Liquid biopsy in gliomas: A RANO review and proposals for clinical applications

BACKGROUND

There is an extensive literature highlighting the utility of blood-based liquid biopsies in several extracranial tumors for diagnosis and monitoring.

METHODS

The RANO (Response Assessment in Neuro-Oncology) group developed a multidisciplinary international Task Force to review the English literature on liquid biopsy in gliomas focusing on the most frequently used techniques, that is circulating tumor DNA, circulating tumor cells, and extracellular vesicles in blood and CSF.

RESULTS

ctDNA has a higher sensitivity and capacity to represent the spatial and temporal heterogeneity in comparison to circulating tumor cells. Exosomes have the advantages to cross an intact blood-brain barrier and carry also RNA, miRNA, and proteins. Several clinical applications of liquid biopsies are suggested: to establish a diagnosis when tissue is not available, monitor the residual disease after surgery, distinguish progression from pseudoprogression, and predict the outcome.

CONCLUSIONS

There is a need for standardization of biofluid collection, choice of an analyte, and detection strategies along with rigorous testing in future clinical trials to validate findings and enable entry into clinical practice.

Comparative Efficacy of Systemic Agents for Brain Metastases From Non-Small-Cell Lung Cancer With an EGFR Mutation/ALK Rearrangement: A Systematic Review and Network Meta-Analysis

BACKGROUND

Brain metastases (BM) from non-small-cell lung cancer (NSCLC) are frequent and carry significant morbidity, and current management options include varying local and systemic therapies. Here, we performed a systematic review and network meta-analysis to determine the ideal treatment regimen for NSCLC BMs with targetable EGFR-mutations/ALK-rearrangements.

METHODS

We searched MEDLINE, EMBASE, Web of Science, ClinicalTrials.gov, CENTRAL and references of key studies for randomized controlled trials (RCTs) published from inception until June 2020. Comparative RCTs including ≥10 patients were selected. We used a frequentist random-effects model for network meta-analysis (NMA) and assessed the certainty of evidence using the GRADE approach. Our primary outcome of interest was intracranial progression-free survival (iPFS).

RESULTS

We included 24 studies representing 19 trials with 1623 total patients. Targeted tyrosine kinase inhibitors (TKIs) significantly improved iPFS, with second-and third- generation TKIs showing the greatest benefit (HR=0.25, 95%CI 0.15-0.40). Overall PFS was also improved compared to conventional chemotherapy (HR=0.47, 95%CI 0.36-0.61). In EGFR-mutant patients, osimertinib showed the greatest benefit in iPFS (HR=0.32, 95%CI 0.15-0.69) compared to conventional chemotherapy, while gefitinib + chemotherapy showed the greatest overall PFS benefit (HR=0.26, 95%CI 0.10-0.70). All ALKi improved overall PFS compared to conventional chemotherapy, with alectinib having the greatest benefit (HR=0.13, 95%CI 0.07-0.24).

CONCLUSIONS

In patients with NSCLC BMs and EGFR/ALK mutations, targeted TKIs improve intracranial and overall PFS compared to conventional modalities such as chemotherapy, with greater efficacy seen using newer generations of TKIs. This data is important for treatment selection and patient counseling, and highlights areas for future RCT research.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=179060.

Cross-sectional survey of patients, caregivers, and physicians on diagnosis and treatment of brain metastases

BACKGROUND

The development of brain metastases (BM) is one of the most feared complications of cancer due to the substantial neurocognitive morbidity and a grim prognosis. In the past decade, targeted therapies and checkpoint inhibitors have demonstrated promising intracranial response rates for tumors of multiple histologies. As overall survival for these patients improves, there is a growing need to identify issues surrounding patient survivorship and to standardize physician practice patterns for these patients. To date, there has not been an adequate study to specifically explore these questions of survivorship and practice standardization for patients with advanced cancer and BM.

METHODS

Here, we present results from a cross-sectional survey in which we analyze responses from 237 patients, 209 caregivers, and 239 physicians to identify areas of improvement in the clinical care of BM.

RESULTS

In comparing physician and patient/caregiver responses, we found a disparity in the perceived discussion of topics pertaining to important aspects of BM clinical care. We identified variability in practice patterns for this patient population between private practice and academic physicians. Many physicians continue to have patients with BM excluded from clinical trials. Finally, we obtained patient/physician recommendations on high-yield areas for federal funding to improve patient quality of life.

CONCLUSION

By identifying potential areas of unmet need, we anticipate this wealth of actionable information will translate into tangible benefits for both patients and caregivers. Future studies are needed to validate our findings.

Impact of MRI timing on tumor volume and anatomic displacement for brain metastases undergoing stereotactic radiosurgery

Background

The objective of this study was to evaluate the impact of the time interval between planning imaging and stereotactic radiosurgery (SRS) delivery on tumor volumes and spatial anatomic displacements of brain metastases (BM).

