Progressive Brain Metastases Research Articles

Envonalkib versus crizotinib for treatment-naive ALK-positive non-small cell lung cancer: a randomized, multicenter, open-label, phase III trial

Anaplastic lymphoma kinase (ALK) rearrangements are present in about 5–6% of non-small cell lung cancer (NSCLC) cases and associated with increased risks of central nervous system (CNS) involvement. Envonalkib, a novel ALK inhibitor, demonstrated promising anti-tumor activity and safety in advanced ALK-positive NSCLC in the first-in-human phase I study. This phase III trial (ClinicalTrials.gov NCT04009317) investigated the efficacy and safety of first-line envonalkib in advanced ALK-positive NSCLC cases. Totally 264 participants were randomized 1:1 to receive envonalkib (n = 131) or crizotinib (n = 133). Median independent review committee (IRC)-assessed progression-free survival (PFS) times were 24.87 (95% confidence interval [CI]: 15.64–30.36) and 11.60 (95% CI: 8.28–13.73) months in the envonalkib and crizotinib groups, respectively (hazard ratio [HR] = 0.47, 95% CI: 0.34–0.64, p < 0.0001). IRC-assessed confirmed objective response rate (ORR) was higher (81.68% vs. 70.68%, p = 0.056) and duration of response was longer (median, 25.79 [95% CI, 16.53–29.47] vs. 11.14 [95% CI, 9.23–16.59] months, p = 0.0003) in the envonalkib group compared with the crizotinib group. In participants with baseline brain target lesions, IRC-assessed CNS-ORR was improved with envonalkib compared with crizotinib (78.95% vs. 23.81%). Overall survival (OS) data were immature, and median OS was not reached in either group (HR = 0.84, 95% CI: 0.48–1.47, p = 0.5741). The 12-month OS rates were 90.6% (95% CI, 84.0%–94.5%) and 89.4% (95% CI, 82.8%–93.6%) in the envonalkib and crizotinib groups, respectively. Grade ≥3 treatment-related adverse events were observed in 55.73% and 42.86% of participants in the envonalkib and crizotinib groups, respectively. Envonalkib significantly improved PFS and delayed brain metastasis progression in advanced ALK-positive NSCLC.

Prediction of brain metastases progression and overall survival in patients with metastatic non-small cell lung cancer treated by immune checkpoint inhibitors using a radiomic model.

e21169 Background: Brain metastases (BMs) incidence is high in patients with metastatic non-small cell lung cancer (NSCLC). Immune Checkpoints Inhibitors (ICIs) are now standard of care for metastatic NSCLC in the first-line or beyond settings. However, less than half of patients will have a tumor response, and the determinants of BMs response to ICIs remain unknown. This study aims to evaluate the value of radiomics to predict control/progression of BMs at a lesion level, and outcomes at a patient level in the BM+ NSCLC population treated by ICIs. Methods: We conducted a retrospective multicenter (5 European centers) study including consecutive patients with NSCLC BMs and available baseline MRI before ICIs (evaluation cohort) or chemotherapy (control cohort) with a 2:1 ratio, between 2011 and 2021. After modified RANO (Response Assessment in Neuro-Oncology) assessment of individual BMs, we developed a radiomic model to predict BMs control/progression to ICIs at the first brain follow-up imaging. The ICIs cohort was split into two datasets used for (i) model training with 5-fold cross-validation and (ii) model testing. The Chemotherapy cohort was used to ensure the specificity of our model to ICIs-treated patients. Results: Ninety-four and 49 patients were included in the ICIs and Chemotherapy cohorts respectively, of which 56 (59.6%, N = 227 BMs) and 39 (79.6%, N = 192 BMs) patients had available brain follow-up imaging. The ICIs cohort was specifically enriched in radiomic features which were significantly associated to BMs progression. Our final model, based on extreme gradient boosting (xgboost) on BMs &gt; 10mm from the training set (N = 39 BMs), could predict individual BMs progression to ICIs with an area under curve (AUC) of 0.77 (p-value = 0.029, 95% CI [0.56-0.98]) in the test set (N = 20 BMs). We further generated a radiomic score to stratify BM+ NSCLC ICIs-treated patients between High-Risk or Low-Risk groups according to the predicted individual BMs progression. High-risk patients were associated with worse overall survival (OS) (median OS of 6.3 months, 95% CI [3.02-10.49]) compared to Low-risk patients (median OS of 11.87 months, 95% CI [7.02-21.90], p = 0.042). The prognostic value of the radiomic score on OS was validated in a multivariate analysis in the ICIs cohort (Table). Conclusions: To our knowledge, this is the first study to explore the value of radiomics in the prediction of BMs response to immunotherapy. Prospective evaluation will confirm the generalizability of our model in clinical practice.[Table: see text]

The Vicious Cycle of Melanoma-Microglia Crosstalk: Inter-Melanoma Variations in the Brain-Metastasis-Promoting IL-6/JAK/STAT3 Signaling Pathway.

Previous studies from our lab demonstrated that the crosstalk between brain-metastasizing melanoma cells and microglia, the macrophage-like cells of the central nervous system, fuels progression to metastasis. In the present study, an in-depth investigation of melanoma-microglia interactions elucidated a pro-metastatic molecular mechanism that drives a vicious melanoma-brain-metastasis cycle. We employed RNA-Sequencing, HTG miRNA whole transcriptome assay, and reverse phase protein arrays (RPPA) to analyze the impact of melanoma-microglia interactions on sustainability and progression of four different human brain-metastasizing melanoma cell lines. Microglia cells exposed to melanoma-derived IL-6 exhibited upregulated levels of STAT3 phosphorylation and SOCS3 expression, which, in turn, promoted melanoma cell viability and metastatic potential. IL-6/STAT3 pathway inhibitors diminished the pro-metastatic functions of microglia and reduced melanoma progression. SOCS3 overexpression in microglia cells evoked microglial support in melanoma brain metastasis by increasing melanoma cell migration and proliferation. Different melanomas exhibited heterogeneity in their microglia-activating capacity as well as in their response to microglia-derived signals. In spite of this reality and based on the results of the present study, we concluded that the activation of the IL-6/STAT3/SOCS3 pathway in microglia is a major mechanism by which reciprocal melanoma-microglia signaling engineers the interacting microglia to reinforce the progression of melanoma brain metastasis. This mechanism may operate differently in different melanomas.

