p < 0.05). On Cox regression, Grade IV tumors and primary antral tumors were significant predictable parameters for poor prognosis. Overall Survival (OS) and Cancer-Specific Survival (CSS) were prolonged in patients who had undergone surgery. Brain metastasis in gastric cancer is associated with significantly worse survival. Employing large-scale screening for high-risk patients holds a promising impact to improve survival rates, but it must be accurately balanced with a comprehensive understanding of clinicopathological aspects for accurate diagnosis and treatment.

Treatment modalities and survival outcomes in prostate cancer parenchymal brain metastasis.

Prostate cancer (PCa) parenchymal brain metastases are uncommon and troubling observations in the course of the disease. Our study aims to evaluate the prevalence of brain metastases among PCa patients while reporting various therapeutic modalities, clinical features, and oncological outcomes. We retrospectively identified 34 patients with parenchymal brain metastasis out of 4575 patients using a prospectively maintained database that contains clinicopathologic characteristics of PCa patients between January 2012 and December 2021. Based on the three treatment modalities used, the patients were divided into three groups: stereotactic radiosurgery (SRS), whole brain radiotherapy (WBRT), and systemic therapy alone. The Kaplan-Meier curve was used to calculate overall survival [OS] probability and the Cox proportional hazards regression model was used to compare between groups. At the time of brain metastasis diagnosis, the median age was 66 years, the median (interquartile range [IQR]) prostate-specific antigen (PSA) was 2.2 (0.1-26.6) ng/ml and the median (IQR) months from initial PCa diagnosis to brain metastasis development was 70.8 (27.6-100.9). The median (IQR) primary Gleason score was 8 (7-9) and over a median (IQR) follow-up time of 2.2 (1.2-16.5) months, 76.5% (n = 26) of the patients died. Thirteen (38.2%) patients had solitary lesion, whereas 21 (61.8%) had ≥2 lesions. The lesions were supratentorial in 19 (55.9%) patients, infratentorial in six (17.6%), and both sides in nine (26.5%). Among all 34 patients, 10 (29.4%) were treated with SRS, seven (20.6%) with WBRT, and 17 (50%) with systemic therapy alone. OS varied greatly between the three treatment modalities (log-rank test, p = 0.049). Those who were treated with SRS and WBRT had better OS compared with patients who were treated with systemic therapy alone (hazard ratio: 0.37, 95% confidence interval: 0.16-0.86, p = 0.022). In our single-institutional study, we confirmed that PCa brain metastasis is associated with poor survival outcomes and more advanced metastatic disease. Furthermore, we found that SRS and WBRT for brain metastasis in patients with recurrent PCa appear to be associated with improved OS as compared with systemic therapy alone and are likely secondary to selection bias.

1347P Peripheral osimertinib (osi) plasma trough concentration (Cmin,SS) as surrogate parameter for development and progression of brain metastasis (BM) in patients (pts) with EGFR+ advanced non-small cell lung cancer (aNSCLC)

1347P Peripheral osimertinib (osi) plasma trough concentration (Cmin,SS) as surrogate parameter for development and progression of brain metastasis (BM) in patients (pts) with EGFR+ advanced non-small cell lung cancer (aNSCLC)

1960P Clinical outcomes of the patients with alveolar soft part sarcoma developed brain metastasis

1960P Clinical outcomes of the patients with alveolar soft part sarcoma developed brain metastasis

Stereotactic Radiotherapy or Whole Brain Radiotherapy Combined with Pyrotinib and Capecitabine in HER2-Positive Advanced Breast Cancer Patients with Brain Metastases (BROPTIMA): A Prospective, Phase Ib/II Single-Arm Clinical Study

