Non-small Cell Lung Cancer Brain Metastases Research Articles

Stereotactic radiosurgery in the management of non-small cell lung cancer brain metastases: a prospective study using the NeuroPoint Alliance Stereotactic Radiosurgery Registry.

The literature on non-small cell lung cancer (NSCLC) brain metastases (BMs) managed using stereotactic radiosurgery (SRS) relies mainly on single-institution studies or randomized controlled trials (RCTs). There is a literature gap on clinical and radiological outcomes of SRS for NSCLC metastases in real-world practice. The objective of this study was to benchmark mortality and progression outcomes in patients undergoing SRS for NSCLC BMs and identify risk factors for these outcomes using a national quality registry. The SRS Registry of the NeuroPoint Alliance was used for this study. This registry included patients from 16 enrolling sites who underwent SRS from 2017 to 2022. Data are prospectively collected without a prespecified research purpose. The main outcomes of this analysis were overall survival (OS), out-of-field recurrence, local progression, and intracranial progression. All time-to-event investigations included Kaplan-Meier analyses and multivariable Cox regressions. Two hundred sixty-four patients were identified, with a mean age of 66.7 years and a female proportion of 48.5%. Most patients (84.5%) had a Karnofsky Performance Status (KPS) score of 80-100, and the mean baseline EQ-5D score was 0.539 quality-adjusted life years. A single lesion was present in 53.4% of the patients, and 29.1% of patients had 3 or more lesions. The median OS was 28.1 months, and independent predictors of mortality included no control of primary tumor (hazard ratio [HR] 2.1), KPS of 80 (HR 2.4) or lower (HR 2.4), coronary artery disease (HR 2.8), and 5 or more lesions present at the time of SRS treatment (HR 2.3). The median out-of-field progression-free survival (PFS) was 24.8 months, and the median local PFS was unreached. Intralesional hemorrhage was an independent risk factor of local progression, with an HR of 6.0. The median intracranial PFS was 14.0 months and was predicted by the number of lesions at the time of SRS (3-4 lesions, HR 2.2; 5-14 lesions, HR 2.5). In this real-world prospective study, the authors used a national quality registry and found favorable OS in patients with NSCLC BMs undergoing SRS compared with results from previously published RCTs. The intracranial PFS was mainly driven by the emergence of new lesions rather than local progression. A greater number of lesions at baseline was associated with out-of-field progression, while intralesional hemorrhage at baseline was associated with local progression.

Blocking the MIF-CD74 axis augments radiotherapy efficacy for brain metastasis in NSCLC via synergistically promoting microglia M1 polarization.

Brain metastasis is one of the main causes of recurrence and death in non-small cell lung cancer (NSCLC). Although radiotherapy is the main local therapy for brain metastasis, it is inevitable that some cancer cells become resistant to radiation. Microglia, as macrophages colonized in the brain, play an important role in the tumor microenvironment. Radiotherapy could activate microglia to polarize into both the M1 and M2 phenotypes. Therefore, searching for crosstalk molecules within the microenvironment that can specifically regulate the polarization of microglia is a potential strategy for improving radiation resistance. We used databases to detect the expression of MIF in NSCLC and its relationship with prognosis. We analyzed the effects of targeted blockade of the MIF/CD74 axis on the polarization and function of microglia during radiotherapy using flow cytometry. The mouse model of brain metastasis was used to assess the effect of targeted blockade of MIF/CD74 axis on the growth of brain metastasis. Our findings reveals that the macrophage migration inhibitory factor (MIF) was highly expressed in NSCLC and is associated with the prognosis of NSCLC. Mechanistically, we demonstrated CD74 inhibition reversed radiation-induced AKT phosphorylation in microglia and promoted the M1 polarization in combination of radiation. Additionally, blocking the MIF-CD74 interaction between NSCLC and microglia promoted microglia M1 polarization. Furthermore, radiation improved tumor hypoxia to decrease HIF-1α dependent MIF secretion by NSCLC. MIF inhibition enhanced radiosensitivity for brain metastasis via synergistically promoting microglia M1 polarization in vivo. Our study revealed that targeting the MIF-CD74 axis promoted microglia M1 polarization and synergized with radiotherapy for brain metastasis in NSCLC.

Abstract LB396: The power of NetraAI: Precision medicine in oncology through sub-insight learning from small data sets

