Collagen deposition within brain metastases is associated with leptomeningeal failure after cavity-directed radiosurgery

Background

Leptomeningeal failure (LMF) represents a devastating progression of disease following resection of brain metastases (BrM). We sought to identify a biomarker at time of BrM resection that predicts for LMF using mass spectrometry-based proteomic analysis of resected BrM and to translate this finding with histochemical assays.

Methods

We retrospectively reviewed 39 patients with proteomic data available from resected BrM. We performed an unsupervised analysis with false discovery rate adjustment (FDR) to compare proteomic signature of BrM from patients that developed LMF versus those that did not. Based on proteomic analysis, we applied trichrome stain to a total of 55 patients who specifically underwent resection and adjuvant radiosurgery. We used competing risks regression to assess predictors of LMF.

Results

Of 39 patients with proteomic data, FDR revealed type I collagen-alpha-1 (COL1A1, P = .045) was associated with LMF. The degree of trichrome stain in each block correlated with COL1A1 expression (β = 1.849, P = .001). In a cohort of 55 patients, a higher degree of trichrome staining was associated with an increased hazard of LMF in resected BrM (Hazard Ratio 1.58, 95% CI 1.11-2.26, P = .01).

Conclusion

The degree of trichrome staining correlated with COL1A1 and portended a higher risk of LMF in patients with resected brain metastases treated with adjuvant radiosurgery. Collagen deposition and degree of fibrosis may be able to serve as a biomarker for LMF.

Outcomes of radiation-induced meningiomas treated with stereotactic radiosurgery

PURPOSE

Data on the efficacy and safety of stereotactic radiosurgery (SRS) for treatment of radiation-induced meningiomas (RIMs) are limited.

METHODS

A single institution database of Cobalt-60 SRS cases from 08/1999 to 10/2020 was reviewed. Radiation-induced meningiomas were identified using Cahan's criteria. Endpoints included overall survival (OS), progression free survival (PFS), local control (LC), treatment failure, and treatment toxicity. Univariate and multivariate analyses were performed using cox proportional hazard models.

RESULTS

A total of 29 patients with 86 RIM lesions were identified. Median follow-up after SRS was 59 months. The median dose prescribed to the 50% isodose line was 14 Gy (range 12-20 Gy). The actuarial 5-yr OS and PFS were 96% and 68%, respectively. Patients treated for recurrent RIMs had a significantly lower PFS (45% vs 94% at 3 yr, p < 0.005) than patients treated in the upfront setting. Patients with presumed or WHO grade I RIMs had a significantly greater PFS (3-year PFS 96% vs 20%) than patients with WHO grade II RIMs (p < 0.005). On a per-lesion basis, local control (LC) at 1-, 3-, and 5-yrs was 82%, 76%, 74%, respectively. On multivariate analysis, female gender was associated with improved LC (p < 0.001), while marginal doses > 14 Gy were associated with worse local control (p < 0.001). Grade I-III toxicity following treatment was 9.0%.

CONCLUSIONS

Stereotactic radiosurgery is a safe and effective treatment option for radiographic RIMs, WHO grade I RIMs, or lesions treated in the upfront setting. WHO grade II lesions and recurrent lesions are at increased risk for disease progression.

SURG-23. EFFICACY OF LASER INTERSTITIAL THERMAL THERAPY (LITT) FOR NEWLY DIAGNOSED AND RECURRENT IDH WILD-TYPE GLIOBLASTOMA

Treatment options for glioblastoma remain limited, particularly for those who are not eligible for traditional resection, whether due to lesion location or inability to tolerate open craniotomy. Maximal-safe resection followed by radiation with concurrent and adjuvant temozolomide offers the best outcomes for patients. Unfortunately, not all tumors are amenable to conventional surgical resection at the time of diagnosis with only about 1/3 of patients able to receive a gross-total resection and 15-25% of patients receiving biopsy only, thus reducing their projected overall survival to 9 months. Laser interstitial thermal therapy (LITT) is a minimally invasive, cytoreductive tool, that has demonstrated safety as a surgical approach to treat primary brain tumors.

METHODS

Data from LAANTERN prospective multicenter registry (NCT02392078) was analyzed to determine clinical outcomes for patients with new and recurrent IDH wild-type glioblastoma (N=89). Demographics, intraprocedural data, adverse events, KPS, health-economics, and survival data were prospectively collected then analyzed separately for newly diagnosed GBM (N=29) and recurrent GBM (N=60).

RESULTS

Median overall-survival was 9.73 months (95% CI: 5.16, 15.91) for newly diagnosed patients and median post-procedure survival was 8.97 (6.94, 12.36) months for recurrent patients. Median overall-survival for newly diagnosed patients receiving post-LITT chemoradiotherapy was 16.14 months (6.11, not reached). The median length of hospital stay was 50 hours and 80% of patients were discharged to home.

CONCLUSIONS

LITT offers an effective cytoreductive approach for patients with newly diagnosed and recurrent IDH wild-type glioblastoma. Importantly, its use in newly diagnosed patients who receive post-LITT chemoradiotherapy leads to a median OS similar to that of patients treated with conventional surgical resection. LITT remains an important alternative for patients with inoperable tumors or those not amenable to resection. Enrollment in LAANTERN is ongoing and these cohorts will be revisited as data continues to mature. Benefits beyond cytoreduction are also being actively explored.