Approximately half of patients with advanced HER2-positive breast cancer (BC) will develop brain metastases (BM) over time. Local therapy including stereotactic radiotherapy (SRT) and whole brain radiotherapy (WBRT) is the main initial treatment in malignant tumor patients with BM. However, more than 50% patients after radiotherapy in one year suffered intracranial recurrence. Pyrotinib, a small molecule, irreversible, pan-ErbB receptor tyrosine kinase inhibitor (TKI), has a high potency for controlling BM and reducing the occurrence of brain metastases in advanced HER2-positive BC patients. We hypothesized that SRT or WBRT combined with pyrotinib and capecitabine could decrease intracranial progression in HER2 positive BC with newly diagnosed BM. In this prospective single-arm phase Ib/II trial (NCT04582968), eligible patients were assigned to either fractionated stereotactic radiotherapy (FSRT) or whole-brain radiation therapy (WBRT), combined with pyrotinib and capecitabine. The primary endpoint was one-year CNS progression-free survival (PFS) rate. Secondary endpoints included intracranial objective response rate (IC-ORR) according to RANO-BM criteria, progression-free survival (PFS), overall survival (OS) and evaluation of safety and neurocognitive function. From January 2020 to August 2022, 40 patients were enrolled. Twenty-nine patients were treated with FSRT in 8 Gy per fraction with 3 to 5 fractions and 11 were treated with WBRT in 3 Gy per fraction with 10 fractions, and then received chemotherapy in a time frame starting from 0 to 7 days after radiotherapy. At a median follow-up of 17.3 months, 1-year CNS-PFS rate was 74.9% (95% CI 61.9-90.7%) and median CNS-PFS was 18 months (95% CI, 15.5 to NA months). One-year PFS rate was 66.9% (53.1-84.2%) and median PFS time was 17.6 months (95% CI 12.8-34.1 months). The best intracranial response rate (IC-ORR: complete response and partial response) was 92.5% (37/40). The most common grade 3 or worse toxicity was diarrhea (7.5%) and asymptomatic radiation necrosis was detected in 4 of 67(6.0%) lesions treated with FSRT. No differences of neurocognitive function evaluated by MMSE (Mini-Mental State Exam) were observed between different groups at any time point. Radiotherapy combined with pyrotinib and capecitabine resulted in a promising efficacy that crossed the pre-specified boundary in patients with HER2-positive advanced breast cancer with brain metastases. This is the first prospective study showing the efficacy and safety of CNS radiotherapy concurrent with pyrotinib and capecitabine in patients with BM from HER2-positive breast cancer. Further investigation in a randomized controlled study is warranted.

Predictive Value of Pre-Treatment MRI Radiomics for Distant Brain Metastases Following Stereotactic Radiosurgery/Radiotherapy

Local intracranial therapy for brain metastases (BM) has taken on particular importance as survival among metastatic patients improves. However, the development of distant BMs (DBMs) outside the treated area remains a stubborn problem for which canonical clinical features (age, histology, ECOG PS) have limited predictive capability. In this study, we hypothesized that MRI-based "radiomic" features (sub-visual cues extracted from diagnostic images) can accurately predict the time-to-DBM development (TTDD) on a retrospectively curated dataset of patients treated with stereotactic radiosurgery/radiotherapy (SRS/SRT). We queried our treatment planning system for patients treated with brain SRS/SRT between 2014 and 2021, and curated the incidence/timing of DBMs manually. Pre-RT MRI sequences (T1 pre, T1 post, T2, and FLAIR) and planning data were obtained for each patient. MRI and CT simulations were co-registered using affine transformations, and regions of interest (ROIs) were identified based on contoured structures (GTV) and discrete isodose ranges (0-25%, 25-50%, 50-75%, 75%+). Radiomic features were extracted from these ROIs, and clinical features (ECOG PS, tumor volume, age) were recorded for baseline comparison. Features were selected using Wald test scores from univariate Cox proportional hazard (CPH) models. Multivariate CPH models were then trained to predict TTDD using combinations of selected features. Predictive capability was evaluated using concordance index (c-index) values. A radiomic risk score (RRS) was created to discriminate patients with low and high-risk for DBMs, and evaluated using a log-rank test. A total of 105 patients were selected with a median follow up of 356 days. 53 patients developed DBMs (median time 118 days). Radiomic CPH models achieved a c-index of 0.63 compared to clinical baseline of 0.49. The combination of radiomic and clinical features achieved the highest c-index of 0.69. Overall, radiomic features with and without clinical features were able to stratify patients into low and high-risk groups with statistically significant differences in TTDD development (see Table 1). Clinical features alone were not significant. The most predictive radiomic features were identified within the T1 pre-contrast MRI from the 50-75% isodose regions, followed by T2 FLAIR/GTV and T2/GTV combinations. Radiomic features from routine MR scans were more predictive of TTDD than baseline clinical features. The contribution from the 50-75% isodose region suggests importance within the peritumoral environment in addition to the tumor itself.