Ceramide Synthase 1 Inhibits Brain Metastasis of Non-Small Cell Lung Cancer by Interacting with USP14 and Downregulating the PI3K/AKT/mTOR Signaling Pathway

Brain metastasis (BM) is common in patients with non-small cell lung cancer (NSCLC) and is associated with a poor prognosis. Ceramide synthase 1 (CERS1) participates in malignancy development, but its potential role in NSCLC BM remains unclear. This study aimed to explore the physiological effects and molecular mechanism of CERS1 in NSCLC BM. CERS1 expression was evaluated in NSCLC tissues and cell lines, and its physiological roles were subsequently explored in vivo and in vitro. Mass spectrometry and co-immunoprecipitation were performed to explore CERS1-interacting proteins. The associated signaling pathways of CERS1 in NSCLC BM were further investigated using bioinformatics analysis and molecular biotechnology. We demonstrated that CERS1 was significantly downregulated in NSCLC cell lines and BM tissues, and its upregulation was associated with better prognoses. In vitro, CERS1 overexpression inhibited cell migration, invasion, and the ability to penetrate the blood-brain barrier. Moreover, CERS1 interacted with ubiquitin-specific protease 14 (USP14) and inhibited BM progression by downregulating the PI3K/AKT/mTOR signaling pathway. Further, CERS1 expression substantially suppressed BM tumor formation in vivo. This study demonstrated that CERS1 plays a suppressor role in NSCLC BM by interacting with USP14 and downregulating the PI3K/AKT/mTOR signaling pathway, thereby serving as a novel therapeutic target for NSCLC BM.

Abstract GS5-07: Estradiol represses anti-tumoral immune response to promote progression of triple-negative breast cancer brain metastases

Abstract Background: Younger women with breast cancer have increased risk of development of brain metastases irrespective of the tumor subtype. We have shown that pre-menopausal levels of 17-β-Estradiol (E2) contributes to the promotion of brain metastases by influencing the tumor microenvironment. E2 promotes brain metastasis (BM) of estrogen receptor negative (ER¯) BC cells by inducing neuroinflammatory ER+ astrocytes in the brain niche to secrete pro-metastatic factors critical for early brain colonization. Ovarieoctomy (OVX) in combination with the aromatase inhibitor (Letrozole) prevented brain colonization of triple negative (TNBC) (ER-PR-HER2-) human xenografts (MDA231BR/NSG) and murine models (E0711/C57Bl6, 4T1/BALBc) through paracrine activation of EGFR and TRKB, pathways involved in increased invasion and early tumor initiation. Yet, the extent to which E2-depletion therapies can decrease progression of established BM in combination with current standard of care for brain metastasis remains unknown. Goal: Current standard of care (SOC) for patients with TNBC brain metastasis includes irradiation (SRS, whole brain) and immunotherapy (PD-1/PDL-1 inhibitors). The goal of this study was to assess how E2-depletion therapies affects brain immune function in the context of SOC for brain metastatic progression of TNBC. Results: To assess whether E2-depletion could decrease BM progression in a model that mimics standard of care for BM, TNBC E0771-GFP-luc cells were injected intracardially in syngeneic ovariectomized (OVX)-female C57Bl6 mice supplemented with pre-menopausal levels of E2. Seven days after injection (when cancer cells have colonized), mice received a single 15Gy dose brain irradiation and were randomized to continue receiving E2, E2 withdrawal (E2WD) or E2WD plus the aromatase-inhibitor letrozole (E2WD+LET). Brain metastatic burden significantly decreased in E2WD and E2WD+Letrozole treated mice as compared to E2-treated mice. Injection of E0711 cells in immunocompromised NSG mice or in the absence of brain irradiation abolished this effect, suggesting that E2-depletion therapies decrease BM progression through boosting radiation-induced anti-tumor immunity. Accordingly, there were no differences in BM progression in E2, E2WD or E2WD+let treated mice in a xenograft model (F2-7 TNBC cells) in NSG mice, even in the presence of brain irradiation. Immune-profiling of brains from OVX+E2, OVX and OVX+Let C57BL6 mice carrying BMs showed dynamic changes in immune populations at early and late stages of brain metastatic colonization. At early stages post brain colonization (3 days post ic injection) E2-treated mice showed a decreased fraction of CD11b+CD45Int CD206+ microglia/CNS macrophages as compared to OVX+LET-treated mice, without significant changes in the fraction of infiltrated lymphocytes, suggesting E2 represses early immunosurveillance through repression of microglia/CNS macrophage activation. At later stages of brain colonization (7 days post ic injection), E2-treated mice showed an increased fraction of proinflammatory microglia and decreased fraction of T and B cells as compared to OVX or OVX+let treated mice. While E2-depletion increased the recruitment of T cells to the brain niche, the fraction of CD279 (PD1+) brain T cells was similar among groups. Ongoing studies assess the efficacy of E2-depletion therapies in combination with brain radiation and PD-1 inhibitors to decrease metastatic burden and improve survival in preclinical models. Conclusion: Our results support the hypothesis that estradiol promotes brain metastatic progression by stimulating an immunosuppressive brain microenvironment. As such, FDA-approved E2-depletion therapies (aromatase inhibitors and selective-estrogen modulators) could be used in combination with brain irradiation and PD-1 inhibitors to promote a more effective anti-tumoral immune response. Citation Format: Diana Cittelly, Maria J. Contreras-Zarate, Karen ALvarez-Eraso, Vesna Tesic, Nicole Tsuji, Leanna Chafee, Sana Karam, D. Ryan Ormond, Peter Kabos. Estradiol represses anti-tumoral immune response to promote progression of triple-negative breast cancer brain metastases [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr GS5-07.

