Institutional Validation Study Inferring 2% MGMT Methylation Positive Impact on Survival in Newly Diagnosed Glioblastoma (GBM) Patients

PURPOSE/OBJECTIVE(S)

O6-methylguanine DNA methyltransferase (MGMT) MATERIALS/METHODS: is a well-established prognostic factor in patients with newly diagnosed glioblastoma (GBM). However, there is no consensus on a standardized method of threshold for MGMT testing. Previous studies have reported levels of as little as 1-3% to confer better prognosis. This study reports a single institutional experience of determining methylation status via methylation-sensitive high-resolution melting (MS-HRM). Previous literature suggests 10% cutoff for MGMT methylation using MS-HRM. We hereby report clinical outcomes using a lower threshold of 2%.

MATERIALS/METHODS

GBM patients treated at our institution retrospectively reviewed between the years 2013 and 2022 were included in the study. Patients who received hypofractionated radiation (<60 Gy) were excluded. All patients had MS-HRM test for MGMT methylation status. A real-time PCR assay was used to amplify a 62 base-pair region of MGMT for both methylated and unmethylated alleles. PCR products underwent HRM analysis and the fraction of methylated DNA was determined by comparison with a standard curve. Clinical data were collected retrospectively. Kaplan-Meier and log-rank tests were performed to compare survival.

RESULTS

A total of 181 patients with newly diagnosed GBM were initially included in this study. 42 patients treated with hypofractionated radiation were excluded. All patients received concurrent and maintenance temozolomide. Median age was 61.5 years. A total of 84 patients had MGMT methylation levels <2%, and 55 patients had MGMT methylation level ≥ 2% with a median methylation level of 28.5% (Range 0.8%-100%). Patients with MGMT methylation level ≥ 2% had an improved median overall survival (25.1 vs 16.0 months; p = 0.006) and improved median progression free survival (11.3 vs 7.9 months; p = 0.017). In a multivariable mode that included age, use of tumor-treating fields, KPS, sex, and BMI, only age, KPS, and MGMT remained significant.

CONCLUSION

Our institutional review confirmed low level of MGMT hypermethylation (≥ 2%) predicts improved outcome in patients with newly diagnosed GBM. Further investigation on optimal cut off level for MGMT methylation is still warranted.

Body Mass Index (BMI) at Time of Diagnosis as a Prognostic Indicator in Patients with Newly Diagnosed Glioblastoma (GBM)

PURPOSE/OBJECTIVE(S)

Glioblastoma (GBM) is the most common primary brain cancer in adults with very poor prognosis. Metabolic drivers of tumorigenesis are highly relevant within the central nervous system, where glucose is the sole source of energy. The impact of obesity on survival outcomes in patients with GBM has not been well reported and some initial results are inconsistent. This study investigates the factor of body mass index (BMI) in patients diagnosed with GBM. This study evaluated the prognostic association of BMI with survival outcomes in patients with newly diagnosed GBM.

MATERIALS/METHODS

Patientswith newly diagnosed GBM at our institution from 2015-2022 were included in this study. All patients were >18 years of age and received 60 Gy of radiation therapy with concurrent and adjuvant temozolomide following maximal safe resection. Through retrospective chart review, patient BMI at the time of diagnosis and overall survival (OS) were recorded. Analysis was done between patient groups of underweight/normal weight (BMI <25) and overweight/obese (BMI ≥ 25.00). The subgroup of overweight patients was also divided into subgroups of overweight (BMI 25.00-29.99) and obese (BMI≥30.00). A difference in clinical outcomes of overall survival was evaluated between the groups using Gehan-Breslow-Wilcoxon and log-rank tests.

RESULTS

Atotal of 393 patients met inclusion criteria. Median age 57.3 years, range 18.8-92.7. 185 female and 208 were male. 120 patients had a BMI <25 and 273 had a BMI ≥ 25.00. Median survival in patients with BMI <25 was 24.90 months and in patients with BMI ≥ 25.00, 18.20 months (p = 0.0001; HR 0.6552, 95% CI 0.5299-0.8101). We further divided patients with BMI ≥ 25.00 to 25-29.99 (n = 152) and BMI≥30.00 (n = 121). Both groups' OS were significantly worse than patients with BMI < 25 (p = 0.006). There was no difference in survival outcomes between patients with a BMI 25.00-29.99 and BMI≥30.00, with median OS 19.0 months and 18.1 months, respectively.

CONCLUSION

Patient baseline BMI <25 appears to be a prognostic indicator and correlates to improves overall survival for patients with newly diagnosed GBM. This study adds to the existing literature supporting overweight/obesity is associated with worse survival for GBM patients. Additional studies are warranted for further analysis of BMI and survival outcomes in GBM patients across patient demographics.

Differences in clinical outcomes based on molecular markers in glioblastoma patients treated with concurrent tumor-treating fields and chemoradiation: exploratory analysis of the SPARE trial

BACKGROUND

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. Despite enormous research efforts, GBM remains a deadly disease. The standard-of-care treatment for patients with newly diagnosed with GBM as per the National Cancer Comprehensive Cancer Network (NCCN) is maximal safe surgical resection followed by concurrent chemoradiation and maintenance temozolomide (TMZ) with adjuvant tumor treating fields (TTF). TTF is a non-pharmacological intervention that delivers low-intensity, intermediate frequency alternating electric fields that arrests cell proliferation by disrupting the mitotic spindle. TTF have been shown in a large clinical trial to improve patient outcomes when added to radiation and chemotherapy. The SPARE trail (Scalp-sparing radiation with concurrent temozolomide and tumor treating fields) evaluated adding TTF concomitantly to radiation and chemotherapy.

METHODS

This study is an exploratory analysis of the SPARE trial looking at the prognostic significance of common GBM molecular alterations, namely MGMT, EGFR, TP53, PTEN and telomerase reverse transcriptase (TERT), in this cohort of patients treated with concomitant TTF with radiation and chemotherapy.

RESULTS

As expected, MGMT promoter methylation was associated with improved overall survival (OS) and progression-free survival (PFS) in this cohort. In addition, TERT promoter mutation was associated with improved OS and PFS in this cohort as well.

CONCLUSIONS

Leveraging the molecular characterization of GBM alongside advancing treatments such as chemoradiation with TTF presents a new opportunity to improve precision oncology and outcomes for GBM patients.

RADT-19. CHEMORADIATION (CRT) TREATMENT WITH OR WITHOUT CONCURRENT TUMOR-TREATING FIELDS (TTFIELDS) IN PATIENTS WITH NEWLY DIAGNOSED GLIOBLASTOMA (GBM)

OBJECTIVES

Standard of care for newly diagnosed glioblastoma after resection includes concurrent temozolomide (TMZ) and radiation therapy followed by adjuvant TTF with maintenance TMZ. Preclinical studies suggest TTF and radiotherapy work synergistically. We evaluate the benefit of concurrent TTF with CRT vs adjuvant TTF with TMZ after CRT.

METHODS

Concurrent TTF with CRT patients were enrolled in a single-arm pilot study (clinicaltrials.gov Identifier: NCT03477110). For the comparison control of adjuvant TTF, adult patients with newly diagnosed GBM that had a KPS ≥ 60 who received treatment with CRT and adjuvant TMZ + TTF from three institutions were included. The adjuvant TTF cohort excluded patients who progressed during CRT or did not receive TMZ. PFS and OS were compared between groups.

RESULTS

A total of 87 patients were included in this study, of which 30 received concurrent TTF with CRT. Median patient age was 58 in the concurrent TTF group and 59 in the adjuvant TTF group. The median KPS in both groups was. MGMT methylation was present in 33.3% of the concurrent TTF and 32.0% in the adjuvant TTF group. 40% received GTR in the concurrent group and 38% received GTR in the adjuvant group. Multifocal disease was appreciated in 40% of patients in the concurrent TTF group. There was no significant difference in median OS (p=0.38) or PFS (p=0.76).

CONCLUSIONS

There was no difference in OS or PFS between concurrent or adjuvant TTF treatment groups. However, the adjuvant TTF group is expected to be a better prognosis due to the elimination of patients that progressed or declined after initial CRT. The current study suggested concurrent TTF treatment achieved outcomes to that of a better prognosis group. The survival benefit of concurrent TTF with CRT vs adjuvant TTF is being tested in the phase 3 TRIDENT EF-32 clinical trial (NCT04471844).