Abstract The capabilities of artificial intelligence (AI) and machine learning (ML) are pivotal for refining patient stratification and subtype discrimination in clinical trials. Conventional ML methods often rely on large data sets for meaningful discoveries. NetraAI is a novel ML approach designed and trained to work with smaller data sets. The challenge with smaller data sets is that they do not reflect the totality of the disease that they represent. NetraAI employs a novel approach termed “Sub-Insight Learning”, utilizing validated mathematical methods to analyze even small patient data sets. This allows the system to decompose the data sets into high and low confidence patient subpopulations, enhancing predictive model accuracy and reducing overfitting. Further, the system explains what variables are driving the etiology defining the subpopulations of patients. Using two non-small cell lung cancer (NSCLC) data sets (GSE18842 and GSE10245) consisting of only 104 samples from adenocarcinoma (ADC) and squamous cell carcinoma (SCC), NetraAI distinguished the two subtypes through unique genetic signatures. Notably, nine of the ten variables identified correlate with known NSCLC markers, with PIGX emerging as a novel target. Leveraging protein-protein interaction networks (PPI) revealed connections between PIGX and BACE1. BACE1 has been implicated as a driver of NSCLC brain metastasis. These findings shed light on the biology of membrane proteins and their post-translational modifications, a factor implicated in various diseases, prompting further exploration. NetraAI demonstrates a significant breakthrough in precision medicine for oncology, capable of generating meaningful insights from small data sets. The discovery of novel biomarkers and their implications in cancer and other diseases underline the potential of this AI-driven approach in advancing current research paradigms and patient-specific treatments. Citation Format: Bessi Qorri, Mike J. Tsay, Paul Leonchyk, Larry Alphs, Luca Pani, Joseph Geraci. The power of NetraAI: Precision medicine in oncology through sub-insight learning from small data sets [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB396.

Brain Metastasis of Non-small Cell Lung Cancer After Disease-Free Survival of 5 years: Case Series and Comprehensive Literature Review

BackgroundIn the treatment of non-small cell lung cancer (NSCLC), a disease-free survival (DFS) of 5 years is a criterion for cure. This study aimed to evaluate the characteristics and outcomes of patients with brain metastases of NSCLC after a DFS of 5 years (late recurrent brain metastasis, LRBM). MethodsWe reviewed 1,281 consecutive patients with brain metastasis of lung cancer at a single institute between November 2014 and December 2022. Relevant articles were retrieved from PubMed. Only peer-reviewed journals published in English were included. ResultsSix patients (0.47%) showed LRBM. Three were male. The median age at lung cancer diagnosis was 45 years. The histological diagnosis of all patients was adenocarcinoma. Driver gene mutations were observed in five patients. The median latency period from lung cancer treatment to the development of brain metastasis was 13 years. All patients had no metastasis to any other organs and underwent craniotomies. The median follow-up duration after craniotomy was 3.5 years. No local intracranial recurrences were observed. Three patients had distant intracranial recurrences at 7, 2, and 0.6 years after craniotomy. Five patients survived for 8, 4, 3, 2, and 0.3 years after craniotomy. One patient experienced re-recurrence in the lung 4 years after craniotomy and died 3.7 years later. In our systematic review, only six studies described LRBM of NSCLC. ConclusionsLRBM is rare in patients with NSCLC. In our institution, many of these patients harbored driver gene mutations, and achieved long-term survival with aggressive local therapy. Multicenter analysis is mandatory.

Abstract 7019: Identifying cell free DNA methylation signatures in cerebrospinal fluids for the early detection of brain metastasis in non-small cell lung cancer

Abstract Brain metastasis (BM) is major complication for adult cancer patients. Up to 2% of all cancer patients develop BM. Non-small cell lung cancer (NSCLC) contributes up to 55% of all BM. Approximately 15-20% of NSCLC patients show metastases at diagnosis, and approximately half will develop BM during their clinical course. Even after treatments like surgery, radiation and immunotherapy, the prognosis is dismal with median overall survival less than 13 months. No standard screening or early diagnostic testing exists for BM now. There is an urgent need to identify genomic features that predispose towards brain metastasis - these biomarkers could be used for early detection and disease monitoring. The cfDNA methylation and fragmentation patterns provide potential epigenetic biomarkers for detecting cancer. These patterns are specific to cell/tissue origin and cancer types. DNA methylation refers to a chemical modification of a specific carbon with an added methyl group in the cytosine. Hypomethylation in the gene body and hypermethylation in the promoter region lead to cancer development. We hypothesize that there are specific cfDNA methylation and fragmentation signatures in CSF that reflect the epigenetic states of BMs, and cancer predisposition for brain metastasis. We applied a novel single molecule sequencing approach to study CSF cfDNA methylation of BM from NSCLC. Our cohort consisted of ten patients with NSCLC-BM (samples N=14) and eleven healthy controls (N=11). Briefly, extracted cfDNA was obtained from CSF samples. Multiplexed sequencing libraries were prepared following an optimized protocol, and sequenced on PromethION flow cell for 72hr by Oxford nanopore technologies. Data were processed with the onboard base and methylation calling, followed by our bioinformatic pipelines for cfDNA size and methylation analysis. Distinct methylation patterns were found on significant CpG sites (fdr-corrected p<0.01) between cancer patients and controls, in both gene-body and promoter region. Biological pathway analysis showed enrichment in essential functions involving PI3K, ERBB2, TNF-α signaling (p<0.03), all of which play a role in NSCLC. Enriched mono-nucleosome levels (p = 1.07e-03) and differentiated mono-/tri- nucleosome ratios (p = 1.34e-03) were found in cancer vs. controls. Overall, our results suggest that a combination of cfDNA methylation and fragmentation can detect NSCLC-BM. This study will benefit BM patients with early detection and better prognosis, and extend our understanding in brain metastases in NSCLC. Citation Format: Tianqi (Kiki) Chen, Billy T. Lau, Xiangqi Bai, Melanie Hayden Gephart, Hanlee P. Ji. Identifying cell free DNA methylation signatures in cerebrospinal fluids for the early detection of brain metastasis in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7019.

