Selective suppression of melanoma lacking IFN-γ pathway by JAK inhibition depends on T cells and host TNF signaling

Therapeutic resistance to immune checkpoint blockers (ICBs) in melanoma patients is a pressing issue, of which tumor loss of IFN-γ signaling genes is a major underlying mechanism. However, strategies of overcoming this resistance mechanism have been largely elusive. Moreover, given the indispensable role of tumor-infiltrating T cells (TILs) in ICBs, little is known about how tumor-intrinsic loss of IFN-γ signaling (IFNγR1^KO) impacts TILs. Here, we report that IFNγR1^KO melanomas have reduced infiltration and function of TILs. IFNγR1^KO melanomas harbor a network of constitutively active protein tyrosine kinases centered on activated JAK1/2. Mechanistically, JAK1/2 activation is mediated by augmented mTOR. Importantly, JAK1/2 inhibition with Ruxolitinib selectively suppresses the growth of IFNγR1^KO but not scrambled control melanomas, depending on T cells and host TNF. Together, our results reveal an important role of tumor-intrinsic IFN-γ signaling in shaping TILs and manifest a targeted therapy to bypass ICB resistance of melanomas defective of IFN-γ signaling.

Stereotactic radiosurgery for ruptured versus unruptured intracranial arteriovenous malformations

Background:

There are a limited data examining the effects of prior hemorrhage on outcomes after stereotactic radiosurgery (SRS). The goal of this study was to identify risk factors for arteriovenous malformation (AVM) rupture and compare outcomes, including post-SRS hemorrhage, between patients presenting with ruptured and unruptured AVMs.

Methods:

A retrospective review of consecutive patients undergoing SRS for intracranial AVMs between 2009 and 2019 at our institution was conducted. Chi-square and multivariable logistic regression analyses were utilized to identify patient and AVM factors associated with AVM rupture at presentation and outcomes after SRS including the development of recurrent hemorrhage in both ruptured and unruptured groups.

Results:

Of 210 consecutive patients with intracranial AVMs treated with SRS, 73 patients (34.8%) presented with AVM rupture. Factors associated with AVM rupture included smaller AVM diameter, deep venous drainage, cerebellar location, and the presence of intranidal aneurysms (P < 0.05). In 188 patients with adequate follow-up time (mean 42.7 months), the overall post-SRS hemorrhage rate was 8.5% and was not significantly different between ruptured and unruptured groups (10.3 vs. 7.5%, P = 0.51). There were no significant differences in obliteration rate, time to obliteration, or adverse effects requiring surgery or steroids between unruptured and ruptured groups.

Conclusion:

Smaller AVM size, deep venous drainage, and associated intranidal aneurysms were associated with rupture at presentation. AVM rupture at presentation was not associated with an increased risk of recurrent hemorrhage or other complication after SRS when compared to unruptured AVM presentation. Obliteration rates were similar between ruptured and unruptured groups.

Predictive Factors for AVM Obliteration after Stereotactic Radiosurgery: A Single Center Study

BACKGROUND

SRS is particularly useful for deep AVMs in eloquent territory with a high associated surgical risk. Prior studies have demonstrated high rates of AVM obliteration with SRS typically ranging 60-80% in a latency period of 2-4 years for complete obliteration. Studies have identified several factors associated with successful obliteration of the AVM nidus, however, these present inconsistent and conflicting data.

OBJECTIVE

To present a single center study examining factors associated with successful obliteration of AVMs treated with SRS.

METHODS

We performed a retrospective review of 210 consecutive patients undergoing SRS for brain AVMs between 2010 and 2019 at our institution. Chi square and logistic regression analyses were utilized to identify patient and AVM factors associated with successful obliteration.

RESULTS

Younger age (p=0.034) and prior embolization (p=0.012) were associated with complete obliteration. Figure 2 demonstrates survival curves for those with complete obliteration comparing those with prior embolization (n = 6) to those without prior embolization (n = 182). The presence of coronary artery disease (CAD) was associated with incomplete obliteration (p=0.04). There were no AVM characteristics statistically associated with complete obliteration although superficial venous drainage (p=0.08) and frontal location (p=0.06) trended towards significance.

CONCLUSIONS

Successful obliteration of the AVM nidus was significantly associated with younger age and prior embolization. The presence of coronary artery disease negatively affected obliteration rates. These results add to the mixed results seen in the literature and emphasize the need for continued studies to delineate more specific patient and AVM factors that contribute to successful obliteration.

Seizure Rates After Stereotactic Radiosurgery for Cerebral AVMs: A Single Center Study

OBJECTIVES

Seizure control after stereotactic radiosurgery (SRS) for arteriovenous malformations (AVMs) is an area of growing interest, with previous studies reporting up to 70% seizure freedom after treatment. The goals of this study were to identify specific patient and AVM characteristics associated with seizure presentation and seizure outcomes after SRS treatment.

METHODS

A retrospective review of consecutive patients undergoing SRS for brain AVMs between 2009 and 2019 at our institution was conducted. Chi-squared and logistic regression analyses were utilized to identify patient and AVM factors associated with preoperative seizure presentation and development of new onset seizures after SRS.

RESULTS

Two hundred ten consecutive patients presenting with AVMs treated with SRS were reviewed. Factors associated with seizure presentation included larger AVM size (P = 0.02), superficial venous drainage (P < 0.05), and parietal location (P = 0.04). Of 188 patients with follow-up (90%), 30 patients presented with seizures and 14 (47%) were seizure-free post-SRS. Of 158 patients presenting without seizure, 29 (18%) developed de novo seizures during follow-up. De novo post-SRS seizures were associated with prior craniotomy for resection of AVM (P = 0.04), post-treatment hemorrhage (P = 0.02), parietal location (P = 0.05), adverse effect requiring steroids (P < 0.01), and adverse effect requiring surgery (P < 0.01).

