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Purpose/Objectives: Local immune activity as measured by tumor infiltrating lymphocytes (TILs) has been correlated with improved outcomes in triple negative breast cancer (TNBC) and HER2+ disease. Furthermore, increased TILs after pre-operative systemic therapy for TNBC are also correlated with improved outcomes. However, the role of TILs in predicting outcomes in ER/PR+ breast cancer is less well-established. Radiation therapy (RT) can enhance immune cell infiltration in various tumors. However, breast cancer RT is typically given post-operatively, limiting the ability to determine whether RT enhances the %TILs in breast tumors. Here we report %TILs and tumor responses after pre-operative accelerated partial breast irradiation (APBI) as part of a clinical trial to determine whether RT enhances %TILs and whether this correlates with RT response. Materials/Methods: A breast pathologist assessed blindly the % stromal TILs and % tumor cellularity in biopsy and post-RT surgical specimens for patients treated on an in-house pre-operative APBI trial in patients with ER/PR+ breast cancer (NCT02728076). Patients received APBI to 30 Gy in 5 fractions on non-consecutive days, followed by surgery after no less than 5 weeks. Correlation between %TILs and pathologic response was assessed. Results: Thirty-five patients were enrolled and completed treatment. Median age was 65 (50-80). All patients were clinically node-negative and ER/PR+; one was HER2+. Median MRI tumor size was 0.9 cm (0.4-2.1 cm); 54% were grade 2 and 46% grade 1. 23/35 patients had 21- or 70-gene recurrence scores (RS), with 1 high RS; 2 patients received adjuvant chemotherapy and 33/35 received endocrine therapy after surgery. Most patients demonstrated robust tumor responses to RT, with 16/35 (46%) having &lt5% cellularity after RT. With a median cellularity at diagnosis of 40%, 27/35 (77%) had a >20% decrease in cellularity, with only 3 patients having no decrease (range 0-59%). All tumors had low levels of TILs (median 5%, range 1-20%). There was minimal change in %TILs from biopsy to surgery, with 10/35 (28%) patients having increase of TILs &gt4%, 2/35 with an increase of 10%, 2/35 having a decrease of 10% and the remainder with no %TIL increase. There were no correlations between %TILs (at diagnosis or post-RT) and tumor response to RT or RS. Conclusions: Pre-operative APBI in ER/PR+ breast cancers did not significantly increase the %TILs after 5 weeks, despite leading to significant tumor responses as measured by % cellularity. Low %TILs were seen, with no more than a 10% TIL increase after RT. These findings suggest this RT dose and fractionation schedule causes only mild immune changes, as measured by TILs, in this mostly favorable cohort of ER/PR+ cancers. Alternatively, the timing of surgery may have missed maximum TIL levels. Further characterization of TILs along with further studies in similar cohorts and in other breast cancer subtypes are warranted and will be performed to examine the role of pre-operative RT on breast cancer immune responses. Citation Format: Adam Currey, Julie M Jorns, Nina Desai, Tracy R Kelly, Joseph Bovi, Amanda L Kong, Anubha Wadhwa, Eric Paulson, Carmen Bergom. Minimal increases in tumor infiltrating lymphocytes despite excellent tumor responses after pre-operative accelerated partial breast irradiation in early stage ER+ breast cancer patients [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-19-04.

Glioblastoma (GBM) is a disease with a poor prognosis. For decades, radiotherapy has played a critical role in the management of GBM. The standard of care radiation prescription is 60 Gy in 30 fractions, but landmark trials have historically excluded patients older than 70 years. Currently, there is considerable variation in the management of elderly patients with GBM. Shortened radiation treatment (hypofractionated) regimens have been explored since conventional treatment schedules are lengthy and many elderly patients have functional, cognitive, and social limitations. Clinical trials have demonstrated the effectiveness of hypofractionated radiotherapy (40 Gy in 15 fractions) to treat elderly or frail patients with GBM. Although previous studies have suggested these unique hypofractionation prescriptions effectively treat these patients, there are many avenues for improvement in this patient population. Herein, we describe the unique tumor biology of glioblastoma, key hypofractionated radiotherapy studies, and health-related quality of life (HRQOL) studies for elderly patients with GBM. Hypofractionated radiation has emerged as a shortened alternative and retrospective studies have suggested survival outcomes are similar for elderly patients with GBM. Prospective studies comparing hypofractionation with conventional treatment regiments are warranted. In addition to evaluating survival outcomes, HRQOL endpoints should be incorporated into future studies.

A novel approach of department-focused electronic health record (EHR) training was implemented to improve efficiency and time management of EHR use. Based off baseline log data, 5 in-person training sessions were designed, focusing on the common inefficiencies of 6 chosen participants. Log data of 4 key metrics and 2 efficiency scores were analyzed 4 months post-training. A survey was conducted to assess self-reported EHR competence. Individually, several participants had improved efficiency scores. There was a reduced average time spent in the inbox per day, in notes per dictation, and in notes per day. This translated to an average of 8.9 min saved per day (range 0–29.1 min/day) and 37.1 hours saved per year (range 0–116.2 hours/year). From the post-training surveys, all participants felt more efficient in their use of the EHR. This study demonstrates an example of department-focused EHR training and log-based analysis improving time management and efficiency.

Pituitary carcinoma (PC) is an uncommon intracranial malignancy with a high rate of metastasis, mortality, and inconsistent response to therapy. Because PC is a rare condition (0.1%-0.2% of pituitary tumors), prospective studies and observable data are scarce. Some PC may have an endocrine secretory function and can arise from existing pituitary adenomas. Treatment often includes a combination of surgical resection, radiotherapy, and systemic therapies. Because of the poor treatment response rate and rapid progression, treatment is often palliative. Here we describe a unique, complete amelioration of severe Cushing's disease due to an ACTH secreting pituitary carcinoma followed by the development of pituitary hypoadrenalism after re-irradiation with concurrent temozolomide.