Abstract 1797: Investigating the significance of OXPHOS activity in non-small cell lung cancer brain metastases

Abstract Background: Brain metastasis is a common and devastating occurrence for patients with non-small cell lung cancer (NSCLC). NSCLC patients with brain metastases have a poor median overall survival of 2-3 months, highlighting the urgency for novel treatment strategies. One approach to understanding and potentially targeting metastasis is via cancer metabolism. During the metastatic cascade, cancer cells must survive and adapt to the differential nutrient environments they encounter, including the brain. The blood brain barrier limits the availability of many metabolites, leading metastatic cells to alter their nutrient use to survive. RNA sequencing analyses of NSCLC brain metastases suggest that increased oxidative phosphorylation (OXPHOS) may be one such metabolic adaptation in the brain. The aim of this study was to determine the necessity of OXPHOS activity as a metabolic adaptation for NSCLC cells to proliferate in the unique metabolic environment of the brain. Materials and Methods: NSCLC cells were cultured in media mimicking the metabolic environments of the brain and blood. Expression of mitochondrial markers were evaluated by immunoblot in cells cultured across media conditions. The effects of the OXPHOS inhibitor IACS-010759 were assessed by cell growth as well as stable isotope tracing with [U-13C] glucose. Patient derived xenografts (PDXs) were derived from a cohort of patients with NSCLC who underwent stable isotope tracing with [U-13C] glucose. Mice bearing subcutaneously implanted PDXs were treated daily with 5mg/kg IACS-010759 and metastatic burden was measured by flow cytometry and histology. Results: Tracing studies in patients revealed that high enrichment in OXPHOS-related metabolites in the primary tumor correlated with worse patient outcomes. Compared with other media conditions, cells cultured in media replicating the metabolic environment of the brain have increased expression of mitochondrial proteins, increased 13C glucose labeling in the TCA cycle, and a larger reduction in proliferation with IACS-010759 treatment. Using our PDX models, inhibition of OXPHOS with IACS-010759 had little effect on subcutaneous tumor growth but reduced metastasis in the lung and the brain. Conclusions: OXPHOS activity may be enhanced in NSCLC brain metastases due to the unique metabolic environment of the brain. This elevated OXPHOS activity may be necessary for NSCLC brain metastasis growth, as OXPHOS inhibition reduced metastasis in the brain. NSCLC cells may undergo mitochondrial biogenesis to support survival in this unique metabolic environment, and this may represent an area of therapeutic vulnerability for brain metastases. Citation Format: Nia G. Hammond, Massar Alsamraae, Mayher Kaur, Rachel Zuckerman, Brianna Chang, Robert Cameron, Aaron Dyas, Brandon Faubert. Investigating the significance of OXPHOS activity in non-small cell lung cancer brain metastases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1797.

Abstract 703: GABA(A) receptor activation drives GABARAP-Nix mediated autophagy to radiosensitize primary and metastatic lung adenocarcinoma tumors

Abstract In non-small cell lung cancer (NSCLC) treatment, targeted therapies help a subset of patients, and radiotherapy responses are not durable and toxicity limits therapy. Most advanced-stage NSCLC patients have brain metastases that render an abysmal prognosis. Standard-of-care radiation therapy for NSCLC brain metastasis includes stereotactic radiosurgery (SRS) if the number of lesions is less than ten, otherwise whole brain radiation therapy (WBRT) is administered. Challenges in applying radiotherapy include overcoming radiation resistance and reducing significant associated co-morbidities. Cancer neuroscience is an evolving area, and the purpose of this study is to determine if activation of GABA(A) receptors intrinsic to NSCLC cells can improve radiation efficacy in primary NSCLC and its brain metastasis. We find that a GABA(A) receptor activator, AM-101, impairs the viability and clonogenicity of NSCLC primary and brain metastatic cells. Employing a human-relevant ex vivo ‘chip’, AM-101 is as efficacious as docetaxel, a chemotherapeutic used with radiotherapy for advanced-stage NSCLC. In vivo, AM-101 potentiates radiation, including conferring a significant survival benefit to mice bearing NSCLC intracranial tumors generated using a patient-derived metastatic line. GABA(A) receptor activation stimulates a selective-autophagic response via multimerization of GABA(A) Receptor-Associated Protein (GABARAP), stabilization of mitochondrial receptor Nix, utilization of ubiquitin-binding protein p62, and upregulation of Beclin-1. A high-affinity peptide disrupting Nix binding to GABARAP inhibits the cytotoxicity of AM-101. This supports a model of GABA(A) receptor activation driving a GABARAP-Nix multimerization axis that triggers autophagy. In NSCLC brain metastases patients, GABA(A) receptor activation may improve radiation efficacy and tumor control while allowing radiation dose de-intensification to reduce toxicity. Citation Format: Debanjan Bhattacharya, Riccardo Barrile, Donatien Kamdem Toukam, Vaibhavkumar S. Gawali, Laura Kallay, Taukir Ahmed, Hawley Brown, Sepideh Rezvanian, Aniruddha Karve, Pankaj B. Desai, Mario Medvedovic, Kyle Wang, Dan Ionascu, Nusrat Harun, Chenran Wang, Andrew M. Baschnagel, Joshua A. Kritzer, James Cook, Daniel A. Pomeranz Krummel, Soma Sengupta. GABA(A) receptor activation drives GABARAP-Nix mediated autophagy to radiosensitize primary and metastatic lung adenocarcinoma tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 703.