Incidence and Risk Factors for Brain Metastases in Patients with Lung Cancer: A Systematic Review and Meta-Analysis

Brain metastases (BM) are a very common metastatic site in lung cancer, but the exact rate of metastasis is still controversial. Risk factors for BM development are also largely lacking, hampering personalized treatment strategies. This study aimed to identify the incidence and possible risk factors for BM in lung cancer. A systematic review, based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guide-lines, was conducted using PubMed, Medline databases and Cochrane Library databases from inception until February 2023. Two investigators independently searched and selected literature, included in randomized controlled trials and cohort studies. Heterogeneity was assessed using the χ2 test and the I2 statistic. Significant heterogeneity was indicated by P <0.05 in Cochrane Q tests and a ratio greater than 40% in I2 statistics. The review is registered on PROSPERO, number: CRD42022370173. Forty-nine studies were included in the meta-analysis. The results showed that the incidence rate of BM in non-small cell lung cancer (NSCLC) was 0.24 (95% confidence interval [CI]: 0.23-0.25; I2 = 97.1%). The incidence rate in early NSCLC was 0.11 (95% CI: 0.10-0.13), locally advanced NSCLC was 0.32 (95% CI: 0.29-0.34), and advanced NSCLC was 0.37 (95% CI: 0.35-0.38). Lung adenocarcinoma was more prone to BM in NSCLC (risk ratio [RR] = 3.59, 95% CI: 1.97-6.54; P<0.001). The BM rate of NSCLC with EGFR mutation was also higher (hazard ratio [HR] = 1.49, 95% CI: 1.14-1.94; P = 0.004). Sex and smoking had no significant effect on the incidence of BM in NSCLC. Prophylactic Cranial Irradiation (PCI) could significantly reduce BM in NSCLC (HR = 0.36, 95% CI: 0.23-0.56; P<0.001), but chemotherapy had no obvious effect on decreasing the rate of BM (HR = 0.91, 95% CI: 0.54-1.54; P = 0.73). The incidence rate of BM in small cell lung cancer (SCLC) was 0.28 (95% CI: 0.27-0.30; I2 = 95.9%), and 0.23 (95% CI: 0.20-0.25) in the limited-stage SCLC. Older age (≥65) (HR = 0.70, 95% CI: 0.54-0.92; P = 0.01) were associated with less BM in SCLC. A higher T stage (≥T3) (HR = 1.72, 95% CI: 1.16-2.56; P = 0.007) was a significant risk factor for BM, while sex, smoking dose were not. PCI could also significantly decreased BM in SCLC (HR = 0.47, 95% CI: 0.38-0.58; P<0.001). This study is the first meta-analysis of BM incidence rate in lung cancer, and further explores the factors affecting BM, providing some suggestions for clinical decision-making of BM prevention in patients with lung cancer.

Inflammasome activation in peritumoral astrocytes is a key player in breast cancer brain metastasis development

Inflammasomes, primarily responsible for the activation of IL-1β, have emerged as critical regulators of the tumor microenvironment. By using in vivo and in vitro brain metastasis models, as well as human samples to study the role of the NLRP3 inflammasome in triple-negative breast cancer (TNBC) brain metastases, we found NLRP3 inflammasome components and IL-1β to be highly and specifically expressed in peritumoral astrocytes. Soluble factors from TNBC cells induced upregulation and activation of NLRP3 and IL-1β in astrocytes, while astrocyte-derived mediators augmented the proliferation of metastatic cells. In addition, inhibition of NLRP3 inflammasome activity using MCC950 or dampening the downstream effect of IL-1β prevented the proliferation increase in cancer cells. In vivo, MCC950 reduced IL-1β expression in peritumoral astrocytes, as well as the levels of inflammasome components and active IL-1β. Most importantly, significantly retarded growth of brain metastatic tumors was observed in mice treated with MCC950. Overall, astrocytes contribute to TNBC progression in the brain through activation of the NLRP3 inflammasome and consequent IL-1β release. We conclude that pharmacological targeting of inflammasomes may become a novel strategy in controlling brain metastatic diseases.