RADT-16. CLINICAL OUTCOMES FOR HIGH RISK WHO GRADE II GLIOMA PATIENTS TREATED WITH UPFRONT TMZ-BASED CHEMORADIOTHERAPY

OBJECTIVE

RTOG 9802 demonstrated improved survival using chemoradiotherapy (CRT) over radiotherapy (RT) alone for WHO Grade II gliomas (LGG) using PCV with RT. We analyze our retrospective dataset of predominantly temozolomide (TMZ)-based CRT in LGG patients who would have been eligible for RTOG 9802.

METHODS

Retrospective review of LGG patients (2000–2017) treated at a single institution (67 patients). Histologies included oligodendroglioma(OD), astrocytoma(AC) or astrocytoma (OA). Those who received upfront RT +/- chemotherapy were included. The CRT cohort (n=40) consisted primarily of TMZ (n=36) administered concurrently with RT. 27 patients received RT alone. RT for both cohorts consisted of a median dose of 54 Gy (range 50.4 - 54 Gy). 65/67 patients had “high risk” LGG as defined by RTOG 9802 criteria. Kaplan Meier analysis was used to assess overall survival (OS) and progression free survival (PFS).

RESULTS

5-year PFS for patients receiving CRT was 64% vs. 44% in those receiving RT alone (log rank p=0.009). Difference in PFS due to chemotherapy was driven by AC histology (57% vs. 21% PFS at 5 years, log rank p=0.002) while OD/OA PFS was not statistically altered (79% vs. 72% PFS at 5 years, p=0.21). 5-year OS for patients receiving CRT was 76% vs. 69% in those receiving RT alone (p=0.11). Cox Proportional Hazards analysis showed that use of upfront CRT (HR=0.4, p=0.009) was the only factor that decreased the risk of earlier progression.

CONCLUSION

Use of upfront, predominantly TMZ-based CRT, has a PFS benefit over RT alone in a population of WHO grade II gliomas. This benefit appears to be driven by AC histology and also appears to extend beyond the “very high risk” cohort from RTOG 0424 to include the “high risk” group from RTOG 9802.

PTCH1 mutant small cell glioblastoma in a patient with Gorlin syndrome: A case report

Gorlin syndrome or nevoid basal cell carcinoma syndrome is a rare genetic disease characterized by predisposition to congenital defects, basal cell carcinomas and medulloblastoma. The syndrome results from a heritable mutation in PATCHED1 (PTCH1), causing constitutive activation of the Hedgehog pathway. The present study described a patient with Gorlin syndrome who presented early in life with characteristic basal cell carcinomas and later developed a small cell glioblastoma (GBM), World Health Organization grade IV, associated with a Patched 1 (PTCH1) N97fs*43 mutation. Comprehensive genomic profiling of GBM tissues also revealed multiple co-occurring alterations including cyclin-dependent kinase 4 (CDK4) amplification, receptor tyrosine-protein kinase 3 (ERBB3) amplification, a fibroblast growth factor receptor 1 and transforming acidic coiled-coil containing protein 1 (FGFR1-TACC1) fusion, zinc finger protein (GLI1) amplification, E3 ubiquitin-protein ligase (MDM2) amplification and spectrin α chain, erythrocytic 1 (SPTA1) T1151fs*24. After the biopsy, imaging revealed extensive leptomeningeal enhancement intracranially and around the cervical spinal cord due to leptomeningeal disease. The patient underwent craniospinal radiation followed by 6 months of adjuvant temozolomide (150 mg/m²) with good response. She was then treated with vismodegib for 11 months, first combined with temozolomide and then with bevacizumab, until disease progression was noted on MRI, with no significant toxicities associated with the combination therapy. She received additional therapies but ultimately succumbed to the disease four months later. The current study presents the first documentation in the literature of a primary (non-radiation induced) glioblastoma secondary to Gorlin syndrome. Based on this clinical experience, vismodegib should be considered in combination with standard-of-care therapies for patients with known Gorlin syndrome-associated glioblastomas and sonic hedgehog pathway mutations.

CTIM-13. PHASE 1 CLINICAL TRIAL OF ONCOLYTIC VIRAL IMMUNOTHERAPY WITH CAN-2409 + VALACYCLOVIR IN COMBINATION WITH NIVOLUMAB AND STANDARD OF CARE (SOC) IN NEWLY DIAGNOSED HIGH-GRADE GLIOMA (HGG)

BACKGROUND

CAN-2409 is a replication-deficient adenovirus that delivers HSV thymidine kinase to cancer cells, resulting in local conversion of orally administered valacyclovir into a toxic metabolite. Previously, a phase 1b/2 clinical trial of CAN-2409 combined with standard-of-care (SOC) demonstrated safety and improved survival in HGG patients. Addition of CAN-2409 to nivolumab has the potential to activate locally recruited lymphocytes and teach them to recognize tumor neoantigens, changing the ‘cold’ immunosuppressive tumor microenvironment, and synergizing with the activity mediated by immune checkpoint inhibitors. This notion is supported by preclinical experiments showing that the combination of CAN-2409 with anti-PD1 therapy was more effective than either treatment alone.