CONCLUSIONS

Seizures are a common presentation of brain AVMs and can be treated effectively with SRS. However, seizures can also be a complication of SRS and are associated with post-treatment hemorrhage, edema, and need for future open surgery.

NCOG-68. COMPARING COGNITIVE PROFILES OF PERSONS WITH BRAIN AND NON-BRAIN METASTATIC CANCER

OBJECTIVE

Cognitive impairment in primary cancer and brain metastatic (BM) cancer has been well-documented. However, to date, there are no neuropsychological studies comparing the cognitive profiles of people with BM and non-brain metastatic cancer (NBM). The present study addressed this gap in the literature by comparing the cognitive profiles of participants with BM and NBM.

METHOD

The study sample consisted of 61 BM, 40 NBM, and 37 healthy control (HC) participants. All participants completed the same neuropsychological battery, including tests of processing speed, attention, working memory, expressive language, auditory-verbal memory, and executive functioning.

RESULTS

Both clinical groups showed reduced processing speed, verbal learning/memory, and executive functions. BM participants performed below HC participants across all neuropsychological tests, while NBM participants performed below control participants on tests of processing speed and executive functioning. The clinical groups differed in semantic verbal fluency (NBM &gt; BM). Fifty-seven percent of BM participants had ≥ 3 impaired scores (i.e., ≤ 5th percentile), and 25% of NBM participants had the same level of cognitive impairment.

CONCLUSION

Over half of BM participants were cognitively impaired on at least three neuropsychological tests, and 25% of NBM participants also demonstrated this same level of cognitive impairment. In the BM group, the elevated rate of cognitive dysfunction is likely due to the greater neurologic disease burden posed by brain metastases, while in the NBM group, the cognitive deficits are possibly due to systemic illness and treatment effects.

RADT-36. PROSPECTIVELY ASSESSED TUMOR CONTROL AND TOXICITY OF BENIGN INTRACRANIAL PATHOLOGIES TREATED WITH AUTOMATED VMAT RADIOSURGERY – INITIAL 2 YEAR EXPERIENCE WITH FIRST 100 PATIENTS

BACKGROUND

HyperArc is a treatment planning technology that automates treatment planning and delivery of single-isocenter VMAT radiosurgery (SRS). The technique generates high quality, rapidly deliverable plans. It is unknown whether HyperArc is effective for commonly-encountered, benign, intracranial conditions managed with SRS. Under IRB-approved prospective registry, we collected data on treatment planning/delivery, and clinical outcomes of non-malignant conditions managed with single-fraction or fractionated SRS since deployment in October 2017.

METHODS

Patients received either single-fraction or fractionated SRS with HyperArc™ (Varian Medical Systems) between October 2017 & October 2019. Patients with &lt; 3 months follow-up were censored. All patients treated received prescription dose to ≥ 99% of gross tumor volume without PTV expansion. All treatments were delivered on Varian Edge linac with 10MV flattening-filter free beam at 2400 MU/min with high-definition (2.5mm) multi-leaf collimator. Standard pathology-specific outcomes and toxicities were assessed. Significant CNS toxicity was defined as Grade 3 or higher event by CTCAE.

RESULTS

Total of 100 targets (min=0.13cc, max=58.9cc) were treated. 55 received single-fraction SRS (12-22Gy), two received 2-fraction fSRS boost (12Gy) following fractionated treatment, and 43 received 5-fraction fSRS (25-30Gy). The most common pathology was meningioma (n=55), followed by AVM (n=18), non-secretory pituitary adenoma (n=12), acoustic schwannoma (n=9), secretory pituitary adenoma (n=3), glomus tumor (n=2), pineocytoma (n=1), and paraganglioma (n=1). Follow-up ranged from 1.2 to 19.5 months (median 7.2). There were three local failures, all in atypical meningiomas. One patient in the cohort experienced ≥Gr3 toxicity. Each radiosurgery session used median of 3 arcs, with median treatment and beam-on time of 12.03 and 2.3 minutes. Plan quality was excellent; median RTOG conformity was 1.15, and median Paddick GI was 3.52.

CONCLUSION

Although HyperArc was developed for automated multiple-metastasis radiosurgery, we found it effective and efficient for benign intracranial indications too. Early clinical outcomes appear congruent with historical controls.

EPID-14. RACIAL DIFFERENCES AND DISPARITIES IN PATIENTS WITH GLIOMAS: A SINGLE COMPREHENSIVE CANCER CENTER EXPERIENCE FROM 2008–2020

BACKGROUND

Disparities in healthcare delivery in the United States based on race and socioeconomic status are well-documented. Our study examined these disparities along with demographic differences in patients with gliomas.

METHODS

Data was collected retrospectively from an NCI Comprehensive Cancer Center between 2008–2020; 163 African-American patients and 1207 non-Hispanic white patients were included. Demographic variables were entered as predictors of tumor grade and type in an ANOVA model and multinomial logistic regression, respectively. A MANOVA model was used to assess differences in treatments received. Predictors of outcome were determined using cox regression.

RESULTS

Significant differences (p&lt; 0.05) were found between African-American and non-Hispanic white patient groups in; age at diagnosis (48.68 vs 56.12 years, respectively), male/female gender ratio (0.75 vs 1.22), annual household income ($29,442 vs $40,028), insurance type (53.1% private and 42% public vs 63.4% private and 33.6% public) and marital status (43% married vs 74.1%). When controlling for these, there were no significant differences in tumor grade, type, MGMT methylation or IDH1 alteration statuses. Race alone did not predict treatment received, however, two-way interactions between race and other variables did. While gender differences in resection were small for non-Hispanic white controls, resection took place more often in African-American females than males (F = 4.779, p = 0.029). The deleterious effect of increased age on overall survival was diminished in African-Americans (B = -0.033, p &lt; 0.001), while the effect of tumor grade was more pronounced (B = 0.595, p &lt; 0.001).

