Leptomeningeal disease in melanoma: An update on the developments in pathophysiology and clinical care

Leptomeningeal disease (LMD) remains a major challenge in the clinical management of metastatic melanoma patients. Outcomes for patient remain poor, and patients with LMD continue to be excluded from almost all clinical trials. However, recent trials have demonstrated the feasibility of conducting prospective clinical trials in these patients. Further, new insights into the pathophysiology of LMD are identifying rational new therapeutic strategies. Here we present recent advances in the understanding of, and treatment options for, LMD from metastatic melanoma. We also annotate key areas of future focus to accelerate progress for this challenging but emerging field.

Postoperative Management of Recurrence After Radiosurgery and Surgical Resection for Brain Metastases and Predicting Benefit From Adjuvant Radiation

Stereotactic radiosurgery (SRS) is often used as upfront treatment for brain metastases. Progression or radionecrosis after SRS is common and can prompt resection. However, postoperative management strategies after resection for SRS failure vary widely, and no standard practice has been established. In this approved study, we retrospectively reviewed patients who received SRS for a brain metastasis followed by resection of the same lesion. We extracted patient-, disease-, and treatment-related variables and information on disease-related outcomes. Univariate and multivariate analyses of clinicopathologic variables were used to create a model to predict factors associated with local failure (LF). A total of 225 patients with brain metastases treated with SRS from 2009 to 2017 followed by surgical resection were identified. Overall, 65% of cases had gross total resection (GTR) on postoperative imaging review. Twenty-one patients (9.3%) received adjuvant radiation therapy to the surgical cavity, and 204 (90.7%) were observed. Of these 204 patients, 118 had GTR with evidence of tumor within the pathology specimen. With a median follow-up of 13 months after resection, 47 patients (40%) developed LF after surgery. After salvage resection of a brain metastasis initially treated with SRS, the observed LF rate was 40% among those who had a GTR and evidence of tumor on pathologic examination. This LF rate is sufficiently high that adjuvant radiation to the surgical bed after salvage resection should be considered in these cases when there is tumor in the pathology, even after a GTR.

Frameless Fractionated Linear Accelerator-Based Stereotactic Radiotherapy for Brain Metastases: Results of a Single-Arm Phase II Multi-Institutional Clinical Trial

PURPOSE/OBJECTIVE(S)

Stereotactic radiotherapy (SRT) yields high rates of local control for brain metastases while minimizing neurocognitive side effects. While advanced SRT platforms are widely available in urban centers, rural/suburban patients face geographic and socioeconomic barriers to access SRS. For this reason, we conducted a multi-institutional Phase 2 clinical trial to test the safety and efficacy of 3-5 fraction frameless fractionated stereotactic radiotherapy (FFSRT) for brain metastases in an integrated academic satellite network MATERIALS/METHODS: This IRB-approved Phase 2 trial was conducted for patients ≥18-years-old with 1-4 brain metastases. Brain metastases involving the optic pathway or brainstem were excluded. Gross tumor volume (GTV) was delineated with a volumetric brain MRI and planning target volume (PTV) was GTV + 2 mm margin. Radiation dose was based on GTV size: < 3.0 cm, 27 Gy in 3 fractions, and 3.0-3.9 cm, 30 Gy in 5 fractions. Toxicity was evaluated using the Common Terminology Criteria for Adverse Events (CTCAE) version 4.

RESULTS

Of 76 evaluable patients, the median age was 67 years, 56.6% were female, 82.9% were white/Caucasian and 89.6% had an Eastern Cooperative Oncology Group performance status ≤ 2. Most brain metastases were from lung cancer (51.3%) and breast cancer (15.7%). With median follow-up of 10 months, local control was 93%, median survival was 1.8 years (95% confidence interval (CI): 1.5-2.4 years), 1-year OS was 73.8% (95% CI: 0.59-0.84), and 2-year OS was 31% (95% CI: 0.12-0.52). There were no CTCAE Grade ≥ 3 protocol-related adverse events.

CONCLUSION

Outcomes of this trial compare favorably with contemporary SRT trials for brain metastases. FFSRT may provide opportunities to expand SRS access for underserved populations across the MDACC enterprise and in future clinical trials for brain metastases.

MD Anderson Phase III Randomized Preoperative Stereotactic Radiosurgery (SRS) vs. Postoperative SRS for Brain Metastases Trial

PURPOSE/OBJECTIVE(S)

Postoperative stereotactic radiation therapy/radiosurgery (SRT/SRS) is being evaluated in comparison to Preoperative SRT for brain metastases (mets) in a limited number of prospective clinical trials. Our objective is to address the significant knowledge gap concerning the logistics of preoperative SRT in comparison to postoperative SRT in a randomized controlled study.

MATERIALS/METHODS

Patients with brain mets with at least 1 surgically operable met were randomized (1:1) to Preop vs Postop SRT. In this abstract, we present non-primary endpoint data on the trial concept and logistics of treatment for this data safety monitoring board reviewed study. Patients enrolled had 1-2 lesions resected and <15 lesions treated at time of SRT to best reflect the standard population that receive SRT and surgery at our institution.