METHODS

This ongoing phase 1 clinical trial evaluates safety and initial efficacy of CAN-2409 combined with nivolumab and SOC in newly diagnosed HGG. CAN-2409 is injected during neurosurgery into the tumor bed, followed by 14-days of valacyclovir. Radiation starts within 8 (+/-4) days of surgery. Temozolomide is administered to MGMT-methylation positive patients only. Nivolumab is given every 2 weeks, up to 52-weeks. Deep immune profiling studies are ongoing and initial results will be available shortly.

RESULTS

From February 2019 to March 2021, 41 patients were enrolled and 35 were evaluable for safety from the combination of CAN-2409, nivolumab and SOC: 24 male and 11 female; 34 glioblastoma, 1 diffuse astrocytoma; 33 IDH-wildtype, 2 IDH-mutant; 15 MGMT-methylated, 20 unmethylated. Median age was 62-years (range 28-79), median KPS 90 (range 80-100). With 13 months median follow-up, no unexpected serious adverse events were observed, and 23 patients are still alive. The most frequent possibly related adverse events (&gt;10%) were nausea, fatigue, fever, headache, and increased ALT.

CONCLUSIONS

The combination of CAN-2409 + nivolumab + SOC was well tolerated. Clinical follow-up and extensive biomarker analyses will provide a better understanding of the therapeutic potential of this approach.

Convection-Enhanced Arborizing Catheter System Improves Local/Regional Delivery of Infusates Versus a Single-Port Catheter in Ex Vivo Porcine Brain Tissue

Standard treatment for glioblastoma is noncurative and only partially effective. Convection-enhanced delivery (CED) was developed as an alternative approach for effective loco-regional delivery of drugs via a small catheter inserted into the diseased brain. However, previous CED clinical trials revealed the need for improved catheters for controlled and satisfactory distribution of therapeutics. In this study, the arborizing catheter, consisting of six infusion ports, was compared to a reflux-preventing single-port catheter. Infusions of iohexol at a flow rate of 1 μL/min/microneedle were performed, using the arborizing catheter on one hemisphere and a single-port catheter on the contralateral hemisphere of excised pig brains. The volume dispersed (Vd) of the contrast agent was quantified for each catheter. Vd for the arborizing catheter was significantly higher than for the single-port catheter, 2235.8 ± 569.7 mm3 and 382.2 ± 243.0 mm3, respectively (n = 7). Minimal reflux was observed; however, high Vd values were achieved with the arborizing catheter. With simultaneous infusion using multiple ports of the arborizing catheter, high Vd was achieved at a low infusion rate. Thus, the arborizing catheter promises a highly desirable large volume of distribution of drugs delivered to the brain for the purpose of treating brain tumors.

LGG-21. MR-GUIDED LASER INTERSTITIAL THERMAL THERAPY FOR UNRESECTABLE AND SYMPTOMATIC PEDIATRIC LOW GRADE GLIOMA

BACKGROUND

Pediatric low-grade gliomas (LGG) not amenable to resection, while often indolent, represent a significant source of cancer-related morbidity and an unmet therapeutic need. Standardly, these patients are treated with sequential lines of chemotherapy, while delaying as long as possible radiation. Magnetic resonance-guided laser interstitial therapy (LITT) is a minimally invasive procedure that utilizes real-time MR thermography to ablate brain lesions.

METHODS

A 15-year-old girl was diagnosed with a suprasellar, hypothalamic LGG, BRAF V600E mutation positive. The tumor was unresectable, and due to progressive vision loss and headaches, the patient underwent treatment. Despite sequential trials of thioguanine/procarbazine/lomustine/vincristine, carboplatin/vincristine, dabrafenib, and combination dabrafenib/trametinib, the patient continued to experience debilitating headaches, malnutrition, school absenteeism, and overall poor quality-of-life. Using real-time, sequential MRI-thermometry and the Neuroblate cooled directional laser catheter, the bulk of the enhancing tumor was heated to a killing temperature.

RESULTS

At 1-year post LITT, the patient’s symptoms were dramatically improved, including greatly improved headaches, malnutrition, school absenteeism, and overall quality of life. LITT was generally well tolerated, though the patient had slight progressive left homonymous hemianopia, thought secondary to LITT impact on the optic tracts. The tumor progressively shrank over the year post-LITT to a peak of 42% volume reduction.

CONCLUSION

We report a case of a pediatric patient with an unresectable low grade glioma who underwent LITT with excellent clinical and radiographic effects. LITT should be considered for children with unresectable and morbid LGGs that fail to respond to more conventional therapies.

EXTH-34. PHASE I TRIAL OF CONVECTION-ENHANCED DELIVERY OF IL13RA2 AND EPHA2 RECEPTOR TARGETED CYTOTOXINS IN DOGS WITH SPONTANEOUS INTRACRANIAL GLIOMAS