DISCUSSION

This study suggests that disparities in outcomes are identified when race is considered within the context of other demographic, socioeconomic, and clinical factors. Moreover, these observations demonstrate the need for further studies into intersectional effects on treatment access and clinical outcomes, along with aggressive countermeasures to ensure equity of care.

Design and Rationale for First-in-Human Phase 1 Immunovirotherapy Clinical Trial of Oncolytic HSV G207 to Treat Malignant Pediatric Cerebellar Brain Tumors

Brain tumors represent the most common pediatric solid neoplasms and leading cause of childhood cancer-related morbidity and mortality. Although most adult brain tumors are supratentorial and arise in the cerebrum, the majority of pediatric brain tumors are infratentorial and arise in the posterior fossa, specifically the cerebellum. Outcomes from malignant cerebellar tumors are unacceptable despite aggressive treatments (surgery, radiation, and/or chemotherapy) that are harmful to the developing brain. Novel treatments/approaches such as oncolytic virotherapy are urgently needed. Preclinical and prior clinical studies suggest that genetically engineered oncolytic herpes simplex virus (HSV-1) G207 can safely target cerebellar malignancies and has potential to induce an antitumor immune response at local and distant sites of disease, including spinal metastases and leptomeningeal disease. Herein, we outline the rationale, design, and significance of a first-in-human immunotherapy Phase 1 clinical trial targeting recurrent cerebellar malignancies with HSV G207 combined with a single low-dose of radiation (5 Gy), designed to enhance virus replication and innate and adaptive immune responses. We discuss the unique challenges of inoculating virus through intratumoral catheters into cerebellar tumors. The trial utilizes a single arm open-label traditional 3 + 3 design with four dose cohorts. The primary objective is to assess safety and tolerability of G207 with radiation in recurrent/progressive malignant pediatric cerebellar tumors. After biopsy to prove recurrence/progression, one to four intratumoral catheters will be placed followed by a controlled-rate infusion of G207 for 6 h followed by the removal of catheters at the bedside. Radiation will be given within 24 h of virus inoculation. Patients will be monitored closely for toxicity and virus shedding. Efficacy will be assessed by measuring radiographic response, performance score, progression-free and overall survival, and quality of life. The data obtained will be invaluable in our efforts to produce more effective and less toxic therapies for children with high-grade brain tumors.

Clinical correlates of the ability to consent to research participation in brain metastasis

OBJECTIVE

Impairment in the ability to provide informed consent is common in persons with brain metastasis. However, little is known about what factors contribute to this impairment in the patient group. Our objective is to determine if the associations between demographic, cognitive, and clinical variables correlate with the ability to provide informed consent in persons with brain metastasis.

METHODS

We administered a comprehensive neuropsychological battery to a group of 61 persons with brain metastasis. Demographic and clinical information was also collected. All diagnoses were made by board-certified oncologists and were verified histologically. Statistical analyses included Pearson's product-moment correlations, point biserial correlations, and linear regression.

RESULTS

Results indicated that combinations of education, verbal memory, executive function, whole brain radiation therapy, and chemotherapy affected various aspects of the ability to provide informed consent. Subsequent regression models demonstrated that these variables contributed a significant amount of shared variance to the ability to provide informed consent.

CONCLUSION

We found that the ability of persons with brain metastasis to provide informed consent is a cognitively complex ability that is also affected by education and treatment variables. This information can help clinical researchers in identifying persons with brain metastasis at risk of an impaired ability to provide informed consent and aid in the consenting process.

Capacity to consent to research participation in adults with metastatic cancer: comparisons of brain metastasis, non-CNS metastasis, and healthy controls

Background

To evaluate the ability of individuals with metastatic cancer to provide informed consent to research participation, we used a structured vignette-based interview to measure 4 consenting standards across 3 participant groups.

Methods

Participants included 61 individuals diagnosed with brain metastasis, 41 individuals diagnosed with non-CNS metastasis, and 17 cognitively intact healthy controls. All groups were evaluated using the Capacity to Consent to Research Instrument (CCRI), a performance-based measure of research consent capacity. The ability to provide informed consent to participate in research was evaluated across 4 consent standards: expressing choice, appreciation, reasoning, and understanding. Capacity performance ratings (intact, mild/moderate impairment, severe impairment) were identified based on control group performance.

Results

Results revealed that the brain metastasis group performed significantly lower than healthy controls on the consent standard of understanding, while both metastatic cancer groups performed below controls on the consent standard of reasoning. Both metastatic cancer groups performed similar to controls on the standards of appreciation and expressing choice. Approximately 60% of the brain metastasis group, 54% of the non-CNS metastasis group, and 18% of healthy controls showed impaired research consent capacity.

Conclusions

Our findings, using a performance-based assessment, are consistent with other research indicating that the research consent process may be overly cumbersome and confusing. This, in turn, may lead to research consent impairment not only in patient groups but also in some healthy adults with intact cognitive ability.