Methods

Consecutive patients diagnosed with BM treated with SRS over a 3-year period were evaluated. Only patients who underwent an institutionally standardized diagnostic MRI (MRI-1) and a treatment planning MRI (MRI-2) were included. The impact of histology, inter-scan time interval, lesion location, tumor volume, and diameter were evaluated on final lesion diameter, volume, anatomic displacement, and ultimate need for change in management (ie, expanding margins, rescanning).

Results

101 patients (531 lesions) with a median inter-scan time interval of 8 days (range: 1-42 days) met the inclusion criteria. The median percentage increase in BM diameter and volume were 9.5% (IQR: 2.25%-24.0%) and 20% (IQR: 0.7%-66.7%). Overall, 147 lesions (27.7%) in 57 patients (56.4%) required a change in management. There was a statistically significant relationship between initial tumor diameter (cm) and change in management (OR: 2.69, 95% CI: 1.93-3.75; P < .001). Each day between MRI-1 and MRI-2 was associated with a change in management with an OR of 1.05 (95% CI: 1.03-1.07; P < .001).

Conclusions

Changes in tumor diameter, volume, and spatial position occur as a function of time. Planning imaging for SRS is recommended to occur in close temporal proximity to treatment; for those with delays, a larger setup margin may need to be used to ensure tumor coverage and account for positional changes.

Systematic review and meta-analysis of lung cancer brain metastasis and primary tumor receptor expression discordance

BACKGROUND

Treatment paradigms for metastatic non-small cell lung cancer are increasingly based on biomarker-driven therapies, with the most common alteration being mutation in the epidermal growth factor receptor (EGFR). Change in expression of such biomarkers could have a profound impact on the choice and efficacy of a selected targeted therapeutic, and hence the objective of this study was to analyze discordance in EGFR status in patients with lung cancer brain metastasis (LCBM).

METHODS

Using PRISMA guidelines, a systematic review was performed of series in the Medline database of biopsied or resected LCBM published before May, 2020. Key words included "lung cancer" and "brain metastasis" combined with "epidermal growth factor receptor/EGFR," and "receptor conversion/discordance or concordance." Weighted random effects models were used to calculate pooled estimates.

RESULTS

We identified 501 patients from 19 full-text articles for inclusion in this study. All patients underwent biopsy or resection of at least one intracranial lesion to compare to the primary tumor. On primary/LCBM comparison, the weighted pooled estimate for overall EGFR receptor discordance was 10% (95% CI 5-17%). The weighted effects model estimated a gain of an EGFR mutation in a brain metastases in patients with negative primary tumors was 7% (95% CI 4-12%). Alternatively, the weighted effects model estimate of loss of an EGFR mutation in patients with detected mutations in the primary tumor was also 7% (95% CI 4-10%). KRAS testing was also performed on both primary tumors and LCBM in a subset of 148 patients. The weighted effects estimate of KRAS-mutation discordance among LCBM compared to primary tumors was 13% (95% CI 5-27%). The weighted effects estimated of KRAS gain and loss in LCBM was 10% (95% CI 6-18%) and 8% (95% CI 4-15%), respectively. Meta-regression analysis did not find any association with any factors that could be associated with discordances.

CONCLUSIONS

EGFR and KRAS mutation status discordance between primary tumor and LCBM occurs in approximately 10% and 13% of patients, respectively. Evaluation of LCBM receptor status is key to biomarker-driven targeted therapy for intracranial disease and awareness of subtype switching is critical for those patients treated with systemic therapy alone for intracranial disease.

Systematic evaluation and plan quality assessment of the Leksell® gamma knife® lightning dose optimizer

To compare stereotactic radiosurgery (SRS) plan quality metrics of manual forward planning (MFP) and Elekta Fast Inverse Planning™ (FIP)-based inversely optimized plans for patients treated with Gamma Knife®. Clinically treated, MFP SRS plans for 100 consecutive patients (115 lesions; 67 metastatic and 48 benign) were replanned with the FIP dose optimizer based on a convex linear programming formulation. Comparative plans were generated to match or exceed the following metrics in order of importance: Target Coverage (TC), Paddick Conformity Index (PCI), beam-on time (BOT), and Gradient Index (GI). Plan quality metrics and delivery parameters between MFP and FIP were compared for all lesions and stratified into subgroups for further analysis. Additionally, performance of FIP for multiple punctate (<4 mm) metastatic lesions on a subset of cases was investigated. A Wilcoxon signed-rank test for non-normal distributions was used to assess the statistical differences between the MFP and FIP treatment plans. Overall, 76% (87/115) of FIP plans showed a statistically significant improvement in plan quality compared to MFP plans. As compared to MFP, FIP plans demonstrated an increase in the median PCI by 1.1% (p<0.01), a decrease in GI by 3.7% (p< 0.01), and an increase in median number of shots by 74% (p< 0.01). TC and BOT were not statistically significantly different between MFP and FIP plans (p>0.05). FIP plans showed a statistically significant increase in use of 16 mm (p< 0.01) and blocked shots (p< 0.01), with a corresponding decrease in 4 mm shots (p< 0.01). Use of multiple shots per coordinate was significantly higher in FIP plans (p<0.01). The FIP optimizer failed to generate a clinically acceptable plan in 4/115 (3.5%) lesions despite optimization parameter changes. The mean optimization time for FIP plans was 5.0 min (Range: 1.0 - 10.0 min). In the setting of multiple punctate lesions, PCI for FIP was significantly improved (p<0.01) by changing the default low-dose/BOT penalty optimization setting from a default of 50/50 to 75-85/40. FIP offers a significant reduction in manual effort for SRS treatment planning while achieving comparable plan quality to an expert planner-substantially improving overall planning efficiency. FIP plans employ a non-intuitive increased use of blocked sectors and shot-in-shot technique to achieve high quality plans. Several FIP plans failed to achieve clinically acceptable treatments and warrant further investigation.