RESULTS

From 12/2018 to 12/2022, 99 patients with 1-2 operable brain mets were enrolled and randomized to Preop (n = 49) or Postop (n = 50) SRT. Males represented 56% of the cohort compared to females, and <25% were age 18-49 years, while 27%, 29, and 19% respectively were 50-59, 60-69, and > = 70. The most frequent histologies enrolled were lung (29%), renal cell (15%), melanoma (14%), and breast (11%) cancers. The majority of patients (83%) had 1-4 brain mets on their baseline MRI and 91% subsequently had a single lesion resected. Seventy-nine patients completed both SRT and surgery, while 9% received no therapy due to drop out before study therapy initiation. Among patients receiving both therapies in the combined cohort, 68% received a non-invasive stereotactic radiosurgery instrument to the randomized cavity lesion compared to 32% receiving LINAC based SRT. Treatment of the lesion or cavity with single fraction SRT was 51% in the Preop arm vs 31% in the Postop arm. Multi-fraction (3-5 SRT) was 67% in the Postop cohort in contrast to 47% in the Preop cohort. Time from randomization to RT was 5.6 days and 33.7 days in the Preop and Postop cohorts respectively, and for surgery was 10.2 days vs 12.9 days in the Postop vs Preop cohorts. The average time from RT to surgery was 7.3 days in the Preop arm and 23.5 days in the Postop arm (to allow for incisional healing time).

CONCLUSION

In one of the early initiated randomized prospective cohorts of Preop vs Postop SRT, we demonstrated logistical feasibility with an efficient clinical trial workflow for study treatment. Differences in Preop vs Postop logistics reflect clinical practice differences in time-to-treatment. Therapy with various modalities reflected real-world practice and possibly provider preferences in technique when addressing the nature of delineating cavities and changes in cavity volume with regard to fractionation. Independent of the primary outcomes, our data provides insights in the practical management of patients receiving these two modalities of therapy, and further data at the completion of trial will address relevant primary outcomes.

Hierarchical settlement behaviours of coral larvae to common coralline algae

Natural regeneration of degraded reefs relies on the recruitment of larvae to restore populations. Intervention strategies are being developed to enhance this process through aquaculture production of coral larvae and their deployment as spat. Larval settlement relies on cues associated with crustose coralline algae (CCA) that are known to induce attachment and metamorphosis. To understand processes underpinning recruitment, we tested larval settlement responses of 15 coral species, to 15 species of CCA from the Great Barrier Reef (GBR). CCA in the family Lithophyllaceae were overall the best inducer across most coral species, with Titanoderma cf. tessellatum being the most effective species that induced at least 50% settlement in 14 of the coral species (mean 81%). Taxonomic level associations were found, with species of Porolithon inducing high settlement in the genus Acropora; while a previously understudied CCA, Sporolithon sp., was a strong inducer for the Lobophyllidae. Habitat-specific associations were detected, with CCA collected from similar light environment as the coral inducing higher levels of settlement. This study revealed the intimate relationships between coral larvae and CCA and provides optimal coral-algal species pairings that could be utilized to increase the success of larval settlement to generate healthy spat for reef restoration.

Melanoma central nervous system metastases: An update to approaches, challenges, and opportunities

Brain metastases are the most common brain malignancy. This review discusses the studies presented at the third annual meeting of the Melanoma Research Foundation in the context of other recent reports on the biology and treatment of melanoma brain metastases (MBM). Although symptomatic MBM patients were historically excluded from immunotherapy trials, efforts from clinicians and patient advocates have resulted in more inclusive and even dedicated clinical trials for MBM patients. The results of checkpoint inhibitor trials were discussed in conversation with current standards of care for MBM patients, including steroids, radiotherapy, and targeted therapy. Advances in the basic scientific understanding of MBM, including the role of astrocytes and metabolic adaptations to the brain microenvironment, are exposing new vulnerabilities which could be exploited for therapeutic purposes. Technical advances including single-cell omics and multiplex imaging are expanding our understanding of the MBM ecosystem and its response to therapy. This unprecedented level of spatial and temporal resolution is expected to dramatically advance the field in the coming years and render novel treatment approaches that might improve MBM patient outcomes.

NEIM-06 COMBINING CLINICAL VARIABLES AND RADIOMIC FEATURES TO HELP DISTINGUISH RADIATION NECROSIS FROM TUMOR IN PATIENTS WITH MELANOMA BRAIN METASTASES TREATED WITH RADIOSURGERY

BACKGROUND

Following Gamma Knife SRS (GK-SRS), the conventional imaging characteristics of radiation necrosis (RN) mimic those of tumor progression, introducing considerable uncertainty in diagnosis. Previous studies have identified clinical variables associated with RN; however, diagnosis primarily relied on interpretation of imaging with only a minority confirmed using the gold standard of pathological examination. Furthermore, the cohorts of these studies included a mix of primary histologies.

PURPOSE

To identify the combination of clinical variables and radiomic features most predictive of RN in patients with melanoma brain metastasis (BM) with GK-SRS in order to train a machine learning classifier to distinguish RN from tumor progression.

METHODS

We retrospectively studied 86 patients with a melanoma BM that received initial GK-SRS followed by resection, thereby pathologically confirming tumor or RN. Clinical variables including lesion volume, age at surgery, GK-SRS dose, lesion hemorrhage, lesion location, gender, BM velocity, and drug therapy type were obtained from chart review. We extracted radiomic features from contrast-enhanced T1-weighted MR images using PyRadiomics. A consensus clustering algorithm identified representative radiomic features. Non-parametric hypothesis testing was performed on the clinical variables and representative radiomic features.

RESULTS

Of the 86 patients, 17 (19.8%) patients exhibited RN and 69 exhibited tumor progression. Lesion volume was associated with development of RN (p = 0.038&lt;0.05) with a median volume of 1.5 cc (0.01-26.71 cc). Clustering analysis identified seven representative radiomic features; five were found to have statistically significant association with development of RN.