LINAC based stereotactic radiosurgery for multiple brain metastases: guidance for clinical implementation

Introduction: Stereotactic radiosurgery (SRS) is a promising treatment option for patients with multiple brain metastases (BM). Recent technical advances have made LINAC based SRS a patient friendly technique, allowing for accurate patient positioning and a short treatment time. Since SRS is increasingly being used for patients with multiple BM, it remains essential that SRS be performed with the highest achievable quality in order to prevent unnecessary complications such as radionecrosis. The purpose of this article is to provide guidance for high-quality LINAC based SRS for patients with BM, with a focus on single isocenter non-coplanar volumetric modulated arc therapy (VMAT). Methods: The article is based on a consensus statement by the study coordinators and medical physicists of four trials which investigated whether patients with multiple BM are better palliated with SRS instead of whole brain radiotherapy (WBRT): A European trial (NCT02353000), two American trials and a Canadian CCTG lead intergroup trial (CE.7). This manuscript summarizes the quality assurance measures concerning imaging, planning and delivery. Results: To optimize the treatment, the interval between the planning-MRI (gadolinium contrast-enhanced, maximum slice thickness of 1.5 mm) and treatment should be kept as short as possible (< two weeks). The BM are contoured based on the planning-MRI, fused with the planning-CT. GTV-PTV margins are minimized or even avoided when possible. To maximize efficiency, the preferable technique is single isocenter (non-)coplanar VMAT, which delivers high doses to the target with maximal sparing of the organs at risk. The use of flattening filter free photon beams ensures a lower peripheral dose and shortens the treatment time. To bench mark SRS treatment plan quality, it is advisable to compare treatment plans between hospitals. Conclusion: This paper provides guidance for quality assurance and optimization of treatment delivery for LINAC-based radiosurgery for patients with multiple BM.

RADI-18. STEREOTACTIC RADIOSURGERY OR FRACTIONATED STEREOTACTIC RADIOSURGERY FOR BRAIN METASTASES FROM SMALL CELL LUNG CANCER

BACKGROUND: Current standard of care (SOC) management of the brain differs between non-small cell lung cancer (NSCLC) & small cell lung cancer (SCLC). For SCLC, WBRT is considered SOC, even for solitary metastasis. In the setting of no-known metastases, prophylactic cranial irradiation (PCI) is considered SOC. SRS is occasionally utilized in SCLC, e.g. in setting of limited metastasis after WBRT/PCI, or limited metastasis after excellent systemic response to extracranial therapy, or if patient declines WBRT. In this study, we sought to understand more about the nature and outcomes of patients with SCLC who received intracranial SRS at our institution. METHODS: We reviewed radiosurgery treatments from 2005 thru 2019 for patients with SCLC who received SRS. Variables included were: time interval between diagnosis/SRS and death, prior WBRT/ PCI, number of targets, performance status, modality (GK or linac), prior surgery, and available follow-up. RESULTS: We identified 92 SRS treatments among 74 patients. 30 received upfront SRS, the remainder as post-WBRT/PCI salvage. Median survival after initial diagnosis was 22.0 months (min = 6.6, max 55.4). Median survival after first SRS was 6.1 months (min = 0.5, max = 40.4). Median recorded KPS was 75.6. Mean number of mets treated was 3.4 (min = 1, max = 12). Prescription dose range was 12 to 20Gy in single fraction, and 25 to 30Gy in five fraction treatment. 53 treatments were performed on Gamma Knife, 37 with linear accelerator. Four patients were treated post-operatively, one patient was treated pre-operatively. CONCLUSIONS: Survival in our cohort of SCLC patients receiving intracranial SRS compared favorably with historical SCLC controls (8-13mo after dx). Future work will seek to clarify whether there is a difference in brain metastasis velocity between patients treated with upfront PCI/WBRT or SRS, and also seek to address the minimum necessary dose to control SCLC metastases.

RADI-31. MULTI-INSTITUTIONAL VALIDATION OF BRAIN METASTASIS VELOCITY, A RECENTLY DEFINED PREDICTOR OF OUTCOMES FOLLOWING STEREOTACTIC RADIOSURGERY

INTRODUCTION: Brain metastasis velocity (BMV) is a prognostic metric that describes the recurrence rate of new brain metastases after initial treatment with radiosurgery (SRS). We have previously risk stratified patients into high, intermediate, and low-risk BMV groups, which correlates with overall survival (OS). We sought to externally validate BMV in a multi-institutional setting. METHODS: Patients from nine academic centers were treated with upfront SRS; the validation cohort consisted of data from eight institutions not previously used to define BMV. Patients were classified by BMV into low (< 4 BMV), intermediate (4–13 BMV), and high-risk groups (>13 BMV). Time-to-event outcomes were estimated using the Kaplan-Meier method. Cox proportional hazards methods were used to estimate the effect of BMV and salvage modality on OS. RESULTS: Of 2829 patients, 2092 patients were included in the validation dataset. Of these, 921 (44.0%) experienced distant brain failure (DBF). Median OS from initial SRS was 11.2 mo. Median OS for BMV < 4, BMV 4–13, and BMV > 13 were 12.5 mo, 7.0 mo, and 4.6 mo (p < 0.0001). Compared to initial salvage with WBRT, salvage SRS was associated with improved OS following DBF for BMV < 4 (p = 0.05), BMV 4–13 (p = 0.002) and BMV > 13 (p = 0.0001). CONCLUSIONS: This multi-institutional dataset validates BMV as a predictor of OS following initial SRS. BMV is being utilized in upcoming multi-institutional randomized controlled trials as a stratification variable for salvage whole brain radiation vs salvage SRS after DBF.

OTHR-05. THE ABILITY TO MAKE INFORMED TREATMENT DECISIONS IS COMPROMISED IN ADULTS WITH ADVANCED STAGE CANCER

OBJECTIVE: To investigate medical decision-making capacity (MDC) in patients with advanced stage cancer. METHODS: Participants were 113 newly diagnosed adults with brain metastases and 41 adults with metastatic cancer without brain metastases who were recruited from an academic medical center and 40 demographically-matched healthy controls recruited from the community. We evaluated MDC using the Capacity to Consent to Treatment Instrument (CCTI) Vignette B and its four clinically relevant consent standards (expressing a treatment choice, appreciation, reasoning, and understanding). Capacity impairment ratings (no impairment, mild/moderate impairment, and severe impairment) on the consent standards were also assigned to each participant using cutoff scores derived statistically from the performance of the control group. RESULTS: Both of the metastatic cancer groups (with and without brain metastasis) performed significantly below controls on consent standards of understanding and reasoning. The brain metastasis group performed below the non-metastatic cancer group on understanding. Capacity compromise was defined as performance ≤1.5 standard deviations (SD) below the control group mean. Using this definition, approximately 65% of the participants with brain metastases and 51% of participants with metastatic cancer without brain metastases were impaired on at least one MDC standard. CONCLUSION: Over half of participants with metastatic cancer regardless of whether they have brain disease have reduced capacity to make treatment decisions. The finding of impaired MDC in patients without brain metastases is surprising and suggests this group likely exhibits cognitive deficits that impact their ability to understand and reason about different treatment options. The reasons underlying this impairment will be investigated. This highlights the importance of routine clinical assessment of MDC in all patients with metastatic cancer when important treatment decisions are being discussed. These results also indicate a need for the development and investigation of interventions to support or improve MDC in this patient population.