Survival benefit with checkpoint inhibitors versus chemotherapy is modified by brain metastases in patients with recurrent small cell lung cancer.

Small cell lung cancer (SCLC) is a rapidly growing malignancy with early distant metastases. Up to 70% will develop brain metastases, and the poor prognosis of these patients has not changed considerably. The potential of checkpoint inhibitors (CPI) in treating recurrent (r/r) SCLC and their effect on brain metastases remain unclear. In this retrospective multicenter study, we analyzed r/r SCLC patients receiving second or further-line CPI versus chemotherapy between 2010 and 2020. We applied multivariable-adjusted Cox regression analysis to test for differences in 1-year mortality and real-world progression. We then used interaction analysis to evaluate whether brain metastases (BM) and/or cranial radiotherapy (CRT) modified the effect of CPI versus chemotherapy on overall survival. Among 285 patients, 99 (35%) received CPI and 186 (65%) patients received chemotherapy. Most patients (93%) in the CPI group received nivolumab/ipilimumab. Chemotherapy patients were entirely CPI-naïve and only one CPI patient had received atezolizumab for first-line treatment. CPI was associated with a lower risk of 1-year mortality (adjusted Hazard Ratio [HRadj] 0.59, 95% CI 0.42 to 0.82, p=0.002). This benefit was modified by BM and CRT, indicating a pronounced effect in patients without BM (with CRT: HRadj 0.34, p=0.003; no CRT: HRadj 0.50, p=0.05), while there was no effect in patients with BM who received CRT (HRadj 0.85, p=0.59). CPI was associated with a lower risk of 1-year mortality compared to chemotherapy. However, the effect on OS was significantly modified by intracranial disease and radiotherapy, suggesting the benefit was driven by patients without BM.

MEF2C and miR-194-5p: New Players in Triple Negative Breast Cancer Tumorigenesis.

Among breast cancer (BC) subtypes, the most aggressive is triple negative BC (TNBC), which is prone to metastasis. We previously found that microRNA (miR)-194-5p is downregulated at the early stages of TNBC brain metastasis development. Additionally, the transcription factor myocyte enhancer factor 2 (MEF2)C, a bioinformatically predicted miR-194-5p target, was increasingly expressed throughout TNBC brain metastasis formation and disease severity. However, the contributions of these two players to malignant cells' features remain undetermined. This study aimed at disclosing the role of miR-194-5p and MEF2C in TNBC tumorigenesis. The transfection of 4T1 cells with a silencer for MEF2C or with a pre-miRNA for miR-194-5p was employed to study TNBC cells' phenotypic alterations regarding epithelial and mesenchymal markers, as well as migratory capability alterations. MEF2C-silenced cells presented a decline in both vimentin and cytokeratin expression, whereas the overexpression of miR-194-5p promoted an increase in cytokeratin and a reduction in vimentin, reflecting the acquisition of an epithelial phenotype. Both treatments reduced TNBC cells' migration. These results suggest that MEF2C may determine TNBC cells' invasive properties by partially determining the occurrence of epithelial-mesenchymal transition, while the overexpression of miR-194-5p promotes a decline in TNBC cells' aggressive behavior and reinforces this miRNA's role as a tumor suppressor in TNBC.

Identifying New Contributors to Brain Metastasis in Lung Adenocarcinoma: A Transcriptomic Meta-Analysis.