INNV-09. IMPACT OF MOLECULAR MARKERS ON TREATMENT OUTCOME OF GLIOBLASTOMA PATIENTS TREATED WITH CONCURRENT TUMOR-TREATING FIELDS (TTF) AND CHEMORADIATION: SECONDARY ANALYSIS OF SPARE TRIAL

OBJECTIVES

SPARE trial (Scalp-sparing radiation with concurrent temozolomide and tumor treating fields; NCT03477110) is a single-arm pilot study that evaluated the safety and feasibility of concurrent TTF with chemoradiation for adult patients with newly diagnosed GBM. The current study is a secondary analysis evaluating the impact of molecular markers (PTEN, TP53, EGFR, and TERT) on overall survival (OS) and progression-free survival (PFS) of the patients in the trial.

METHODS

Molecular markers of histologically-confirmed, IDH-wildtype GBM patients age ≥ 18 years old with a KPS ≥ 60 who received concurrent chemoradiation and TTF followed by maintenance TMZ + TTF were evaluated. Molecular profile was evaluated with next-generation sequencing. Impact of mutations in PTEN, TP53, EGFR, and TERT on OS and PFS was evaluated using a multivariable backward model.

RESULTS

A total of 30 patients were enrolled in the SPARE trial, and 1 patient with IDH-mutant was excluded from the current analysis. All patients underwent concurrent TTF and chemoradiation. The median age is 58 and KPS was 90. 9 patients had methylated MGMT promotor. 14 patients were found to have PTEN mutation, 9 patients with EGFR, 7 with TP53 mutation, and 23 patients with TERT mutated. MGMT methylation remained statistically significant for an increased OS (p=0.032; HR 7.18). TERT mutation had a statistically significant improvement in PFS (P=0.003) and OS (p=0.012). However, neither EGFR, TP53, nor PTEN showed any association of PFS or OS for patients who received concurrent TTF and CRT.

CONCLUSIONS

In this secondary analysis, patients with MGMT methylation showed better PFS and OS as expected. Neither EGRF, TP53, or PTEN mutation showed any association with PFS or OS. Patients with TERT mutant showed improved OS of patients treated with concurrent TTF with chemoradiation. A TERT mutation may be a new molecular biomarker in the described treatment approach.

Scalp-Sparing Radiation With Concurrent Temozolomide and Tumor Treating Fields (SPARE) for Patients With Newly Diagnosed Glioblastoma

Introduction

Standard-of-care treatment for patients with newly diagnosed glioblastoma (GBM) after surgery or biopsy includes concurrent chemoradiation followed by maintenance temozolomide (TMZ) with tumor treating fields (TTFields). Preclinical studies suggest TTFields and radiotherapy work synergistically. We report the results of our trial evaluating the safety of TTFields used concurrently with chemoradiation.

Methods

This is a single-arm pilot study (clinicaltrials.gov Identifier: NCT03477110). Adult patients (age ≥ 18 years) with newly diagnosed glioblastoma and a Karnofsky performance score (KPS) of ≥ 60 were eligible. All patients received concurrent scalp-sparing radiation (60 Gy in 30 fractions) with TMZ (75 mg/m² daily) and TTFields (200 kHz). Maintenance therapy included TMZ and continuation of TTFields. Scalp-sparing radiation treatment was used to reduce radiation dermatitis. Radiation treatment was delivered through the TTFields arrays. The primary endpoint was safety and toxicity of tri-modality treatment within 30 days of completion of chemoradiation treatment.

Results

There were 30 patients enrolled, including 20 (66.7%) men and 10 (33.3%) women, with a median age of 58 years (range 19 to 77 years). Median KPS was 90 (range 70 to 100). A total of 12 (40%) patients received a gross total resection and 18 (60%) patients had a subtotal resection. A total of 12 (40%) patients had multifocal disease at presentation. There were 20 (66.7%) patients who had unmethylated O(6)-methylguanine-DNA-methyltransferase (MGMT) promotor status and 10 (33.3%) patients who had methylated MGMT promoter status. Median follow-up was 15.2 months (range 1.7 to 23.6 months). Skin adverse events were noted in 83.3% of patients, however, these were limited to Grade 1 or 2 events, which resolved spontaneously or with topical medications. The primary end point was met; no TTFields discontinuation occurred during the evaluation period due to high grade scalp toxicity. A total of 27 (90%) patients had progression, with a median progression-free survival (PFS) of 9.3 months (95% confidence interval (CI): 8.5-11.6 months). The 1-year progression-free survival was 23% (95% CI: 12%-45%). The median overall survival (OS) was 15.8 months (95% CI: 12.5 months-infinity). The 1-year overall survival was 66% (95% CI: 51%-86%).

Conclusions

Concurrent TTFields with scalp-sparing chemoradiation is a feasible and well-tolerated treatment option with limited toxicity. A phase 3, randomized clinical trial (EF-32, clinicaltrials.gov Identifier: NCT04471844) investigating the clinical benefit of concurrent TTFields with chemoradiation treatment is currently enrolling.

Clinical Trial Registration

Clinicaltrials.gov, identifier NCT03477110.

Impact of lymphopenia on survival for elderly patients with glioblastoma: A secondary analysis of the CCTG CE.6 (EORTC 26062-22061, TROG03.01) randomized clinical trial

Background

Lymphopenia may lead to worse outcomes for glioblastoma patients. This study is a secondary analysis of the CCTG CE.6 trial evaluating the impact of chemotherapy and radiation on lymphopenia, and effects of lymphopenia on overall survival (OS).

Methods

CCTG CE.6 randomized elderly glioblastoma patients (≥ 65 years) to short-course radiation alone (RT) or short-course radiation with temozolomide (RT + TMZ). Lymphopenia (mild-moderate: grade 1–2; severe: grade 3–4) was defined per CTCAE v3.0, and measured at baseline, 1 week and 4 weeks post-RT. Preselected key factors for analysis included age, sex, ECOG, resection extent, MGMT methylation, Mini-Mental State Examination, and steroid use. Multinomial logistic regression and multivariable Cox regression models were used to identify lymphopenia-associated factors and association with survival.

Results

Five hundred and sixty-two patients were analyzed (281 RT vs 281 RT+TMZ). At baseline, both arms had similar rates of mild-moderate (21.4% vs 21.4%) and severe (3.2% vs 2.9%) lymphopenia. However, at 4 weeks post-RT, RT+TMZ was more likely to develop lymphopenia (mild-moderate: 27.9% vs 18.2%; severe: 9.3% vs 1.8%; p<0.001). Developing any lymphopenia post-RT was associated with baseline lymphopenia (P < .001). Baseline lymphopenia (hazard ratio [HR] 1.3) was associated with worse OS (HR: 1.30, 95% confidence interval [CI] 1.05–1.62; P = .02), regardless of MGMT status.

Conclusions

Development of post-RT lymphopenia is associated with addition of TMZ and baseline lymphopenia and not with RT alone in patients treated with short-course radiation. However, regardless of MGMT status, only baseline lymphopenia is associated with worse OS, which may be considered as a prognostic biomarker for elderly glioblastoma patients.