The interleukin 13 receptor alpha 2 (IL13RA2) and ephrin type-A receptor 2 (EPHA2) receptors are attractive therapeutic targets, being expressed in ~90% of canine and human gliomas, and absent in normal brain. Clinical trials using an earlier generation IL-13 based cytotoxin showed encouraging clinical effects in human glioma, but met with technical barriers associated with the convection enhanced delivery (CED) method. In this study, IL-13 mutant and Ephrin-A1 (EFNA1)-based bacterial cytotoxins targeted to IL13RA2 and EPHA2 receptors, respectively, were administered locoregionally by CED to dogs with intracranial gliomas to evaluate their safety and preliminary efficacy. In this Phase I, 3 + 3 dose escalation trial, cytotoxins were infused by CED in 17 dogs with gliomas expressing IL13RA2 or EPHA2 receptors. CED was performed using a shape-fitting therapeutic planning algorithm, reflux-preventing catheters, and real-time intraoperative MRI-monitoring. The primary end point was to determine the maximum tolerated dose of the cytotoxic cocktail in dogs with gliomas. Consistent intratumoral delivery of the cytotoxic cocktail was achieved, with a median target coverage of 70% (range, 40–94%). Cytotoxins were well tolerated over a dose range of 0.012–1.278 mg/mL delivered to the target volume (median, 0.099 mg/mL), with no dose limiting toxicities observed. Objective tumor responses, up to 94% tumor volume reduction, were observed in 50% (8/16) of dogs, including at least one dog in each dosing cohort &gt;0.05 mg/mL. This study provides pre-clinical data fundamental to the translation of this multi-receptor targeted therapeutic approach to the human clinic.

NCOG-76. BASELINE COGNITIVE ASSESSMENT IN GLIOMA PATIENTS WITH MGMT PROMOTOR METHYLATION AND/OR 1p19q CODELETION

INTRODUCTION

Methylguanine methyltransferase (MGMT) methylation status is associated with better overall survival while 1p19q co-deletion is associated with long-term survival. Cognitive dysfunction is a common complication of brain tumors and treatment; however, information regarding the relationship between MGMT status, 1p19q codeletion, and cognition is limited.

METHOD

Baseline neuropsychological testing was performed in patients with malignant glioma prior to radiation and/or chemotherapy administration. A retrospective data analysis was conducted. We calculated composite and subdomain scores for attention/executive functioning, memory, and language in patients with or without MGMT promotor methylation and/or 1p19q codeletion.

RESULTS

Thirty-eight patients (Age M = 48.73 ± 14.98; 50% female) diagnosed with glioma (29% grade II, 16% grade III, 21% grade IV; Karnofsky Performance Status score (KPS) M = 88.75 ± 14.24) were selected from a retrospective. Memory was marginally significant, such that methylated participants performed better on memory tasks than the unmethylated group (p = .053). Independent samples t-test revealed no significant differences between either marker across the overall cognitive composite (methylated M = 41.35; unmethylated: M = 39.91; p = .955; 1p19q co-deleted: M = 50.94; 1p19q intact: M = 43.66; p = .158) and subdomains attention/executive functioning (p = .585; p = .157) and language (p = .581; p = .765). Logistic regression showed MGMT does not predict cognitive status (p =.052) and there were not enough cases to complete the model with 1p19q.

CONCLUSION

MGMT status may be correlated with baseline cognitive status as MGMT methylated patients had better memory scores than their unmethylated counterparts. We did not find any significant association between the remaining cognitive domains and MGMT or 1p19q although sample size is a significant limitation. These results suggest further assessment of changes in cognition during treatment through serial neuropsychological testing of glioma populations with defined marker status is warranted.

EPID-09. QUANTIFYING SOCIAL DETERMINANTS OF HEALTH AMONG GLIOMA PATIENTS

BACKGROUND

Social determinants of health (SDH) are modifiable factors that contribute to health outcomes. Despite studies linking SDHs with cervical, ovarian, and prostate cancer outcomes, few studies have explored SDHs in glioma patients. We conducted a cross-sectional survey to characterize and contextualize SDHs in glioma patients by community income, rural/urban residence, and treatment status.

METHODS

Two validated instruments: PRAPARE (Protocol for responding to and assessing patents’ assets risks and experiences) and AHC (accountable health communities instrument) quantified SDHs; along with study-specific supplemental questions. Risk scores were calculated and combined into an overall and domain-specific (economic, education, neighborhood environment, social context, and healthcare) SDH risk, with a higher score being indicative of higher SDH risk. Scores were compared between low-income (LIC) vs high-income (HIC) communities (defined by median household income), urban vs rural (defined by zip code), and active treatment vs surveillance (determined by patient medical record) using Wilcoxon rank-sum test.

RESULTS

100 glioma patients were enrolled: mean age 53 years (range: 22–78); 49% male; 18% oligodendroglioma, 34% diffuse astrocytoma, 38% glioblastoma, 10% other glioma; 68% resided in LICs, 27% in rural zip codes, and 51% were on active treatment. Overall, SDH risk scores were low (mean= 4.43-out-of-38). Scores in the healthcare domain were the highest. Compared to patients from LICs, patients from HICs had higher healthcare risk scores (p&lt; 0.05). Surveillance patients had higher overall SDH risk on the AHC than patients in active treatment (p&lt; 0.05), with age being a confounder. In multivariable analysis, younger age, and astrocytoma histology were associated with higher social health risk.

CONCLUSION

Glioma patients report relatively few SDH risk factors on standardized instruments designed for general clinic populations. The higher health risk observed in patients in HICs and higher AHC risk for those in surveillance will be further explored in planned qualitative analysis.