Lung tumors frequently metastasize to the brain. Brain metastasis (BM) is common in advanced cases, and a major cause of patient morbidity and mortality. The precise molecular mechanisms governing BM are still unclear, in part attributed to the rarity of BM specimens. In this work, we compile a unique transcriptomic dataset encompassing RNA-seq, microarray, and single-cell analyses from BM samples obtained from patients with lung adenocarcinoma (LUAD). By integrating this comprehensive dataset, we aimed to enhance understanding of the molecular landscape of BM, thereby facilitating the identification of novel and efficient treatment strategies. We identified 102 genes with significantly deregulated expression levels in BM tissues, and discovered transcriptional alterations affecting the key driver 'hub' genes CD69 (a type II C-lectin receptor) and GZMA (Granzyme A), indicating an important role of the immune system in the development of BM from primary LUAD. Our study demonstrated a BM-specific gene expression pattern and revealed the presence of dendritic cells and neutrophils in BM, suggesting an immunosuppressive tumor microenvironment. These findings highlight key drivers of LUAD-BM that may yield therapeutic targets to improve patient outcomes.

P11.02.B DO GENOMIC ALTERATIONS INFLUENCE THE DEVELOPMENT OF BRAIN METASTASES IN ADVANCED AND METASTATIC NON-SMALL CELL LUNG CANCER?

Abstract BACKGROUND Lung cancer is the most common cause of cancer deaths worldwide. Development of brain metastases (BM) in patients with advanced (Stage III) and metastatic (Stage IV) non-small cell lung cancer (NSCLC) is linked with poor prognosis. Identifying mutations associated with BM development could influence screening and determine targeted treatment paradigms. We aimed to establish BM prevalence and incidence in patients with advanced and metastatic NSCLC, stratified by genomic alterations. MATERIAL AND METHODS A systematic review and meta-analysis was conducted in accordance with PRISMA guidelines (PROSPERO ID CRD42022315915). Three databases were searched, and articles published between January 2000-May 2022 included (Search date 30th April 2022). Prevalence at diagnosis, and incidence of new BM per year were obtained, including patients with EGFR, ALK, KRAS, ROS1, RET, MET, and other genomic alterations. Pooled incidence rates were calculated using random effects models. RESULTS Of 960 articles identified, 65 were included in the study (24,784 patients). Pooled BM prevalence at diagnosis was 28.6% (45 studies, 95% Confidence Interval [CI] 26.1-31.0), and highest in patients with ALK (34.9%) and RET translocations (32.2%). With a median follow-up of 24 months, the per-year incidence of new BM was 12.5% in the wild-type group (14 studies, 95% CI 10.9-15.9). Incidence in the subgroups with different genomic alterations was 15.6% in the EGFR group (16 studies, 95% CI 11.4-21.2), 17.0% in the ALK group (6 studies, 95% CI 11.3-25.8), 9.8% in the KRAS group (4 studies, 95% CI 5.5-17.5), 12.5% in the ROS1 group (3 studies, 95% CI 5.7-27.6), and 11.8% in the RET group (2 studies, 95% CI 8.0-17.5). At the end of the follow-up period, a median of 55.0% of patients had BM (IQR 44.2-67.8). CONCLUSION This is the first study to show prevalence, and incidence of BM development in advanced and metastatic NSCLC, stratified by genomic alterations. Our data indicates a higher prevalence and incidence of BM in patients with targetable genomic alterations. This supports brain imaging at staging and follow-up, underlining the need for NSCLC therapies with brain penetrance and efficacy.