Abstract OT3-09-01: Clinical Trial of Alpelisib and Tucatinib in Patients with PIK3CA-Mutant HER2-Positive Metastatic Breast Cancer

Abstract Phosphatidylinositol 3-kinase (PI3K) pathway plays a key role in resistance to the drugs targeting human epidermal growth factor receptor 2 (HER2). Activating mutations in the gene encoding alpha catalytic subunit of PI3K (PIK3CA) are present in approximately 30% of HER2+ tumors. PIK3CA mutations are linked to drug resistance and decreased survival in patients with HER2+ breast cancer. To overcome this resistance mechanism, we designed a phase IB/II clinical trial to evaluate the combination of HER2 small molecule inhibitor tucatinib with PI3K inhibitor alpelisib in patients with HER2+ metastatic breast cancer (NCT05230810). This multicenter clinical trial is conducted through the Academic Breast Cancer Consortium (ABRCC), with the University of Colorado Cancer Center as the lead site. Target enrollment: 40 patients. This is a run-in phase IB/roll-over phase II study. Phase IB will follow Time-to-Event Bayesian Optimal Interval design and enroll from 9 to 19 patients to find the maximum tolerated doses (MTDs) of tucatinib and alpelisib. From 21 to 31 patients will be enrolled in phase II part, for a total of 40 patients in the final efficacy analysis. Main inclusion criteria: 1. Women and men ≥ 18 years old 2. Eastern Cooperative Oncology Group (ECOG) performance status 0-1 3. Presence of activating PIK3CA mutation in the tumor 4. Patients with HR-/HER2+ or HR+/HER2+ breast cancer may enroll; ovarian suppression is mandatory for premenopausal patients with HR+/HER2+ disease 5. HR+/HER2+ patients should be agreeable to concomitant treatment with fulvestrant 6. Prior treatment with at least two FDA-approved HER2-targeted agents 7. Measurable or evaluable disease. Bone only disease is allowed. 8. Subjects with untreated central nervous system (CNS) metastases not needing immediate local therapy, and subjects with previously treated stable or progressive brain metastases may enroll, provided that there is no indication for immediate re-treatment. For patients with treated CNS metastases: time from treatment of CNS disease until the first dose of study drugs should be as follows: WBRT ≥ 21 days, surgical resection ≥ 14 days, SRS ≥ 7 days. 9. Adequate organ and marrow function Main exclusion criteria: 1. Contraindications to undergo contrast brain MRI 2. Leptomeningeal disease 3. Poorly controlled seizures 4. Diabetes mellitus type I, or uncontrolled diabetes mellitus type II 5. Acute pancreatitis within 1 year of screening, or history of chronic pancreatitis 6. History of severe cutaneous hypersensitivity reactions 7. Toxicities of prior cancer therapies that have not resolved to grade 1 or less, except peripheral neuropathy, which must have resolved to grade 2 or less, and alopecia 8. Previous treatment with EGFR or HER2 tyrosine kinase inhibitors, or PI3K/mTOR/AKT inhibitors. 9. Systemic anti-cancer therapy, palliative radiation to extracranial sites, or surgery within 2 weeks of the first dose of study drugs 10. Active bacterial, fungal, or viral infections, hepatitis B, C, or HIV 11. Clinically significant cardio-vascular disease Primary objectives: • Phase IB: safety and tolerability of combination therapy • Phase II: efficacy by progression free survival Exploratory assessment of biomarkers will be performed in the liquid biopsy samples. Study contact: Elena Shagisultanova, MD, PhD, elena.shagisultanova@cuanschutz.edu Citation Format: Elena Shagisultanova, Kari B. Wisinski, Chelsea D. Gawryletz, Farrah M. Datko, Diana Medgyesy, Jennifer R. Diamond, Virginia F. Borges, Peter Kabos. Clinical Trial of Alpelisib and Tucatinib in Patients with PIK3CA-Mutant HER2-Positive Metastatic Breast Cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT3-09-01.

Abstract OT1-10-01: Treatment with Tucatinib in addition to Pertuzumab and Trastuzumab in patients with HER2-positive metastatic breast cancer (HER2+ MBC) after local therapy of isolated brain progression: InTTercePT, a UCBG/GINECO study