EXTH-12. INHIBITION OF EPIDERMAL GROWTH FACTOR RECEPTOR AND PLATELET-DERIVED GROWTH FACTOR RECEPTOR-ALPHA EXERTS SYNERGISTIC EFFICACY IN GLIOBLASTOMA

Epidermal growth factor receptor (EGFR) alterations, including amplification and activating mutations, occur in more than half of GBM cases. EGFR is located on Chr. 7, and Chr. 7 gain is one of the earliest events precipitating gliomagenesis. EGFR inhibitors, monoclonal antibodies, vaccines, and CAR-T cells have failed in GBM due to intrinsic heterogeneity and receptor tyrosine kinase (RTK) bypass pathways that mediate therapeutic resistance. New targeted therapeutic approaches to leverage synergistic combinations are desperately needed to improve GBM prognosis. Using the TCGA and other GBM databases, we previously demonstrated that PDGFRA amplification in patients with EGFR-amplified GBM carries significantly worse survival. EGFR and PDGFRA co-expression occur in more than one-third of GBM patients. The PDGFRA ligand PDGFA is also located on Chr. 7, and its expression is significantly increased with Chr. 7 gain and EGFR copy number increase. Therefore, Chr. 7 gain inherently leads to co-activation of both EGFR and PDGFRA signaling. We used patient-derived glioblastoma cells with Chr. 7 gain to test combined inhibition of EGFR and PDGFRA in vitro. We found that combined inhibition of both EGFR and PDGFRA using FDA-approved EGFR-targeted agents (Erlotinib, Gefitinib, Dacomitinib, Neratinib, and Osimertinib) and Crenolanib, respectively, leads to synergistic cytotoxicity in vitro. Inhibition of either EGFR or PDGFRA led to receptor cross-activation, and EGF and PDGF-AA-induced RTK activation was blocked by Neratinib and Crenolanib. Immunoprecipitation experiments and proximity ligation assays demonstrated that combined inhibition prevents EGFR and PDGFRA heterodimerization and pathways of therapeutic resistance. This combined inhibition led to decreased activation of downstream signaling pathways, including PI3K and MAPK. We show that combined inhibition of EGFR and PDGFRA exerts synergistic cytotoxicity in GBM and prevents resistance pathways that emerge during single-agent targeted therapy. These pathways are targetable with FDA-approved agents that could be used in patients with GBM with Chr. 7 gain.

CTNI-19. CONCURRENT CHEMORADIATION AND TUMOR TREATING FIELDS (TTFields, 200 kHz) FOR PATIENTS WITH NEWLY DIAGNOSED GLIOBLASTOMA MAY INCREASE THE RATE OF DISTANT RECURRENCE

INTRODUCTION: Current standard of care for glioblastoma (GBM) includes concurrent chemoradiation and maintenance temozolomide (TMZ) along with Tumor Treating Fields (TTFields). Preclinical studies suggest TTFields and radiation treatment have synergistic effects. Secondary analysis of EF14 trial demonstrated TTFields treatment may increase the rate of distant recurrence. We report our experience evaluating areas of progression in our pilot clinical trial of concurrent chemoradiation with TTFields. METHODS: This is a single arm pilot study (clinicaltrials.gov Identifier: NCT03477110). Adult patients (age ≥ 18 years) with KPS ≥ 60 with newly diagnosed GBM were eligible. All patients received concurrent scalp-sparing radiation (60 Gy in 30 fractions), standard concurrent TMZ (75 mg/m2 daily), and TTFields. Maintenance therapy included standard TMZ and continuation of TTFields. Radiation treatment was delivered through TTFields arrays. Incidence and location of progression was documented. Distant recurrence was defined as recurrence more than 2 cm from primary enhancing lesion. RESULTS: A total of 30 patients were enrolled on the trial. Twenty were male, and ten were female, with median age 58 years (19-77 years). Median KPS was 90 (70-100). Median follow-up was 11.6 months (1.7-22.1 months). Twenty (66.7%) patients had an unmethylated MGMT promotor status and ten (33.3%) patients had a methylated promoter status. Twenty patients (66.7%) had progression, with median PFS of 9.1 months (range 1.6 to 12.9 months). Five patients (26%) of patient presented with distant recurrence, with median distance from primary lesion of 5.1 cm (2.26-9.12 cm). One infratentorial progression was noted. Another patient transferred care and location of progression is unknown. CONCLUSIONS: Concurrent chemoradiation with TTFields for patients with newly diagnosed glioblastoma may have increased incidence of distant recurrence. This finding is suggestive of improved local control of primary site. Further data are needed to validate this finding.

RADT-22. CONCURRENT TTFIELDS (200 KHZ) WITH CHEMORADIATION FOR PATIENTS WITH NEWLY DIAGNOSED GLIOBLASTOMA MAY INCREASE THE RATE OF PSEUDOPROGRESSION: ANALYSIS OF A PILOT CLINICAL TRIAL

OBJECTIVE

The standard of care for the adjuvant treatment of glioblastoma is concurrent chemoradiation, maintenance temozolomide, and Tumor Treating Fields (TTFields). TTFields may reversibly impact the blood-brain barrier, most significantly at 100 kHz. We hypothesized that this may increase the rate of pseudoprogression (PsP) in patients who receive concurrent chemoradiation with TTFields (200 kHz).

METHODS

This is a single arm pilot study (clinicaltrials.gov Identifier: NCT03477110). Patients with newly diagnosed glioblastoma, age ≥ 18 years, and KPS ≥ 60 were eligible. They received concurrent temozolomide (75 mg/m2), scalp-sparing radiation (60 Gy in 30 fractions), and TTFields (200 kHz). Radiation was delivered through the TTFields arrays. PsP was defined as radiographic progression of enhancing lesions without clinical decline that improved or remained stable upon subsequent imaging. The rate of PsP was determined by an evaluation of the 2nd MRI at our multidisciplinary tumor board after the completion of trimodality treatment. These findings were confirmed with official radiology reports.

RESULTS

30 patients were enrolled. Of these, 29 had imaging available for evaluation. Male-to-female ratio was 20:10. Median follow-up was 11.6 months (1.6-22.4 months), median age was 58 years (19-77 years), and median KPS was 90 (70-100). 20 (66.7%) patients had unmethylated and 10 (33.3%) had methylated MGMT promotor. Median time from surgery to initiation of radiation was 34 days (26-49 days). Median time from completion of trimodality treatment to 2nd follow-up MRI was 90 days (29-109 days). 15/29 (51.7%) patients had PsP. Patients with methylated and unmethylated MGMT promotor had 50.0% (5/10) and 52.6% (10/19) rates of progression respectively.

CONCLUSIONS

51.7% of the patients who received concurrent chemoradiation with TTFields demonstrated PsP. The incidence is greater than historical reports. However, these findings should be explored in larger cohorts as this study was limited by a small sample size.

RADT-13. SPARE TRIAL: SCALP-SPARING RADIATION WITH CONCURRENT TEMOZOLOMIDE AND TUMOR TREATING FIELDS FOR PATIENTS WITH NEWLY DIAGNOSED GLIOBLASTOMA

INTRODUCTION

Current adjuvant treatment for patients with newly diagnosed glioblastoma includes concurrent chemoradiation and maintenance temozolomide with Tumor Treating Fields (TTFields). We report our clinical trial evaluating feasibility and tolerability of scalp-sparing radiation with concurrent temozolomide and TTFields.

METHODS

Adult patients (age ≥ 18 years) with newly diagnosed glioblastoma with a KPS of ≥ 60 were eligible. All patients received concurrent scalp-sparing radiation (60 Gy in 30 fractions) with temozolomide (75 mg/m2 daily) and TTFields (200 kHz). Maintenance therapy included temozolomide and continuation of TTFields. Radiation treatment was delivered through TTFields arrays. The primary endpoint was safety and toxicity of tri-modality treatment within 30 days of completion of chemoradiation treatment.

RESULTS

Thirty patients were enrolled. Twenty were male and ten were female, with a median age of 58 years (range 19 to 77 years). Median follow-up was 10.8 months (range 1.6 to 21.3 months). Twenty (66.7%) patients had unmethylated MGMT promotor and ten (33.3%) patients had methylated promoter. Scalp dose constraints were achieved for all patients. Skin adverse events (erythema, dermatitis, irritation, folliculitis) were noted in 83.3% of patients, however, these were limited to Grade 1 or 2 events, which resolved spontaneously or with topical medications. No patient had radiation treatment interruption due to skin AEs. Other Grade 1 events included pruritus (33.3%), fatigue (30%), nausea (13.3%), headache (10%), dizziness (6.7%), and cognitive impairment (3.3%). Other Grade 2 events included headache (3.3%). The median PFS for the entire cohort was 9.1 months (at least 8.5 months, 95% confidence). The median PFS for patients with MGMT promoter methylation status was 11.4 months (at least 9.5 months, 95% confidence). Overall survival was not reached.

CONCLUSIONS

Concurrent TTFields with scalp-sparing chemoradiation is feasible treatment option with limited toxicity. Future randomized prospective trials are warranted to define therapeutic advantages of concurrent TTFields with chemoradiation.