CONCLUSION

In this dataset with pathologically confirmed diagnoses in a histologically homogeneous patient cohort, we reproduced previously reported findings that the clinical variable of lesion volume is associated with RN and we identified several radiomic features associated with RN in patients with melanoma BM. We are using these variables and features to train a machine learning classifier to distinguish RN from tumor.

Exposure-response relationship between K. brevis blooms and reporting of upper respiratory and neurotoxin-associated symptoms

In southwest Florida, Karenia brevis (K. brevis) blooms occur frequently, can be very intense and persist over several years. Individuals living in coastal communities around the Gulf of Mexico are particularly vulnerable to brevetoxins released by K. brevis in seawater and carried inland within marine aerosol. Exposure to K. brevis occurs during residential, recreational, and occupational activities and has been associated with upper respiratory tract (URT) symptoms in healthy and medically vulnerable individuals. Additionally, ingestion of brevetoxin-contaminated seafood causes neurotoxic shellfish poisoning (NSP), and severe headaches prompting emergency department visits which occur in excess during K. brevis blooms. The current study examined a dose-response relationship between K. brevis in coastal waters and URT and NSP-like symptoms and headaches among southwest Florida residents. Data on past medical history (PMH) and medical symptoms were collected from the participants (n = 258) in five southwest Florida counties between June 2019 to August 2021. A dose-response relationship was observed between K. brevis blooms and reporting of URT and NSP-like symptoms and headaches. Reporting of NSP-like symptoms was higher among participants with a PMH of migraines, chronic fatigue syndrome (CFS) and mild memory loss, while the association of headaches with K. brevis blooms was accentuated among individuals with a PMH of migraines. These results suggest further investigations into the threshold of aerosolized brevetoxin dose required to elicit URT, headaches and/or NSP-like symptoms. These symptoms ultimately cause significant public health safety concerns, primarily among vulnerable populations with preexisting neurological conditions.

Abstract 3045: Distinct oral microbial signatures are associated with primary and metastatic brain tumors

Background: The role of microbiome in different steps of tumor development and progression has been shown across various tumor types. However, the contribution of microbiome to brain tumors is yet to be understood. A crosstalk between the gut and oral microbiota and the brain microenvironment has been demonstrated in the context of neurological and neurodegenerative diseases. We hypothesize that distinct gut and oral microbial signatures are associated with primary and metastatic brain tumors.

Methods: Matched stool, saliva, and buccal swab samples were collected prospectively from patients with primary or metastatic brain tumors who underwent surgical tumor resection at the University of Texas MD Anderson Cancer Center. Samples were collected using the OMNIgene microbiome collection and stabilization kits (DNAgenotek, Kit Number OM-200, OMR-120, and OM-505 for stool, buccal swab, and saliva, respectively). Samples were then processed, aliquoted, and stored at -80 C. Samples from 10 patients for each disease type were sequenced via metagenomic shotgun sequencing. Taxonomic profiling was conducted through MetaPhlAn and Virmap, for bacterial and viral taxa, respectively. Beta diversity was analyzed using Bray-Curtis and UniFrac analyses. Biom files were further analyzed to identify the signatures associated with each disease type, using the Phyloseq and Microbiome packages in R and heatmaps were generated using the Pheatmap package.

Results: Microbiome beta diversity analysis demonstrated distinct clustering of stool, saliva, and buccal swab samples in both primary and metastatic brain tumor patients, which confirmed high sample quality and lack of cross-contamination between buccal swab and oral samples during sample collection. Analysis of oral microbiome samples demonstrated distinct bacterial and viral signatures that were enriched in metastatic brain tumors in comparison to primary brain tumors. In contrast, the composition of gut microbial taxa was comparable between metastatic and primary brain tumors and demonstrated enrichment in Bacteroides and Microviridae families.

Conclusion: Our analysis of gut and oral microbiome in patients with primary and metastatic brain tumors suggest that distinct bacterial and viral taxa within the oral microbiome are enriched in metastatic brain tumors. We are in the process of expanding our clinical cohort to further validate these findings. Moreover, mechanistic studies are ongoing to understand the contribution of microbial signatures to the development and progression of metastatic and primary tumors. (These studies were supported by the National Institute of Health (F32CA260769) and the Glioblastoma Moonshot Program at the MD Anderson Cancer Center.)

Citation Format: Golnaz Morad, Matthew Lastrapes, Matthew Wong, Pranoti Sahasrabhojane, Sherise Ferguson, Nadim Ajami, Jennifer Wargo. Distinct oral microbial signatures are associated with primary and metastatic brain tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3045.

Absolute calibration of Fujifilm BAS-TR image plate response to laser driven protons up to 40 MeV

Image plates (IPs) are a popular detector in the field of laser driven ion acceleration, owing to their high dynamic range and reusability. An absolute calibration of these detectors to laser-driven protons in the routinely produced tens of MeV energy range is, therefore, essential. In this paper, the response of Fujifilm BAS-TR IPs to 1-40 MeV protons is calibrated by employing the detectors in high resolution Thomson parabola spectrometers in conjunction with a CR-39 nuclear track detector to determine absolute proton numbers. While CR-39 was placed in front of the image plate for lower energy protons, it was placed behind the image plate for energies above 10 MeV using suitable metal filters sandwiched between the image plate and CR-39 to select specific energies. The measured response agrees well with previously reported calibrations as well as standard models of IP response, providing, for the first time, an absolute calibration over a large range of proton energies of relevance to current experiments.