Abstract Treatment with Tucatinib in addition to Pertuzumab and Trastuzumab in patients with HER2-positive metastatic breast cancer (HER2+ MBC) after local therapy of isolated brain progression: InTTercePT, a UCBG/GINECO study. Background HER2+ MBC patient on first line treatment with pertuzumab and trastuzumab have a 13% risk of developing brain metastasis (BM) as the first site of progression. For such patient with isolated brain progression, guidelines recommend to use central nervous system (CNS) directed therapy whenever possible (stereotactic radiosurgery or surgery or both). These patients will have a higher risk of subsequent brain and systemic progression after local treatment. Therefore, whether systemic treatment should be continued or changed remains an open question. The tyrosine kinase inhibitor tucatinib is an orally bioavailable HER2 inhibitor with validated antineoplastic activity and the ability to cross the blood brain barrier. The randomized HER2CLIMB study, demonstrated that adding tucatinib to trastuzumab/capecitabine improved both progression-free survival (PFS) and overall survival (OS) among HER2+ MBC patients previously treated with trastuzumab, pertuzumab and T-DM1. Particularly, this regimen demonstrated improved antitumor activity in patients with BM, in terms of CNS-PFS and OS. Exploratory analysis of HER2CLIMB and in a phase 1b study, showed patients who continued systemic treatment with tucatinib (in combination either with trastuzumab/capecitabine or TDM-1) after CNS-directed treatment had a better outcome compared with those that discontinued systemic tucatinib-based treatment. These results suggest that for patient in the first line metastatic setting who experience isolated brain progression, adding tucatinib to the trastuzumab/pertuzumab regimen could help control BM, improve PFS, OS and patients’ quality of life. Trial design InTTercePT is an open-label, single-arm, national, multicentric, phase II trial assessing the combination of tucatinib, pertuzumab and trastuzumab. Tucatinib will be administered orally twice daily at 300 mg. Pertuzumab and trastuzumab will be administered at the initial dose of 840 mg and 8 mg/kg respectively following by a maintenance dose of 420 mg and 6mg/kg respectively, 3-weekly. If indicated, hormone therapy is allowed in combination with HER2-directed therapy. Eligibility criteria include HER2+ MBC with isolated brain progression (new or progressive BM with stable or responding systemic disease) under pertuzumab/trastuzumab treatment (± taxane) after complete local treatment (surgery and/or radiation therapy). There is no limit to the number and size of BM. Specific aims To evaluate the efficacy, in terms of PFS rate (RECIST v1.1) of tucatinib in combination with pertuzumab/trastuzumab. Secondary endpoints include OS, brain PFS (RECIST v1.1) and BM response in patient not in complete remission at the brain level after local treatment and safety (NCI-CTCAE v5.0). Statistical methods Given the lack of safety data from this association, two interim safety analysis are planned: after 10 and 20 patients having received at least one dose of the treatments combination during at least one cycle. The number of patients to be included was calculated using Fleming’s single-stage procedure for phase II trials. The sample size calculation was based on a minimum success (non-progression rate at 6 months) considered of interest of p1 = 75% and an uninteresting rate of p0 = 60%. Assuming a unilateral type I error alpha of 10% and a power of 85%, 52 patients are needed. Considering 5% of the patients may be non-evaluable, 55 patients will be included. At the time of analysis, if at least 37 successes are observed, the treatment will be considered as interesting for further investigation. The study is recruiting. By July 1, 2022, 10 patients have been screened and 8 treated (NCT05041842). Funding SeaGen Contact information thomas.bachelot@lyon.unicancer.fr Citation Format: Thomas Bachelot, Christelle Jouannaud, Benjamin Verret, Sylvie Chabaud, Camille Petrau, Laetitia Stefani, Mony Ung, Isabelle Desmoulins, William Jacot, Caroline Bailleux, Sandrine Marques, Jérôme Lemonnier, Anne-Claire Hardy-Bessard. Treatment with Tucatinib in addition to Pertuzumab and Trastuzumab in patients with HER2-positive metastatic breast cancer (HER2+ MBC) after local therapy of isolated brain progression: InTTercePT, a UCBG/GINECO study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT1-10-01.

Abstract P1-10-09: AQP4 inhibition prevents cytotoxic edema of AQP4+ astrocytes but promotes tumor growth of AQP4+ breast cancer brain metastasis

Abstract Brain edema is a complication of radiation used to treat brain metastasis (BM) in which the brain parenchyma accumulates fluid and ions, often leading to the suspension of systemic anticancer treatment. While brain edema is often attributed to disruption of the Blood Brain Barrier (BBB), RTx induces cytotoxic-edema, a premorbid cellular process whereby extracellular Na+ and other cations enter into neurons and astrocytes and accumulate intracellularly, resulting in osmotic expansion of the cells and necrotic cell death. Aquaporin 4 (AQP4) is a main regulator of osmotic expansion (water intake) in astrocytes and we have shown that RTx upregulates AQP4 in astrocytes and leads to astrocytic swelling in vitro. However, whether pharmacological modulation of AQP4 could be used to prevent cytotoxic brain edema in RTx-treated BM and its impact on metastatic tumor progression remains unknown. Goal: To determine if the FDA-approved drug Topiramate (TPM), an anti-epileptic drug able to inhibit AQP4) can prevent astrocytic swelling in vitro, reduce RTx-induced brain edema and modulate brain metastatic progression. Results: Electron microscopy of brain cortex from mice treated with 35 Gy RTx showed acute astrocytic end-feet swelling and increase in AQP4 expression compared with non-irradiated mice. A single 8 Gy dose increased astrocytic cell area of human astrocytes by 4.8 fold compared with non-irradiated cells 24 h after RTx. This increased cell-swelling did not result from senescence-associated cellular hypertrophy, as staining of senescent β-galactosidase positive (SA-β-Gal+) cells showed that Rtx-induced astrocytic area only increased significantly in non-senescent (SA-β-Gal- cells). shAQP4s reduced AQP4 levels by 60% and 50%, respectively, and significantly reduced RTx-induced astrocytic swelling. Since there are no FDA-approved AQP4 inhibitors, we tested whether the AQP4-blocking function of TPM could be sufficient to prevent cytotoxic edema, prevent BBB dysfunction and protect from necrotic cell death in vitro. TPM pretreatment did not alter radiation-induced ERK1/2 or AKT activation (a known maker of radioprotection) in astrocytes, but TPM decreased radiation-induced PARP-cleavage, pP38 and pJNK levels. TPM prevented loss of Trans-electric epithelial resistance (TEER) of Rtx-treated astrocytes, but was not able to protect astrocytes from ultimate cell death. Immunohistochemical analysis of a cohort of breast cancer BM showed heterogeneous AQP4 expression in cancer cells ranging from 1.6% to 91% AQP4+ tumoral areas and from 0.6% to 86.9% in stroma. AQP4 inhibition using shRNAs decreased proliferation and survival of AQP4 + 231BR, and EO711 cells in vitro. However, TPM did not alter survival of AQP4+ or AQP4- cells in vitro, suggesting that while AQP4 expression is important for survival of AQP4+ cells in vitro, the inhibition of AQP4 function by TPM is not sufficient to decrease their growth. To determine if TPM could decrease brain edema without negatively impacting tumor progression, female NSG mice were injected intracardially with JmT1BR3 AQP4-cells and ten days later randomized to (1) RTx + vehicle, (2) RTx + TPM (2 days prior to irradiation), (3) Non-RTx + vehicle, and (4) Non-RTx + TPM. TPM decreased brain-water content (a marker of brain edema) in irradiated mice as compared with vehicle-treated mice, without alteration of metastatic burden 21 days post-injection. However, a similar study using AQP4+ E0711 cells in C57Bl6 mice showed TPM was less effective in decreasing brain water content and resulted in a significant increase in extracranial metastatic tumor burden, suggesting that TPM can promote tumor progression by non-tumor intrinsic mechanisms. Conclusions: while TPM shows promise in preventing RTx-induced brain edema, our results show a potential pro-tumorigenic mechanism for TPM that warrants further investigation. Citation Format: Maria J. Contreras-Zarate, Karen ALvarez-Eraso, Nicole Tsuji, Peter Kabos, D.Ryan Ormond, Sana Karam, Diana Cittelly. AQP4 inhibition prevents cytotoxic edema of AQP4+ astrocytes but promotes tumor growth of AQP4+ breast cancer brain metastasis [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-10-09.