Prognostic implications of epidermal and platelet-derived growth factor receptor alterations in 2 cohorts of IDHwt glioblastoma

Background

Glioblastoma remains a deadly brain cancer with dismal prognosis. Genetic alterations, including IDH mutations, 1p19q co-deletion status and MGMT promoter methylation have been proven to be prognostic and predictive to response to treatment in gliomas. In this manuscript, we aimed to correlate other mutations and genetic alterations with various clinical endpoints in patients with IDH-wild-type (IDHwt) glioblastoma.

Methods

We compiled a comprehensive clinically annotated database of IDHwt GBM patients treated at the Ohio State University Wexner Medical Center for whom we had mutational data through a CLIA-certified genomic laboratory. We then added data that is publicly available from Memorial Sloan Kettering Cancer Center through cBioPortal. Each of the genetic alterations (mutations, deletions, and amplifications) served as a variable in univariate and multivariate Cox proportional hazard models.

Results

A total of 175 IDHwt GBM patients with available MGMT promoter methylation data from both cohorts were included in the analysis. As expected, MGMT promoter methylation was significantly associated with improved overall survival (OS). Median OS for MGMT promoter methylated and unmethylated GBM was 26.5 and 18 months, respectively (HR 0.45; P = .003). Moreover, EGFR/ERBB alterations were associated with favorable outcome (HR of 0.37 (P = .003), but only in MGMT promoter unmethylated GBM. We further found that patients with EGFR/ERBB alterations who also harbored PDGFRA amplification had a significantly worse outcome (HR 7.89; P = .025).

Conclusions

Our data provide further insight into the impact of genetic alterations on various clinical outcomes in IDHwt GBM in 2 cohorts of patients with detailed clinical information and inspire new therapeutic strategies for IDHwt GBM.

Assessment of Leptomeningeal Carcinomatosis Diagnosis, Management and Outcomes in Patients with Solid Tumors Over a Decade of Experience

Objective

Leptomeningeal carcinomatosis (LMC), a common complication of advanced malignancies, is associated with high morbidity and mortality, yet diagnosis and treatment decisions remain challenging. This study describes the diagnostic and treatment modalities for LMC and identifies factors associated with overall survival (OS).

Materials and Methods

We performed a single-institution retrospective study (registration #: OSU2016C0053) of 153 patients diagnosed with LMC treated at The Ohio State University, Comprehensive Cancer Center, (OSUCCC)-James between January 1, 2010 and December 31, 2015.

Results

Median age at diagnosis was 55.7 years, and 61% had Eastern Cooperative Oncology Group baseline performance status ≤1. Most common primary tumors were breast (43%), lung (26%), and cutaneous melanoma (10%). At presentation, most patients were stage III-IV (71%) with higher grade tumors (grade III: 46%). Metastases to bone (36%), brain (33%), and lung (12%) were the most common sites with a median of 0.5 years (range, 0-14.9 years) between the diagnosis of first metastasis and of LMC. 153 (100%) patients had MRI evidence of LMC. Of the 67 (44%) who underwent lumbar puncture (LP), 33 (22%) had positive cerebrospinal fluid (CSF) cytology. Most patients received radiotherapy for LMC (60%) and chemotherapy (93%) for either the primary disease or LMC. 28 patients received intrathecal chemotherapy, 22 of whom had a primary diagnosis of breast cancer. 98% died with median OS of all patients was 1.9 months (95% CI: 1.3-2.5 months).

Conclusion

Despite improved treatments and targeted therapies, outcomes of LMC remain extremely poor. Positive CSF cytology was associated with lower OS in patients who had cytology assessed and specifically in patients with breast cancer. CSF cytology serves as an important indicator for prognosis and helps aid in developing individualized therapeutic strategies for patients with LMC.

Targeted Therapy for BRAF Mutant Brain Tumors

OPINION STATEMENT

Molecular heterogeneity has confounded attempts to target individual pathways in brain tumors. However, gliomas with BRAF mutations have been identified as being uniquely vulnerable to targeted therapies. Such mutations are predominantly seen in brain tumors of the adolescent and young adult population. Given that accurate and timely identification of such mutations is essential for offering appropriate treatment, treatment centers should offer both immunohistochemical and sequencing methods for detection of these mutations to guide treatment. Additional studies of these tumors at recurrence would also allow identification of breakthrough resistance mechanisms that may also be targetable for treatment. Due to the relative rarity of these tumors, multicenter collaborative studies will be essential in achieving long term control of these tumors.

P13.18 Inhibition of epidermal growth factor receptor and platelet-derived growth factor receptor-alpha exerts synergistic efficacy in glioblastoma

BACKGROUND

Despite our understanding of the genetic changes that precipitate gliomagenesis, targeted therapy has failed in glioblastoma (GBM) with median survival not significantly improved over the past two decades. Epidermal growth factor receptor (EGFR) alterations, including amplification and activating mutations, are among the most common genetic changes in GBM, occurring in more than half of cases. EGFR is located on Chr. 7, and Chr. 7 gain is one of the earliest events precipitating gliomagenesis. Various EGFR inhibitors, including tyrosine kinase inhibitors, monoclonal antibodies, vaccines, and CAR-T cells have failed in GBM due to intrinsic heterogeneity and receptor tyrosine kinase bypass pathways that mediate therapeutic resistance. New targeted therapeutic approaches to leverage synergistic combinations are desperately needed to improve GBM prognosis. Using the TCGA and other GBM databases, we have previously demonstrated that the presence of PDGFRAamplification in patients with EGFR-amplified GBM carries significantly worse survival. EGFR and PDGFRA co-expression occur in more than one-third of GBM patients. The PDGFRA ligand PDGFA is also located on Chr. 7, and its expression is significantly increased with Chr. 7 gain and EGFR copy number increase. Therefore, Chr. 7 gain inherently leads to co-activation of both EGFR and PDGFRA signaling pathways.

MATERIALS AND METHODS

We used models of patient-derived glioblastoma cells to test combined inhibition of epidermal growth factor receptor and platelet-derived growth factor receptor-alpha in vitro.

RESULTS

Using patient-derived GBM models with Chr. 7 gain, we found that combined inhibition of both EGFR and PDGFRA using a variety of FDA-approved EGFR-targeted agents (Erlotinib, Gefitinib, Dacomitinib, Neratinib, and Osimertinib) and Crenolanib, respectively, leads to synergistic cytotoxicity in vitro. We found that inhibition of either EGFR or PDGFRA alone led to receptor cross-activation, and EGF and PDGF-AA-induced receptor tyrosine kinase activation was blocked by Neratinib and Crenolanib. Immunoprecipitation experiments and proximity ligation assays demonstrated that combined inhibition prevents EGFR and PDGFRA heterodimerization and pathways of therapeutic resistance. This combined inhibition led to decreased activation of downstream signaling pathways, including phosphatidylinositol 3-kinase and mitogen-activated protein kinase.

CONCLUSIONS

We show that combined inhibition of EGFR and PDGFRA exerts synergistic cytotoxicity in GBM and prevents resistance pathways that emerge during single-agent targeted therapy against these receptor tyrosine kinases. These pathways are targetable with FDA-approved agents that could be used in patients with GBM with Chr. 7 gain.