Purpose: Dismal prognosis and limited treatment options for recurrent high-grade glioma have provoked interest in various forms of reirradiation. Pulsed reduced dose rate radiation therapy (pRDR) is a promising technique that exploits low-dose hyper-radiosensitivity of proliferating tumor cells while sparing adjacent nonproliferating normal brain tissue. Large radiation treatment volumes can thus be used to target both contrast-enhancing and FLAIR abnormalities thought to harbor recurrent gross and microscopic disease, respectively. The aim of this retrospective study was to determine whether the addition of pRDR to bevacizumab improves survival over bevacizumab alone for recurrent high-grade glioma. Methods and Materials: Eighty patients with recurrent high-grade glioma were included in this study; 47 patients received bevacizumab monotherapy (BEV), and 33 patients received pRDR with bevacizumab (BEV/pRDR). Progression-free survival (PFS) and overall survival were compared between the BEV and BEV/pRDR groups. Regression analysis was performed to identify and control for confounding influences on survival analyses. Results: Significant (P

Introduction This study proposes contouring recommendations for radiation treatment planning target volumes and organs-at-risk (OARs) for both low grade and high grade gliomas. Methods Ten cases consisting of 5 glioblastomas and 5 grade II or III gliomas, including their respective gross tumor volume (GTV), clinical target volume (CTV), and OARs were each contoured by 6 experienced neuro-radiation oncologists from 5 international institutions. Each case was first contoured using only MRI sequences (MRI-only), and then re-contoured with the addition of a fused planning CT (CT-MRI). The level of agreement among all contours was assessed using simultaneous truth and performance level estimation (STAPLE) with the kappa statistic and Dice similarity coefficient. Results A high level of agreement was observed between the GTV and CTV contours in the MRI-only workflow with a mean kappa of 0.88 and 0.89, respectively, with no statistically significant differences compared to the CT-MRI workflow (p = 0.88 and p = 0.82 for GTV and CTV, respectively). Agreement in cochlea contours improved from a mean kappa of 0.39 to 0.41, to 0.69 to 0.71 with the addition of CT information (p Conclusions Consensus contouring recommendations for low grade and high grade gliomas were established using the results from the consensus STAPLE contours, which will serve as a basis for further study and clinical trials by the MR-Linac Consortium.

Aim/objectives/background Timely, accurate, and effective communications are critical to quality in contemporary medical practices. Radiation oncology incorporates the science and technology of complex integrated radiation treatment delivery and the art of managing individual patients. Through written physical and/or electronic reports and direct communication, radiation oncologists convey critical information regarding patient care, services provided, and quality of care. Applicable practice parameters need to be revised periodically regarding medical record documentation for professional and technical components of services delivered. Methods The ACR-ASTRO Practice Parameter for Communication: Radiation Oncology was revised according to the process described on the American College of Radiology (ACR) Web site ("The Process for Developing ACR Practice Parameters and Technical Standards," www.acr.org/ClinicalResources/Practice-Parametersand-Technical-Standards) by the Committee on Practice Parameters of the ACR Commission on Radiation Oncology in collaboration with the American Society for Radiation Oncology (ASTRO). Both societies then reviewed and approved the document. Results This practice parameter addresses radiation oncology communications in general, including (a) medical record, (b) electronic, and (c) doctor-patient communications, as well as specific documentation for radiation oncology reports such as (a) consultation, (b) clinical treatment management notes (including inpatient communication), (c) treatment (completion) summary, and (d) follow-up visits. Conclusions The radiation oncologist's participation in the multidisciplinary management of patients is reflected in timely, medically appropriate, and informative communication with the referring physician and other members of the health care team. The ACR-ASTRO Practice Parameter for Communication: Radiation Oncology is an educational tool designed to assist practitioners in providing appropriate communication regarding radiation oncology care for patients.

PURPOSE Radiation dose to the neuroregenerative zone of the hippocampus has been found to be associated with cognitive toxicity. Hippocampal avoidance (HA) using intensity-modulated radiotherapy during whole-brain radiotherapy (WBRT) is hypothesized to preserve cognition. METHODS This phase III trial enrolled adult patients with brain metastases to HA-WBRT plus memantine or WBRT plus memantine. The primary end point was time to cognitive function failure, defined as decline using the reliable change index on at least one of the cognitive tests. Secondary end points included overall survival (OS), intracranial progression-free survival (PFS), toxicity, and patient-reported symptom burden. RESULTS Between July 2015 and March 2018, 518 patients were randomly assigned. Median follow-up for alive patients was 7.9 months. Risk of cognitive failure was significantly lower after HA-WBRT plus memantine versus WBRT plus memantine (adjusted hazard ratio, 0.74; 95% CI, 0.58 to 0.95; P = .02). This difference was attributable to less deterioration in executive function at 4 months (23.3% v 40.4%; P = .01) and learning and memory at 6 months (11.5% v 24.7% [ P = .049] and 16.4% v 33.3% [ P = .02], respectively). Treatment arms did not differ significantly in OS, intracranial PFS, or toxicity. At 6 months, using all data, patients who received HA-WBRT plus memantine reported less fatigue ( P = .04), less difficulty with remembering things ( P = .01), and less difficulty with speaking ( P = .049) and using imputed data, less interference of neurologic symptoms in daily activities ( P = .008) and fewer cognitive symptoms ( P = .01). CONCLUSION HA-WBRT plus memantine better preserves cognitive function and patient-reported symptoms, with no difference in intracranial PFS and OS, and should be considered a standard of care for patients with good performance status who plan to receive WBRT for brain metastases with no metastases in the HA region.