Modified Dynamic Conformal Arcs With Forward Planning for Radiosurgery of Small Brain Metastasis: Each Double Arc and Different To-and-Fro Leaf Margins to Optimize Dose Gradient Inside and Outside the Gross Tumor Boundary.

Dynamic conformal arcs (DCA) are a widely used technique for stereotactic radiosurgery (SRS) of brain metastases (BM) using a micro-multileaf collimator (mMLC), while the planning design and method considerably vary among institutions. In the usual forward planning of DCA, the steepness of the dose gradient outside and inside the gross tumor volume (GTV) boundary is simply defined by the leaf margin (LM) setting to the target volume edge. The dose fall-off outside the small GTV tends to be excessively precipitous, especially with an MLC of 2.5-mm leaf width, which is predisposed to the insufficient coverage of microscopic brain invasion and other inherent inaccuracies. Meanwhile, insufficient dose increase inside the GTV boundary, i.e., less inhomogeneous GTV dose, likely leads to inferior and less sustainable tumor response. The more inhomogeneous GTV dose is prone to the steeper dose gradient outside the GTV and vice versa. Herein, we describe an alternative simply modified DCA (mDCA) planning that was uniquely devised to optimize the dose gradient outside and inside the GTV boundary for further enhancing and consolidating local control of small BM. For a succinct exemplification, a 10-mm spherical target was assumed as a GTV for DCA planning using a 2.5-mm mMLC. The benchmark plan was generated by adding a 0-mm LM to the GTV edge byassigning a single fraction of 30 Gy to the isocenter, in which the GTV coverage by 24 Gy with 80% isodose surface (IDS) was 96%, i.e., D96%, while the coverage of GTV + isotropic 2 mm volume by 18 Gy with 60% IDS was 70%, with the D98% being 12 Gy with 40% IDS, viz., too steep dose fall-off outside the GTV boundary. Alternatively, the increase of LM with or without decreasing the isocenter dose enablesthe increase of the GTV + 2 mm coverage by 18 Gy while resulting in an inadequate GTV dose with either a less inhomogeneous dose or an excessive marginal dose. Meanwhile, in the newly devised mDCA planning, everysingle arc was converted to a double to-and-fro arcwith different LM settings under the same spatial arrangement, which enabled GTV + 2 mm volume coverage with 18 Gy while preserving the GTV marginal dose and inhomogeneity similar to those for the benchmark plan. Additionally, the different collimator angle (CA) setting for the to-and-fro arcs led to further trimming of the dose conformity. The limitations of general forward planning with only adjusting the LM for everysingle arc were demonstrated, which can be a contributing factor for local tumor progressionof small BM. Alternatively, the mDCA with each double to-and-fro arc and different LM and CA settings enables optimization of the dose gradient both outside and inside the GTV boundary according to the planners' intent, e.g., moderate dose spillage margin outside the GTV and steep dose increase inside the GTV boundary.

Deciphering Brain Metastasis Stem Cell Properties From Colorectal Cancer Highlights Specific Stemness Signature and Shared Molecular Features

Brain metastases (BMs) from colorectal cancer (CRC) are associated with significant morbidity and mortality, with chemoresistance and short overall survival. Migrating cancer stem cells with the ability to initiate BM have been described in breast and lung cancers. In this study, we describe the identification and characterization of cancer stem cells in BM from CRC. Four brain metastasis stem cell lines from patients with colorectal cancer (BM-SC-CRC1 to BM-SC-CRC4) were obtained by mechanical dissociation of patient's tumors and selection of cancer stem cells by appropriate culture conditions. BM-SC-CRCs were characterized invitro by clonogenic and limiting-dilution assays, as well as immunofluorescence and Western blot analyses. In ovo, a chicken chorioallantoic membrane (CAM) model and invivo, xenograft experiments using BALB/c-nude mice were realized. Finally, a whole exome and RNA sequencing analyses were performed. BM-SC-CRC formed metaspheres and contained tumor-initiating cells with self-renewal properties. They expressed stem cell surface markers (CD44v6, CD44, and EpCAM) in serum-free medium and CRC markers (CK19, CK20 and CDX-2) in fetal bovine serum-enriched medium. The CAM model demonstrated their invasive and migratory capabilities. Moreover, mice intracranial xenotransplantation of BM-SC-CRCs adequately recapitulated the original patient BM phenotype. Finally, transcriptomic and genomic approaches showed a significant enrichment of invasiveness and specific stemness signatures and highlighted KMT2C as a potential candidate gene to potentially identify high-risk CRC patients. This original study represents the first step in CRC BM initiation and progression comprehension, and further investigation could open the way to new therapeutics avenues to improve patient prognosis.

Dual-center validation of using magnetic resonance imaging radiomics to predict stereotactic radiosurgery outcomes.