RADI-12. LEPTOMENINGEAL FAILURE AFTER PREOPERATIVE VERSUS POSTOPERATIVE RADIOSURGERY

INTRODUCTION: Postoperative stereotactic radiosurgery (postop SRS) is potentially complicated by difficulty defining the target volume and the risk of leptomeningeal seeding at the time of surgery. It is hypothesized that preop SRS may render cells less viable to disseminate in the leptomeningeal space. This retrospective study compares the leptomeningeal dissemination (LMD) rate for preop versus postop radiosurgery METHODS: We identified 140 patients with brain metastases who underwent resection and radiosurgery at the University of Alabama at Birmingham including 91 postop patients (2005–2015) and 49 preop patients (2011–2018). The preop group included 19 patients enrolled in a phase I trial of preoperative radiosurgery (12–15 Gy) for tumors 2–6 cm in greatest diameter. In that study 15 Gy was found to be safe in the preop setting but further escalation was not attempted. An additional 30 patients received preop SRS off-study (median dose 15 Gy). The median postop dose was 16 Gy. LMD recurrence was defined as focal pachymeningeal or diffuse leptomeningeal enhancement of the brain, spinal cord, or cauda equina, dural enhancement beyond 5 mm from the index metastasis, subependymal enhancement, or enhancement of cranial nerves. This definition is not limited to carcinomatosis. All events were categorized and confirmed by at least two physicians. RESULTS: 40/140 (29%) patients developed new focal or diffuse LMD. Preop SRS was associated with a higher freedom from leptomeningeal recurrence (84% vs 60% at one year, p=0.021 Breslow, p=0.128 log-rank). Since later LMD may not be related to surgery, a second analysis censoring follow-up at one year was performed and confirmed this trend (p=0.008 Breslow, p=0.014 log-rank). CONCLUSIONS: Preoperative SRS is associated with a reduction in the risk of LMD compared to postop SRS. Focal pachymeningeal dissemination may not always be recognized as related to surgery. A randomized trial of preop vs postop SRS is warranted.

Predictive biomarkers for immune checkpoint blockade and opportunities for combination therapies

Immune checkpoint blockade therapies (ICBs) are a prominent breakthrough in cancer immunotherapy in recent years (named the 2013 “Breakthrough of the Year” by the Science magazine). Thus far, FDA-approved ICBs primarily target immune checkpoints CTLA-4, PD-1, and PD-L1. Notwithstanding their impressive long-term therapeutic benefits, their efficacy is limited to a small subset of cancer patients. In addition, ICBs induce inadvertent immune-related adverse events (irAEs) and can be costly for long-term use. To overcome these limitations, two strategies are actively being pursued: identification of predictive biomarkers for clinical response to ICBs and multi-pronged combination therapies. Biomarkers will allow clinicians to practice a precision medicine approach in ICBs (biomarker-based patient selection) such as treating triple-negative breast cancer patients that exhibit PD-L1 staining of tumor-infiltrating immune cells in ≥1% of the tumor area with nanoparticle albumin-bound (nab)–paclitaxel plus anti-PD-L1 and treating patients of MSI-H or MMR deficient unresectable or metastatic solid tumors with pembrolizumab (anti-PD-1). Importantly, the insights gained from these biomarker studies can guide rational combinatorial strategies such as CDK4/6 inhibitor/fractionated radiotherapy/HDACi in conjunction with ICBs to maximize therapeutic benefits. Further, with the rapid technological advents (e.g., ATCT-Seq), we predict more reliable biomarkers will be identified, which in turn will inspire more promising combination therapies.

Diagnosing growth in low-grade gliomas with and without longitudinal volume measurements: A retrospective observational study

BACKGROUND

Low-grade gliomas cause significant neurological morbidity by brain invasion. There is no universally accepted objective technique available for detection of enlargement of low-grade gliomas in the clinical setting; subjective evaluation by clinicians using visual comparison of longitudinal radiological studies is the gold standard. The aim of this study is to determine whether a computer-assisted diagnosis (CAD) method helps physicians detect earlier growth of low-grade gliomas.