EXTH-23. MULTIVALENT TARGETED CYTOLYTIC AGENTS FOR GLIOBLASTOMA TREATMENT

Glioblastoma (GBM) complexity and heterogeneity requires treatment that addresses those pathobiological features. We have been developing selective cytotoxic agents able to target at the same time several GBM-associated factors. The chosen targets are responsible for the disease progression and/or recurrence as well as for resistance to the existing therapies. As a proof of concept, a Phase I clinical trial of a cytotoxic cocktail targeting IL-13RA2 and EphA2 receptors demonstrated dramatic anti-tumor responses in dogs with spontaneous gliomas that represent the closest translational model to human disease. To this end, we have developed multivalent agents that target four receptors specific to GBM: IL-13RA2, EphA2, EphA3, and EphB2, the combined expression of which covers virtually the whole tumor microenvironment. We have designed a multivalent protein termed QUAD 3.0 that contains an IgG1 scaffold, ephrinA5, which is a ligand for the EphA2, EphA3, and EphB2 receptors, and IL-13.E13K, a mutated version of interleukin 13 (IL-13), which binds preferentially to IL-13RA2. In QUAD 3.0, there is a cysteine at the C-terminal end of the protein to allow site-specific conjugation to cytotoxic cargo. QUAD 3.0 bound effectively to the four receptors in vitro and in vivo. QUAD 3.0 was conjugated to a modified form of Pseudomonas Exotoxin A (PE38QQR) and highly potent DNA binding agents based on modified doxorubicin (WP936, WP1737 and WP1244). All conjugates were highly cytotoxic to established and primary GBM cells with IC50s &lt; 50 nM. We also treated the first dogs with QUAD 3.0-PE38QQR and QUAD 3.0-WP936 at a dose of 1.6 mg/ml using real-time monitored convection-enhanced delivery and observed up to 60% of tumor shrinkage and long-term survival. Thus, multivalent targeted agents demonstrate highly promising anti-tumor activity as single pharmaceutical, off-the-shelf agents. We also expect that our targeted drug candidates produce immune responses against tumors amplifying their cytolytic anti-tumor effect

Community economic factors influence outcomes for patients with primary malignant glioma

Background

Community economics and other social health determinants influence outcomes in oncologic patient populations. We sought to explore their impact on presentation, treatment, and survival in glioma patients.

Methods

A retrospective cohort of patients with glioma (World Health Organization grades III-IV) diagnosed between 1999 and 2017 was assembled with data abstracted from medical record review. Patient factors included race, primary care provider (PCP) identified, marital status, insurance status, and employment status. Median household income based on zip code was used to classify patients as residing in high-income communities (HICs; ie, above the median state income) or low-income communities (LICs; ie, below the median state income). The Kaplan-Meier method was used to assess overall survival (OS); Cox proportional hazards regression was used to explore associations with OS.

Results

Included were 312 patients, 73% from LICs. Survivors residing in LICs and HICs did not differ by age, sex, race, tumor grade, having a PCP, employment status, insurance, time to presentation, or baseline performance status. Median OS was 4.1 months shorter for LIC patients (19.7 vs 15.6 mo; hazard ratio [HR], 0.75; 95% CI: 0.56-0.98, P = 0.04); this difference persisted with 1-year survival of 66% for HICs versus 61% for LICs at 1 year, 34% versus 24% at 3 years, and 29% versus 17% at 5 years. Multivariable analysis controlling for age, grade, and chemotherapy treatment showed a 25% lower risk of death for HIC patients (HR, 0.75; 95% CI: 0.57-0.99, P < 0.05).

Conclusions

The economic status of a glioma patient's community may influence survival. Future efforts should investigate potential mechanisms such as health care access, stress, treatment adherence, and social support.

Multireceptor targeting of glioblastoma

BACKGROUND

Treatment for glioblastoma (GBM) remains an unmet need in medicine. Novel therapies that address GBM complexity and heterogeneity in particular are warranted. To this end, we target 4 tumor-associated receptors at a time that span virtually all of the GBM microenvironment including bulk tumor cells, infiltrating tumor cells, neovasculature, and tumor-infiltrating cells with one pharmaceutical agent delivering a cytotoxic load.

METHODS

We engineered multivalent ligand-based vector proteins termed QUAD with an ability to bind to 4 of the following GBM-associated receptors: IL-13RA2, EphA2, EphA3, and EphB2. We conjugated QUAD with a modified bacterial toxin PE38QQR and tested it in vitro and in vivo.

RESULTS

The QUAD variants preserved functional characteristics of the respective ligands for the 4 receptors. The QUAD 3.0 variant conjugate was highly cytotoxic to GBM cells, but it was nontoxic in mice, and the conjugate exhibited strong antitumor effect in a dog with spontaneous GBM.

CONCLUSION

The QUAD addresses, to a large extent, the issues of intra- and intertumoral heterogeneity and, at the same time, it targets several pathophysiologically important tumor compartments in GBM through multiple receptors overexpressed in tumors allowing for what we call "molecular resection." QUAD-based targeted agents warrant further pre- and clinical development.