MRI radiomic features and machine learning have been used to predict brain metastasis (BM) stereotactic radiosurgery (SRS) outcomes. Previous studies used only single-center datasets, representing a significant barrier to clinical translation and further research. This study, therefore, presents the first dual-center validation of these techniques. SRS datasets were acquired from 2 centers (n = 123 BMs and n = 117 BMs). Each dataset contained 8 clinical features, 107 pretreatment T1w contrast-enhanced MRI radiomic features, and post-SRS BM progression endpoints determined from follow-up MRI. Random decision forest models were used with clinical and/or radiomic features to predict progression. 250 bootstrap repetitions were used for single-center experiments. Training a model with one center's dataset and testing it with the other center's dataset required using a set of features important for outcome prediction at both centers, and achieved area under the receiver operating characteristic curve (AUC) values up to 0.70. A model training methodology developed using the first center's dataset was locked and externally validated with the second center's dataset, achieving a bootstrap-corrected AUC of 0.80. Lastly, models trained on pooled data from both centers offered balanced accuracy across centers with an overall bootstrap-corrected AUC of 0.78. Using the presented validated methodology, radiomic models trained at a single center can be used externally, though they must utilize features important across all centers. These models' accuracies are inferior to those of models trained using each individual center's data. Pooling data across centers shows accurate and balanced performance, though further validation is required.

The value of stereotactic biopsy of primary and recurrent brain metastases in the era of precision medicine.

Brain metastases (BM) represent the most frequent intracranial tumors with increasing incidence. Many primary tumors are currently treated in protocols that incorporate targeted therapies either upfront or for progressive metastatic disease. Hence, molecular markers are gaining increasing importance in the diagnostic framework of BM. In cases with diagnostic uncertainty, both in newly diagnosed or recurrent BM, stereotactic biopsy serves as an alternative to microsurgical resection particularly whenever resection is not deemed to be safe or feasible. This retrospective study aimed to analyze both diagnostic yield and safety of an image-guided frame based stereotactic biopsy technique (STX). Our institutional neurosurgical data base was searched for any surgical procedure for suspected brain metastases between January 2016 and March 2021. Of these, only patients with STX were included. Clinical parameters, procedural complications, and tissue histology and concomitant molecular signature were assessed. Overall, 467 patients were identified including 234 (50%) with STX. Median age at biopsy was 64 years (range 29 - 87 years). MRI was used for frame-based trajectory planning in every case with additional PET-guidance in 38 cases (16%). In total, serial tumor probes provided a definite diagnosis in 230 procedures (98%). In 4 cases (1.7%), the pathological tissue did not allow a definitive neuropathological diagnosis. 24 cases had to be excluded due to non-metastatic histology, leaving 206 cases for further analyses. 114 patients (49%) exhibited newly diagnosed BM, while 46 patients (20%) displayed progressive BM. Pseudoprogression was seen in 46 patients, a median of 12 months after prior therapy. Pseudoprogression was always confirmed by clinical course. Metastatic tissue was found most frequently from lung cancer (40%), followed by breast cancer (9%), and malignant melanoma (7%). Other entities included gastrointestinal cancer, squamous cell cancer, renal cell carcinoma, and thyroid cancer, respectively. In 9 cases (4%), the tumor origin could not be identified (cancer of unknown primary). Molecular genetic analyses were successful in 137 out of 144 analyzed cases (95%). Additional next-generation sequencing revealed conclusive results in 12/18 (67%) cases. Relevant peri-procedural complications were observed in 5 cases (2.4%), which were all transient. No permanent morbidity or mortality was noted. In patients with BM, frame-based stereotactic biopsy constitutes a safe procedure with a high diagnostic yield. Importantly, this extended to discerning pseudoprogression from tumor relapse after prior therapy. Thus, comprehensive molecular characterization based on minimal-invasive stereotactic biopsies lays the foundation for precision medicine approaches in the treatment of primary and recurrent BM.

A Phase II Single-arm Study of Palbociclib in Patients With HER2-positive Breast Cancer With Brain Metastases and Analysis of ctDNA in Patients With Active Brain Metastases

IntroductionPalbociclib is highly efficacious and well tolerated in hormone-receptor positive (HR+) metastatic breast cancer (BC) but its activity for HER2+ BC with brain metastases (BM) is unknown. MethodsIn a single-arm phase II study we evaluated palbociclib with trastuzumab for patients with HER2+ MBC and BM. The primary endpoint was BM response rate. Circulating tumor DNA (ctDNA) was evaluated at baseline, and in a subset of patients at cycle 3 and progression. We also retrospectively identified additional patients with metastatic BC, active BM, and a ctDNA assessment prior to therapy for BM. ResultsTwelve patients with HER2+ MBC were enrolled, 4 with HR+ and 8 with HR- disease. No responses were seen. Best response was stable disease for 6 patients and progressive disease for 6 patients. The median PFS was 2.2 months, interquartile range (IQR) was 1.56 to 3.63 months. The median OS was 13.1 months and IQR was 9.4 to 23.8 months The CNS was the primary site of progression for all patients. The median variant allele fraction (VAF) of the dominant variant in each patient was 0.18% (interquartile range [IQR] 0.12%-0.47%) with a median number of somatic alterations of 1. We additionally evaluated ctDNA results from 26 patients with BC and active BM, among whom the median VAF was 11.8% (IQR 3.9%-27.3%) with a median number of alterations was 6 (IQR 4-9). Notably, progressive systemic disease was significantly less frequent in the trial cohort compared with additional retrospectively identified patients (8% vs. 81%). ConclusionPalbociclib did not demonstrate activity in HER2+ MBC with BM. Patients with progressive BM but stable, responding, or absent systemic disease have low VAF and number of alterations detected by ctDNA analysis from blood.