Background Nearly all meningiomas express somatostatin receptor 1/2 (SSTR1/SSTR2); therefore, SSTR ligands such as 68Ga-DOTATATE can be utilized for meningioma radiotherapy treatment planning. Incorporation of 68Ga-DOTATATE PET assists with target delineation and may reduce the dose to organs-at-risk (OARs). We hypothesize that 68Ga-DOTATATE PET-based treatment plans will reduce dose to OARs when compared to MRI-based plans. METHODS All treatment plans were rendered on computed tomography (CT) planning datasets, using RapidArc and 6MV photon energy. Two arcs were positioned on the coplanar axis with alternated collimator settings of 0 and 90 degrees to promote MLC sparing with a third unique vertex arc chosen independently to spare normal brain tissue and associated organs at risk (OAR). For MRI structures, a 1 cm expansion from the gross tumor volume (GTV) created a clinical treatment volume (CTV)60. A 2 cm expansion created a CTV54. For PET structures, a 1 cm expansion from the GTV created a CTV60. A 3 mm isotropic expansion created planning treatment volumes (PTVs). Plans were optimized such that Dmax to brainstem remained limited to 60Gy or less and Dmax to optic structures was limited to 54Gy or less. RESULTS 18 meningioma patients were included (9 post-operative, 9 intact). The mean PTV volume using MRI was 258 ccs (306 ccs for post-operative, 210 ccs for intact), and the mean PTV volume using PET was 60 ccs (97 ccs for post-operative, 91 ccs for intact). The mean radiation dose to both optic nerves, the optic chiasm, both hippocampi, and the brainstem was reduced favoring PET-based treatment plans for both post-operative and intact patients. CONCLUSION Our study shows that incorporation of 68Ga-DOTATATE PET can reduce dose to OARs for post-operative and intact patients, and this difference may translate to reduced toxicity. 68Ga-DOTATATE PET guided radiation treatments are worthy of future prospective investigation.

BACKGROUND The assessment of BM response to WBRT and its impact on NCF in clinical trials has been limited by lack of standardized imaging protocols. NRG-CC001 is a randomized clinical trial requiring pre-specified MRI protocols at baseline and 6-months, providing a uniform dataset to investigate if RR correlates with NCF changes. METHODS NRG-CC001 randomized patients with BM to hippocampal avoidance WBRT (HA-WBRT) or WBRT. NCF was analyzed using 6-month standardized change scores and deterioration, defined using the reliable change index. Chi-square and t-tests were used for pretreatment characteristic comparisons. Inter-rater reliability between central and institutional assessment of RR was assessed with weighted kappa, κ. Linear regression was used to test trends in NCF change scores across types of response and multivariable logistic regression was used to test the association of RR to NCF deterioration. RESULTS 149 and 135 patients were evaluable for RR and NCF assessment, respectively. Pretreatment characteristics were well-balanced, except for post-high school education (70.6% HA-WBRT vs. 52.5% WBRT, p=0.023). Inter-rater reliability between central and institutional assessment of RR was fair (κ=0.36). There was no difference between arms in RR (p=0.41) with overall rates of 14.1% CR, 42.2% PR, 17% SD, and 26.7% PD. Patients with CR had improved 6-month NCF change as measured by HVLT-R Total Recall (p=0.0005), HVLT-R Delayed Recall (p=0.0003), HVLT-R Delayed Recognition (p=0.011), TMT-B (p=0.033), COWA (p=0.016), and Clinical Trial Battery Composite score (p=0.0011). Multivariable analysis demonstrated less deterioration in HVLT-R Delayed Recall for CR (p=0.019) and PR (p=0.0086) vs. SD/PD and HVLT-R Recognition for PR (p=0.031) vs. SD/PD. CONCLUSIONS HA-WBRT and WBRT result in similar RR at 6-months. CR or PR is associated with better NCF preservation. This suggests investigation into treatment escalation for patients with SD/PD may provide further NCF benefit along with HA-WBRT and memantine.Grant support from NCI-UG1CA189867 and U24CA180803.

Purpose: NRG Oncology's RTOG 0933 demonstrated benefits to memory preservation after hippocampal avoidant whole-brain radiation therapy (HA-WBRT), the avoidance of radiation dose to the hippocampus (using intensity modulated radiation planning and delivery techniques) during WBRT, supporting the hypothesis of hippocampal radiosensitivity and associated memory specificity. However, some patients demonstrated cognitive decline, suggesting mechanisms outside hippocampal radiosensitivity play a role. White matter injury (WMI) has been implicated in radiation therapy–induced neurocognitive decline. This secondary analysis explored the relationship between pretreatment WMI and memory after HA-WBRT. Methods and Materials: Volumetric analysis of metastatic disease burden and disease-unrelated WMI was conducted on the pretreatment magnetic resonance image. Correlational analyses were performed examining the relationship between pretreatment WMI and Hopkins Verbal Learning Test-Revised (HVLT-R) outcomes at baseline and 4 months after HA-WBRT. Results: In the study, 113 patients received HA-WBRT. Of 113 patients, 33 underwent pretreatment and 4-month posttreatment HVLT testing and pretreatment postcontrast volumetric T1 and axial T2/fluid-attenuated inversion recovery magnetic resonance imaging. Correlation was found between larger volumes of pretreatment WMI and decline in HVLT-R recognition (r = 0.54, P

INTRODUCTION: NRG protocols for glioblastoma allow for clinical target volume (CTV) reductions at natural barriers; however, literature examining CTV contouring and the relevant white matter pathways is lacking. This study proposes consensus CTV guidelines, with a focus on areas of controversy while highlighting common errors in glioblastoma target delineation. METHODS: Ten academic radiation oncologists specializing in brain tumor treatment contoured CTVs on 4 glioblastoma cases. CTV expansions were based on NRG trial guidelines. Contour consensus was assessed and summarized by kappa statistics. A meeting was held to discuss the mathematically averaged contours and form consensus contours and recommendations. RESULTS: Contours of the cavity plus enhancement (mean kappa 0.69) and T2-FLAIR signal (mean kappa 0.74) showed moderate to substantial agreement. Experts were asked to trim off anatomic barriers while respecting pathways of spread to develop their CTVs. Submitted CTV_4600 (mean kappa 0.80) and CTV_6000 (mean kappa 0.81) contours showed substantial to near perfect agreement. Simultaneous Truth and Performance Level Estimation (STAPLE) contours were then reviewed and modified by group consensus. Anatomic trimming reduced the amount of total brain tissue planned for radiation targeting by a 13.6% (range 8.7% - 17.9%) mean proportional reduction. Areas for close scrutiny of target delineation were described, with accompanying recommendations. CONCLUSIONS: Consensus contouring guidelines were established based on expert contours. Careful delineation of anatomic pathways and barriers to spread can spare radiation to uninvolved tissue without compromising target coverage. Further study is necessary to accurately define optimal target volumes beyond isometric expansion techniques for individual patients.