NCMP-11. THE CANCER AND COGNITION CLINIC AT WAKE FOREST BAPTIST HOSPITAL: SATISFYING AN UNMET NEED

Preservation of cognitive functioning is a top priority for brain tumor patients but is often not addressed in a systematic manner. To address this unmet need, we established a virtual neurocognitive clinic within our brain tumor center. The aim was to incorporate standardized neuropsychological examinations into routine care. To make neuropsychological testing achievable for patients with primary brain tumors, we developed a one-hour battery to measure core cognitive functions. We established a process where patients are offered cognitive testing at initial consult by neuro-oncology or radiation oncology. To reduce the burden of an extra appointment, patients are seen by neuropsychology in the Cancer Center (as opposed to the main hospital). Appointments are coordinated on the same day as other essential visits. Results are reviewed in multidisciplinary tumor boards. When possible, patients are seen for serial cognitive assessments at 3, 6 and 12 months after RT treatment. Providers in neuro-oncology, neurosurgery, and radiation oncology were encouraged to refer survivors to neuropsychology. After the clinic launch in 2017, 143 brain tumor patients were referred to neuropsychology. Prior to the clinic launch, 22 referrals were made over a comparable timeframe. Cognitive deficits were identified in most patients. After testing, patients received education on the brain-function relationship pertaining to their deficits. The patients’ referring provider received a full report containing recommendations for interventions based on testing outcomes 11 of the 38 patients who underwent pre-treatment assessments underwent testing 6 months post-RT. With the recent addition of a dedicated clinical coordinator, the rate of successful post-treatment cognitive evaluation is increasing. The cognitive, emotional, behavioral, and psychosocial impact of a brain tumor can be difficult to categorize and treat without formal evaluation. Integrating neuropsychological examination into routine care has resulted in a massive increase in the number of brain tumor patients getting a neuropsychologic assessment.

C-51 Long Term Neuropsychological Follow-Up of Radiation Induced Cognitive Decline (RICD) in Cerebellar Medulloblastoma

Objective

We expanded upon an early case study suggesting long-term, sequential neurocognitive evaluation and academic interventions following pediatric cerebellar medulloblastoma. This five-year-old patient (now forty) has indeed undergone lifespan assessment and clearly benefitted from appropriate interventions to date.

Method

This left-handed, white, male is status post (s/p) gross total resection and whole brain radiation. In adulthood, he developed radiation necrosis with hemorrhage and refractory seizures (s/p right temporal lobectomy). More recently, radiation induced bilateral parietal meningiomas were identified (s/p gamma knife).

Results

We analyzed cognitive, medical/oncological, imaging and interventional data at developmentally meaningful time points and found consistent declines in intellectual skills and cognitive function spanning attention/concentration, processing speed, visual perceptual/organization and visually based learning/memory; however, we noted stabilization and even improvement in important areas. Areas of age-appropriate functioning were noted in expressive vocabulary, verbal abstract reasoning, delayed verbal memory, and problem-solving, among others.

Conclusions

Although some studies have addressed long-term outcomes in pediatric medulloblastoma, we provide a unique perspective to the literature by documenting serial neurocognitive findings in addition to interventions across the lifespan. Our findings suggest that appropriate academic interventions/neurocognitive rehabilitation strategies are in fact meaningful at the individual level and propose that a focus on strengths can improve outcomes. We propose that this previously recommended model of assessment/intervention truly become the available standard of care in all pediatric oncologic populations.

Surgical resection and postoperative radiosurgery versus staged radiosurgery for large brain metastases

PURPOSE

The purpose of this study was to retrospectively evaluate the new treatment paradigm of staged stereotactic radiosurgery (SRS) for the treatment of large brain metastases (BM) compared to the standard of surgical resection followed by SRS.

METHODS

We evaluated 78 patients with large BM treated 2012-2017 with surgical resection and postoperative SRS (surgery + SRS) or staged SRS separated by 1 month. Overall survival (OS) was estimated using the Kaplan Meier method and compared across groups using the log-rank test. Cumulative incidence of neurologic death and local and distant brain failure (LF, DBF) were estimated using competing risk methodology.

RESULTS

Forty patients were treated with surgery + SRS and 38 patients were treated with staged SRS. Median follow-up was 23.2 months (95% CI 20.5-39.3). Median OS was 13.2 months for staged SRS compared to surgery + SRS 9.7 months (p = 0.53). Cumulative incidence of neurologic death at 1 year was 23% after surgery + SRS, 27% after staged SRS (p = 0.69); cumulative incidence of LF at 1 year was 6% and 8% (p = 0.65) and 1-year DBF was 59% and 21% (p ≤ 0.01). Overall rates of leptomeningeal failure and radiation necrosis were similar between the groups (p = 0.63 and p = 1.0).

CONCLUSIONS

Though surgery and postoperative SRS is the standard, staged SRS represents an attractive treatment paradigm for treating large BM without sacrificing LC or survival, and potentially decreases DBF. Prospective studies are needed to validate these findings.

Ameliorating Spinal Cord Injury in an Animal Model With Mechanical Tissue Resuscitation

BACKGROUND

Traumatic spinal cord injury (SCI) is a major worldwide cause of mortality and disability with limited treatment options. Previous research applying controlled negative pressure to traumatic brain injury in rat and swine models resulted in smaller injuries and more rapid recovery.

OBJECTIVE

To examine the effects of the application of a controlled vacuum (mechanical tissue resuscitation [MTR]) to SCI in a rat model under several magnitudes of vacuum.

METHODS

Controlled contusion SCIs were created in rats. Vacuums of -50 and -75 mm Hg were compared. Analysis included open-field locomotor performance, magnetic resonance imaging (in vivo T2, ex vivo diffusion tensor imaging and fiber tractography), and histological assessments.