METHODS AND FINDINGS

We reviewed 165 patients diagnosed with grade 2 gliomas, seen at the University of Alabama at Birmingham clinics from 1 July 2017 to 14 May 2018. MRI scans were collected during the spring and summer of 2018. Fifty-six gliomas met the inclusion criteria, including 19 oligodendrogliomas, 26 astrocytomas, and 11 mixed gliomas in 30 males and 26 females with a mean age of 48 years and a range of follow-up of 150.2 months (difference between highest and lowest values). None received radiation therapy. We also studied 7 patients with an imaging abnormality without pathological diagnosis, who were clinically stable at the time of retrospective review (14 May 2018). This study compared growth detection by 7 physicians aided by the CAD method with retrospective clinical reports. The tumors of 63 patients (56 + 7) in 627 MRI scans were digitized, including 34 grade 2 gliomas with radiological progression and 22 radiologically stable grade 2 gliomas. The CAD method consisted of tumor segmentation, computing volumes, and pointing to growth by the online abrupt change-of-point method, which considers only past measurements. Independent scientists have evaluated the segmentation method. In 29 of the 34 patients with progression, the median time to growth detection was only 14 months for CAD compared to 44 months for current standard of care radiological evaluation (p < 0.001). Using CAD, accurate detection of tumor enlargement was possible with a median of only 57% change in the tumor volume as compared to a median of 174% change of volume necessary to diagnose tumor growth using standard of care clinical methods (p < 0.001). In the radiologically stable group, CAD facilitated growth detection in 13 out of 22 patients. CAD did not detect growth in the imaging abnormality group. The main limitation of this study was its retrospective design; nevertheless, the results depict the current state of a gold standard in clinical practice that allowed a significant increase in tumor volumes from baseline before detection. Such large increases in tumor volume would not be permitted in a prospective design. The number of glioma patients (n = 56) is a limitation; however, it is equivalent to the number of patients in phase II clinical trials.

CONCLUSIONS

The current practice of visual comparison of longitudinal MRI scans is associated with significant delays in detecting growth of low-grade gliomas. Our findings support the idea that physicians aided by CAD detect growth at significantly smaller volumes than physicians using visual comparison alone. This study does not answer the questions whether to treat or not and which treatment modality is optimal. Nonetheless, early growth detection sets the stage for future clinical studies that address these questions and whether early therapeutic interventions prolong survival and improve quality of life.

Stereotactic radiosurgery with MLC-defined arcs: Verification of dosimetry, spatial accuracy, and end-to-end tests

Purpose

To measure dosimetric and spatial accuracy of stereotactic radiosurgery (SRS) delivered to targets as small as the trigeminal nerve (TN) using a standard external beam treatment planning system (TPS) and multileaf collimator‐(MLC) equipped linear accelerator without cones or other special attachments or modifications.

Methods

Dosimetric performance was assessed by comparing computed dose distributions to film measurements. Comparisons included the γ‐index, beam profiles, isodose lines, maximum dose, and spatial accuracy. Initially, single static 360° arcs of MLC‐shaped fields ranging from 1.6 × 5 to 30 × 30 mm² were planned and delivered to an in‐house built block phantom having approximate dimensions of a human head. The phantom was equipped with markings that allowed accurate setup using planar kV images. Couch walkout during multiple‐arc treatments was investigated by tracking a ball pointer, initially positioned at cone beam computed tomography (CBCT) isocenter, as the couch was rotated. Tracks were mapped with no load and a 90 kg stack of plastic plates simulating patient treatment. The dosimetric effect of walkout was assessed computationally by comparing test plans that corrected for walkout to plans that neglected walkout. The plans involved nine 160° arcs of 2.4 × 5 mm² fields applied at six different couch angles. For end‐to‐end tests that included CT simulation, target contouring, planning, and delivery, a cylindrical phantom mimicking a 3 mm lesion was constructed and irradiated with the nine‐arc regimen. The phantom, lacking markings as setup aids was positioned under CBCT guidance by registering its surface and internal structures with CTs from simulation. Radiochromic film passing through the target center was inserted parallel to the coronal and the sagittal plane for assessment of spatial and dosimetric accuracy.

Results

In the single‐arc block phantom tests computed maximum doses of all field sizes agreed with measurements within 2.4 ± 2.0%. Profile widths at 50% maximum agreed within 0.2 mm. The largest targeting error was 0.33 mm. The γ‐index (3%, 1 mm) averaged over 10 experiments was >1 in only 1% of pixels for field sizes up to 10 × 10 mm² and rose to 4.4% as field size increased to 20 × 20 mm². Table walkout was not affected by load. Walkout shifted the target up to 0.6 mm from CBCT isocenter but, according to computations shifted the dose cloud of the nine‐arc plan by only 0.16 mm. Film measurements verified the small dosimetric effect of walkout, allowing walkout to be neglected during planning and treatment. In the end‐to‐end tests average and maximum targeting errors were 0.30 ± 0.10 and 0.43 mm, respectively. Gamma analysis of coronal and sagittal dose distributions based on a 3%/0.3 mm agreement remained <1 at all pixels. To date, more than 50 functional SRS treatments using MLC‐shaped static field arcs have been delivered.

Conclusion

Stereotactic radiosurgery (SRS) can be planned and delivered on a standard linac without cones or other modifications with better than 0.5 mm spatial and 5% dosimetric accuracy.

Multi-institutional competing risks analysis of distant brain failure and salvage patterns after upfront radiosurgery without whole brain radiotherapy for brain metastasis

Background

In this study, we use a competing risks analysis to assess factors predictive of early-salvage whole brain radiotherapy (WBRT) and early death after upfront stereotactic radiosurgery (SRS) alone for brain metastases in an attempt to identify populations that benefit less from upfront SRS.

Patients and methods

Patients from eight academic centers were treated with SRS for brain metastasis. Competing risks analysis was carried out for distant brain failure (DBF) versus death prior to DBF as well as for salvage SRS versus salvage WBRT versus death prior to salvage. Linear regression was used to determine predictors of the number of brain metastases at initial DBF (nDBF).

Results

A total of 2657 patients were treated with upfront SRS alone. Multivariate analysis (MVA) identified an increased hazard of DBF associated with increasing number of brain metastases (P < 0.001), lowest SRS dose received (P < 0.001), and melanoma histology (P < 0.001), while there was a decreased hazard of DBF associated with increasing age (P < 0.001), KPS < 70 (P < 0.001), and progressive systemic disease (P = 0.004). MVA for first salvage SRS versus WBRT versus death prior to salvage revealed an increased hazard of first salvage WBRT seen with increasing number of brain metastases (P < 0.001) and a decreased hazard with widespread systemic disease (P = 0.002) and increasing age (P < 0.001). Variables associated with nDBF included age (P = 0.02), systemic disease status (P = 0.03), melanoma histology (P = 0.05), and initial number of brain metastases (P < 0.001).