Calibration of BAS-TR image plate response to GeV gold ions

The response of the BAS-TR image plate (IP) was absolutely calibrated using a CR-39 track detector for high linear energy transfer Au ions up to ∼1.6 GeV (8.2 MeV/nucleon), accelerated by high-power lasers. The calibration was carried out by employing a high-resolution Thomson parabola spectrometer, which allowed resolving Au ions with closely spaced ionization states up to 58⁺. A response function was obtained by fitting the photo-stimulated luminescence per Au ion for different ion energies, which is broadly in agreement with that expected from ion stopping in the active layer of the IP. This calibration would allow quantifying the ion energy spectra for high energy Au ions, which is important for further investigation of the laser-based acceleration of heavy ion beams.

Abstract PD4-02: Safety and efficacy of a tucatinib-trastuzumab-capecitabine regimen for treatment of leptomeningeal metastasis (LM) in HER2-positive breast cancer: Results from TBCRC049, a phase 2 non-randomized study

Background: Treatment options for patients (pts) with leptomeningeal metastasis (LM) are limited, and the prognosis is poor (median overall survival (OS) ~ 4-5 months). Tucatinib is a potent and highly selective HER2-targeted tyrosine kinase inhibitor approved for use in combination with trastuzumab and capecitabine in pts with metastatic HER2+ breast cancer who have received ≥1 prior HER2-based regimen in the metastatic setting, including pts with brain metastases. TBCRC049 (NCT03501979) is an investigator-initiated, phase 2, single-arm study evaluating the safety and efficacy of tucatinib, trastuzumab and capecitabine in HER2+ breast cancer with newly diagnosed LM. We have previously demonstrated therapeutic levels of tucatinib in CSF in pts with HER2+ LM (Stringer-Reasor et al, ASCO 2021). We now report efficacy outcomes of the study. Methods: Eligible pts were adults with HER2+ metastatic breast cancer, Karnofsky performance status (KPS) &gt; 50, and newly diagnosed, untreated LM (defined as positive CSF cytology and/or radiographic evidence of LM, plus clinical signs/symptoms). Pts with treated or concurrent/new brain metastases were allowed. Pts received tucatinib 300 mg orally twice daily starting with cycle 1, day 1 (C1D1); capecitabine 1000 mg/m2 orally twice daily on days 1-14 of a 21-day cycle, starting on C1D1; and trastuzumab loading dose of 8 mg/kg IV on C1D1, and then 6 mg/kg IV once every 21 days, starting with C2D1. The primary endpoint was OS. Planned enrollment was 30 pts; however, due to lack of accrual since the FDA approval of tucatinib (4/2020), the study was closed after 17 patients were enrolled. Results: Baseline disease characteristics at LM diagnosis are shown in Table 1. Eight pts (47%) had abnormal CSF cytology (positive or equivocal). All pts had MRI evidence of LM in the brain, and 14/17 (82%) had brain metastases, of which 11 (65%) had received prior treatment for brain metastases. Median age at study treatment initiation was 53 years. Median number of treatment cycles received was 5 (range: 2-27). Median OS time was 11.9 months (95% CI: 4.1, NR). At data cutoff (6/22/21), 7/17 pts (41%) remained alive and median followup was 17 months(8-26). Median time to CNS progression was 6.9 months (95% CI: 2.8, 13.8). Conclusions: In pts with LMD from HER2+ metastatic breast cancer who were treated with tucatinib, trastuzumab, and capecitabine, the median OS time was nearly 1 year. This is the first prospective evidence of clinical benefit with a systemic regimen for HER2+ LM. Further studies evaluating brain-penetrant oral drugs in this rare pt population are needed.

Baseline Disease Characteristics (N=17)Number%Baseline CSF cytologyPositive529%Negative847%Equivocal318%None obtained1*6%Symptoms attributable to LMDYes1588%No212%MRI evidence of LMDBrain only1165%Brain and Spine635%History of brain metastasisYes1482%Prior treatment1165%New/concurrent diagnosis – no prior treatment318%No318%Extra-CNS DiseaseYes1165%No635%*One patient had VP shunt and difficulty sampling fluid; all CSF sent for research PK and non-PK studies

Citation Format: Rashmi K Murthy, Barbara O'Brien, Donald A Berry, Akshara Singareeka-Raghavendra, Maria Gule Monroe, Jason Johnson, Jason White, Jennifer Childress, Justin Sanford, Jill Schwartz-Gomez, Michelle Melisko, Aki Morikawa, Sherise Ferguson, John F de Groot, Ian Krop, Vicente Valero, Mothaffar Rimawi, Antonio Wolff, Debu Tripathy, Nancy U Lin, Erica Stringer-Reasor. Safety and efficacy of a tucatinib-trastuzumab-capecitabine regimen for treatment of leptomeningeal metastasis (LM) in HER2-positive breast cancer: Results from TBCRC049, a phase 2 non-randomized study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD4-02.

CNTM-04. Alterations in structural connectomic properties associated with neurocognitive changes following glioma resection

BACKGROUND

Patients with brain tumors often experience decline in neurocognitive functioning (NCF) following surgical tumor resection. Connectomic studies have begun to uncover how abnormalities to underlying cerebral networks contribute to NCF deficits; however, few studies have investigated relationships between pre- to postoperative changes in structural connectomics and NCF.

METHODS

Fifteen right-handed adults with left perisylvian tumors underwent MRI of the brain with diffusion tensor imaging (DTI) and neuropsychological assessment before and after awake tumor resection. Graph theoretical analysis was applied to DTI-derived connectivity matrices to calculate structural network properties. Structural network properties and NCF measures were compared across the pre- to postoperative periods with matched pairs Wilcoxon signed-rank tests. Associations between pre- to postoperative change in network properties and change in NCF were determined with Spearman rank-order correlations (ρ).