Performance sensitivity analysis of brain metastasis stereotactic radiosurgery outcome prediction using MRI radiomics

Recent studies have used T1w contrast-enhanced (T1w-CE) magnetic resonance imaging (MRI) radiomic features and machine learning to predict post-stereotactic radiosurgery (SRS) brain metastasis (BM) progression, but have not examined the effects of combining clinical and radiomic features, BM primary cancer, BM volume effects, and using multiple scanner models. To investigate these effects, a dataset of n = 123 BMs from 99 SRS patients with 12 clinical features, 107 pre-treatment T1w-CE radiomic features, and BM progression determined by follow-up MRI was used with a random decision forest model and 250 bootstrapped repetitions. Repeat experiments assessed the relative accuracy across primary cancer sites, BM volume groups, and scanner model pairings. Correction for accuracy imbalances across volume groups was investigated by removing volume-correlated features. We found that using clinical and radiomic features together produced the most accurate model with a bootstrap-corrected area under the receiver operating characteristic curve of 0.77. Accuracy also varied by primary cancer site, BM volume, and scanner model pairings. The effect of BM volume was eliminated by removing features at a volume-correlation coefficient threshold of 0.25. These results show that feature type, primary cancer, volume, and scanner model are all critical factors in the accuracy of radiomics-based prognostic models for BM SRS that must be characterised and controlled for before clinical translation.

Direct Evaluation of Treatment Response in Brain Metastatic Disease with Deep Neuroevolution.

Cancer centers have an urgent and unmet clinical and research need for AI that can guide patient management. A core component of advancing cancer treatment research is assessing response to therapy. Doing so by hand, for example, as per RECIST or RANO criteria, is tedious and time-consuming, and can miss important tumor response information. Most notably, the prevalent response criteria often exclude lesions, the non-target lesions, altogether. We wish to assess change in a holistic fashion that includes all lesions, obtaining simple, informative, and automated assessments of tumor progression or regression. Because genetic sub-types of cancer can be fairly specific and patient enrollment in therapy trials is often limited in number and accrual rate, we wish to make response assessments with small training sets. Deep neuroevolution (DNE) is a novel radiology artificial intelligence (AI) optimization approach that performs well on small training sets. Here, we use a DNE parameter search to optimize a convolutional neural network (CNN) that predicts progression versus regression of metastatic brain disease. We analyzed 50 pairs of MRI contrast-enhanced images as our training set. Half of these pairs, separated in time, qualified as disease progression, while the other 25 image pairs constituted regression. We trained the parameters of a CNN via "mutations" that consisted of random CNN weight adjustments and evaluated mutation "fitness" as summed training set accuracy. We then incorporated the best mutations into the next generation's CNN, repeating this process for approximately 50,000 generations. We applied the CNNs to our training set, as well as a separate testing set with the same class balance of 25 progression and 25 regression cases. DNE achieved monotonic convergence to 100% training set accuracy. DNE also converged monotonically to 100% testing set accuracy. We have thus shown thatDNE can accurately classify brain metastatic disease progression versus regression. Future work will extend the input from 2D image slices to full 3D volumes, and include the category of "no change." We believe that an approach such as ours can ultimately provide a useful and informative complement to RANO/RECIST assessment and volumetric AI analysis.

Distinguishing Brain Metastasis Progression From Radiation Effects After Stereotactic Radiosurgery Using Longitudinal GRASP Dynamic Contrast-Enhanced MRI.

Differentiating brain metastasis progression from radiation effects or radiation necrosis (RN) remains challenging. Golden-angle radial sparse parallel (GRASP) dynamic contrast-enhanced MRI provides high spatial and temporal resolution to analyze tissue enhancement, which may differ between tumor progression (TP) and RN. To investigate the utility of longitudinal GRASP MRI in distinguishing TP from RN after gamma knife stereotactic radiosurgery (SRS). We retrospectively evaluated 48 patients with brain metastasis managed with SRS at our institution from 2013 to 2020 who had GRASP MRI before and at least once after SRS. TP (n = 16) was pathologically confirmed. RN (n = 16) was diagnosed on either resected tissue without evidence of tumor or on lesion resolution on follow-up. As a reference, we included a separate group of patients with non-small-cell lung cancer that showed favorable response with tumor control and without RN on subsequent imaging (n = 16). Mean contrast washin and washout slopes normalized to the superior sagittal sinus were compared between groups. Receiver operating characteristic analysis was performed to determine diagnostic performance. After SRS, progression showed a significantly steeper washin slope than RN on all 3 follow-up scans (scan 1: 0.29 ± 0.16 vs 0.18 ± 0.08, P = .021; scan 2: 0.35 ± 0.19 vs 0.18 ± 0.09, P = .004; scan 3: 0.32 ± 0.12 vs 0.17 ± 0.07, P = .002). No significant differences were found in the post-SRS washout slope. Post-SRS washin slope differentiated progression and RN with an area under the curve (AUC) of 0.74, a sensitivity of 75%, and a specificity of 69% on scan 1; an AUC of 0.85, a sensitivity of 92%, and a specificity of 69% on scan 2; and an AUC of 0.87, a sensitivity of 63%, and a specificity of 100% on scan 3. Longitudinal GRASP MRI may help to differentiate metastasis progression from RN.

CNSC-02. BREAST TO BRAIN METASTASIS IS EXACERBATED WITH CHEMOTHERAPY THROUGH BLOOD-CEREBRAL SPINAL FLUID-BARRIER AND INDUCES ALZHEIMER’S-LIKE PATHOLOGY

Abstract Control of breast to brain metastasis remains an urgent unmet clinical need. While chemotherapies are essential in reducing systemic tumor burden, they have also shown to promote non-brain metastatic invasiveness and drug-driven neurocognitive deficits through formation of neurofibrillary tangles (NFT) independently. Now, in this study we investigated the effect of chemotherapy on brain metastatic progression and promoting tumor-mediated NFT. Results show chemotherapies promote increased brain-barrier permeability and facilitate enhanced tumor infiltration, particularly through the blood-cerebrospinal fluid-barrier (BCSFB). This is attributed to increased expression of matrix metalloproteinase 9 (MMP9) which, in turn, mediates loss of Claudin-6 within the choroid plexus cells of the BCSFB. Importantly, increased MMP9 activity in the choroid epithelium following chemotherapy results in cleavage of Tau released from breast cancer cells. This cleaved Tau forms tumor-derived NFT that further destabilize the BCSFB. Our results underline for the first time the importance of the BCSFB as a vulnerable point of entry for brain-seeking tumor cells post-chemotherapy and indicate that tumor cells themselves contribute to Alzheimer’s-like tauopathy.