Stereotactic radiosurgery (SRS) for treatment of vestibular schwannoma (VS) is usually planned with magnetic resonance imaging (MRI) with and without contrast. This report describes a case of a patient with vestibular schwannoma with contraindications to MRI and intravascular contrast who underwent successful SRS using computed tomography (CT) cisternography for planning. The patient is a 76-year-old female with a complicated medical history including an MRI-incompatible cardiac pacemaker, prior severe anaphylactic reaction to intravascular iodinated contrast, and an enlarging left-sided cerebellopontine angle (CPA) neoplasm, presumed to be a VS. Due to her imaging limitations, CT cisternography was used in the planning of her Gamma Knife® SRS. She ultimately underwent successful Gamma Knife® treatment of her VS. CT cisternography for planning of SRS is a novel strategy for VS treatment that may be considered in patients with contraindications to MRI and intravascular iodinated contrast.

MRI is the standard modality to assess anatomy and response to treatment in brain and spine tumors given its superb anatomic soft tissue contrast (e.g., T1 and T2) and numerous additional intrinsic contrast mechanisms that can be used to investigate physiology (e.g., diffusion, perfusion, spectroscopy). As such, hybrid MRI and radiotherapy (RT) devices hold unique promise for Magnetic Resonance guided Radiation Therapy (MRgRT). In the brain, MRgRT provides daily visualizations of evolving tumors that are not seen with cone beam CT guidance and cannot be fully characterized with occasional standalone MRI scans. Significant evolving anatomic changes during radiotherapy can be observed in patients with glioblastoma during the 6-week fractionated MRIgRT course. In this review, a case of rapidly changing symptomatic tumor is demonstrated for possible therapy adaptation. For stereotactic body RT of the spine, MRgRT acquires clear isotropic images of tumor in relation to spinal cord, cerebral spinal fluid, and nearby moving organs at risk such as bowel. This visualization allows for setup reassurance and the possibility of adaptive radiotherapy based on anatomy in difficult cases. A review of the literature for MR relaxometry, diffusion, perfusion, and spectroscopy during RT is also presented. These techniques are known to correlate with physiologic changes in the tumor such as cellularity, necrosis, and metabolism, and serve as early biomarkers of chemotherapy and RT response correlating with patient survival. While physiologic tumor investigations during RT have been limited by the feasibility and cost of obtaining frequent standalone MRIs, MRIgRT systems have enabled daily and widespread physiologic measurements. We demonstrate an example case of a poorly responding tumor on the 0.35 T MRIgRT system with relaxometry and diffusion measured several times per week. Future studies must elucidate which changes in MR-based physiologic metrics and at which timepoints best predict patient outcomes. This will lead to early treatment intensification for tumors identified to have the worst physiologic responses during RT in efforts to improve glioblastoma survival.

Purpose/objective(s) Telehealth, until recently, has been underutilized. With the pandemic, telehealth has quickly taken on new prominence that will likely sustain in the post-pandemic setting. Mobile health applications (apps) can be used as part of the oncologic telehealth encounter to monitor patient-reported outcomes (PROs), recorded sensor data and facilitate rapid communication. The goal of this study was to describe the characteristics of patient-centered oncology apps and associated functionalities that can improve outcomes and enhance patient-physician relationships. Materials/methods A review of apps with symptom tracking capabilities available on the iOS-based App Store and Android-based Play Store was completed in late 2020. The search terms used included: cancer, oncology, symptom tracker, radiation oncology, radiotherapy and radiation therapy. Apps were initially included if they had symptom tracking capabilities, and were further evaluated to assess patient journaling, wearable device syncing, bi-directional communication, and specificity for radiation oncology. Functionalities were tallied and compared using Microsoft Excel to examine totals and percentage distributions. Results The primary search in the app stores populated 1240 unique applications in English with 91 included in the secondary selection process after title and descriptive screening. After downloading free apps to confirm capabilities, 33 apps were eligible for the study. Of the 33 included apps, 21 (63.60%) were general symptom trackers, and 12 (36.40%) were oncology specific. None of the oncology-specific symptom tracking apps were specific for radiation oncology, but 6 (50%) of the oncology-specific apps allowed for the addition of custom symptoms. Of the 12 oncology-specific apps, 7 (58.3%) allowed for patient journaling, 3 (25%) could sync data from wearable devices, and 2 (16.7%) allowed for bi-directional communication between the patient and medical team. Of the 2 apps that included bi-directional communication, 1 (50%) app provided a chat function, and 1 (50%) app provided a video function. Comparisons of the prevalence of important functionalities between general symptom and oncology symptom trackers is shown in Table 1. Conclusion We present a comprehensive characterization of oncology-specific apps currently available. Apps focused on oncology are limited and largely unexplored. Future app development to optimize PRO collection, mobile sensor data assessment, and integration with telehealth encounters in needed. Such data can increase symptom recognition, provide timely feedback and improve quality of data collection for oncologists.