RESULTS

Nearly 90% of the sample showed postoperative decline on 1 or more NCF measures. Significant postoperative NCF decline was found across measures of verbal memory, processing speed, executive functioning, receptive language, and the Clinical Trial Battery Composite (CTB COMP) index. Regarding connectomic properties, significant postoperative changes were observed in global and local efficiency, characteristic path length, clustering coefficient, betweenness centrality, and assortativity, with medium effect sizes. Significant associations (ρ = .59 to .62, all p &lt; .05) were observed between changes in aspects of NCF and connectomic properties.

CONCLUSIONS

Decline in NCF was common following resection and some postoperative outcomes were associated with changes in structural connectomic properties following surgery.

RADT-13. EARLY CONCURRENT IMMUNOTHERAPY WITH STEREOTACTIC RADIOSURGERY IS ASSOCIATED WITH PROLONGED SURVIVAL AND DECREASED DISTANT BRAIN FAILURE IN PATIENTS WITH NEWLY DIAGNOSED MELANOMA BRAIN METASTASES (MBM)

INTRODUCTION

We evaluated outcomes of patients with newly diagnosed MBM treated with concurrent immune checkpoint inhibition (ICI) and stereotactic radiosurgery (SRS) (concurrentTx), defined as treatment delivery within 30 days of each other.

METHODS

Screening of 2,617 melanoma patients who received ICI (anti-CTLA4/anti-PD1/both) between 2011-2019 identified 151 pts who received concurrentTx for MBM. Among these, 51 had newly-diagnosed MBM and received no prior ICI or SRS, and were included in the current study. Overall survival (OS) and distant brain failure (DBF) were estimated using the Kaplan-Meier method. Incidence of radiation necrosis (RN) was captured.

RESULTS

Median follow up from treatment initiation (either ICI or SRS, whichever occurred first) was 37 months. Median OS was 30 months. Median interval between ICI/SRS was 12 days (range: 1-29). Twenty-two patients received ICI first and 29 received SRS first, without differences in OS (p=0.22), DBF (p=0.91), or development of RN (p=0.86). However, the interval between ICI and SRS was significant. Patients who received concurrentTx 1-11 days apart (n=25, “early”) experienced a significant improvement in OS and DBF compared to 12-29 days apart (n=26, “delayed”) (p=0.01, HR 2.8; 95%CI 1.3-6.2 for OS and p=0.02, HR 2.5; 95%CI 1.2-5.6 for DBF). OS and DBF at 36 months were 67% vs. 26% and 60% vs. 27%, respectively, for the early vs. delayed groups. Time to concurrentTx as a continuous variable was significantly associated with DBF (p=0.02), but not OS (p=0.06). Although not significant, more patients developed RN in the early (26.0%) versus delayed (3.8%) group (p=0.07). No additional patient or treatment differences were identified.

CONCLUSIONS

Early concurrentTx was associated with prolonged OS and improved DBF in newly diagnosed MBM patients who did not receive prior CNS-directed therapy. This finding suggests therapeutic synergism related to combined early treatment and should be validated in a prospective clinical trial.

Profiling of patients with glioma reveals the dominant immunosuppressive axis is refractory to immune function restoration

In order to prioritize available immune therapeutics, immune profiling across glioma grades was conducted, followed by preclinical determinations of therapeutic effect in immune-competent mice harboring gliomas. T cells and myeloid cells were isolated from the blood of healthy donors and the blood and tumors from patients with glioma and profiled for the expression of immunomodulatory targets with an available therapeutic. Murine glioma models were used to assess therapeutic efficacy of agents targeting the most frequently expressed immune targets. In patients with glioma, the A2aR/CD73/CD39 pathway was most frequently expressed, followed by the PD-1 pathway. CD73 expression was upregulated on immune cells by 2-hydroxyglutarate in IDH1 mutant glioma patients. In murine glioma models, adenosine receptor inhibitors demonstrated a modest therapeutic response; however, the addition of other inhibitors of the adenosine pathway did not further enhance this therapeutic effect. Although adenosine receptor inhibitors could recover immunological effector functions in T cells, immune recovery was impaired in the presence of gliomas, indicating that irreversible immune exhaustion limits the effectiveness of adenosine pathway inhibitors in patients with glioma. This study illustrates vetting steps that should be considered before clinical trial implementation for immunotherapy-resistant cancers, including testing an agent’s ability to restore immunological function in the context of intended use.

Immune profiling of glioma patients reveals that the immune suppressive adenosine axis predominates but is refractory to modulation.

TMIC-60. COMPREHENSIVE SPATIAL CHARACTERIZATION OF IMMUNE CELLS IN THE CNS BRAIN TUMOR MICROENVIRONMENT

Previous immune profiling in brain tumors has mostly focused on the high-density tumor areas, and as such, little is known about the nature and types of immunological responses that occur across the tumor landscape, including at the tumor-central nervous system (CNS) interface. En bloc resections of glioblastomas (n=10) and CNS lung metastases (n=10) were oriented on slides as whole mount wedges spanning three anatomical areas including the invasive edge, tumor region, and necrotic core. Tumor segmentation was performed and regional differences were immunologically analyzed for 770 immune genes using the NanoString nCounter System with CIBERSORT analysis to delineate immune gene signatures. The analysis was validated using multiplex immunohistochemistry (IHC). The top upregulated immune genes in the GBM necrotic core were associated with macrophages, including the CD163 lineage marker, chemotactic factors (such as CCL18 and SAA1), and the phagocytosis stimulatory factors (such as IL-8 and MARCO). The necrotic core downregulates GBM antigens (such as IL13RA2 and MAGEB2), markers of dendritic cells (such as LILRA4), and immune stimulatory processes including MHC, IFN, IL-12, TNF, and ICOS expression. In direct contrast, the infiltrating edge of the GBM relative to the tumor is enriched with stimulators for NK cytotoxicity (i.e., CD244, the fractalkine receptor for immune cells), chemokines for thymocytes and dendritic cells, and immune stimulatory IL-12 receptors. Glioblastoma has rare focal isolated areas of CD3 T-cell reactivity within the tumor. Similar to GBM, the necrotic center of lung metastases is enriched in immune suppressive macrophages, as reflected by CD163 IHC staining and arginase expression; however, they are more frequently infiltrated with M1 macrophages. Yet the majority of lung cancers are more diffusely infiltrated with CD3 T cells, especially at the infiltrating edge. In general, we noted distinct inter- and intratumoral immune gene signatures, with macrophages dominating the brain tumors, especially the necrotic core.