P11.54.A BRAIN RELAPSE IN HER2-POSITIVE BREAST CANCER AFTER NEOADJUVANT TREATMENT: AN INTERNATIONAL MULTICENTRIC STUDY

Abstract BACKGROUND The incidence of central nervous system relapse among patients with breast cancer appears to be increasing, despite advances in systemic treatment. Although achieving pathological complete response (pCR) following neoadjuvant treatment has been associated with improved survival outcomes, it does not seem to prevent brain relapse. In early stage HER 2 positive disease between 10-14% will develop brain metastases and the risk is higher in endocrine receptor-negative setting. Identifying patients who are at greater risk of brain relapse can help to indicate those who need new treatment options to prevent it. This study aimed to assess the incidence of brain relapse in a multicenter cohort of patients who underwent neoadjuvant treatment across nine hospitals located in Portugal, Spain, and Chile, and to identify factors associated with it. MATERIAL AND METHODS We conducted a retrospective analysis of patients diagnosed and treated for HER2-positive breast cancer in nine hospitals located in Portugal, Spain, and Chile between January 2017 and December 2022. To be eligible for inclusion, patients must have undergone neoadjuvant anti-HER2 therapy followed by surgery. Data such as age at diagnosis, endocrine receptor expression, chemotherapy regimen, pathological response, adjuvant anti-HER2 treatment, endocrine therapy, and first local of relapse were analysed. RESULTS A total of 396 patients with a mean age of 52.9 years were included in the study. All patients received a neoadjuvant chemotherapy regimen and double anti-HER2 therapy with trastuzumab and pertuzumab, with a pathological complete response (pCR) achieved in 59.6% of patients. Nearly all patients (98.2%) received adjuvant anti-HER2 therapy, with 83.81% receiving trastuzumab, 12.85% receiving TDM1, and 3.34% receiving trastuzumab plus pertuzumab. Over a follow-up period of 3.5 years, 23 patients (5.81%) experienced relapse. Among these cases, 10 patients (2.5%) had brain relapse as first site, accounting for 43.48% of the total recurrences. Brain relapse was not associated with pathological response, but rather with a more advanced stage at diagnosis (T3/4 or Nodal positive) (p&amp;lt;0.05). CONCLUSION In CONCLUSION , our multicentric cohort study provides valuable insights into the incidence and factors associated with brain metastasis in HER2-positive breast cancer patients who underwent neoadjuvant treatment. Our findings suggest that although neoadjuvant treatment resulted in a high rate of pCR, it did not prevent brain relapse. Importantly, our study identified advanced disease stage at diagnosis as a significant risk factor for brain relapse. Further studies are needed to identify additional factors associated with brain metastasis and explore potential preventive strategies in patients with higher risk.

P10.12.B MOLECULAR MECHANISMS INVOLVED IN THE DEVELOPMENT OF BRAIN METASTASIS FROM THE MATCHED PAIRED LUNG ADENOCARCINOMA AND BREAST CANCER

Abstract BACKGROUND Up to 50% of patients with common cancers will develop brain metastases and incidences of this devastating complication are still rising. In our recent work, we found that the immune response in the brain is significantly stronger when the metastasis develops from lung adenocarcinoma (LUAD) compared to breast cancer (BC). Importantly, we discovered the higher expression of the drug target, VISTA, only in the brain metastasis of the LUAD. The aim of the current study was to investigate the molecular mechanisms driving the formation of brain metastasis from the two different lineages of cancer. In addition, we aimed to examine the expression level of the drugable molecules between primary tumors and their brain metastasis. MATERIAL AND METHODS Primary tumor and their matched brain metastasis samples of 11 LUAD and 11 breast cancer (total = 44 samples) were included in this study. RNA was extracted from the FFPE samples and the targeted gene expression profiles were measured using the PanCancer IO360™ Panel that includes 770 cancer-related genes (NanoString technology). Data were analysed using the nSolver software. RESULTS A first comparison was made between the primary tumors with their brain metastases for LUAD and BC separately. The second comparison was made between the common genes of both lineages. Pathway analysis indicated that there is higher metabolic stress in breast cancer-brain metastasis compared to that in the lung. In addition, we identified 12 common up-regulated genes in brain metastasis, despite the origin of the primary tumor. Importantly, by comparing the primary tumors of BC and LUAD with their brain metastasis, we found that VISTA is predominantly highly expressed in the primary tumors of LUAD and their matched brain metastasis. CONCLUSION Although the general mechanisms of metastasis have been described, our study demonstrates that different cancer lineages utilize various genes/pathways to metastasize to the brain. Moreover, primary LUAD and their brain metastasis express high levels of VISTA highlighting the possibilities for targeted therapy.