PURPOSE/OBJECTIVE(S) Outcomes of low-risk meningioma from NRG/RTOG-0539. MATERIALS/METHODS Outcomes of the intermediate and high-risk cohorts from this phase II trial have been previously reported. Low-risk (Group 1: new WHO grade 1) patients were observed after gross total (GTR) or subtotal resection (STR). Progression-free (PFS) and overall (OS) were estimated using Kaplan-Meier. CTCAE v3 AE grading was employed. RESULTS Group 1 enrolled 65 patients. 56/60 (93.4%) evaluable patients had investigator-reported GTR. Sufficient imaging for central confirmation was available for 48: GTR in 35 and STR in 13. Median follow-up for living patients was 9.1 years (y). For all evaluable patients 5 and 10 y PFS and OS rates were 89.4 and 85.0%, and 98.3 and 93.8%, respectively. For patients with centrally-confirmed STR, 5/10 y PFS rates were 72.7/72.7%, with 100% 10 y OS. For patients with centrally-confirmed GTR, 5/10 y PFS and OS rates were 94.3/87.6 and 97.1/90.4%, respectively. For combined study cohorts (Groups 1–3) with central-review (n=104), the median centrally-measured largest pre-operative tumor dimension was 4.3 cm (range 0.4 - 14.4); this was significantly associated with OS (hazard ratio [HR]=1.03, p=0.021) and PFS (HR=1.03, p=0.003). No grade 4 or 5 protocol-related adverse events were reported. There were 1 grade 3 (infection), 4 grade 2 (neurologic, pulmonary, gastrointestinal, and pain), and 5 grade 1 (3 neurologic, 1 occulovisual, 1 constitutional) events from 5 patients. CONCLUSION These results prospectively validate high OS and PFS outcomes for low-risk meningioma managed with surgery followed by observation, but raise questions regarding optimal management following STR (5 y PFS 72.7%), a subcohort that could potentially benefit from adjuvant therapy. However, we identified considerable discordance between local and central assessments of resection extent. Pre-operative tumor size has a significant impact on OS and PFS. Supported by: U10CA180868 and U10CA180822 from the National Cancer Institute (NCI)

PURPOSE Previous secondary analysis of NRG/RTOG 0933 provided hypothesis-generating data supporting a relationship between larger volumes of MR-determined pre-treatment WMI and developing neurocognitive decline following HA-WBRT. The current study examines the relationship between pre-treatment WMI and neurocognitive function (NCF) following WBRT+memantine +/-HA in a substantially larger cohort. METHODS NCF testing was performed at baseline,2,4,6,and 12 months post-WBRT, and included Hopkins Verbal Learning Test–Revised (HVLT-R), Trail Making Test (TMT) Parts A and B, and Controlled Oral Word Association (COWA). Pre-treatment WMI was measured by FLAIR volume corrected for whole brain volume and corrected for the FLAIR volume associated with metastases (FLAIR/(whole brain volume – metastasis FLAIR volume). Pearson correlation coefficients were used to assess association between pre-treatment WMI and change from baseline for each standardized NCF score. RESULTS Of 518 randomized patients, 442 (217,WBRT+Memantine; 225,HA-WBRT+Memantine) had WMI data and were included. In the entire cohort, mean FLAIR volume was 9.3cc (0.1-68.2cc), mean metastases FLAIR volume was 61.5cc (0-423.5cc), mean Whole Brain volume was 1336.4cc (949.4-2397.8cc). At 2 months, there were no significant correlations between neurocognitive test change scores and pre-treatment WMI volume. However, at 4 months, both HVLT-R Total Recall and TMT Part B change score and pre-treatment WMI volume were significantly negatively correlated on the HA-WBRT+Memantine arm (ρ=-0.22 p=0.042 and ρ=-0.27, p=0.013). At 12 months, both TMT Part A and TMT Part B change scores and pre-treatment WMI volume were significantly negatively correlated on the HA-WBRT+Memantine arm (ρ=-0.30, p=0.046 and ρ=-0.53, p< 0.001). CONCLUSIONS Pre-treatment WMI volume was a significant imaging-biomarker predictor of post-treatment neurocognitive decline at 4-and 12-months following HA-WBRT+Memantine. This suggests patients with greater pre-treatment WMI were more susceptible to neurocognitive decline, specifically when undergoing HA-WBRT, but not following standard WBRT. Dose heterogeneity inherent to HA-WBRT delivery may contribute to these findings and are hypothesis generating.

PURPOSE GK-SRS is an accepted definitive treatment option for appropriately selected patients with VS. To assess long-term outcomes in VS patients treated with GK-SRS, we retrospectively evaluated all patients treated at our institution from 2007-2019. METHODS For VS patients treated with GK-SRS from 2007-2019, clinical data (symptoms, physical exams, audiograms, and imaging) was collected via retrospective chart review at pre-treatment and standard follow-up intervals (6 weeks, 6 months, 12 months, then annually). Descriptive analyses, including the proportions of patients in different grades of clinical parameters, are reported. For each clinical parameter, only patients with both pre- and post-treatment data were included in the evaluation set used for analysis. RESULTS Of 177 patients identified, 46 were excluded from the evaluable set (age < 18 years, prior resection, NF-2, or no follow-up). Among the remaining 131, median follow-up was 42 months (6 weeks to 11 years), and 36.6% completed 5+ years of follow-up. At time of treatment, median age was 61 years, and median Karnofsky Performance Score was 90. 58.0% of lesions were left-sided, and 42.0% were right-sided. The majority were Koos grade II (37.4%) or III (38.2%); the remainder were grade I (13.0%) or IV (11.5%). Pre-treatment central necrosis and ventriculomegaly were present in 39.7% and 4.6%, respectively. Following treatment, audiogram analysis with Gardner-Robertson Hearing Score demonstrated no change in 48.9%, some level of decline in 47.8%, and improvement in 3.3% at last follow-up. 97.7% had House-Brackmann scores of I at diagnosis; the remainder were House-Brackmann II. House-Brackmann scores remained unchanged at last follow-up for 96.9%, improved for 1.6%, and worsened for 1.6%. Salvage therapy in the form of surgery (n=5) or repeat GK-SRS (n=2) was necessary in 5.3% (n=6 for progression; n=1 for trigeminal symptoms). CONCLUSION Long-term follow-up demonstrates that GK-SRS remains a well-tolerated, primary definitive treatment for VS.