Exploring the Molecular Tumor Microenvironment and Translational Biomarkers in Brain Metastases of Non-Small-Cell Lung Cancer.

Brain metastases represent a significant clinical challenge in the treatment of non-small-cell lung cancer (NSCLC), often leading to a severe decline in patient prognosis and survival. Recent advances in imaging and systemic treatments have increased the detection rates of brain metastases, yet clinical outcomes remain dismal due to the complexity of the metastatic tumor microenvironment (TME) and the lack of specific biomarkers for early detection and targeted therapy. The intricate interplay between NSCLC tumor cells and the surrounding TME in brain metastases is pivotal, influencing tumor progression, immune evasion, and response to therapy. This underscores the necessity for a deeper understanding of the molecular underpinnings of brain metastases, tumor microenvironment, and the identification of actionable biomarkers that can inform multimodal treatment approaches. The goal of this review is to synthesize current insights into the TME and elucidate molecular mechanisms in NSCLC brain metastases. Furthermore, we will explore the promising horizon of emerging biomarkers, both tissue- and liquid-based, that hold the potential to radically transform the treatment strategies and the enhancement of patient outcomes.

Intracranial response pattern, tolerability and biomarkers associated with brain metastases in non-small cell lung cancer treated by tislelizumab plus chemotherapy.

Programmed cell death protein-1/programmed cell death protein-ligand 1 (PD-1/PD-L1) inhibitor and chemotherapy are the standard treatment for advanced non-small cell lung cancer (NSCLC) without sensitizing mutations. However, patients with untreated, symptomatic or recently-irradiated brain metastases (BMs) are mostly excluded from immunochemotherapy trials. This study aims to evaluate the intracranial response pattern, tolerability and biomarkers of tislelizumab plus chemotherapy in NSCLC with untreated, symptomatic or recently-irradiated BM. This multicenter, single-arm, phase 2 trial enrolled patients with treatment-naïve, brain-metastasized NSCLC. BM could be untreated or irradiated. Symptomatic or recently-irradiated BMs that were deemed clinically stable were allowed. Patients received tislelizumab (200 mg) plus pemetrexed (500 mg/m2) and carboplatin (AUC =5) on day 1 every 3 weeks for 4 cycles, followed by maintenance with tislelizumab plus pemetrexed. Primary endpoint was 1-year progression-free survival (PFS) rate. Secondary endpoints included intracranial efficacy and tolerability. PD-L1 expression, tumor mutational burden (TMB) and genomic alterations were evaluated as potential biomarkers. A total of 36 patients were enrolled, 19.2% had prior brain radiotherapy, 8.3% had symptomatic BMs that required corticosteroids ≤10 mg/d or antiepileptics. Confirmed systemic and intracranial ORR (iORR) was 43.8% and 46.7%, respectively. One-year systematic PFS rate and One-year iPFS rate was 36.8% and 55.8%, respectively. About 41.7% patients had neurological adverse events, 90% patients had concordant intracranial-extracranial responses. No intracranial pseudoprogression or hyperprogression occurred. Patients with prior brain radiation trended towards higher systemic (83.3% vs. 34.6%) and iORR (75.0% vs. 42.3%). Similar intracranial efficacy was observed in tumors with different PD-L1 and TMB levels, while alterations in cytokine receptors pathway predicted higher iORR (P=0.081), prolonged systematic PFS [hazard ratio (HR) =0.16, P=0.021] and overall survival (OS) (HR =0.71, P=0.029). Untreated or irradiated BMs in NSCLC follows a conventional response and progression pattern under immunochemotherapy with altered cytokine receptors pathway being a potential biomarker for systemic and intracranial outcomes.

Survival Predictive Nomograms for Non-Surgical Brain Metastases Patients From Non-Small Cell Lung Cancer Receiving Radiotherapy: A Population-Based Study.