LPTO-09. INTRATHECAL TOPOTECAN FOR LEPTOMENINGEAL METASTASIS IN SOLID TUMORS: THE MD ANDERSON EXPERIENCE

BACKGROUND: Leptomeningeal metastasis (LM) is a devastating complication of cancer resulting in progressive neurologic decline. Although intrathecal (IT) methotrexate and cytarabine are commonly used for solid tumor LM, we routinely use IT topotecan due to previously demonstrated similar efficacy and modest side effect profile. We report updated data on our experience. METHODS: We reviewed clinical records of patients with solid tumor LM treated with IT topotecan at MD Anderson Cancer Center from 2008–2018. Patient characteristics and course were summarized by descriptive statistics. Overall survival (OS) was estimated with Kaplan-Meier, and the association of KPS with OS evaluated with log-rank test. RESULTS: 138 patients were treated with IT topotecan. The median age was 54 years (range, 22–76), 81% were female. Breast cancer (62%) was the most common primary, then lung (21%), melanoma (4%). Median time from primary diagnosis to LM was 3.4 (range, 0.07–25.2) years. LM was diagnosed by CSF cytology alone in 8 (6%), MRI alone in 21 (15%), CSF+MRI in 108 (78%). Patients most commonly presented with headache (39%) or sensory changes (18%), and had a median KPS of 80 (range, 60–100). 66% had prior/concurrent brain metastasis. 71 patients (52%) received WBRT following LM diagnosis. 41% had adverse effects, most commonly nausea/vomiting (22%) and headache (20%). The majority were grade 1 (63%); 7 were grade 4 (2 Ommaya malfunctions and 5 infections). Patients received a median of 9 (range, 1–79) doses, most stopped due to CNS progression (42%). Median OS was 6.5 months (95% CI 4.7, 7.8). OS was 3.8 mos with KPS ≤70, vs. 7.5 mos with KPS >70 (p< 0.001). CONCLUSIONS: IT topotecan has a modest side effect profile. Patients with higher functional status at diagnosis had significantly better survival. This study supports the continued use of IT topotecan as a well-tolerated option for LM.

MLTI-10. ESTABLISHMENT OF A MULTIDISCIPLINARY BRAIN METASTASIS CLINIC TO FACILITATE PATIENT-CENTERED CARE AND COORDINATED RESEARCH

BACKGROUND: ~30% cancer patients develop brain metastases (BM), reflected by ~1600 BM patients treated at MD Anderson Cancer Center annually. With advances in systemic therapy and extracranial disease control, BM is a growing challenge. Multi-disciplinary BM management is critical and complex requiring coordination of multiple oncology sub-specialties. There is limited data on pragmatic clinic models to streamline and advance care. METHODS: Recognizing deficiency in BM treatment and research, a steering committee was formed at MDACC to establish an interdisciplinary BM clinic (BMC), with a multi-disciplinary BM research retreat held in 2016. The goal of BMC was to centralize patient referrals, improve patient outcomes and experience, and advance research by developing clinical trials and biomarker discovery programs. Meetings were held to address BMC format, workflow, EMR integration, data collection infrastructure, and staffing model. RESULTS: MDACC BMC clinic opened in 01/2019 with two half-day clinics staffed by neurosurgery, neuro-radiation oncology, neuro-radiology and medical/neuro oncology. A dedicated advanced practice provider screens the referrals according to a well-developed algorithm. A multidisciplinary conference is held immediately before each clinic where patient images are reviewed, cases are discussed and consensus recommendations are developed. The treatment plan and follow up appointments are arranged at the completion of the clinic visit to expedite care. ~50 patients have been seen with excellent patient satisfaction response and reduced time to treatment. ~20% patients had major change in treatment plan following multi-disciplinary evaluation. Additional efforts to develop a central BM database along with clinical and translational research programs are on-going. CONCLUSIONS: Establishment of a multi-disciplinary BMC to facilitate care and centralize research programs addresses a critical need for coordinated patient-centered BM management. This endeavor has enhanced patient experience through multi-specialty collaboration. Our program demonstrates the feasibility and effectiveness of a dedicated BMC in the treatment of this complex patient population.