P11.64.A TREATMENT STRATEGIES BEFORE THE DIAGNOSIS OF BRAIN METASTASIS IN PATIENTS WITH RENAL CELL CANCER (RCC)

Abstract BACKGROUND Metastatic renal cell cancer (mRCC) is known for its variable disease course and can be categorized according to the International Metastatic RCC Database Consortium (IMDC) criteria. As patients with mRCC who have a favorable IMDC score and/or a low tumor burden usually have an indolent disease course, watchful waiting is often considered in daily clinical practice. However, it is unknown whether watchful waiting impacts the development of brain metastasis (BM). Therefore, we investigated variables that may affect the interval between first diagnosis of mRCC and BM (BM-free interval) in patients with RCC and BM. MATERIAL AND METHODS A single-center, retrospective cohort study was performed at the Erasmus MC Cancer Institute (Rotterdam, the Netherlands). All consecutive patients with a diagnosis of RCC and BM between 01-01-2011 and 31-07-2022 were included. The primary outcome was the BM-free interval. Secondary outcomes were intracranial progression-free survival (iPFS), progression-free survival (PFS) and overall survival (OS), since diagnosis of BM. Subgroups included patients with and without systemic treatment prior to the diagnosis of BM. Kaplan-Meier (Logrank test) and Cox Proportional Hazards Model (Likelihood ratio test) analyses were performed with significance considered at p-values &amp;lt;0.05. RESULTS A total of 46 patients with RCC and BM were included; 80% was male and 89.1% had a clear cell RCC subtype. In 84.8% of patients, BMs were diagnosed metachronous (&amp;gt;1 month) after the diagnosis of extracranial metastasis (ECM) and 80.4% of patients had symptomatic BM at BM diagnosis. After the diagnosis of BM, the median iPFS was 7.6 (IQR 3.5-12.2) months, the median PFS was 3.7 (IQR 2.3-8.7) months and the median OS was 10.1 (IQR 5.1-22.8) months. Prior to the diagnosis of BM, 25 (54.3%) patients had received systemic therapy, whereas 21 (45.7%) patients were treatment naïve. The median BM-free interval was 22.3 (IQR 5.7-46.7) months. The median BM-free interval was significantly shorter for treatment naïve patients (6.8 [IQR 1.0-7.0] months) as compared to patients who received previous systemic therapy (29.0 [IQR 12.6-57.0]; p=0.02). In multivariate analysis, a longer BM-free interval was significantly associated with nephrectomy (HR 0.10 [95%CI 0.03-0.31]) and systemic treatment prior to BM diagnosis (HR 0.10 [95%CI 0.03-0.30]). CONCLUSION In this cohort of patients with RCC BM, patients who had not received systemic treatment for ECM were earlier diagnosed with BM than patients who had received prior systemic treatment. Although the retrospective nature of this small selective cohort is a limitation, these results indicate that watchful waiting should be carefully considered for patients with mRCC.

P10.03.A ANTIPSYCHOTICS TO TREAT BRAIN TUMORS: DRUG REPURPOSING TO BYPASS THE BLOOD BRAIN BARRIER

Abstract BACKGROUND Approximately half of late-stage melanoma patients develop brain metastases (BM), once metastasized to the brain, survival is generally measured in months. Current treatments, although increasingly effective, are not sufficient for this patient group, necessitating development of new therapeutic options. Drugs targeting BM specifically are a scarcity. To broaden therapeutic options, drug repurposing, i.e. novel uses of drugs already approved for other medical conditions, may prove to be a valuable asset. By design, antipsychotics effectively cross an intact blood-brain barrier. Interestingly, although carrying an increased burden of comorbidity, the schizophrenic population has a similar incidence of cancer when compared to the normal population. Hypotheses regarding the antitumor effect of antipsychotics have therefore been postulated along with several other theories that seek to explain these seemingly contradictory incidence rates. We currently present preliminary data showing that clozapine, a second-generation antipsychotic, effectively inhibits growth of human melanoma brain metastasis (MBM) cell lines in vitro. Objective: To explore the potential of antipsychotics in treating MBM. METHODS Cell cultures including H1, H2, H3 MBM cell lines, as well as normal human astrocytes (NHA) were selected for our experiments. Monolayer, 3D, and IncuCyte viability experiments were performed to determine IC50 doses. FBRO, fetal rat brain organoids were used to study clozapine’s effect on the normal brain environment. Cell migration was measured by scratch wound assays. Apoptosis was studied by flow cytometry. Colony formation assays were performed using 2D clonogenic assays. A protein array was used to find signaling proteins potentially affected by clozapine, which where verified by western blots. RESULTS A viability screening using 6 different neuroleptics showed that clozapine was most effective in inhibiting MBM cell viability, with a favorable therapeutic window to astrocytes. Doses significantly above MBM IC50 doses did not affect viability of brain organoids. MBM cells exhibited a dose-dependent inhibition of cell proliferation, migration, and clonogenic formation. Flow cytometry demonstrated that apoptosis was a major mechanism of cytotoxicity. The protein array showed that CCL3, IL8 and VEGF were downstream targets of clozapine. These results were confirmed by western blots. A partnership with the Dept. of Chemistry (UiB) has resulted in the development and testing of several novel clozapine derivates to reduce therapeutic doses and hopefully minimize potential side effects. CONCLUSION Clozapine shows proof of concept in treating BM with antipsychotics and should be explored further as an adjuvant treatment for melanoma patients at risk of developing brain metastasis.