The incidence of brain metastasis is increasing as improvements in systemic therapy lead to increased survival. This provides new and challenging clinical decisions for patients who are trying to balance the risk of recurrence or progression with treatment-related side effects, and it requires appropriate management strategies from multidisciplinary teams. Improvements in prognostic assessment and systemic therapy with increasing activity in the brain allow for individualized care to better guide the use of local therapies and/or systemic therapy. Here, we review the current landscape of brain-directed therapy for the treatment of brain metastasis in the context of recent improved systemic treatment options. We also discuss emerging treatment strategies including targeted therapies for patients with actionable mutations, immunotherapy, modern whole-brain radiation therapy, radiosurgery, surgery, and clinical trials.

Purpose This study investigated the treatment of primary CNS lymphoma with methotrexate, temozolomide (TMZ), and rituximab, followed by hyperfractionated whole-brain radiotherapy (hWBRT) and subsequent TMZ. The primary phase I end point was the maximum tolerated dose of TMZ. The primary phase II end point was the 2-year overall survival (OS) rate. Secondary end points were preirradiation response rates, progression-free survival (PFS), neurologic toxicities, and quality of life. Patients and Methods The phase I study increased TMZ doses from 100 to 150 to 200 mg/m2. Patients were treated with rituximab 375 mg/m2 3 days before cycle 1; methotrexate 3.5 g/m2 with leucovorin on weeks 1, 3, 5, 7, and 9; TMZ daily for 5 days on weeks 4 and 8; hWBRT 1.2 Gy twice-daily on weeks 11 to 13 (36 Gy); and TMZ 200 mg/m2 daily for 5 days every 28 days on weeks 14 to 50. Results Thirteen patients (one ineligible) were enrolled in phase I of the study. The maximum tolerated dose of TMZ was 100 mg/m2. Dose-limiting toxicities were hepatic and renal. In phase II, 53 patients were treated. Median follow-up for living eligible patients was 3.6 years, and 2-year OS and PFS were 80.8% and 63.6%, respectively. Compared with historical controls from RTOG-9310, 2-year OS and PFS were significantly improved (P = .006 and .030, respectively). In phase II, the objective response rate was 85.7%. Among patients, 66% (35 of 53) had grade 3 and 4 toxicities before hWBRT, and 45% (24 of 53) of patients experienced grade 3 and 4 toxicities attributable to post-hWBRT chemotherapy. Cognitive function and quality of life improved or stabilized after hWBRT. Conclusion This regimen is safe, with the best 2-year OS and PFS achieved in any Radiation Therapy Oncology Group primary CNS lymphoma trial. Randomized trials that incorporate this regimen are needed to determine its efficacy compared with other strategies.

BACKGROUND Brain metastasis (BM) is the most common form of brain cancer affecting 20-40% of cancer patients. Advancements in cancer therapy has prolonged survival but BM incidence has increased. BM management requires a multidisciplinary approach to individualize care via an ever-growing sum of surgical, radiation, and systemic therapy options. Consensus is achieved by multidisciplinary tumor board meeting (MTBm). Nevertheless, BM diagnosis predicts poor prognosis. Palliative Care (PC) is essential for proper BM management. Yet, formal PC assessment may not be available for MTBm. We evaluated whether MTBm consensus recommendations were followed. RESULTS Our weekly MTBm discussed 157 BM cases during 2019 (median age: 64 years [range 28-91], male/female: 82/75). The most common primary diagnosis was lung (n=49, 31%), breast (n=24, 15%), melanoma (n=16, 10%). The majority was newly diagnosed BM (n=143, 91%). MTBm recommendations were divided into three not-mutually-exclusive categories: surveillance/workup (n=78, 50%), BM-directed treatment (n=101, 64%) and GOC discussion (n=7, 4%). MTBm recommendations were fully followed in 113 cases (72%), partially in 13(8%), and not followed in 25(16%). Of the 38 patients whose recommendations were partially/not followed, the main reason was transition to hospice/death (n=26, 68%). Of the 101 patients recommended treatment, 68% (n=68) fully followed it, yet 31% (n=21) of them died within 3 months; for those living longer than 3 months (n=47, 69%), median KPS at 3 months was 70 (range 30-90). Of the entire cohort (n=157), only 20 (13%) established consistent PC follow-up (>1 outpatient visit) and 69 cases (44%) transitioned to hospice/died within 6 months, 30 of which (43%) still completed surgery (n=6) or radiotherapy (n=24) within this period. CONCLUSION Periodic assessment of MTBm recommendations is relevant for sensible BM management. Balancing treatment while focusing on QoL in a patient population with limited survival is challenging. PC assessment at MTBm could close this gap.

INTRODUCTION Patients with Brain Metastases (BM) are complex, mandating multidisciplinary care. Our BM patients are discussed at in-person, weekly Brain Tumor Boards (BTB). However, BM patients diagnosed outside weekly BTBs wait several days for the next BTB, causing delays in generating multidisciplinary plans-of-care, prolonging LOS. We created a custom mobile app for our Brain Metastases Program to have a ‘Brain Metastases Virtual Tumor Board’ (BMVTB) discussion, in real-time, resulting in faster plans-of-care, decreasing LOS. METHODS The current pathway for navigating multidisciplinary discussions for patients with BM was examined by members of our Brain Metastases Program. We identified the need for all disciplines to participate in a BMVTB, outside of our in-person, weekly BTB. We developed a secure app that can be downloaded on any provider’s mobile device. The app includes a digital BM treatment algorithm for providers to understand comprehensive, data-driven, BM management. The app also gives our multidisciplinary Brain Metastases Program access to a BMVTB messenging tool to securely communicate and generate real-time consensus plans-of-care. Using a Vizient Clinical Database, we retrospectively calculated LOS index (observed LOS/expected LOS) for 184 BM patients over 21 months, creating a baseline. After launching our app and BMVTB workflow we prospectively evaluated LOS index in 45 BM patients over 6 months. RESULTS Over 21-months, 184 patients demonstrated baseline LOS index of 1.073. After launching our mobile app and BMVTB workflow, 45 patient admissions over 6-months demonstrated LOS index of 0.850. Using Levene’s test for equal variances, LOS variance with the app and BMVTB was lower than LOS variance at baseline (p = 0.049). This demonstrates a 38% reduction in LOS when the app and BMVTB generated real-time plans-of-care. CONCLUSION We demonstrated utility of a custom BM app coupled with a BMVTB to generate real-time plans-of-care for BM patients, reducing LOS.