LPTO-08. INTRATHECAL TRASTUZUMAB PLUS/MINUS IT TOPOTECAN FOR PATIENTS WITH HER2+ BREAST CANCER AND LEPTOMENINGEAL METASTASIS

BACKGROUND: Leptomeningeal metastasis (LM) is an aggressive complication of cancer. No standard therapies exist, although at our institution we commonly use IT topotecan in good-risk patients. We report our experience in patients with HER2+ breast cancer (BC) LM treated with intrathecal (IT) trastuzumab +/- IT topotecan. METHODS: We retrospectively reviewed records of patients managed with IT trastuzumab at MD Anderson Cancer Center from 2016–2019. Demographics, clinical course, and outcomes data (Kaplan-Meier) were collected and analyzed. RESULTS: 14 female patients (median age 49, range 33–67) with HER2+ BC (29% hormone receptor (HR) positive, 71% negative) were treated with IT trastuzumab (titrated to 40 mg -100 mg/week); 8 (57%) received concurrent IT topotecan. LM diagnosis was made in 64% by MRI alone, and 36% by both MRI and CSF cytology; 79% had brain metastases (BM), and of those, 55% (6/11) had active BM at LM diagnosis; 57% received WBRT prior to initiation of IT therapy. Median KPS was 90 (range, 60–100). Of those with initially positive cytology, 50% (4/8) converted to negative during treatment. MRI findings improved in 79%; 79% were symptomatic at diagnosis (most commonly ataxia, cranial neuropathy, headache); 70% (7/10) had symptom improvement on IT therapy. The only IT-associated symptom reported was mild nausea that occurred in 29%. Median time from diagnosis of metastatic BC was 10.7 mos. (range 0–83 mos); 36% had active extra-CNS disease and 86% received concurrent systemic therapy; 57% underwent change in systemic therapy during IT treatment; 91% were progression-free at 6 months, 32% at 24 months. Median overall survival from LM diagnosis was 24.7 months (95% CI 10.7, NR). CONCLUSIONS: IT trastuzumab is a safe and promising therapy for patients with HER2+ BC and LM. Dual IT therapy with trastuzumab and topotecan was well-tolerated and warrants further investigation in a larger study.

Abstract 3040: Radiomics discriminates pseudo-progression from true progression in glioblastoma patients: A large-scale multi-institutional study

BACKGROUND: Treatment-related imaging changes are often difficult to distinguish from true tumor progression. Treatment-related changes or pseudoprogression (PsP) subsequently subside or stabilize without any further treatment, whereas progressive tumor requires a more aggressive approach in patient management. Pseudoprogression can mimic true progression radiographically and may potentially alter the physician's judgment about the recurrent disease. Hence, it can predispose a patient to overtreatment or be categorized as a non-responder and exclude him from the clinical trials. This study aims at assessing the potential of radiomics to discriminate PsP from progressive disease (PD) in glioblastoma (GBM) patients.

METHODS: We retrospectively evaluated 304 GBM patients with new or increased enhancement on conventional MRI after treatment, of which it was uncertain for PsP versus PD. 149 patients had the histopathological evidence of PD and 27 of PsP. Remaining 128 patients were categorized into PD and PsP based on RANO criteria performed by a board-certified radiologist. Volumetrics using 3D slicer 4.3.1 and radiomics texture analysis were performed of the enhancing lesion(s) in question.

RESULTS: Using the MRMR feature selection method, we identified 100 significant features that were used to build a SVM model. Five texture features (E, CS, SA, MP, CP) were found to be most predictive of pseudoprogression. On Leave One Out Cross-Validation (LOOCV), sensitivity, specificity and accuracy were 97%, 72%, and 90%, respectively. Using 70% of the patient data for training and 30% for validation, an AUC of 94% was achieved, with the sensitivity of 97% and specificity of 75%.

CONCLUSION: 3D radiomic texture features of conventional MRI successfully discriminated pseudoprogression from true progression in a large cohort of GBM patients.

Citation Format: Srishti Abrol, Aikaterini Kotrotsou, Ahmed Hassan, Nabil Elshafeey, Tagwa Idris, Naveen Manohar, Anand Agarwal, Islam Hassan, Kamel Salek, Nikdokht Farid, Carrie McDonald, Shiao-Pei Weathers, Naeim Bahrami, Samuel Bergamaschi, Ahmed Elakkad, Kristin Alfaro-Munoz, Fanny Moron, Jason Huse, Jeffrey Weinberg, Sherise Ferguson, Evangelos Kogias, Amy Heimberger, Raymond Sawaya, Ashok Kumar, John de Groot, Meng Law, Pascal Zinn, Rivka R. Colen. Radiomics discriminates pseudo-progression from true progression in glioblastoma patients: A large-scale multi-institutional study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3040.

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Profiling in wildlife crime: Recovery of human DNA deposited outside

Incidents of bird of prey persecution receive a lot of media coverage in the UK, with investigations rarely recovering sufficient evidence to proceed to prosecution. One of the main challenges is to identify a suspect, as these offences are carried out in remote locations without witnesses, and crime scenes may not be found for days. However, traps, poisoned baits and bird of prey carcasses can be recovered from these crime scenes. This study aimed to determine whether reportable human DNA profiles could be recovered from any of these substrates after periods of time outside. Experiments depositing human touch DNA on duplicate substrates (traps, rabbit baits and corvid carcasses) set for 0, 1, 2, 4, 7 and 10 days outside were carried out, with DNA recovery and profiling following standard operating procedures for Scottish Police Authority Forensic Services. Weather conditions varied among experiments, including some heavy rainfall. Results demonstrated that it was possible to obtain reportable DNA profiles from all substrates after at least 1 day outside. Most promisingly, the traps showed no drop-off in DNA persistence over the experiments as complete DNA profiles were obtained after the full 10 days outside. A further experiment using 4 bird of prey carcasses confirmed that it is possible to obtain reportable human DNA profiles from them after 1 day outside (n = 2 reportable profiles). These results show that touch DNA can persist in an outdoor environment, and provide a tantalising avenue for inquiry in bird of prey persecution investigations.