A high number of Non-Small Cell Lung Cancer (NSCLC) patients with brain metastasis who have not had surgery often have a negative outlook. Radiotherapy remains a most common and effective method. Nomograms were developed to forecast the cancer-specific survival (CSS) and overall survival (OS) in NSCLC individuals with nonoperative brain metastases who underwent radiotherapy. Information was gathered from the Surveillance, Epidemiology, and End Results (SEER) database about patients diagnosed with NSCLC who had brain metastases not suitable for surgery. Nomograms were created and tested using multivariate Cox regression models to forecast CSS and OS at intervals of 1, 2, and 3years. The research involved 3413 individuals diagnosed with NSCLC brain metastases who had undergone radiotherapy but had not experienced surgery. These participants were randomly divided into two categories. The analysis revealed that gender, age, ethnicity, marital status, tumor location, tumor laterality, tumor grade, histology, T stage, N stage, chemotherapy, tumor size, lung metastasis, bone metastasis, and liver metastasis were significant independent predictors for OS and CSS. The C-index for the training set for predicting OS was .709 (95% CI, .697-.721), and for the validation set, it was .705 (95% CI, .686-.723), respectively. The C-index for predicting CSS was .710 (95% CI, .697-.722) in the training set and .703 (95% CI, .684-.722) in the validation set, respectively. The nomograms model, as suggested by the impressive C-index, exhibits outstanding differentiation ability. Moreover, the ROC and calibration curves reveal its commendable precision and distinguishing potential. For the first time, highly accurate and reliable nomograms were developed to predict OS and CSS in NSCLC patients with non-surgical brain metastases, who have undergone radiotherapy treatment. The nomograms may assist in tailoring counseling strategies and choosing the most effective treatment method.

A Multistage‐Responsive Antibody‐Delivery Strategy to Improve Immunotherapy for NSCLC Brain Metastasis by Ultrasensitive Releasing and Tumor‐Anchoring

AbstractImmune checkpoint blockade (ICB) therapy has emerged as a promising approach in clinical oncology. For brain metastases, the presence of the robust blood–brain barrier (BBB) and potential immune‐related adverse events (irAEs) pose significant challenges. Here, a multistage‐responsive antibody‐delivery strategy is developed for non‐small cell lung cancer (NSCLC) brain metastases, with the ultra‐pH sensitivity borate bonds. The antibody‐delivery nanoformulation (MB‐aPDL1) is able to maintain the “silent state” in health tissue, cross the BBB/BTB by the GLUT1‐mediated transcytosis, release the functionalized aPDL1 responsively, and promote the aPDL1 tumor‐anchoring. In the in vivo tumor region, the MB‐aPDL1 rapidly releases the activated BPA6‐aPDL1, which successfully anchors to the tumor cells and improves the efficiency of ICB therapy. The two in vivo ICB therapy studies show a significant tumor growth inhibition from the MB‐aPDL1 with an encouraging cure rate of 20% for the NSCLC brain metastases, due to enhanced immune response in tumor, commendably with less behavioral adverse reactions and liver damage. Taken together, this antibody‐delivery strategy holds substantial potential for application in clinical treatment of brain metastases.

Prognostic impact of the number and total tumor burden of secondary cerebral lesions in patients with resected brain metastases of non-small cell lung cancers.

Systemic therapeutic advancements have improved the prognosis of cancer patients, leading to surgery more frequently being carried out for patients with multiple brain metastases (BM). The underlying evidence for the strategy is currently lacking. This study aimed to evaluate the prognostic significance of the number of BM and total tumor burden (TTB) on the overall survival (OS) of patients with resected BM of non-small cell lung cancer (NSCLC) in a modern series. In this monocentric retrospective series, patients who underwent resection of BM of NSCLC between 2015 and 2021 were included. Demographic, clinical, and histological parameters were collected, and formal radiological volumetric analyses were performed. Prognostic biomarkers for cerebral progression-free survival (C-PFS) and OS were analyzed with univariate and multivariate Cox proportional hazards analysis. One hundred eighty-four patients were included in the study. Among these, 108 patients (58.7%) presented with a single brain metastasis, 36 patients (19.6%) with 2 BM, 22 patients (11.9%) with 3 BM, and 18 patients (9.8%) with more than 3 BM (maximum 15 BM). The mean ± SD (range) preoperative tumor burden was 23.1 ± 25.3 (1.1-145.3) cm3. The mean residual tumor burden after surgery was 0.3 ± 0.8 (0.0-6.3) cm3. By the time of the analysis, 128 patients (69.6%) had died. The median follow-up duration was 49.0 months (95% CI 39.6-63.6). The median OS was 19.2 months (95% CI 13.2-24.0), and the survival rates at 6 months, 1 year, and 2 years were 76% (95% CI 69%-82%), 61% (95% CI 53%-67%), and 43% (95% CI 35%-50%), respectively. The median C-PFS was 8.4 months (95% CI 7.2-12.0). In the Cox multivariate regression model, younger age (< 65 years), single brain metastasis, adjuvant brain radiation therapy, adjuvant use of targeted therapy, and TTB < 7 cm3 were all independent predictors of longer OS. In this era of modern systemic treatments for cancer, the number of BM and total cerebral tumor burden remain significant prognostic factors of OS. However, resection should be considered as an option even in those patients with multiple BM in order to enhance patient clinical status, enable further local and systemic treatment delivery, and improve their survival and quality of life.