Comparative Efficacy of Treatments for Brain Metastases from Non-Small Cell Lung Cancer without an EGFR-Mutation/ALK-Rearrangement: A Systematic Review and Network Meta-Analysis

INTRODUCTION

As many as 30% of patients with non-small cell lung cancer (NSCLC) will develop brain metastases (BMs) over the course of their illness. Here, we quantitatively compare the efficacy of the various emerging regimens for NSCLC BMs without a definitive targetable epidermal growth factor receptor mutation/ALK rearrangement.

METHODS

We searched MEDLINE, EMBASE, Web of Science, ClinicalTrials.gov, CENTRAL, and references of key studies for randomized controlled trials (RCTs) published from inception until June 2020. Comparative RCTs that included ≥10 patients were included. We used a frequentist fixed or random-effects model for network meta-analysis. The outcomes of interest included intracranial progression-free survival (iPFS), overall survival (OS), and overall progression-free survival.

RESULTS

In total, 18 studies representing 17 trials (n = 2726 patients) were identified. Immune checkpoint inhibitor regimens showed significant improvement in OS compared with chemotherapy alone, including pembrolizumab and chemotherapy (6 studies, hazard ratio [HR] 0.36, 95% confidence interval [CI] 0.21-0.62), atezolizumab alone (HR 0.54, 95% CI 0.33-0.89), and nivolumab and ipilimumab (HR 0.64, 95% CI 0.42-0.97). An improvement in overall PFS was seen with use of pembrolizumab and chemotherapy compared with chemotherapy alone (3 studies, HR 0.42, 95% CI 0.26-0.68). Studies evaluating checkpoint inhibitors did not report iPFS data, and we did not find improvement in iPFS or OS with the addition of any chemotherapy regimen to whole-brain radiation therapy.

CONCLUSIONS

In this network meta-analysis, we demonstrate the promising survival benefit with use of checkpoint inhibitor-based regimens in NSCLC BMs without a targetable epidermal growth factor receptor mutation/ALK rearrangement. Moving forward, large-scale BM-focused RCTs are necessary to establish the iPFS benefit of immune checkpoint inhibitor-based immunotherapy in this patient population.

Impact of KRAS mutation status on the efficacy of immunotherapy in lung cancer brain metastases

Immune checkpoint inhibitors (ICIs) have resulted in improved outcomes in non-small cell lung cancer (NSCLC) patients. However, data demonstrating the efficacy of ICIs in NSCLC brain metastases (NSCLCBM) is limited. We analyzed overall survival (OS) in patients with NSCLCBM treated with ICIs within 90 days of NSCLCBM diagnosis (ICI-90) and compared them to patients who never received ICIs (no-ICI). We reviewed 800 patients with LCBM who were diagnosed between 2010 and 2019 at a major tertiary care institution, 97% of whom received stereotactic radiosurgery (SRS) for local treatment of BM. OS from BM was compared between the ICI-90 and no-ICI groups using the Log-Rank test and Cox proportional-hazards model. Additionally, the impact of KRAS mutational status on the efficacy of ICI was investigated. After accounting for known prognostic factors, ICI-90 in addition to SRS led to significantly improved OS compared to no-ICI (12.5 months vs 9.1, p < 0.001). In the 109 patients who had both a known PD-L1 expression and KRAS status, 80.4% of patients with KRAS mutation had PD-L1 expression vs 61.9% in wild-type KRAS patients (p = 0.04). In patients without a KRAS mutation, there was no difference in OS between the ICI-90 vs no-ICI cohort with a one-year survival of 60.2% vs 54.8% (p = 0.84). However, in patients with a KRAS mutation, ICI-90 led to a one-year survival of 60.4% vs 34.1% (p = 0.004). Patients with NSCLCBM who received ICI-90 had improved OS compared to no-ICI patients. Additionally, this benefit appears to be observed primarily in patients with KRAS mutations that may drive the overall benefit, which should be taken into account in the development of future trials.

RADI-11. Evaluating the Tissue Effects of Dose-escalated Pre-operative Stereotactic Radiotherapy for Resectable Brain Metastasis

Background

Although the classic radiobiologic principles of radiotherapy are well understood, the unique effects of the large fractional does that characterize stereotactic radiotherapy (SRT), specifically in terms of antitumor immune cellular processes, vascular damage, tumor necrosis, and apoptosis on brain metastasis have yet to be adequately demonstrated. The objective of this study is to provide the first in-human evaluation of the biological effects of SRT in resected brain metastasis.