Conclusions

Patients with a higher initial number of brain metastases were more likely to experience DBF, have a higher nDBF, and receive early-salvage WBRT, while patients who were older, had lower KPS, or had more systemic disease were more likely to experience death prior to DBF or salvage WBRT.

Expert consensus on re-irradiation for recurrent glioma

Purpose

To investigate radiation oncologists’ opinions on important considerations to offering re-irradiation (re-RT) as a treatment option for recurrent glioma.

Materials and methods

A survey was conducted with 13 radiation oncologists involved in the care of central nervous system tumor patients. The survey was comprised of 49 questions divided into 2 domains: a demographic section (10 questions) and a case section (5 re-RT cases with 5 to 6 questions representing one or several re-RT treatment dilemmas as may be encountered in the clinic). Respondents were asked to rate the relevance of various factors to offering re-RT, respond to the cases with a decision to offer re-RT vs. not, volume to be treated, margins to be employed, dose/fractionation suggested and any additional comments with respect to rationale in each scenario.

Results

Sixty nine percent of responders have been practicing for greater than 10 years and 61% have re-RT 20 to 100 patients to date, with 54% seeing 2–5 re-RT cases per month and retreating 1–2 patients per month. Recurrent tumor volume, time since previous radiation therapy, previously administered dose to organs at risk and patient performance status were rated by the majority of responders (85%, 92%, 77%, and 69% respectively) as extremely relevant or very relevant to offering re-RT as an option.

Conclusion

The experts’ practice of re-RT is still heterogeneous, reflecting the paucity of high-quality prospective data available for decision-making. Nevertheless, practicing radiation oncologists can support own decisions by referring to the cases found suitable for re-RT in this survey.

Electronic supplementary material

The online version of this article (10.1186/s13014-017-0928-3) contains supplementary material, which is available to authorized users.

Rationale and Design of a Phase 1 Clinical Trial to Evaluate HSV G207 Alone or with a Single Radiation Dose in Children with Progressive or Recurrent Malignant Supratentorial Brain Tumors

Primary central nervous system tumors are the most common solid neoplasm of childhood and the leading cause of cancer-related death in pediatric patients. Survival rates for children with malignant supratentorial brain tumors are poor despite aggressive treatment with combinations of surgery, radiation, and chemotherapy, and survivors often suffer from damaging lifelong sequelae from current therapies. Novel innovative treatments are greatly needed. One promising new approach is the use of a genetically engineered, conditionally replicating herpes simplex virus (HSV) that has shown tumor-specific tropism and potential efficacy in the treatment of malignant brain tumors. G207 is a genetically engineered HSV-1 lacking genes essential for replication in normal brain cells. Safety has been established in preclinical investigations involving intracranial inoculation in the highly HSV-sensitive owl monkey (Aotus nancymai), and in three adult phase 1 trials in recurrent/progressive high-grade gliomas. No dose-limiting toxicities were seen in the adult studies and a maximum tolerated dose was not reached. Approximately half of the 35 treated adults had radiographic or neuropathologic evidence of response at a minimum of one time point. Preclinical studies in pediatric brain tumor models indicate that a variety of pediatric tumor types are highly sensitive to killing by G207. This clinical protocol outlines a first in human children study of intratumoral inoculation of an oncolytic virus via catheters placed directly into recurrent or progressive supratentorial malignant tumors.

Gait Speed and Survival in Patients With Brain Metastases

CONTEXT

Accurate estimation of life expectancy in patients with brain metastases is critical for counseling and choosing appropriate therapy. Performance status is the single greatest determinant of overall survival in this population. However, current measures of performance status are subjective and often based on brief clinical encounters. Gait speed is an objective, reliable predictor of overall health and survival.

OBJECTIVE

The purpose of this study was to evaluate the relationship between gait speed and survival in patients with brain metastases.

METHODS

We conducted a retrospective review of all patients with documented gait speed and Karnofsky performance status seen in consultation for newly diagnosed brain metastases from 2014 to 2015. Gait speed was measured during neurological examination over 4 m at normal pace. Graded prognostic assessment scores were calculated from clinical information. The primary outcomes were overall survival and 30-day mortality.

RESULTS

Eighty-five of 88 patients (97%) met inclusion criteria. Overall, the median gait speed was 0.7 m/s (range 0-1.0 m/s). Gait speed was associated with increased overall survival in addition to graded prognostic assessment score. Median survival was longer in patients with normal gait speed (>0.6 m/s, 11.9 months) compared to those with slow gait speed (≤0.6 m/s, 4.5 months, P < 0.001) or who were nonambulatory (1.1 months, P < 0.001). Thirty-day mortality for normal, slow, and nonambulatory patients was 0%, 15%, and 42%, respectively. The graded prognostic assessment overestimated actual survival for nonambulatory patients (2.2 vs. 1.1 months) and underestimated for those with normal gait speed (4.4 vs. 11.9 months).

CONCLUSION

Gait speed is associated with overall survival in patients with newly diagnosed brain metastases. Gait speed assessment is simple, objective, and may provide additional prognostic information to improve life expectancy estimation and management decisions.

A priori patient-specific collision avoidance in radiotherapy using consumer grade depth cameras

PURPOSE

In this study, we demonstrate and evaluate a low cost, fast, and accurate avoidance framework for radiotherapy treatments. Furthermore, we provide an implementation which is patient specific and can be implemented during the normal simulation process.