Scalp-sparing radiation with concurrent temozolomide and tumor treating fields (SPARE) for patients with newly diagnosed glioblastoma

2056

Background: Standard of care for patients with newly diagnosed glioblastoma includes concurrent chemoradiation and maintenance temozolomide with Tumor Treating Fields (TTFields). Preclinical studies suggest TTFields and radiation treatment have synergistic effects. We report our clinical trial evaluating safety and tolerability of scalp-sparing radiation with concurrent temozolomide and TTFields. Methods: This is a single arm pilot study. Adult patients (age ≥ 18 years) with newly diagnosed glioblastoma and a KPS of ≥ 60 were eligible. All patients received concurrent scalp-sparing radiation (60 Gy in 30 fractions) with temozolomide (75 mg/m2 daily) and TTFields (200 kHz). Maintenance therapy included temozolomide and continuation of TTFields. Radiation treatment was delivered through TTFields arrays. The primary endpoint was safety and toxicity of TTFields concurrent with chemoradiation in patients with newly diagnosed glioblastoma. Results: A total of 30 patients were enrolled in the trial. Twenty were male and ten were female, with a median age of 58 years (range 19 to 77 years). Median KPS was 90 (range 70 to 100). Median follow-up was 8.9 months (range 1.6 to 21.4 months). Twenty (66.7%) patients had unmethylated MGMT promotor status and ten (33.3%) patients had methylated promoter status. Median time from surgery to radiation was 34 days (26 to 49 days). Scalp dose constraints were achieved for all patients, with the mean dose having a median value of 8.3 Gy (range 4.3 to 14.8 Gy), the D20cc median was 26.1 Gy (range 17.7 to 42.8 Gy), and the D30cc median was 23.5 Gy (range 14.8 to 35.4 Gy). Skin adverse events (AEs; erythema, dermatitis, irritation, folliculitis) were noted in 83.3% of patients, however, these were limited to Grade 1 or 2 events, which resolved spontaneously or with topical medications. No patient had radiation treatment interruption due to skin AEs. Other Grade 1 events included pruritus (33.3%), fatigue (30%), nausea (13.3%), headache (10%), dizziness (6.7%), and cognitive impairment (3.3%). Other Grade 2 events included headache (3.3%). Nineteen patients (63.3%) had progression, with a median PFS of 7.6 months (range 1.6 to 12.7 months). Overall survival was not reached. Conclusions: Concurrent TTFields (200 kHz) with scalp-sparing chemoradiation is a safe and feasible treatment option with limited toxicity. Future randomized prospective trials are warranted to define therapeutic advantages of concurrent TTFields with chemoradiation. Clinical trial information: NCT03477110.

The role of VEGF receptor inhibitors in preventing cerebral radiation necrosis: a retrospective cohort study

Background

Radiation necrosis (RN) is a potential complication after radiation therapy for brain tumors. It is hypothesized that VEGF plays an important role in the pathophysiology of RN. Bevacizumab, a monoclonal antibody against VEGF-A, is often successful in the management of RN. The objective of this study is to assess whether VEGF receptor (VEGFR) inhibitors, a group of oral tyrosine kinase inhibitors (TKIs), can prevent or reverse RN.

Methods

We retrospectively studied a cohort of 102 patients with renal cell carcinoma and brain metastases seen at The Ohio State University James Cancer Center between January 1, 2011 and April 30, 2019. We identified those who developed RN and analyzed the temporal relationship between the use of VEGFR TKIs and the development of RN.

Results

The cumulative incidence of RN is 13.7% after radiation treatments that included LINAC-based stereotactic radiosurgery, fractionated stereotactic radiotherapy, or Gamma Knife radiosurgery. There was no statistically significant difference in the cumulative incidence of RN between patients taking TKIs and patients who were off TKIs (9.9% and 11.5% respectively, P = .741). The median time to development of RN was only numerically shorter in patients taking TKIs (151 vs 315 days, P = .315). One patient developed RN after stopping cabozantinib. Eight patients developed RN while on cabozantinib, pazopanib, or sunitinib. One patient was started on axitinib during active RN without significant improvement subsequently.

Conclusions

VEGFR TKIs do not consistently prevent RN. The therapeutic effects of VEGFR TKIs against RN warrant further research.

NCOG-42. INITIAL PRESENTATION AND OUTPATIENT VISIT COMPLIANCE OF INMATES WITH BRAIN TUMORS

INTRODUCTION

While advocacy for inmates with cancer has recently gained momentum, little is known about management of brain tumors in inmates. Delays in acknowledging or recognizing nonspecific initial symptoms can lead to delayed diagnosis and treatment. Inmates with cancer are reported to either be ignored or receive substandard care due in part to cost or logistics (American Civil Liberties Union; ASCO Post 2018).

METHODS

In this retrospective study, we identified inmates with gliomas seen in the Ohio State University Neuro-oncology Center between 1/1/2010-4/20/2019.

RESULTS

Twelve patients were identified. Median age at presentation was 39.5 years (range 28-62). Eleven patients were Caucasian and one was African American. Diagnoses included glioblastoma (GBM) (n=6), anaplastic astrocytoma (n=1), anaplastic oligodendroglioma (n=1), low-grade astrocytoma (n=3) and anaplastic pleomorphic xanthroastrocytoma (n=1). Patients were more likely to present early after seizures or focal neurologic deficits (9/12) than after headaches alone. Patients with GBM started RT 12-71 days after surgery (median 34.5). One patient’s post-RT MRI was delayed by a month and another with GBM had treatment held after 4 cycles of adjuvant temozolomide (TMZ) due to “incarceration issues”. For one patient who received adjuvant TMZ, the facility failed to communicate with the primary team throughout treatment. Two patients suffered significant nausea while on chemotherapy due to inability to obtain ondansetron in prison, or due to wrong timing. 7/12 (58%) patients were lost to follow-up for periods of 3-15 months during treatment. Three patients refused adjuvant treatment.

CONCLUSIONS

Although this is a small series, our results highlight the inequities and challenges faced by inmates with gliomas who are more likely to forego treatments or whose incarceration prevents them from keeping appropriate treatment and follow-up schedules. Additional studies are needed to define and address these deficiencies in the care of inmates with brain tumors and other cancers.

NCMP-01. THE ROLE OF VASCULAR ENDOTHELIAL GROWTH FACTOR RECEPTOR INHIBITORS IN PREVENTING CEREBRAL RADIATION NECROSIS: A RETROSPECTIVE COHORT STUDY

INTRODUCTION

Radiation necrosis (RN) is a potential complication after radiation therapy to primary brain tumors and brain metastases. The pathophysiology of RN is not well understood but it is hypothesized that vascular endothelial growth factor (VEGF) plays an important role. Bevacizumab, a monoclonal antibody against VEGF-A, is often successful in the management of RN. The objective of this study is to assess whether VEGF receptor (VEGFR) inhibitors, a group of oral tyrosine kinase inhibitors (TKIs), can prevent or reverse cerebral radiation necrosis

METHODS

We retrospectively studied a cohort of 102 patients with renal cell carcinoma (RCC) and brain metastases seen at The Ohio State University James Cancer Center between 01/01/2011 and 04/30/2019. We identified those who developed RN and analyzed the temporal relationship between the use of VEGFR TKIs and the development of RN.

RESULTS

The cumulative incidence of RN in our cohort is 13.7% after radiation treatments that included LINAC-based stereotactic radiosurgery, fractionated stereotactic radiotherapy, or Gamma Knife radiosurgery. There was no statistically significant difference in the cumulative incidence of RN between patients taking TKIs and patients who were off TKIs (9.9% and 11.5% respectively, p= 0.741). The median time to development of RN was only numerically shorter in patients taking TKIs (151 versus 315 days, p=0.315). One patient developed RN after stopping cabozantinib. Three other patients developed RN while on cabozantinib. Two patients developed RN while on pazopanib, and 3 patients developed RN while on sunitinib. One patient was started on axitinib during active RN without significant improvement subsequently.

CONCLUSIONS

VEGFR TKIs do not consistently prevent or reverse cerebral radiation necrosis and do not seem to have the efficacy that bevacizumab has against RN.

NCMP-12. RAPIDLY PROGRESSIVE NEUROPATHIES AS THE SOLE PRESENTATION OF NEUROLYMPHOMATOSIS

Neurolymphomatosis (NL) is a rare and challenging entity characterized by hematological neoplastic infiltration of the peripheral nervous system. Only 40% of the cases have malignant cells on CSF sampling. We present a 52-year-old Caucasian male with primary refractory diffuse large B-cell lymphoma (DLBCL) who relapsed within 3 months of achieving complete remission to R-CHOP. First, he experienced right tongue numbness and lumbar pain. Initial MRI of the face, brain and entire spine, and CSF analysis were unremarkable. Three weeks later, he noticed left facial numbness, dysphonia, and left leg weakness. Neuraxis MRI revealed enhancement of left CN V3 and several cervical, thoracic, and lumbar nerve roots. PET/CT showed increased uptake at L4 nerve root. EMG/NGS showed left L5 denervation. After one week, he further developed new right CN VI palsy, left-sided ptosis, anisocoria, and right arm weakness. Repeat MRI showed worsening enhancement and thickening of multiple cranial nerves, cervical and lumbosacral plexus. Extensive testing for infectious, inflammatory, and paraneoplastic processes was negative. Patient underwent plasmapheresis with no response. Biopsy of nerve root was deferred due to potential permanent deficits that would impair his quality of life. Repeat CSF testing was negative for malignancy and PET/CT showed SUV of 23.8 at L4-5 with multiple new hypermetabolic foci in muscle and ribs. He received R-HD-methotrexate with clinical and radiographic (PET/CT) improvement following 2 cycles. He completed 4 cycles of R-HD methotrexate-based chemotherapy followed by autologous hematopoietic stem cell transplantation. Most of his symptoms resolved and he remained stable for about a year when PET/CT showed disease progression. He subsequently received CAR-T cell therapy with adequate tolerance and remains clinically stable. Even with negative initial imaging and CSF studies, a careful exam and attention to uncommon presentations along with serial advanced imaging (MRI, PET/CT) surveillance are key to early detection and timely treatment.