2501 Background: MTX-based chemoradiotherapy is effective in PCNSL, but carries a risk of severe neurotoxicity (NT), especially in the elderly. In a phase II single arm study, R-MPV-A chemotherapy was combined with substantially reduced doses of radiotherapy (23.4 Gy), achieving prolonged progression free survival (PFS) and overall survival (OS) with acceptable NT. Because R-MPV-A had never been tested without radiotherapy, we conducted a randomized study to determine if the low doses of radiation played a role in the observed disease control, and to characterize NT as compared to chemotherapy alone. Methods: Patients were stratified by MSK RPA class and randomized to receive R-MPV-A with LD-WBRT (chemoRT arm) versus R-MPV-A alone (chemo arm). MTX dose was 3.5g/m2 infused over 2 hours. Filgrastim and pegfilgrastim support was given to all patients. LD-WBRT dose was 23.4 Gy (1.8 Gy X 13). The primary endpoint was intent-to-treat (ITT) PFS. A sample size of 89 would provide 80% power to detect a hazard ratio (HR) of 0.63, with one-sided alpha level of 0.15. Results: A total of 91 patients were randomized, of whom 4 were ineligible. Among eligible patients, 43 were enrolled in the chemoRT arm and 44 in the chemo arm. Median age was 66 (chemoRT) and 59 (chemo). Median KPS was 80 for both arms. Response rates following R-MPV were 81% (chemoRT) and 83% (chemo). In the chemoRT arm, 37 patients (86%) received LD-WBRT. After median follow-up of 55 months (m), the median ITT PFS was 25 m in the chemo arm and not reached in the chemoRT arm (HR 0.51; 95% CI [0.27, 0.95]; p = 0.015). The 2-year PFS was 54% (chemo) and 78% (chemoRT). Salvage radiotherapy has been given to 11 patients in the chemo arm. Median OS was not reached in either arm, with data still maturing. In both arms, most common grades 3 or 4 toxicities were anemia (27%), lymphopenia (41%), neutropenia (35%), thrombocytopenia (26%), ALT (23%) and AST (13%). One patient died from sepsis (chemo arm). As per investigators’ assessment, the rate of clinically defined moderate to severe NT was 11.4% (chemo) and 14% (chemoRT), p = 0.75. Conclusions: The study met the primary endpoint, demonstrating the addition of LD-WBRT to R-MPV-A improves PFS in newly diagnosed PCNSL. As per investigator’s assessment, NT rates were not statistically significantly increased, but further neuropsychological testing and neuroimaging analyses are ongoing to characterize cognitive decline and how it compares to other consolidation treatments. Clinical trial information: NCT01399372 .

PURPOSE: To report the long-term outcomes and MGMT analysis of temozolomide (TMZ) and radiotherapy (RT) in a high-risk low-grade gliomas (LGG) population. PATIENTS/ METHODS: For this single-arm phase II study, LGG patients with ≥3 risk factors (age ≥40, astrocytoma, bi-hemispheric tumor, size ≥6 cm or preoperative neurologic function status >1) received RT (54 Gy/30 fractions) with TMZ and up to 12 cycles of post-RT TMZ. The primary endpoint was overall survival (OS) at 3 years after registration. A one-sided Z-test was used to test the hazard rate based on the observed 3-year OS rate versus a prespecified historical control from the EORTC high-risk LGG population. Secondary endpoints included progression-free survival (PFS), and the association of survival outcomes with MGMT methylation status, for which the MGMT-STP27 prediction model was used based on 450k data. The initial report of this study was published in 2015, when the results of the MGMT analysis were unavailable. RESULTS: The study accrued 129 analyzable patients. The median follow-up for surviving patients was 9 years (range: 0.4–11.8), 4 years longer than previously reported. The 3-year OS rate was 73.5% (95% CI: 65.8–81.1%), superior to the historical control of 54% (p

PURPOSE: NRG CC001, a phase III trial of WBRT plus memantine with or without hippocampal avoidance, sought to evaluate the neuro-protective effects of avoiding the hippocampus using intensity-modulated radiotherapy. METHODS: Adult patients with brain metastases were stratified by RPA class and receipt of prior radiosurgery/surgery and randomized to WBRT+memantine (WBRT+M) versus hippocampal-avoidant WBRT+memantine (HA-WBRT+M) (30Gy in 10 fractions). Standardized NCF tests were performed at baseline, 2, 4, 6, and 12 months. The primary endpoint was time to NCF failure, defined as decline on at least one of the following tests using the reliable change index: Hopkins Verbal Learning Test-Revised, Trail Making Test, or Controlled Oral Word Association. Cumulative incidence was used to estimate time to NCF failure (death without NCF failure was treated as competing risk) with between-arms differences tested using Grays test. To detect an 11% absolute reduction in 6-month NCF failure, 382 analyzable patients were required for 90% power with two-sided =0.05. Due to possible non-compliance, the sample size was increased by 25% (510 patients). RESULTS: From July 2016 to March 2018, 518 patients were randomized. Median age was 61.5 years. Median follow-up for alive patients was 6.1 months. Treatment arms did not differ in grade3 toxicity, overall survival, intracranial progression, or baseline NCF. Time to NCF failure was significantly longer in favor of HA-WBRT+M (p=0.012). The 6-month NCF failure rates were 69.1% (95% CI:61.8–75.3%) vs. 58.0% (95% CI:50.2–64.9%) for WBRT+M vs. HA-WBRT+M, respectively. After adjusting for stratification factors, HA-WBRT+M (hazard ratio (HR)=0.73, 95%CI:0.56–0.94, p=0.016) and age 61 years (HR=0.61, 95%CI:0.46–0.81, p=0.0006) remained significant. CONCLUSION: Preliminary analysis confirms that conformal avoidance of the neuro-regenerative hippocampal stem cell compartment during WBRT preserves neurocognitive function while achieving similar intracranial control and survival. Supported by grants UG1CA189867 (NCORP), U10CA180868 (NRG Oncology Operations), DCP from the National Cancer Institute.