A Correlative Study on EGFR Gene Mutation Status of Primary Lung Tumor and Brain Metastases in NSCLC

Objective: This study aims to explore the predictive role of EGFR gene mutation in the primary lung tumor on brain metastases in Non-Small Cell Lung Cancer (NSCLC). Methods: Morphological differences between EGFR gene 19 exon deletion mutant HCC827 and wild-type EGFR gene A549 human lung adenocarcinoma cells were observed under a microscope. The MTT method was employed to detect the proliferation differences between HCC827 and A549 cells. The Transwell in vitro cell invasion experiment was used to compare the invasion capabilities of the two cell lines. Furthermore, the Χ2 test was applied to analyze the relationship between the EGFR mutation in the primary lung tumor and the occurrence of brain metastases in 253 NSCLC patients. Results: A549 cells were smaller in size, resembling paving stones, whereas HCC827 cells were larger and polygonal. MTT analysis revealed that wild-type EGFR A549 human lung adenocarcinoma cells proliferated faster than EGFR mutant HCC827 cells, with a significant difference (P&lt;0.05). The Transwell in vitro cell invasion experiment indicated that HCC827 cells were significantly stronger than A549 cells (P&lt;0.05). The incidence of brain metastases in 253 NSCLC patients was 12.3% (31/253), among which eight cases had EGFR gene mutations in primary lung tumor, with a mutation rate of only 25.81% (8/31). No significant correlation was found between the occurrence of brain metastases and the mutation in primary lung tumor. Conclusion: EGFR gene mutation in NSCLC cells can significantly enhance their invasive activity. However, the correlation between EGFR gene mutation in primary lung tumor and the occurrence of brain metastases warrants further study.

Abstract C053: BACE1 cleaves EGFR to drive lung adenocarcinoma brain metastasis

Abstract Brain metastasis occurs in up to 40% of patients with non-small cell lung cancer (NSCLC). Considerable genomic heterogeneity exists between the primary lung tumour and respective brain metastasis; however, the identity of the genes capable of driving brain metastasis is incompletely understood. Here, we carried out an in vivo genome-wide CRISPR activation (CRISPRa) screen to identify molecular drivers of brain metastasis from a NSCLC patient-derived xenograft model. We discovered activation of the Alzheimer’s disease associated b-site amyloid precursor protein cleaving enzyme 1 (BACE1) led to a significant increase in brain metastasis. Furthermore, BACE1 knockout or inhibition with Verubecestat treatment blocked NSCLC brain metastasis. Mechanistically, we identified BACE1 cleaves an N-terminal fragment of EGFR to activate downstream signalling through MEK and ERK and drive this metastatic phenotype. Together our data highlights the power of in vivo CRISPR screening to unveil novel molecular drivers and potential therapeutic targets of NSCLC brain metastasis. Citation Format: Shawn C Chafe, Kui Zhai, Sheila K Singh. BACE1 cleaves EGFR to drive lung adenocarcinoma brain metastasis [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C053.

EXTH-45. DEVELOPMENT OF COMBINATION THERAPIES OF KRASG12C INHIBITOR ADAGRASIB IN PRECLINICAL MODELS OF BRAIN METASTASIS

Abstract BACKGROUND The highly selective KRASG12C inhibitor adagrasib (MRTX849) is FDA-approved for KRASG12C+ advanced non-small cell lung cancer (NSCLC). We recently provided preclinical evidence of MRTX849 brain penetration and activity, allowing MRTX849 inclusion in a national genomically-guided multicenter clinical trial (NCT03994796) for patients with brain metastasis (BM). However, multiple genetic alterations such as CDKN2A/B deletions, a common driver of NSCLC BM, can limit MRTX849 efficacy. Furthermore, although MRTX849 can sensitize extracranial tumors to immune checkpoint inhibitors (ICI), its intracranial immune benefit is unknown. Our objective was to improve MRTX849 monotherapy, evaluating combination therapies with CDK4/6 inhibitor abemaciclib or anti-PD-1 in preclinical models of BM. METHODS We tested in vitro sensitivity of MRTX849 and abemaciclib, using KRASG12C+, CDKN2A-deleted human lung cancer cell lines SW1573 and H2122. The efficacy of a 5-week treatment of MRTX849 and abemaciclib was evaluated in an intracranial NSCLC BM model in nude mice. Additionally, we utilized a syngeneic murine KrasG12C colorectal cancer BM model (CT26G12C) to test different MRTX849 dosages and assess its therapeutic effects in combination with anti-PD-1 antibody. RESULTS MRTX849 and abemaciclib demonstrated mild synergy in reducing cell viability in vitro. Combination treatment of MRTX849 and abemaciclib significantly improved both survival and intracranial tumor control relative to controls in SW1573 NSCLC BM model. In a syngeneic colorectal BM model, we identified benefit of a 2-week MRTX849 single treatment at 100 mg/kg (BID) in controlling brain tumor growth. In a dual subcutaneous intracranial BM model with CT26G12C, MRTX849 alone and combination therapy mediated complete regression of extracranial tumors. Although monotherapies reduced intracranial tumor growth, MRTX849 combination with anti-PD-1 resulted in a greater benefit. Both MRTX849 monotherapy and the combination therapy extended animal survival. CONCLUSIONS MRTX849 combination therapies with abemaciclib or anti-PD-1 demonstrate intracranial activity, inhibiting BM progression and prolonging survival, in preclinical models of KRASG12C+ BM.