NCMP-07. TREATMENT-INDUCED CEREBRAL NECROSIS IN GLIOMAS: THE OHIO STATE UNIVERSITY COMPREHENSIVE CANCER CENTER (OSUCCC) EXPERIENCE

INTRODUCTION

Treatment-induced cerebral necrosis (TN) is a challenging complication encountered in neuro-oncology. Diagnosis and treatment of TN remains poorly defined.

METHODS

In this single institution, retrospective study, consecutive patients with gliomas and TN between 01/01/2012 and 04/20/2020 at the OSUCCC were identified. Details of the tumor treatment, molecular markers, radiological and pathological findings of TN, as well as treatment, recurrence rate and management upon recurrence were collected.

RESULTS

Of the 53 patients analyzed, 37 had glioblastoma, 7 had anaplastic oligodendroglioma and 9 had grade II or III astrocytoma. MGMT promoter hypermethylation was present in 31/50 (59%) and IDH mutation in 17/53 (32%). Diagnosis of TN was based on histology in 43/53 (81%) or clinical/radiographic features in 10/53 (19%). Worsening of focal weakness (36%), seizures (9%) or being (30%) were common presentations at TN diagnosis. Patient with right compared to left hemisphere involvement were more symptomatic at TN diagnosis. (p=0.049). Bevacizumab (BEV) (51%), resection (28%), steroids only (9%) or Laser Interstitial Thermal Therapy (6%) were used to treat TN. Steroids were weaned off in 20/27 (74%) after receiving BEV. Among all treatments, BEV was significantly associated with a better outcome (resolution or partial improvement of enhancement in 84.6%) (p=0.0006, Bonferroni corrected p&lt; 0.005). TN Recurrence occurred in 36%, 70% and 100% of the patients treated with BEV, resection and LITT respectively. The median duration to TN recurrence was 10 weeks (range: 3–70 weeks). Initial treatment used for TN, MGMT methylation and IDH mutation status did not predict TN recurrence. (p=0.074; p=0.819; p=0.607 respectively).

CONCLUSIONS

BEV appears to be a superior treatment to control TN overall. Recurrence of TN in patients previously treated with BEV was 36%. There was no difference in the risk of developing recurrent TN based on MGMT or IDH status.

Characterizing benefit from temozolomide in MGMT promoter unmethylated and methylated glioblastoma: a systematic review and meta-analysis

Background

The current standard of care for the management of patients with newly diagnosed glioblastoma (GBM) includes maximal safe resection followed by radiotherapy (RT) with concurrent and adjuvant temozolomide (TMZ). While it is well established that TMZ has better efficacy in patients with MGMT promoter methylation, it remains an area of debate whether TMZ should be omitted when treating GBM patients with unmethylated MGMT.

Methods

We conducted a systematic review and meta-analysis to provide separate estimates of median overall survival (OS) and progression-free survival (PFS) for patients with methylated and unmethylated GBM treated with RT with or without TMZ. We searched multiple databases from inception to January 13, 2020.

Results

The median OS for patients with unmethylated GBM treated with RT/TMZ pooled from 5 phase III studies (N = 655) was 14.11 months (95% confidence interval [CI], 13.18–15.04) with a median PFS of 4.99 months (95% CI, 4.25–5.72). In contrast, the median OS for patients with methylated GBM pooled from 6 studies (N = 753) was 24.59 months (95% CI, 22.19–26.99) with a median PFS pooled from 7 studies (N = 805) of 9.51 months (95% CI, 7.41–11.61). There is a paucity of prospective data pertaining to OS/PFS in unmethylated patients treated with RT only and therefore a direct comparison was not possible.

Conclusions

This meta-analysis provides estimates of survival for patients with MGMT methylated or unmethylated GBM treated with RT/TMZ. Further research is needed to delineate whether TMZ should be withheld for patients with unmethylated GBM outside of the setting of clinical trials.

Abstract P2-20-07: Assessment of leptomeningeal carcinomatosis management and outcomes in patients with advanced breast cancer from 2005 to 2015: A single institution experience

Background Leptomeningeal carcinomatosis (LMC) is a complication of advanced malignancies wherein metastatic disease invades the meninges of the central nervous system via contiguous spread from bone or brain metastases or hematogenous spread from systemic disease. Breast cancer is the most common solid tumor etiology of LMC. Approximately 5% of patients (pts) with breast cancer develop LMC. LMC has a median survival of 4 weeks when untreated and 8-16 weeks with treatment. The diagnosis of LMC remains challenging with only 60% of pts having cerebrospinal fluid (CSF) positive for malignant cells. There is no generally accepted standard of care for treatment of LMC but it may involve intrathecal or systemic chemotherapy, whole brain or spinal radiotherapy, or a combination of modalities. We aimed to assess detection and treatment strategies of LMC in pts with breast cancer treated at the Ohio State University Comprehensive Cancer Center-James (OSUCCC-James) to better characterize the disease and guide clinical care. Methods An IRB-approved single-institution retrospective protocol was developed. Medical records of 469 pts who had undergone a procedure related to LMC diagnosis or treatment were identified and reviewed to determine study eligibility. Comprehensive data was obtained through information warehouse and chart review was performed for the eligible 69 pts with breast cancer diagnosed with LMC and treated at the OSUCCC-James between January 1, 2005 and December 31, 2015. Descriptive statistics were used to summarize demographic and clinical characteristics. Overall survival (OS) was defined as time from LMC diagnosis to death or last known follow-up, and was generated using Kaplan Meier methods. Comparisons in OS between groups were analyzed using Log-rank tests. Results Sixty-nine female pts were included in the analysis with the following characteristics: median age 55.7 years (range: 48-60.6 years), Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 (86%; N=59), and Caucasian (78%; N=54). They had the following subtypes hormone receptor positive (HR +), and human epidermal growth factor receptor (HER2) negative (61%, N=42), triple negative (25%, N=17) and HER2 positive (10%, N=7). The most common sites of metastases included bone (42%), brain (28%), and lung (12%). The median time between the diagnosis of first metastasis and LMC was 0.9 years (range: 0-3.2 years). Of the 40 (58%) pts who underwent lumbar puncture, 21 (52%) pts had positive CSF cytology. Sixty-eight pts (99%) had MRI findings suggestive of LMC. The most common treatment modalities were systemic chemotherapy (N=14, 41%), radiotherapy (N=12, 35%), and intrathecal chemotherapy (N=14, 35%). Fifty-six pts (81%) had a change in systemic chemotherapy agent after diagnosis. The median OS of all pts was 2.4 months (95% confidence interval: 1.2-4.4). Pts with ER+/PR+/HER2- had a better OS (4.4 months, 95%CI 1.5, 6.1)) compared to those with HER2+ (1.3 months, 95%CI 0.2, 1.9) or ER-/PR-/HER2- (0.6 months, 95%CI 0.0, 15.8) subtypes (p-value=0.004). Pts with negative CSF cytology had a greater OS compared to those with positive CSF cytology (9.8 vs. 0.7 months, p=0.026) and pts who had a change in systemic treatment had a greater OS compared with patients who had no new treatment (2.5 months vs. 1.2 months, p =0.039). No significant difference was seen in OS between ECOG performance status groups. Conclusions LMC is a relatively rare yet devastating complication of breast cancer. Based on our institutional experience, LMC remains a clinical challenge and is associated with poor OS. Pts with triple negative and HER2 positive disease and those with high disease burden fare worse. Pts who had change in systemic therapy fare better. Dedicated clinical trials are urgently needed to improve outcomes.