METHODS

Four patients and a treatment unit were scanned with a set of consumer depth cameras to create a polygon mesh of each object. Using a fast polygon interference algorithm, the models were virtually collided to map out feasible treatment positions of the couch and gantry. The actual physical collision space was then mapped in the treatment room by moving the gantry and couch until a collision occurred with either the patient or hardware. The physical and virtual collision spaces were then compared to determine the accuracy of the system. To improve the collision predictions, a buffer geometry was added to the scanned gantry mesh and performance was assessed as a function of buffer thickness.

RESULTS

Each patient was optically scanned during simulation in less than 1 min. The average time to virtually map the collision space for 64, 800 gantry/couch states was 5.40 ± 2.88 s. The system had an average raw accuracy and negative prediction rate (NPR) across all patients of 97.3% ± 2.4% and 96.9% ± 2.2% respectively. Using a polygon buffer of 6 cm over the gantry geometry, the NPR was raised to unity for all patients, signifying the detection of all collision events. However, the average accuracy fell from 95.3% ± 3.1% to 91.5% ± 3.6% between the 3 and 6 cm buffer as more false positives were detected.

CONCLUSIONS

We successfully demonstrated a fast and low cost framework which can map an entire collision space a priori for a given patient during the time of simulation. All collisions can be avoided using polygon interference, but a polygon buffer may be required to account for geometric uncertainties of scanned objects.

Quality of Prostate Cancer Treatment Information on Cancer Center Websites

INTRODUCTION

Cancer center websites are trusted sources of internet information about treatment options for prostate cancer. The quality of information on these websites is unknown. The objective of this study was to evaluate the quality of information on cancer center websites addressing prostate cancer treatment options, outcomes, and toxicity.

MATERIALS AND METHODS

We evaluated the websites of all National Cancer Institute-designated cancer centers to determine if sufficient information was provided to address eleven decision-specific knowledge questions from the validated Early Prostate Cancer Treatment Decision Quality Instrument. We recorded the number of questions addressed, the number of clicks to reach the prostate cancer-specific webpage, evaluation time, and Spanish and mobile accessibility. Correlation between evaluation time and questions addressed were calculated using the Pearson coefficient.

RESULTS

Sixty-three websites were reviewed. Eighty percent had a prostate cancer-specific webpage reached in a median of three clicks. The average evaluation time was 6.5 minutes. Information was available in Spanish on 24% of sites and 59% were mobile friendly. Websites provided sufficient information to address, on average, 19% of questions. No website addressed all questions. Evaluation time correlated with the number of questions addressed (R(2) = 0.42, p < 0.001).

CONCLUSIONS

Cancer center websites provide insufficient information for men with localized prostate cancer due to a lack of information about and direct comparison of specific treatment outcomes and toxicities. Information is also less accessible in Spanish and on mobile devices. These data can be used to improve the quality and accessibility of prostate cancer treatment information on cancer center websites.

Prolonged treatment with bevacizumab is associated with brain atrophy: a pilot study in patients with high-grade gliomas

Bevacizumab is widely used for treatment of high-grade gliomas and other malignancies. Because bevacizumab has been shown to be associated with neurocognitive decline, this study is designed to investigate whether prolonged treatment with bevacizumab is also associated with brain atrophy. We identified 12 high-grade glioma patients who received bevacizumab for 12 months at the first recurrence and 13 matched controls and blindly compared the volumes of the contralateral hemispheres and contralateral ventricle in these two groups at baseline and after 12 ± 2 months of the baseline scan by two independent analyses. The volumes of the contralateral hemispheres and ventricles did not differ significantly between the two groups at baseline. Whereas, in the control group the volumes of the contralateral hemisphere changed subtly from baseline to follow-up (p = 0.23), in the bevacizumab-treated group the volumes significantly decreased from baseline to follow-up (p = 0.03). There was significant increase in the contralateral ventricle volume from base line to follow-up scans in both the control group (p = 0.01) and in the bevacizumab group (p = 0.005). Both the absolute and the percentage changes of contralateral hemisphere volumes and contralateral ventricular volumes between the two patient groups were statistically significant (p < 0.05). Results of this study demonstrate prolonged treatment with bevacizumab is associated with atrophy of the contralateral brain hemisphere.

Treatment of adults with recurrent malignant glioma

Virtually all malignant gliomas recur. Treatment options at recurrence have relied upon surgical intervention, radiation therapy or cytotoxic chemotherapy. Unfortunately, none are associated with significant improvements in survival. Advances in treatment options at recurrence have been dependent upon the combination of surgical resection, focal radiation and chemotherapy. Despite aggressive interventions, few patients have meaningful improvements. Current research focuses on novel targeted molecular therapy that will hopeful be able to take advantage of advances in our understanding of the biology of glial neoplasms.

Stereotactic radiosurgical treatment of brain metastasis of primary tumors that rarely metastasize to the central nervous system

We evaluated the local control of gamma knife stereotactic radiosurgery (GKSRS) in the treatment of cerebral metastases from primary tumors that rarely metastasize to the central nervous system (CNS). There is little published data on this subject with very few series on specific primary tumors. We present our experience treating these lesions with GKSRS combined with a review of the salient literature. A retrospective study of 36 patients who collectively underwent 44 GKSRS procedures for CNS metastatic disease was undertaken. Our series includes four patients with sarcoma, two with prostate cancer, three with thyroid cancer, five with endometrial cancer, seven with ovarian cancer, two with cervical cancer, six with esophageal cancer, two with bladder cancer, one with liver cancer, one with pancreatic cancer, and three with testicular cancer. With 44 gamma knife sessions treating 74 tumors, 63 tumors showed no radiographic evidence of progression, and 13 tumors demonstrated radiographic progression between one and 12 months after gamma knife treatment. In six patients in the population, further treatment with GKSRS was necessary due to enlargement of untreated lesions or new metastatic disease. GKSRS for uncommon CNS metastases is appears to be efficacious in controlling the treated tumor. The majority of tumors treated in our study did not progress post gamma knife.