Methods

All paired primary tumors and metastases for patients who underwent dose-escalated preoperative SRT followed by resection were evaluated for tumor necrosis using hematoxylin-eosin staining. T cells (CD3+, CD4+, CD8+), natural killer cells (CD56+), vessel density (CD31+), and apoptotic factors (caspase-3) were determined by immunohistochemical analysis.

Results

Fifteen patients with brain metastases from solid tumors received a median preoperative SRT dose of 18 Gy (range: 15–18 Gy) in 1 fraction, with 2 patients receiving 27–30 Gy in 3–5 fractions, followed by resection within a median interval of 90 hours (Range: 17.1–260 hours). The rate of necrosis was found to be significantly higher in irradiated brain metastases than in non-irradiated primary tumor samples (mean paired difference: 30.47, SD: 29.28, p=0.001). A decrease in all immunomodulatory cell populations was found in irradiated metastasis: CD3 (mean paired difference -19.4, SD: 31.7, p=0.03), CD4 (-10.0, SD: 20, p=0.01), and CD8 (-17.4, SD: 22.1, p=0.008). While irradiated samples had numerically lower CD 31+, CD 56+, and caspase-3 scores, the difference was not statistically significant. Time interval from SRT to surgery had no effect on these parameters.

Conclusions

There is complex interplay between tumor-associated cells and the unique radiobiological effects of SRT on tumor tissue. Although time interval from SRT to surgery was associated with increased tumor necrosis, differences in immunomodulatory factors may be multifactorial, including concurrent corticosteroids or the immunosuppressive effect of SRT.

OTHR-07. Systematic Review and Meta-analysis of Lung Cancer Brain Metastasis and Primary Tumor PD-L1 Expression Discordance

Background

Novel immunotherapeutic strategies, such as those targeting the PD-1/PD-L1 axis, are promising in patients with metastatic lung cancer and are often administered when tumors show PD-L1 positivity. The objective of this study was to analyze PD-L1 receptor discordance in tumor cell between the primary tumor and lung cancer brain metastasis (LCBM).

Methods

A systematic review of series published prior to April 2021 obtained from the Medline database of biopsied or resected LCBM evaluating PD-L1 discordance was performed using PRISMA guidelines. Weighted random effects models were used to calculate pooled estimates.

Results

Six full-text articles (n=247 patients) with a median of 32 patients in each study (range: 24–73 patients) reported PD-L1 receptor expression analyses of both primary lung tumors and brain metastases. The majority of patients (81%) were smokers, with 67% non-small cell lung cancer and 33% small cell lung cancer. The pooled estimate for overall PD-LI receptor concordance between primary and LCBM was 76% (95% CI: 52%-90). The positivity rate varied when analyzed by various cutoff levels of PD-L1 expression; for &lt;1% expression, it was 41% (95% CI: 22%-62%) for primary vs. 58% (95% CI: 35%-78%) for LCBM; for PD-L1 expression of 1–50%, it was 24% (95% CI: 13%-40%) vs. 19% (95% CI: 10%-33%); and for PD-L1 &gt;50% it was 12% (95% CI: 4%-33%) vs. 21% (95% CI: 14%-29%) (p=0.425). The pooled estimate for overall PD-LI receptor discordance between primary and LCBM was 17% (95% CI: 10%-27%). Meta-regression analysis showed that age, sex, smoking status, and histology were not associated with PD-LI receptor discordance.

Conclusions

PD-L1 status discordance in tumor cell occurs in approximately 20% of LCBM, with the greatest discordance in the &lt;1% expression category. Awareness of this discordance is important for the selection of immune checkpoint inhibitor therapy as well as in the analysis of patterns of failures.

Integration of Systemic Therapy and Stereotactic Radiosurgery for Brain Metastases

Simple Summary

In the multi-modal treatment of brain metastasis (BM), the role of systemic therapy has undergone a recent revolution. Due to the development of multiple agents with modest central nervous system penetration of the blood-brain barrier, targeted therapies and immune checkpoint inhibitors are increasingly being utilized alone or in combination with radiation therapy. However, the adoption of sequential or concurrent strategies varies considerably, and treatment strategies employed in clinical practice have rapidly outpaced evidence development. Therefore, this review critically analyzes the data regarding combinatorial approaches for a variety of systemic therapeutics with stereotactic radiosurgery and provides an overview of ongoing clinical trials.