Association of advanced gynecologic cancers and development of brain metastasis (1191)

Association of advanced gynecologic cancers and development of brain metastasis (1191)

Genomic analysis and clinical correlations of non-small cell lung cancer brain metastasis

Up to 50% of patients with non-small cell lung cancer (NSCLC) develop brain metastasis (BM), yet the study of BM genomics has been limited by tissue access, incomplete clinical data, and a lack of comparison with paired extracranial specimens. Here we report a cohort of 233 patients with resected and sequenced (MSK-IMPACT) NSCLC BM and comprehensive clinical data. With matched samples (47 primary tumor, 42 extracranial metastatic), we show CDKN2A/B deletions and cell cycle pathway alterations to be enriched in the BM samples. Meaningful clinico-genomic correlations are noted, namely EGFR alterations in leptomeningeal disease (LMD) and MYC amplifications in multifocal regional brain progression. Patients who developed early LMD frequently have had uncommon, multiple, and persistently detectable EGFR driver mutations. The distinct mutational patterns identified in BM specimens compared to other tissue sites suggest specific biologic underpinnings of intracranial progression.

SDPS-16 CYTOLOGIC AND SEROLOGIC RESPONSE WITH INTRATHECAL METHOTREXATE IN A PATIENT WITH LEPTOMENINGEAL CARCINOMATOSIS FROM OVARIAN CANCER

Abstract Leptomeningeal Carcinomatosis (LMC) is a rare complication of ovarian cancer and there is no established first-line therapy. Treatment of LMC in general can include intrathecal chemotherapy and radiation as well as relevant systemic therapies with CNS activity. We employed the commercially available Biocept CNSide™ assay to detect, quantify, and molecularly characterize tumor cells in the cerebrospinal fluid (CSF). We report a 66-year-old female who was initially diagnosed with stage 3C serous ovarian carcinoma who developed brain metastases one year later, managed with resection and stereotactic radiosurgery. Serum CA-125 continued to rise despite local therapy and subsequent MRI demonstrated leptomeningeal enhancement of bilateral internal auditory canals and the cauda equine concerning for LMC. Exam was notable for a left cranial nerve VII palsy and gait instability. Lumbar puncture with CNSide quantified a baseline tumor cell count and identified HER2 amplification on tumor cells. She began intrathecal methotrexate (IT MTX), followed by decline in both CSF tumor cell count and serum CA-125. She demonstrated clinical benefit with improved imbalance. Over time, she experienced nausea and vomiting with IT MTX and was switched to anti-HER2 therapy with off-label lapatinib and she enjoyed improved quality of life. Notably, tumor cells lost HER2 amplification, raising possibility of clone selection. She later experienced focal progression of LMC and before other therapy could be offered, she succumbed to illness approximately one year from the initial radiographic finding of leptomeningeal enhancement, exceeding the average survival for LMC.Here we demonstrate the activity of IT MTX in ovarian LMC as well as the utility of serial CSF tumor quantification for disease monitoring in conjunction with imaging and the physical exam. Further studies are warranted to evaluate LMC therapy in a prospective setting as well as the possibility of clone selection in the CNS with targeted therapy.