Variability in the primary emissions and secondary gas and particle formation from vehicles using bioethanol mixtures

Bioethanol for use in vehicles is becoming a substantial part of global energy infrastructure because it is renewable and some emissions are reduced. Carbon monoxide (CO) emissions and total hydrocarbons (THC) are reduced, but there is still controversy regarding emissions of nitrogen oxides (NO_x), aldehydes, and ethanol; this may be a concern because all these compounds are precursors of ozone and secondary organic aerosol (SOA). The amount of emissions depends on the ethanol content, but it also may depend on the engine quality and ethanol origin. Thus, a photochemical chamber was used to study secondary gas and aerosol formation from two flex-fueled vehicles using different ethanol blends in gasoline. One vehicle and the fuel used were made in the United States, and the others were made in Brazil. Primary emissions of THC, CO, carbon dioxide (CO₂), and nonmethane hydrocarbons (NMHC) from both vehicles decreased as the amount of ethanol in gasoline increased. NO_x emissions in the U.S. and Brazilian cars decreased with ethanol content. However, emissions of THC, CO, and NO_x from the Brazilian car were markedly higher than those from the U.S. car, showing high variability between vehicle technologies. In the Brazilian car, formation of secondary nitrogen dioxide (NO₂) and ozone (O₃) was lower for higher ethanol content in the fuel. In the U.S. car, NO₂ and O₃ had a small increase. Secondary particle (particulate matter [PM]) formation in the chamber decreased for both vehicles as the fraction of ethanol in fuel increased, consistent with previous studies. Secondary to primary PM ratios for pure gasoline is 11, also consistent with previous studies. In addition, the time required to form secondary PM is longer for higher ethanol blends. These results indicate that using higher ethanol blends may have a positive impact on air quality.

IMPLICATIONS

The use of bioethanol can significantly reduce petroleum use and greenhouse gas emissions worldwide. Given the extent of its use, it is important to understand its effect on urban pollution. There is a controversy on whether there is a reduction or increase in PM emission when using ethanol blends. Primary emissions of THC, CO, CO₂, NO_x, and NMHC for both cars decreased as the fraction of ethanol in gasoline increased. Using a photochemical chamber, the authors have found a decrease in the formation of secondary particles and the time required to form secondary PM is longer when using higher ethanol blends.

Risk factors associated with mortality at a milk-fed veal calf facility: A prospective cohort study

The veal industry experiences calf losses during the growing period, which represents a challenge to animal welfare and profitability. Health status at arrival may be an important predictor of calf mortality. The objectives of this prospective cohort study were to describe the health status of calves arriving at a veal farm and determine the risk factors associated with early and late mortality. Using a standardized health scoring system, calves were evaluated immediately at arrival to a commercial milk-fed veal facility in Ontario, Canada. Weight at arrival and supplier of the calf were recorded. The calves were followed until death or the end of their production cycle. Two Cox proportional hazard models were built to explore factors associated with early (≤21 d following arrival) and late mortality (>21 d following arrival). A total of 4,825 calves were evaluated from November 2015 to September 2016. The overall mortality risk was 7%, with 42% of the deaths occurring in the first 21 d after arrival. An abnormal navel, dehydration, housing location within the farm, arriving in the summer, and the presence of a sunken flank were associated with increased hazard of early mortality. Drover-derived calves and calves with a greater body weight at arrival had lower hazard of early mortality. Housing location within the farm, being derived from auction facilities, and an abnormal navel were associated with higher hazard of late mortality. These results demonstrate that risk factors for mortality can be identified at arrival, which represents a potential opportunity to selectively intervene on these calves to reduce mortality. However, methods of preventing the development of these conditions before arrival need to be explored and encouraged to improve the welfare of the calves entering the veal industry.

Post-operative stereotactic radiosurgery versus observation for completely resected brain metastases: a single-centre, randomised, controlled, phase 3 trial

Background

After brain metastasis resection, whole-brain radiation therapy (WBRT) decreases local recurrence but may cause cognitive decline. We performed this study to determine if stereotactic radiosurgery (SRS) to the surgical cavity improved local tumor tumor-free recurrence rates compared to surgical resection alone as an alternative to the need for immediate WBRT.

Methods

The main entry criteria for the study included patients >3 years of age, with a Karnofsky Performance Score ≥ 70, who were able to undergo an MRI scan and who had a complete resection of 1–3 brain metastases (the maximum diameter of the resection cavity had to be ≤4cm). Patients were assigned randomly to either SRS treatment of the resection cavity (within 30 days of surgery) or observation (OBS). Patients were stratified by histology, tumor size, and number of metastases. Patients were recruited at a single tertiary cancer center. The primary endpoint was time to local recurrence in the resection cavity assessed by blinded central review of brain MRI scans in the intention-to-treat population. The trial was registered at clinicaltrials.gov (Trial NCT00950001, status: closed to new participants).

Findings

Between 8/13/2009 and 2/16/2016, 132 patients were randomized to OBS (N=68) or SRS (N=64), with 128 patients available for analysis. We stratified by metastasis size (maximum diameter of ≥3 cm vs. <3 cm), histology (melanoma vs. other), and number of metastases (one vs. two or three). The 12-month local tumor recurrence-free rate was 43% (OBS) (95% CI 31%–59%) and 72% (SRS) (95% CI 60%–87%) (hazard ratio [HR] 0.46, 95% confidence interval [CI] 0.24–0.88, p=0.015).

Interpretation

This prospective randomized trial of patients undergoing surgical resection for 1–3 brain metastases indicates that SRS administered to the resection cavity significantly lowers local recurrence compared to observation alone. Thus, the use of SRS after brain metastasis resection is an alternative to WBRT.