Abstract

Brain metastasis (BM) represents a common complication of cancer, and in the modern era requires multi-modal management approaches and multi-disciplinary care. Traditionally, due to the limited efficacy of cytotoxic chemotherapy, treatment strategies are focused on local treatments alone, such as whole-brain radiotherapy (WBRT), stereotactic radiosurgery (SRS), and resection. However, the increased availability of molecular-based therapies with central nervous system (CNS) penetration now permits the individualized selection of tailored systemic therapies to be used alongside local treatments. Moreover, the introduction of immune checkpoint inhibitors (ICIs), with demonstrated CNS activity has further revolutionized the management of BM patients. The rapid introduction of these cancer therapeutics into clinical practice, however, has led to a significant dearth in the published literature about the optimal timing, sequencing, and combination of these systemic therapies along with SRS. This manuscript reviews the impact of tumor biology and molecular profiles on the management paradigm for BM patients and critically analyzes the current landscape of SRS, with a specific focus on integration with systemic therapy. We also discuss emerging treatment strategies combining SRS and ICIs, the impact of timing and the sequencing of these therapies around SRS, the effect of corticosteroids, and review post-treatment imaging findings, including pseudo-progression and radiation necrosis.

The impact of sequencing PD-1/PD-L1 inhibitors and stereotactic radiosurgery for patients with brain metastasis

BACKGROUND

The response of brain metastases (BM) treated with stereotactic radiosurgery (SRS) and immune checkpoint inhibitors (ICIs; programmed cell death 1 and its ligand) is of significant interest.

METHODS

Patients were divided into cohorts based on ICI sequencing around SRS. The primary outcome was best objective response (BOR) that was lesion specific. Secondary outcomes included overall objective response (OOR), response durability, radiation necrosis (RN), and overall survival (OS).

RESULTS

One hundred fifty patients underwent SRS to 1003 BM and received ICI. Five hundred sixty-four lesions (56%) treated with concurrent ICI (±5 half-lives) demonstrated superior BOR, OOR, and response durability compared with lesions treated with SRS and delayed ICI. Responses were best in those treated with immediate (±1 half-life) ICI (BOR: -100 vs -57%, P < 0.001; complete response: 50 vs 32%; 12-month durable response: 94 vs 71%, P < 0.001). Lesions pre-exposed to ICI and treated with SRS had poorer BOR (-45%) compared with ICI naive lesions (-63%, P < 0.001); best response was observed in ICI naive lesions receiving SRS and immediate ICI (-100%, P < 0.001). The 12-month cumulative incidence of RN with immediate ICI was 3.2% (95% CI: 1.3-5.0%). First radiographic follow-up and best intracranial response were significantly associated with longer OS; steroids were associated with inferior response rates and poorer OS (median 10 vs 25 mo, P = 0.002).

CONCLUSIONS

Sequencing of ICI around SRS is associated with overall response, best response, and response durability, with the most substantial effect in ICI naive BM undergoing immediate combined modality therapy. First intracranial response for patients treated with immediate ICI and SRS may be prognostic for OS, whereas steroids are detrimental.

Sex Differences in Glioblastoma Immunotherapy Response

Glioblastoma (GBM), the most common primary malignant brain tumor, remains difficult to treat and shares phenotypes, including an aberrant immune response, with other neurological disorders. Understanding the cellular and molecular mechanisms underlying this pathological immune response remains a priority, particularly as standard of care for advanced cancers evolves to include immunotherapies, which have yet to show strong clinical efficacy in GBM. Epidemiological evidence supports a sex difference in GBM, with increased prevalence in males, and recent studies identified differences between males and females ranging from genetic aberrations to cellular programs. Sex differences have also been identified in immune response, and in this mini-review, we present these differences to highlight potential sex-specific cellular and molecular mechanisms that underly GBM growth and response to immunotherapies. These sex differences offer an opportunity to understand GBM pathogenesis and extend beyond GBM to other tumors and neurological disorders to inform the development of next-generation therapies.

Neutrophil to lymphocyte ratio influences impact of steroids on efficacy of immune checkpoint inhibitors in lung cancer brain metastases

Steroids are often utilized to manage patients with non-small cell lung cancer brain metastases (NSCLCBM). Steroids and elevated neutrophil-to-lymphocyte ratio (NLR) have been associated with decreased overall survival (OS) in patients treated with immune checkpoint inhibitors (ICI). We retrospectively investigated patients treated with ICI after the diagnosis of NSCLCBM at a single tertiary care institution examing the impact of steroids and NLR. Overall survival (OS) and intracranial progression-free survival (PFS) were analyzed. 171 patients treated with ICI for NSCLCBM were included. Thirty-six received steroids within 30 days of the start of ICI, and 53 patients had an NLR ≥ 5 before the start of ICI. Upfront steroids was associated with decreased OS on multivariable analysis (median OS 10.5 vs. 17.9 months, p = .03) and intracranial PFS (5.0 vs. 8.7 months, p = .045). NLR ≥ 5 was indicative of worse OS (10.5 vs. 18.4 months, p = .04) but not intracranial PFS (7.2 vs. 7.7 months, p = .61). When NLR and upfront steroids are modeled together, there is a strong interaction (p = .0008) indicating that the impact of steroids depended on the patient’s NLR. In a subgroup analysis, only in patients with NLR < 4 was there a significant difference in OS with upfront steroids (26.1 vs. 15.6 months, p = .032). The impact of steroids on the efficacy of ICI in patients with NSCLCBM is dependent on the patient's NLR underscoring its importance in these patients. Patients with a low NLR, steroid use decreases the efficacy of ICI. These results can inform clinicians about the impact of steroids in patients treated with ICI.