RESULTS

MTR treatment significantly improved the locomotor recovery from a Basso, Beattie, and Bresnahan score of 7.8 ± 1.9 to 11.4 ± 1.2 and 10.7 ± 1.9 at -50- and -75-mm Hg pressures, respectively, 4 weeks after injury. Both pressures also reduced fluid accumulations > 10% by T2-imaging in SCI sites. The mean fiber number and mean fiber length were greater across injured sites after MTR treatment, especially with treatment with -50 mm Hg. Myelin volume was increased significantly by 60% in the group treated with -50 mm Hg.

CONCLUSION

MTR of SCI in a rat model is effective in reducing edema in the injured cord, preserving myelin survival, and improving the rate and quantity of functional recovery.

ABBREVIATIONS

BBB, Basso, Beattie, and BresnahanDTI, diffusion tensor imagingFA, fractional anisotropyMTR, mechanical tissue resuscitationMTR50, mechanical tissue resuscitation with 50-mm Hg subatmospheric pressureMTR75, mechanical tissue resuscitation with 75-mm Hg subatmospheric pressureROI, region of interestSCI, spinal cord injury.

Mechanical tissue resuscitation at the site of traumatic brain injuries reduces the volume of injury and hemorrhage in a swine model

BACKGROUND

Traumatic brain injuries (TBIs) continue to be a devastating problem with limited treatment options. Previous research applying controlled vacuum to TBI in a rat model resulted in smaller injuries and more rapid recovery.

OBJECTIVE

To examine the effects of the application of a controlled vacuum (mechanical tissue resuscitation) to TBI in a large-animal model. The magnitude of vacuum, length of application, and length of delay between injury and the application of mechanical tissue resuscitation were investigated.

METHODS

Localized, controlled cortical injuries were created in swine. Vacuums of -50 and -100 mm Hg were compared. Mechanical tissue resuscitation for 3 or 5 days was compared. Delays of 0, 3, or 6 hours between the creation of the TBI and the initiation of mechanical tissue resuscitation were examined. Analysis included histological assessments, computed tomographic perfusion, and magnetic resonance imaging (T2, proton magnetic spectra).

RESULTS

A -100 mm Hg vacuum resulted in significantly smaller mean contused brain and hemorrhage volumes compared with -50 mm Hg and controls. Magnetic resonance spectra of treated animals returned to near baseline values. All 10 animals with 5-day mechanical tissue resuscitation treatment survived. Three of 6 animals treated for 3 days died after the discontinuation of treatment. A 3-hour delay resulted in similar results as immediate treatment. A 6-hour delay produced significant, but lesser responses.

CONCLUSION

Application of mechanical tissue resuscitation to TBI was efficacious in the large-animal model. Application of -100 mm Hg for 5 days resulted in significantly improved outcomes. Delays of up to 3 hours between injury and the initiation of treatment did not diminish the efficacy of the mechanical tissue resuscitation treatment.

Determination of a clinical value for the repair half-time (T1/2) of the trigeminal nerve based on outcome data from gamma knife radiosurgery for facial pain

Stereotactic radiosurgery (GKRS) using the Leksell Gamma Knife is a treatment option for patients with trigeminal pain. We analyzed a database of 326 GKRS procedures performed over 4.6 years at three discrete dose levels commonly described in the published literature. Logistic regression was used to model the logit of response as a function of treatment time. The resulting coefficient was converted to an estimated probability of response for the shortest and longest treatment times in clinical practice. The two estimated probabilities were then compared to yield the estimated difference in the biologically effective dose (BED) between the two doses, using a modified linear-quadratic model for stereotactic radiosurgery. This difference was used to back-calculate a clinical value for T(1/2), resulting in a range of 1.28-1.77 h for T(1/2). The biological model appeared to accurately predict that, given the doses and treatment times used in general clinical practice, there would be no significant difference in clinical outcome.

A phase II trial of thalidomide (Thal) and procarbazine (Pro) in adults with recurrent or progressive malignant gliomas (MG)

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Background: Thal and Pro are among the few agents with demonstrated activity against MG. A two-stage, phase II trial was initiated within the WFURB to establish the response rate of combination Thal-Pro in patients (pts) with recurrent or progressive MG. Methods: Eligibility included pt age = 18 with measurable tumor on contrast enhanced brain scans; KPS = 60; normal liver, kidney and hematologic function; and treatment with = 2 prior regimens. Pts were required to participate in the S.T.E.P.S. Program and mandated to comply with agreed upon measures to avoid conception. Protocol therapy included Pro 250mg/m2/d x 5d q 28days and Thal 200mg/day continuously. Intrapatient dose escalation of Thal was attempted (increase by 100mg/day weekly as tolerated) to a maximum of 800mg/day. All pts received daily pyridoxine(100mg), warfarin(1mg) and stool softeners/laxatives. MRI/CT scans were performed prior to each odd cycle (every 8 weeks) to assess response based upon changes in the products of the largest bidimensional tumor diameters. Quality of life questionnaires including the FACT-Br were performed at baseline and prior to each odd cycle in all treated pts. Results: 18 pts (11 male) were enrolled (median age 50, range 27–63). One pt refused any therapy and is excluded from the analysis. The 17 treated pts received 36 cycles (median 2) of therapy. The median maximum Thal dose achieved was 400mg (range 200–800). No complete or partial responses were seen; 1 pt (6%) experienced stable disease, 14 (82%) progressed as best response and 2 (12%) were not evaluable for response. Median time to progression was 2.1 months (95% CI, 1.5–2.5). 14 pts have died; median survival was 7.6 months (95% CI, 3.5–9.4). Grade 3/4 drug related toxicity was minimal. Conclusions: Despite modest individual response rates in multiple prior phase II and III trials, the combination of Pro and Thal demonstrated no efficacy in this trial and this combination is unworthy of further investigation in pts with MG. Supported by NCI 1 U10 CA81851 and Celgene.