The value of EGFR in individualized treatment for brain metastases in non-small cell lung cancer

The prognosis of brain metastases in non-small cell lung cancer (NSCLC) is poor, and patients with EGFR mutations are more likely to have brain metastases. The epidermal growth factor receptor (EGFR) gene status has changed the direction of treatment for NSCLC patients with brain metastases. The development of EGFR tyrosine kinase inhibitors (EGFR-TKI) has prolonged the survival time of NSCLC patients with brain metastases. The treatment of patients with NSCLC brain metastases should be individualized according to the clinical symptoms, tumor stage, and different gene mutation status. As cancer is heterogeneous at the molecular level, related biomarker studies looking for individualized characteristics are recommended.

Intracranial Control with Combined Dual Immune-Checkpoint Blockade and SRS for Melanoma and NSCLC Brain Metastases

It is unknown whether the use of dual immune-checkpoint inhibition (D-ICI) combined with stereotactic radiosurgery (SRS) affects local control of brain metastases (BMs). We sought to characterize the efficacy of SRS and D-ICI in patients with BMs in a large, single-institution cohort. Patients with melanoma and non-small cell lung cancer (NSCLC) BMs treated with SRS from January 1, 2016 to August 1, 2022 were evaluated. Patients were stratified by treatment with D-ICI versus single ICI (S-ICI). Concurrent ICI was defined as ICI given within four weeks of SRS. Local recurrence (LR), intracranial progression (IP), and overall survival (OS) were estimated using competing risk and Kaplan-Meier analyses. IP included both local and distant intracranial recurrence. One thousand seven hundred four SRS-treated BMs from 288 patients met inclusion criteria. 55% of patients were symptomatic from their BMs at presentation. Median age, KPS, number of lesions, and SRS courses were 64 (Q1Q3:56-70.5), 90 (80-90), 2 (1-4), and 1 (1-2), respectively. One hundred twenty-eight (44%) melanoma and 160 (56%) NSCLC patients were included. 82 (28.5%), 129 (44.8%), and 77 (26.7%) patients were treated with D-ICI, S-ICI, or SRS alone. Median SRS dose, fractions, and PTV were 20 (Q1Q3:20-25), 1 (1-5), and 0.3cc3 (0.1-1.2). The median follow-up was 14.3 months. One hundred twenty-seven (7.45%) BMs recurred post-SRS and the median time to LR was 4.8 months (Q1Q3:3.0-9.2). On competing risk analysis, LR was significantly reduced with D-ICI (HR: 0.452, p = 0.0024), but not with S-ICI (HR: 0.693, p = 0.0596) compared to SRS alone. The 1-year LR was 3.77% (95% CI = 2.19-6.00), 6.8% (5.19-8.70), and 8.96% (6.48-11.93) with D-ICI, S-ICI, and SRS alone. The median time to IP was 4.1 months (Q1Q3 = 2.9-9.5). On competing risk analysis, IP was significantly reduced with D-ICI (HR = 0.638, p = 0.031), but not with S-ICI (HR = 0.756, p = 0.106) compared to SRS alone. 1-year IP was 40.05% (95% CI = 29.14-50.70), 51.86% (42.78-60.19), and 58.49% (46.30-68.84) with D-ICI, S-ICI, and SRS alone. Concurrent delivery of D-ICI and SRS significantly reduced IP (HR = 0.463, p = 0.0071), whereas other combinations of timing and ICI did not reach significance. Median OS was 11.9 months after SRS. On Kaplan Meier analysis, OS was significantly improved with D-ICI (HR = 0.616, 95% CI = 0.412-0.923, p = 0.019), but not with S-ICI (HR = 0.877, 95% CI = 0.633-1.217, p = 0.433) compared to SRS alone. Hospitalizations (p = 0.021) and immune-related adverse events (irAEs) (p<0.001) were increased with D-ICI. Any grade radiation necrosis (RN) was also increased with D-ICI (p = 0.013), but neurologic adverse events were comparable across cohorts (p = 0.572). D-ICI combined with SRS was associated with improved local control, intracranial control, and overall survival compared to SRS alone, whereas S-ICI was not associated with an improvement in these outcomes. However, D-ICI was also associated with increased risks of irAEs and RN.