Sexually dimorphic radiogenomic models identify distinct imaging and biological pathways that are prognostic of overall survival in glioblastoma

BACKGROUND

Recent epidemiological studies have suggested that sexual dimorphism influences treatment response and prognostic outcome in glioblastoma (GBM). To this end, we sought to (i) identify distinct sex-specific radiomic phenotypes-from tumor subcompartments (peritumoral edema, enhancing tumor, and necrotic core) using pretreatment MRI scans-that are prognostic of overall survival (OS) in GBMs, and (ii) investigate radiogenomic associations of the MRI-based phenotypes with corresponding transcriptomic data, to identify the signaling pathways that drive sex-specific tumor biology and treatment response in GBM.

METHODS

In a retrospective setting, 313 GBM patients (male = 196, female = 117) were curated from multiple institutions for radiomic analysis, where 130 were used for training and independently validated on a cohort of 183 patients. For the radiogenomic analysis, 147 GBM patients (male = 94, female = 53) were used, with 125 patients in training and 22 cases for independent validation.

RESULTS

Cox regression models of radiomic features from gadolinium T1-weighted MRI allowed for developing more precise prognostic models, when trained separately on male and female cohorts. Our radiogenomic analysis revealed higher expression of Laws energy features that capture spots and ripple-like patterns (representative of increased heterogeneity) from the enhancing tumor region, as well as aggressive biological processes of cell adhesion and angiogenesis to be more enriched in the "high-risk" group of poor OS in the male population. In contrast, higher expressions of Laws energy features (which detect levels and edges) from the necrotic core with significant involvement of immune related signaling pathways was observed in the "low-risk" group of the female population.

CONCLUSIONS

Sexually dimorphic radiogenomic models could help risk-stratify GBM patients for personalized treatment decisions.

Impact of EGFR mutation and ALK rearrangement on the outcomes of non-small cell lung cancer patients with brain metastasis

BACKGROUND

The impact of activating alterations in non-small cell lung cancer (NSCLC) (epidermal growth factor receptor [EGFR] mutation/anaplastic lymphoma kinase [ALK] translocation) in prognosticating patients with brain metastasis (BM) is not well defined. This study was sought to identify this impact in NSCLC patients with BM accounting for the known validated variables.

METHODS

Among 1078 NSCLC-BM patients diagnosed/treated between January 1, 2000 and December 31, 2015, three hundred and forty-eight with known EGFR/ALK status were analyzed. Overall survival (OS) and intracranial progression-free survival (PFS) were measured from the time of BM.

RESULTS

Ninety-one patients had either ALK (n = 23) alterations or EGFR (n = 68) mutation and 257 were wild type (WT; negative actionable mutations/alterations). Median age of EGFR/ALK+ NSCLC BM patients was 60 years (range 29.8-82.6 y) and ~50% (n = 44) had Karnofsky performance status (KPS) score >80. Median number of BM was 2 (1 to ≥99). The median OS for the ALK/EGFR+ NSCLC BM was 19.9 versus 10.1 months for the WT (P = 0.028). The number of BM in the EGFR/ALK+ group did not impact OS (BM = 1 with 21.1 months vs 2-3 with 19.1 months and >3 with 23.7 months, P = 0.74), whereas fewer BM in the WT cohort had significantly better OS (BM = 1 with 13.8 mo, 2-3 with 11.0 mo and >3 with 8.1 mo; P = 0.006) with the adjustment of age, KPS, symptoms from BM and synchronicity.

CONCLUSIONS

Number of BM does not impact outcomes in the EGFR/ALK+ NSCLC patients, implying that targeted therapy along with surgery and/or radiation may improve OS irrespective of the number of BM. Number of BM, extracranial metastasis (ECM), and KPS independently affected OS/PFS in WT NSCLC BM, which was consistent with the known literature.

Preclinical Modeling of Surgery and Steroid Therapy for Glioblastoma Reveals Changes in Immunophenotype that are Associated with Tumor Growth and Outcome

PURPOSE

Glioblastoma (GBM) immunotherapy clinical trials are generally initiated after standard-of-care treatment-including surgical resection, perioperative high-dose steroid therapy, chemotherapy, and radiation treatment-has either begun or failed. However, the impact of these interventions on the antitumoral immune response is not well studied. While discoveries regarding the impact of chemotherapy and radiation on immune response have been made and translated into clinical trial design, the impact of surgical resection and steroids on the antitumor immune response has yet to be determined.

EXPERIMENTAL DESIGN

We developed a murine model integrating tumor resection and steroid treatment and used flow cytometry to analyze systemic and local immune changes. These mouse model findings were validated in a cohort of 95 patients with primary GBM.

RESULTS

Using our murine resection model, we observed a systemic reduction in lymphocytes corresponding to increased tumor volume and decreased circulating lymphocytes that was masked by dexamethasone treatment. The reduction in circulating T cells was due to reduced CCR7 expression, resulting in T-cell sequestration in lymphoid organs and the bone marrow. We confirmed these findings in a cohort of patients with primary GBM and found that prior to steroid treatment, circulating lymphocytes inversely correlated with tumor volume. Finally, we demonstrated that peripheral lymphocyte content varies with progression-free survival and overall survival, independent of tumor volume, steroid use, or molecular profiles.