Citation Format: Hannah Rinehardt, Nicole Williams, Evan Morgan, Mahmooud Kassem, Marilly Palettas, Abdul Miah, Iyad Alnahhas, Pilar Guillermo Prieto Eibl, Anupama Suresh, Vinay Puduvalli, Pierre Giglio, Maryam Lustberg, Robert Wesolowski, Sagar Sardesai, Daniel Stover, Jeffrey VanDeusen, Jose Bazan, Bhuvaneswari Ramswamy, Anne Noonan. Assessment of leptomeningeal carcinomatosis management and outcomes in patients with advanced breast cancer from 2005 to 2015: A single institution experience [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-20-07.

INNV-35. INTRODUCING THE EDUCATIONAL NEURO-ONCOLOGY APP

BACKGROUND

The purpose of the Neuro-Oncology Trials App is to promote evidence-based practice in neuro-oncology and educate learners about the clinical trials that have been completed in the field. Evidence-based practice means consulting the literature when treating patients and applying the results of well-designed clinical trials to questions that we encounter in clinical practice. Being well versed in the literature is essential for high-quality patient care.

METHODS

We have developed a reference tool in the form of a smartphone app to provide easily-searched, easy-to-read detailed summaries of the methodology and results of selected pivotal clinical trials in the field of neuro-oncology.

RESULTS

The Neuro-Oncology Trials App includes summaries of select published clinical trials in the field of neuro-oncology. The topics include newly diagnosed glioblastoma, recurrent glioblastoma, low-grade gliomas, primary central nervous system lymphoma and management of gliomas in the elderly. The app includes an intuitive search function that facilitates looking up trials by: tumor histology, names of authors, names of journals, names of chemotherapy medications and acronyms of names of trials. Finally, it is continually updated and made available free of charge to users.

CONCLUSIONS

The Neuro-Oncology Trials App is ideal for practitioners at all levels and learners (medical students, residents and fellows) to look up information and quick summaries of trials in neuro-oncology when seeing patients in clinics or during rounds. The Neuro-Oncology App is soon to be available on the Apple and Android stores.

PATH-12. IDENTIFYING MOLECULAR PROGNOSTIC MARKERS IN IDHwt GLIOBLASTOMA

BACKGROUND

Despite our deeper understanding of the genomic alterations associated with glioblastoma (GBM), only a few genetic and epigenetic modifications have been proven to be meaningful in clinical practice. We have identified molecular parameters of prognostic relevance in IDHwt GBM using patient data from the Ohio State University (OSU) and the publicly available MSK-IMPACT database.

METHODS

A clinically annotated database of glioma patients at OSU- whose tumors were analyzed through Foundation One genomic testing- was utilized to examine mutation and copy number variation (CNV) data. 73 patients with IDHwt GBM were included in this study cohort along with 200 similar patients from the MSK-IMPACT cohort. Data from the MSKCC group was extracted from the cBioPortal database. Altered genes were correlated with clinical outcomes using Cox proportional hazards models. Univariate and multivariate analyses were applied, and variables included: MDM/P53, CDKN2A/B, CDK/CCND, RB1, EGFR/ ERBB, FGFR, PDGFR/KIT, NF1, PI3K, PI3K class 2, MYC and TERT promoter mutations.

RESULTS

Using univariate and multivariate analyses, EGFR activating alterations (amplification, mutations) and RB1 alterations (deletion, mutations) showed significant correlation with favorable outcome in IDHwt GBM: HR 0.496 for EGFR (p< 0.0001) and 0.454 for RB1 (p=0.025). Furthermore, the presence of PDGFR alterations, in EGFR altered tumors only, carried a significantly worse survival in univariate and multivariate analyses: HR 5.094 (p=0.004). This suggests an interaction between EGFR and PDGFR that could be of therapeutic relevance.

CONCLUSIONS

We found that GBM tumors harboring EGFR and/or RB1 alterations have better survival compared to tumors that are EGFR/RB1 wild-type. Moreover, PDGFR alterations worsens survival in EGFR altered GBM. This data provides further insights that might guide targeted therapies in IDHwt GBM.

EPID-32. IS THERE ANY EVIDENCE OF REPORTING AND CITATION BIAS AMONG COMPLETED PHASE III INTERVENTIONAL BRAIN TUMOR TRIALS?

OBJECTIVE

Reporting and citation bias based on positive versus negative outcome among completed phase III interventional brain tumor trials (IBTTs) have not been previously reported. Thus, we aimed to assess the evidence.

METHODS

Clinicaltrials.gov was used to obtain all phase III IBTTs completed prior to December 31st 2016. Trials closed due to poor accrual or non-phase III were excluded. Data about the funding source, type of intervention, conducted at U.S or Non-U.S locations, patients enrolled, primary completion date, time to dissemination of results in months (either reported on clinicaltrials.gov or published in a journal), citations per year (from web of science) and outcome (positive or neutral/negative) were abstracted. Median time to dissemination was estimated using Kaplan-Meier estimates and a log rank test for statistical significance. The number of citations per year for positive and negative/neutral studies was compared using a t-test.

RESULTS

65 studies were analyzed. The median time from primary completion to dissemination of results for trials with a positive outcome was 20 months (n = 20; 95% CI: 12–31) compared to 30 months for trials with a negative outcome (n=35; 95 % CI: 22 – 37) (p = 0.095). The average number of citations per year for trials with a positive outcome is 62.4 (n = 21; range 1.1 – 614.8) compared to 25.0 for trials with a negative outcome (n=35; range 0.14 - 158.8) (p = 0.213). There was no significant difference in time to dissemination based on the funding source, type of intervention or the location where the trial was conducted.

CONCLUSION

Positive phase III IBTTs results are disseminated earlier and are cited more frequently compared to negative trials. However, there is no statistically significant evidence of reporting or citation bias.

Changing paradigms for targeted therapies against diffuse infiltrative gliomas: tackling a moving target

Introduction: Gliomas are highly heterogeneous primary brain tumors which result in a disproportionately high degree of morbidity and mortality despite their locoregional occurrence. Advances in the understanding of the biological makeup of these malignancies have yielded a number of potential tumor-driving pathways which have been identified as rational targets for therapy. However, early trials of agents that target these pathways have uniformly failed to yield improvement in outcomes in patients with malignant gliomas. Areas covered: This review provides an overview of the most common biological features of gliomas and the strategies to target the same; in addition, the current status of immunotherapy and biological therapies are outlined and the future directions to tackle the challenges of therapy for gliomas are examined. Expert opinion: The limitations of current treatments are attributed to the inability of most of these agents to cross the blood-brain barrier and to the intrinsic heterogeneity of the tumors that result in treatment resistance. The recent emergence of immune-mediated and biological therapies and of agents that target metabolic pathways in gliomas have provided strategies that may overcome tumor heterogeneity and ongoing trials of such agents are anticipated to yield improved outcomes.

Assessment of Leptomeningeal Carcinomatosis Diagnosis and Outcomes from 2005 to 2015 at Ohio State University

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Background: Leptomeningeal carcinomatosis (LMC) is a complication of advanced malignancies wherein primary tumors metastasize to the leptomeninges surrounding brain and spinal cord. LMC complicates 4-15% of malignant solid tumors with incidence increasing as survival of patients with advanced cancer improves. Diagnostic methods include magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) cytology. MRI findings may be nonspecific, and the gold standard of diagnosis is malignant cytology on CSF analysis. We assessed detection methods, incidence, and outcomes of LMC at The Ohio State University Comprehensive Cancer Center from 2005-2015. Methods: This was an IRB-approved single-institution retrospective study of 160 patients with confirmed diagnosis of LMC who were treated at the OSUCCC-James between Jan 1, 2005 and Dec 31, 2015. Patients with hematologic and central nervous system malignancies were excluded. Descriptive statistics were used to summarize demographic and clinical characteristics. Overall survival (OS) was defined as time from LMC diagnosis to death or last known follow-up, and was generated using Kaplan-Meier methods. Results: Median age of LMC diagnosis was 55.8 years (range: 48, 62.5). 69 (43%) patients had primary breast cancer, 41 (26%) had lung cancer, and 17 (11%) had melanoma. 73 patients (46%) presented with stage IV disease at initial diagnosis of the primary cancer, 41 (26%) with stage III disease, and 26 (16%) with stage II disease. Median time from diagnosis of primary cancer to diagnosis of LMC was 2 years (range: 0, 31.2). 158 (99%) patients had metastases at the time of LMC diagnosis, predominantly in bone (36%) or brain (36%). Median OS was 1.9 months (CI: 1.3, 2.5). 160 (100%) patients had an MRI of the brain or spine and 155 (97%) had MRI findings consistent with LMC. 75 (47%) patients underwent lumbar puncture, and 39 (52%) had CSF cytology positive for malignancy. Conclusions: Patients with LMC commonly presented with stage IV breast cancer, lung cancer, or melanoma with metastases to the brain or bone. Despite treatment, prognosis remains poor and confirmation of diagnosis can be challenging. Clinicians should have a low threshold for investigating LMC in high risk patients presenting with neurologic signs or symptoms.