Selecting Optimal Timing of Cranial Radiotherapy Based on the Graded Prognostic Assessment for Lung Cancer Using Molecular Markers (Lung-molGPA) in Patients with Non-Small Cell Lung Cancer and Brain Metastases

<h3>Purpose/Objective(s)</h3> The updated Graded Prognostic Assessment for Lung Cancer Using Molecular Markers (Lung-molGPA) index will provide more accurate prediction of expected survival for patients with advanced non-small cell lung cancer (NSCLC) with brain metastases (BM). This retrospective study aims to evaluate optimal timing of cranial radiotherapy (RT) in NSCLC patients with BM stratified by Lung-molGPA index. <h3>Materials/Methods</h3> This study retrospectively screened patients with NSCLC and initially diagnosed BM in our cancer center between February 2012 and July 2018. These enrolled patients were scored and stratified based on lung-molGPA index. The primary endpoint was overall survival time (OS), defined as the interval from the initiation of BM diagnosis to death caused by any reason or the last follow-up. And the secondary endpoint was progression free survival (PFS), referred to the interval from the initiation of BM diagnosis to disease progression or death caused by any reason. The effect of radiotherapy timing on survival time in groups stratified by lung-molGPA index was evaluated. The early RT was defined as receiving RT within three months after initial diagnosis of BM with no progression of BM prior to RT. And the delayed RT was defined as receiving RT after progression of BM or initial diagnosis of BM three months later. <h3>Results</h3> Overall, 471 patients were enrolled in our study, including 260 patients receiving RT. The median follow-up time was 48 months. In entire cohort, median OS time and PFS were 15.0 and 9.0 months, respectively. In lung-molGPA0-2 group, OS of patients with or without RT was no statistical difference (HR, 0.78, 95%CI, 0.59-1.04, P=.071). While in lung-molGPA2.5-4 group, the addition of RT could prolong OS and PFS of patients (OS: HR, 0.51, 95%CI, 0.39-0.67, P<.001; and PFS: HR, 0.66, 95%CI, 0.51-0.85, P<.001). Moreover, in patients scored as 2.5-4.0, the median OS of early RT and delayed RT was 24.0 months and 15.0 months, respectively, and OS of patients receiving early RT was significantly superior to patients receiving delayed RT (HR, 0.50, 95%CI, 0.31-0.79, P<.001). While for patients scored as 0-2, no statistical difference was between OS of patients receiving early RT and delayed RT (HR, 0.75, 95%CI, 0.51-1.10, P=.115). <h3>Conclusion</h3> With regards as patients scored 2.5-4.0 based on lung-molGPA index, early addition of cranial radiotherapy could benefit patients' survival. While for patients scored 0-2, the survival benefit from cranial radiotherapy was limited.

Influence of temporal muscle thickness on the outcome of radiosurgically treated patients with brain metastases from non-small cell lung cancer.

The purpose of this study was to assess the impact of temporal muscle thickness (TMT), a surrogate marker for sarcopenia, in radiosurgically treated patients with brain metastases (BMs) from non-small cell lung cancer (NSCLC). For 566 patients with BMs from NSCLC in the period between June 2012 and December 2019, TMT values were retrospectively measured on the planning brain magnetic resonance imaging (MRI) studies that had been obtained before their first Gamma Knife radiosurgery treatment (GKRS1). Predefined sex-specific TMT cutoff values were used to stratify the study cohort into patients at risk for sarcopenia and patients with normal muscle status. Cox regression models adjusted for other prognostic parameters were used to evaluate sarcopenia as an independent prognostic factor. In sarcopenia patients with a TMT below the sex-specific cutoff values, the risk of death was significantly increased (HR 1.908, 95% CI 1.550-2.349, p < 0.001). In addition, sarcopenia was revealed as an independent prognostic factor even after adjusting for age groups, sex, number of BMs, presence of extracranial metastases, NSCLC subtypes, Karnofsky Performance Status groups, recursive partitioning analysis classes, and concomitant immunotherapy or targeted therapy (HR 1.680, 95% CI 1.347-2.095, p < 0.001). However, patients at risk for sarcopenia showed no significant differences in the estimated mean time until local BM progression after GKRS1, compared to patients with normal muscle status (p = 0.639). TMT obtained from planning MRI studies is an independent prognostic marker in radiosurgically treated patients with BMs from NSCLC and may aid patient stratification in future clinical trials.

MCP-1/CCR2 axis inhibition sensitizes the brain microenvironment against melanoma brain metastasis progression.

Development of resistance to chemo- and immunotherapies often occurs following treatment of melanoma brain metastasis (MBM). The brain microenvironment (BME), particularly astrocytes, cooperate toward MBM progression by upregulating secreted factors, among which we found that monocyte chemoattractant protein-1 (MCP-1) and its receptors, CCR2 and CCR4, were overexpressed in MBM compared with primary lesions. Among other sources of MCP-1 in the brain, we show that melanoma cells altered astrocyte secretome and evoked MCP-1 expression and secretion, which in turn induced CCR2 expression in melanoma cells, enhancing in vitro tumorigenic properties, such as proliferation, migration, and invasion of melanoma cells. In vivo pharmacological blockade of MCP-1 or molecular knockout of CCR2/CCR4 increased the infiltration of cytotoxic CD8+ T cells and attenuated the immunosuppressive phenotype of the BME as shown by decreased infiltration of Tregs and tumor-associated macrophages/microglia in several models of intracranially injected MBM. These in vivo strategies led to decreased MBM outgrowth and prolonged the overall survival of the mice. Our findings highlight the therapeutic potential of inhibiting interactions between BME and melanoma cells for the treatment of this disease.