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.

Stereotactic Radiosurgery (SRS) for Brain Metastasis in the Era of Evolving Systemic Treatment (Immunotherapy or Targeted Therapy) in Patients with Non-Small Cell Lung Cancer (NSCLC)

With evolving role for targeted and immunomodulatory agents, the survival rate of NSCLC has been improved even with brain metastasis. This study analyzed the outcome of brain metastasis treated with SRS in conjunction with immunotherapy and target therapy as well as chemotherapy. After obtaining institutional review board (IRB) approval, 229 patients with NSCLC with brain metastasis treated with SRS at our institution were retrospectively reviewed from 2008-2021. Demographic information (e.g., age, sex, race), performance status (PS), extracranial metastasis (ECM), sequence of systemic therapy (SST) and surgery for BM (SBM) were reviewed and collected. Overall survival (OS) and intracranial recurrence free survival (ICRFS) were analyzed using the Kaplan-Meier method/Cox regression, and time to each event were measured from the date of the first SRS treatment. All statistical analyses were performed using SAS version 9.4 (Carey, NC). Of the 229 pts, the median age of pts at first SRS was 64.1 (range, 34.8- 83.0 years). 38.6% were biomarker (EGFR/ALK/ROS/PDL1) positive, and 30% were PDL1 positive. 28.8 % had surgery before SRS. The median number of SRS was 1 (range, 1 - 6), and 10 patients received salvage whole brain radiation therapy (WBRT) after SRS. With a median follow-up of 9.6 months (mo), median OS and ICRFS were 14.0 mo and 8.1 mo respectively. On univariate outcome analysis, PS, ECM, SBM and PDL1 were associated with OS while biomarker, SBM and SST were closely related to ICRFS. Pts with poor PS had worse median OS of 8.3 mo compared to 29.1 mo with good PS (p = 0.001). Median OS for no ECM vs. ECM were 20.7 mo vs. 9.6 mo respectively (p = 0.002). Patients who underwent SBM initially had better median OS of 28.7 mo compared to 9.9 mo without SBM (p<0.001). There was a trend of significant impact of positive PDL1 on median OS (21.1 mo vs. 11.7 mo, p = 0.06). Similarly, SBM was found closely related to ICRFS with median ICRFS of 8.1 mo vs. 4.9 mo for those with and without SBM respectively. Both positive biomarker (13.1 mo vs. 6.4 mo, P = 0.17) and SRS first SST (8.1 mo vs. 4.9 mo, p = 0.11) demonstrated a trend of increased median ICRFS. On multivariable analyses, no SBM was linked with worse OS (HR: 1.85; 95% CI:1.15 - 2.97; p = 0.01) and decreased ICRFS (HR: 1.65; 95% CI: 1.09 - 2.51; p = 0.02). Of 31 pts with information on cause of death, 3.2% died from brain metastasis related cause. This study demonstrated effective treatment of brain metastasis in NSCLC with multiple SRSs, especially for patients with favorable prognosis. Of noticed there was only a small number of patients received salvage WBRT and most patients didn't die from brain metastasis related progression.

Efficacy and Safety of PD-1/PD-L1 Inhibitors Combined with Radiotherapy in Patients with Brain Metastases Caused by Non-Small Cell Lung Cancer: A Multi-Center Retrospective Analysis

To investigate efficacy and safety of PD-1/PD-L1 inhibitors plus radiotherapy in patients that brain metastases (BMs) from non-small cell lung cancer (NSCLC). All 234 eligible patients were divided into PD-1/PD-L1 inhibitors plus intracranial radiotherapy (BM-RT) group and immunotherapy (non-BM-RT) group. 144 patients in BM-RT group were divided into patients received extracranial radiotherapy for NSCLC (extra-RT) group and had not (non-extra-RT) group. According to the Lung Immune Prognostic Index (LIPI), patients were stratified into good, intermediate, and poor groups. The toxicity was assessed with Common Terminology Criteria for Adverse Events (CTCAE) 5.0. Kaplan-Meier method and Log-rank test were used to analyze intracranial progression-free survival (iPFS) and overall survival (OS). The median iPFS (11.6 months vs. 9.9 months, P = 0.001) and median OS (17.3 months vs. 14.6 months, P = 0.029) had a significant difference in BM-RT group and non-BM-RT group. Meanwhile, median iPFS (15.7 months vs. 10.5 months, P<0.001) and median OS (20.2 months vs. 15.1 months, P = 0.024) in extra-RT group were longer than non-extra-RT group. The median iPFS (12.9 months vs. 10.4 vs. 8.4 months, P = 0.001) and median OS (20.1 months vs. 16.7 months vs. 12.6 months, P = 0.025) were longer in good group than intermediate group and poor group in LIPI. Our data suggested there was a significant difference in iPFS and OS with or without radiotherapy in patients of BMs from NSCLC, and with safety profiles. LIPI helped predict prognosis of BMs in NSCLC.