No significant financial relationships to disclose.

A phase I open-label, dose-escalation, multi-institutional trial of injection with an E1B-Attenuated adenovirus, ONYX-015, into the peritumoral region of recurrent malignant gliomas, in the adjuvant setting

ONYX-015 is an oncolytic virus untested as a treatment for malignant glioma. The NABTT CNS Consortium conducted a dose-escalation trial of intracerebral injections of ONYX-015. Cohorts of six patients at each dose level received doses of vector from 10(7) plaque-forming units (pfu) to 10(10) pfu into a total of 10 sites within the resected glioma cavity. Adverse events were identified on physical exams and testing of hematologic, renal, and liver functions. Efficacy data were obtained from serial MRI scans. None of the 24 patients experienced serious adverse events related to ONYX-015. The maximum tolerated dose was not reached at 10(10) pfu. The median time to progression after treatment with ONYX-015 was 46 days (range 13 to 452 + days). The median survival time was 6.2 months (range 1.3 to 28.0 + months). One patient has not progressed and 1 patient showed regression of interval-increased enhancement. With more than 19 months of follow-up, 1/6 recipients at a dose of 10(9) and 2/6 at a dose of 10(10) pfu remain alive. In 2 patients who underwent a second resection 3 months after ONYX-015 injection, a lymphocytic and plasmacytoid cell infiltrate was observed. Injection of ONYX-015 into glioma cavities is well tolerated at doses up to 10(10) pfu.

Vagus nerve stimulation for essential tremor

Objective: To assess the safety and efficacy of vagus nerve stimulation (VNS) for essential tremor (ET).

Methods: This was a pilot open-treatment trial at three centers, with masked videotape tremor assessments. Inclusion required a severity score of 3 or 4 on the Tremor Rating Scale (TRS) in one or both hands. At baseline, tremor was assessed with TRS and Unified Tremor Rating Assessment (UTRA), accelerometry, and a videotape protocol. The VNS device was implanted with leads placed around the left cervical vagus nerve. Stimulation was adjusted over 4 weeks before the repeat tremor assessments. Two raters masked to the study visit scored the videotapes.

Results: Nine subjects participated, with a mean age of 65 years and a mean age at onset of tremor of 24. Investigators rated hand tremor as mildly improved (TRS 2.3 ± 0.7 during VNS vs 3.0 ± 0.4 during baseline, p = 0.06). Accelerometry-measured total power improved 50.2 ± 31.8% (p < 0.01). Videotape tremor scores were highly correlated between the masked raters and revealed no changes in tremor scores with treatment. VNS was well tolerated, with the most common adverse events being stimulation related.

Conclusions: VNS was judged by investigators to mildly improve upper extremity tremor. This finding was not confirmed in videotape scoring by masked raters. VNS is not likely to have a clinically meaningful effect on ET.

Dose escalation of carmustine in surgically implanted polymers in patients with recurrent malignant glioma: a New Approaches to Brain Tumor Therapy CNS Consortium trial

PURPOSE

This New Approaches to Brain Tumor Therapy CNS Consortium study sought to determine the maximum-tolerated dose (MTD) of carmustine (BCNU) that can be implanted in biodegradable polymers following resection of recurrent high-grade gliomas and the systemic BCNU exposure with increasing doses of interstitial BCNU.

PATIENTS AND METHODS

Forty-four adults underwent tumor debulking and polymer placement. Six patients per dose level were studied using polymers with 6.5%, 10%, 14.5%, 20%, and 28% BCNU by weight. Toxicities were assessed 1 month after implantation by a safety monitoring committee to determine whether subsequent escalations should occur. Nine additional patients were studied at the MTD to confirm safety. BCNU blood levels were obtained before and after polymer implantation.

RESULTS

No dose-limiting toxicities were identified at the 6.5%, 10%, or 14.5% dose levels, although difficulties with wound healing, seizures, and brain edema were noted. At the 20% dose, these effects seemed more prominent, and six additional patients were treated at this dose and tolerated treatment well. Three of four patients receiving the 28% polymers developed severe brain edema and seizures, and accrual to this cohort was stopped. Nine additional patients received 20% polymer, confirming this as the MTD. Maximum BCNU plasma concentrations with the 20% loaded polymers were 27 ng/mL. Overall median survival was 251 days.

CONCLUSION

The MTD of BCNU delivered in polymer to the surgical cavity is 20%. This polymer provides five times more BCNU than standard commercially available BCNU polymers and results in minimal systemic BCNU exposure. Additional studies are needed to establish the efficacy of high-dose BCNU polymers.

Radiation safety issues with high activities of liquid I-125: techniques and experience

The handling of a liquid radioactive source is a procedure that is uncommon for the average clinical medical physicist. A newly approved treatment device utilizes high activities of liquid I-125 solution as the source of radiation. The radiation safety issues and our experience utilizing high activity liquid I-125 sources are presented. To date we have treated 22 patients with infused activities ranging up to 26.8 GBq (724 mCi). The careful manipulation of such solutions is important to maintain a safe environment for the patients and the involved medical staff.