CONCLUSIONS

These data reveal that prior to intervention, increased tumor volume corresponds with reduced systemic immune function and that peripheral lymphocyte counts are prognostic when steroid treatment is taken into account.

Effect of Nivolumab vs Bevacizumab in Patients With Recurrent Glioblastoma: The CheckMate 143 Phase 3 Randomized Clinical Trial

Question

Does programmed cell death 1 immune checkpoint inhibition with nivolumab improve overall survival compared with bevacizumab treatment for patients with recurrent glioblastoma?

Findings

In this randomized phase 3 clinical trial of 369 patients diagnosed with recurrent glioblastoma treated with nivolumab, an improved survival benefit was not observed in patients who received nivolumab compared with bevacizumab-treated control patients.

Meaning

Additional research is needed; nivolumab monotherapy did not improve overall survival compared with bevacizumab in the treatment of recurrent glioblastoma. A study of nivolumab in combination with radiotherapy and temozolomide in patients with newly diagnosed glioblastoma with methylated MGMT promoter is ongoing.

Importance

Clinical outcomes for glioblastoma remain poor. Treatment with immune checkpoint blockade has shown benefits in many cancer types. To our knowledge, data from a randomized phase 3 clinical trial evaluating a programmed death-1 (PD-1) inhibitor therapy for glioblastoma have not been reported.

Objective

To determine whether single-agent PD-1 blockade with nivolumab improves survival in patients with recurrent glioblastoma compared with bevacizumab.

Design, Setting, and Participants

In this open-label, randomized, phase 3 clinical trial, 439 patients with glioblastoma at first recurrence following standard radiation and temozolomide therapy were enrolled, and 369 were randomized. Patients were enrolled between September 2014 and May 2015. The median follow-up was 9.5 months at data cutoff of January 20, 2017. The study included 57 multicenter, multinational clinical sites.

Interventions

Patients were randomized 1:1 to nivolumab 3 mg/kg or bevacizumab 10 mg/kg every 2 weeks until confirmed disease progression, unacceptable toxic effects, or death.

Main Outcomes and Measures

The primary end point was overall survival (OS).

Results

A total of 369 patients were randomized to nivolumab (n = 184) or bevacizumab (n = 185). The MGMT promoter was methylated in 23.4% (43/184; nivolumab) and 22.7% (42/185; bevacizumab), unmethylated in 32.1% (59/184; nivolumab) and 36.2% (67/185; bevacizumab), and not reported in remaining patients. At median follow-up of 9.5 months, median OS (mOS) was comparable between groups: nivolumab, 9.8 months (95% CI, 8.2-11.8); bevacizumab, 10.0 months (95% CI, 9.0-11.8); HR, 1.04 (95% CI, 0.83-1.30); P = .76. The 12-month OS was 42% in both groups. The objective response rate was higher with bevacizumab (23.1%; 95% CI, 16.7%-30.5%) vs nivolumab (7.8%; 95% CI, 4.1%-13.3%). Grade 3/4 treatment-related adverse events (TRAEs) were similar between groups (nivolumab, 33/182 [18.1%]; bevacizumab, 25/165 [15.2%]), with no unexpected neurological TRAEs or deaths due to TRAEs.

Conclusions and Relevance

Although the primary end point was not met in this randomized clinical trial, mOS was comparable between nivolumab and bevacizumab in the overall patient population with recurrent glioblastoma. The safety profile of nivolumab in patients with glioblastoma was consistent with that in other tumor types.

Trial Registration

ClinicalTrials.gov Identifier: NCT02017717

A Phase II and Pharmacodynamic Trial of RO4929097 for Patients With Recurrent/Progressive Glioblastoma

BACKGROUND

Cancer stem-like cells are a major cause of resistance to therapy in patients with glioblastoma (GBM) as well as other cancers. Tumor cells are maintained in a stem-like proliferative state in large part through the Notch signaling pathway. The function of this pathway in turn depends on gamma secretase activity. Inhibition of this enzyme therefore inhibits the Notch pathway and tumor growth as measured by a reduction in the formation of brain tumor neurospheres in murine models. RO4929097 is an oral gamma secretase inhibitor.

OBJECTIVE

To estimate the 6-mo progression-free survival rate (PFS6) in patients with progressive GBM and to inhibit by 50% the generation of neurospheres in fresh tissue resected from patients treated with RO4929097.

METHODS

In this phase II and pharmacodynamic study, patients with recurrent GBM received RO4929097 in a study of 2 groups. Group A patients had unresectable disease and received drug in a standard phase II design. Group B patients had resectable disease and received drug before and after surgical resection. Endpoints included PFS6 and the inhibition of neurosphere formation in the resected tumor samples.