Leptomeningeal spread of glioma in the molecular era

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Background: Leptomeningeal disease (LMD) is an uncommon event in patients with gliomas which is estimated to occur in 4% of cases and is associated with poor outcome. Genomic alterations in gliomas that precipitate LMD have not been characterized. Methods: We performed a retrospective chart review of patients with gliomas (grade II-IV)- for whom we have genomic testing data at The Ohio State University. We identified patients who developed LMD. LMD was defined as leptomeningeal enhancement as seen on brain or spine imaging. Patients with negative cerebrospinal fluid (CSF) cytology were not excluded if imaging was convincing of LMD. Genomic testing was performed through Foundation One. Results: 129 charts of glioma patients were reviewed. We identified 6 patients with LMD. One is still alive. All patients were diagnosed histologically as glioblastoma. One patient had Lynch syndrome. All patients were men with a median age at diagnosis of 44 (range 20-65). All tumors appeared to have extended into the ventricles on brain imaging. 4 tumors had evidence of subependymal spread prior (range 45-93 days) or at the time of LMD enhancement. 4 patients had available CSF studies: 2 of whom had evidence of atypical or malignant cells. CSF protein was elevated in all four samples (range 113-492 mg/dL). CSF glucose was low in all four samples (range < 10-46 mg/dL). 5 tumor samples were IDH wild type whereas 1 had IDH1 R132H mutation. MGMT promoter was methylated in 3 tumors and unmethylated in 3. The genomic alterations varied among samples and included EGFR V765M mutation (N = 1), PDGFR amplification (N = 1), PDGFRA Y849C subclonal mutation (N = 1), CDKN2A/B loss (N = 3), TP53 mutations (N = 4) and TERT promoter mutations (N = 3). No case had EGFR amplification or EGFRvIII mutation. Other alterations observed included DNMT3A mutation, KIT, MYC and MDM2 amplifications and RB1 losses. PD-L1 expression ranged from 5-40%. One intracranial sample had a 20% PD-L1 expression with LMD from this tumor exhibiting 40% PD-L1 expression. Of the five deceased patients (all IDH WT), median overall survival (OS) was 355 days (range 184-557). Median OS after LMD diagnosis was 84 days (range 58-225). Conclusions: In this series, 4.5% of glioma patients developed LMD. Samples were associated with a variety of genomic alterations but without a specific predictor of leptomeningeal involvement. This is possibly due to the small number of cases. Physical proximity of the tumor to the ventricles appears to be a potential risk factor. Larger studies of LMD in gliomas are warranted to identify potential genetic drivers, if any exist.

Autologous Stem-Cell Transplantation for Primary Central Nervous System Lymphoma: Systematic Review and Meta-analysis

BACKGROUND

Primary central nervous system lymphoma (PCNSL) is an aggressive form of non-Hodgkin lymphoma. Methotrexate is first-line chemotherapy. Autologous stem-cell transplantation (ASCT) is increasingly used as an alternative consolidative treatment to whole-brain radiotherapy.

METHODS

A systematic search of several databases was conducted up through January 10, 2018. Two investigators independently assessed study eligibility and extracted the data. Studies that reported survival outcomes after ASCT were included.

RESULTS

We screened 1517 references and included 43 studies. ASCT was used as consolidative treatment or as salvage treatment/at relapse. Thiotepa, busulfan, and cyclophosphamide and carmustine/thiotepa were commonly used conditioning regimens. In the consolidation setting, 94% of patients experienced or maintained complete or partial response after ASCT. The rates of overall survival (OS) and progression-free survival (PFS) were 94%, 86%, 82%, and 70% and 79%, 70%, 64%, and 54% after 1, 2, 3, and 5 years, respectively. The overall risk of relapse at 5 years was 24%. In the salvage/relapse settings, 85% of patients experienced or maintained complete response or partial response after ASCT. The rates of OS and PFS were 75%, 63%, 56%, and 54% and 85%, 62%, 59%, and 54% after 1, 2, 3, and 5 years, respectively. The risk of relapse at 5 years was 29%. Subgroup analysis showed that the use of carmustine and thiotepa as a conditioning regimen carried the lowest risk of transplant-related mortality. The thiotepa, busulfan, and cyclophosphamide regimen, on the other hand, showed numerically superior OS and PFS rates.

CONCLUSION

This review provides estimates for response and survival to aid in decision making when considering ASCT for patients with PCNSL.

Undergraduate medical students' perceptions, attitudes, and competencies in evidence-based medicine (EBM), and their understanding of EBM reality in Syria

Background

Teaching evidence-based medicine (EBM) should be evaluated and guided by evidence of its own effectiveness. However, no data are available on adoption of EBM by Syrian undergraduate, postgraduate, or practicing physicians. In fact, the teaching of EBM in Syria is not yet a part of undergraduate medical curricula. The authors evaluated education of evidence-based medicine through a two-day intensive training course.

Methods

The authors evaluated education of evidence-based medicine through a two-day intensive training course that took place in 2011. The course included didactic lectures as well as interactive hands-on workshops on all topics of EBM. A comprehensive questionnaire, that included the Berlin questionnaire, was used to inspect medical students’ awareness of, attitudes toward, and competencies’ in EBM.

Results

According to students, problems facing proper EBM practice in Syria were the absence of the following: an EBM teaching module in medical school curriculum (94%), role models among professors and instructors (92%), a librarian (70%), institutional subscription to medical journals (94%), and sufficient IT hardware (58%). After the course, there was a statistically significant increase in medical students' perceived ability to go through steps of EBM, namely: formulating PICO questions (56.9%), searching for evidence (39.8%), appraising the evidence (27.3%), understanding statistics (48%), and applying evidence at point of care (34.1%). However, mean increase in Berlin scores after the course was 2.68, a non-statistically significant increase of 17.86%.

Conclusion

The road to a better EBM reality in Syria starts with teaching EBM in medical school and developing the proper environment to facilitate transforming current medical education and practice to an evidence-based standard in Syria.

Tumor lysis syndrome: a systematic review of case series and case reports

Tumor lysis syndrome (TLS) is a clinical condition that is caused by a massive lysis of tumor cells that accumulate very rapidly and disturb hemodynamics. This oncologic emergency requires immediate intervention. Tumor lysis syndrome was first described in the 19th century. Since then, it has become a well-known disease with improved management measures. Tumor lysis syndrome can occur after any type of neoplasm. It is highly associated with rapidly proliferating tumors compared with those that are well demarcated, such as acute lymphoblastic leukemia and high-grade non-Hodgkin lymphoma. Initiation of chemotherapy, radiotherapy, or steroid treatment may trigger TLS, or it may develop spontaneously. The release of massive quantities of intracellular contents may produce hyperkalemia, hyperphosphatemia, secondary hypocalcemia, hyperuricemia, and acute renal failure. Prevention and treatment measures include intravenous hydration, use of allopurinol and rasburicase, management of TLS-associated electrolyte abnormalities, and renal replacement therapy; the use of urine alkalinization remains controversial. In this article, we summarize the findings of case series and case reports published over the past 6 years in an effort to help familiarize clinicians better recognize and manage TLS.