RESULTS

A total of 47 patients received treatment, 7 of whom had tumor resection. The PFS6 was 4%, and the inhibition of neurosphere formation occurred in 1 of 7 patient samples.

CONCLUSION

RO4929097 was inactive in recurrent GBM patients and demonstrated minimal inhibition of neurosphere formation in fresh tissue samples.

Systematic review and meta-analysis of PD-L1 expression discordance between primary tumor and lung cancer brain metastasis

Background

Novel immunotherapeutic strategies targeting the programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) axis are often administered when metastatic tumors show PD-L1 positivity, even in the setting of lung cancer brain metastasis (LCBM). However, biological differences exist between primary tumors and metastatic sites. The objective of this study was to analyze rates of PD-L1 receptor discordance between primary tumors and LCBM.

Methods

A systematic review of studies of biopsied or resected LCBM evaluating PD-L1 discordance published in the Medline database was performed using PRISMA guidelines. Weighted random effects models were used to calculate pooled estimates.

Results

Six full-text articles (n = 230 patients) with a median of 32 patients in each study (range: 24–73) reported PD-L1 receptor expression analyses of both primary lung tumors and brain metastases and met inclusion criteria. The pooled estimate for tumor cell (TC) PD-L1 receptor discordance between primary tumors and LCBM was 19% (95% confidence interval [CI]: 10–27%). For PD-L1 receptor expression in tumor-infiltrating lymphocytes (TIL), the weighted pooled estimate for discordance was 21% (95% CI: 8–44%). For primary versus LCBM, the positive rates by expression levels of <1%, 1–50%, and >50% were 52% (95% CI: 30–73%) versus 56% (95% CI: 34–76%), 30% (95% CI: 22–40%) versus 20% (95% CI: 10–35%), and 15% (95% CI: 6–36%) versus 22% (95% CI: 15–31%) (P = .425), respectively.

Conclusions

PD-L1 discordance occurs in ~20% of LCBM, with the greatest discordance in the 1–50% expression category. Although controversial, confirming discordance might be important for selection of immune checkpoint inhibitor therapy and in the analysis of patterns of failure after treatment.

SATB2 drives glioblastoma growth by recruiting CBP to promote FOXM1 expression in glioma stem cells

Nuclear matrix-associated proteins (NMPs) play critical roles in regulating chromatin organization and gene transcription by binding to the matrix attachment regions (MARs) of DNA. However, the functional significance of NMPs in glioblastoma (GBM) progression remains unclear. Here, we show that the Special AT-rich Binding Protein-2 (SATB2), one of crucial NMPs, recruits histone acetyltransferase CBP to promote the FOXM1-mediated cell proliferation and tumor growth of GBM. SATB2 is preferentially expressed by glioma stem cells (GSCs) in GBM. Disrupting SATB2 markedly inhibited GSC proliferation and GBM malignant growth by down-regulating expression of key genes involved in cell proliferation program. SATB2 activates FOXM1 expression to promote GSC proliferation through binding to the MAR sequence of FOXM1 gene locus and recruiting CBP to the MAR. Importantly, pharmacological inhibition of SATB2/CBP transcriptional activity by the CBP inhibitor C646 suppressed GSC proliferation in vitro and GBM growth in vivo. Our study uncovers a crucial role of the SATB2/CBP-mediated transcriptional regulation in GBM growth, indicating that targeting SATB2/CBP may effectively improve GBM treatment.

Stereotactic radiosurgery with concurrent HER2-directed therapy is associated with improved objective response for breast cancer brain metastasis

BACKGROUND

Patients with breast cancer positive for human epidermal growth factor receptor 2 (HER2) remain at high risk of intracranial relapse following treatment and experience increased rates of intracranial failure after stereotactic radiosurgery (SRS). We hypothesized that the addition of concurrent lapatinib to SRS would improve intracranial complete response rates.

METHODS

Patients with newly diagnosed HER2-amplified breast cancer brain metastases from 2005-2014 who underwent SRS were included and divided into 2 cohorts based on timing of treatment with lapatinib. Outcome variables included the proportion of patients who achieved an intracranial complete response or progressive disease according to the RECIST 1.1 criteria, as well as individual lesion response rates, distant intracranial failure, and radiation necrosis.

RESULTS

Eighty-four patients with 487 brain metastases met inclusion criteria during the study period. Over 138 treatment sessions, 132 lesions (27%) were treated with SRS and concurrent lapatinib, while 355 (73%) were treated with SRS without lapatinib. Compared with patients treated with SRS alone, patients treated with concurrent lapatinib had higher rates of complete response (35% vs 11%, P = 0.008). On a per-lesion basis, best objective response was superior in the concurrent lapatinib group (median 100% vs 70% reduction, P < 0.001). Concurrent lapatinib was not associated with an increased risk of grade 2+ radiation necrosis (1.0% with concurrent lapatinib vs 3.5% without, P = 0.27). Lapatinib had no protective effect on distant intracranial failure rates (48% vs 49%, P = 0.91).

CONCLUSION

The addition of concurrent lapatinib to SRS was associated with improved complete response rates among patients with HER2-positive brain metastases.