The incidence of brain metastases is projected to rise because survival rates of lung cancer, breast cancer, and melanoma continue to improve (1). The brain is being identified as a sanctuary site for harboring metastases despite excellent control of extracranial disease. This is thought to occur because the drug therapies that control extracranial disease have limited central nervous system (CNS) penetration. The development of brain metastases is a devastating diagnosis affecting both quality of life (QOL) and survival. Symptoms after diagnosis can include headache, nausea, vomiting, seizure, neurocognitive decline, and focal neurologic deficit. Some of these symptoms can be irreversible even after successful treatment of intracranial disease. Treatment of brain metastases often necessitates surgery and radiation. There have been some reports of systemic therapies offering an intracranial response however long-term data is lacking. These treatments for CNS metastases can also lead to neurocognitive sequelae impacting quality of life. Therefore, preventing disease from spreading to the brain is a topic that has generated much interest in oncology. Prophylactic cranial Irradiation (PCI) has been used in leukemia, small cell lung cancer (SCLC), and non-small cell lung cancer (NSCLC). While showing effectiveness in preventing intracranial disease development, its carries with it side effects of neurocognitive decline that can affect QOL. There are Clinical trials exploring novel delivery of PCI and concurrent neuroprotective drug therapy to try to mitigate these neurocognitive sequelae. These will be important trials to complete, as PCI has shown promise in controlling disease and prolonging survival in select patient populations. There are also drug therapies that have shown efficacy in preventing CNS metastases development. This review will explore the current therapies available to prevent CNS metastases.

BACKGROUND: NRG CC001, a phase III trial of WBRT+memantine (WBRT+M) with or without Hippocampal Avoidance (HA), sought to assess the neuro-protective effects of lowering the radiation dose received by the hippocampus. METHODS: Patients (pts) with brain metastases were stratified by RPA class and prior radiosurgery/surgery and randomized to either WBRT+M or HA-WBRT+M (30Gy/10 fractions). Standardized neurocognitive function (NCF) tests were performed at baseline, 2, 4, 6, and 12 months (mos.). The primary endpoint was NCF failure, defined as decline using the reliable change index on Hopkins Verbal Learning Test-Revised, Trail Making Test, or Controlled Oral Word Association. Cumulative incidence estimated NCF failure (death without NCF failure was competing risk); between-arms differences tested using Gray’s test. Deterioration at each collection time point was tested using a chi-square test. Patient-reported symptoms were assessed using the MD Anderson Symptom Inventory with Brain Tumor module and analyzed using mixed effects models and t-tests. RESULTS: From 7/2016 to 3/2018, 518 patients were randomized. Median follow-up was 7.9 mos. HA-WBRT+M was associated with lower NCF failure risk (adjusted HR=0.74, p=0.02) due to lower risk of deterioration in executive function at 4 mos. (p=0.01); and encoding (p=0.049) and consolidation (p=0.02) at 6 mos. Age≤61 predicted for lower NCF failure risk (HR=0.60, p=0.0002); non-significant test for interaction indicated independent effects of HA and age. Patient-reported fatigue (p=0.036); difficulty speaking (p=0.049); and problems remembering things (p=0.013) at 6 mos. favored the HA-WBRT+M arm. Imputation models accounting for missing data also favored the HA-WBRT+M arm for patient-reported cognition (p=0.011) and symptom interference (p=0.008) at 6 mos. Treatment arms did not significantly differ in toxicity; intracranial progression or overall survival. CONCLUSIONS: While achieving similar intracranial control and survival; Hippocampal Avoidance during WBRT+M for brain metastases better preserves NCF and patient-reported symptoms. Supported by UG1CA189867 (NCORP) and DCP from the NCI.

OBJECTIVEThis is the first clinical outcomes report of NRG Oncology RTOG 0539, detailing the primary endpoint, 3-year progression-free survival (PFS), compared with a predefined historical control for intermediate-risk meningioma, and secondarily evaluating overall survival (OS), local failure, and prospectively scored adverse events (AEs).METHODSNRG Oncology RTOG 0539 was a Phase II clinical trial allocating meningioma patients to 1 of 3 prognostic groups and management strategies according to WHO grade, recurrence status, and resection extent. For the intermediate-risk group (Group 2), eligible patients had either newly diagnosed WHO Grade II meningioma that had been treated with gross-total resection (GTR; Simpson Grades I–III) or recurrent WHO Grade I meningioma with any resection extent. Pathology and imaging were centrally reviewed. Patients were treated with radiation therapy (RT), either intensity modulated (IMRT) or 3D conformal (3DCRT), 54 Gy in 30 fractions. The RT target volume was defined as the tumor bed and any nodular enhancement (e.g., in patients with recurrent WHO Grade I tumors) with a minimum 8-mm and maximum 15-mm margin, depending on tumor location and setup reproducibility of the RT method. The primary endpoint was 3-year PFS. Results were compared with historical controls (3-year PFS: 70% following GTR alone and 90% with GTR + RT). AEs were scored using NCI Common Toxicity Criteria.RESULTSFifty-six patients enrolled in the intermediate-risk group, of whom 3 were ineligible and 1 did not receive RT. Of the 52 patients who received protocol therapy, 4 withdrew without a recurrence before 3 years leaving 48 patients evaluable for the primary endpoint, 3-year PFS, which was actuarially 93.8% (p = 0.0003). Within 3 years, 3 patients experienced events affecting PFS: 1 patient with a WHO Grade II tumor died of the disease, 1 patient with a WHO Grade II tumor had disease progression but remained alive, and 1 patient with recurrent WHO Grade I meningioma died of undetermined cause without tumor progression. The 3-year actuarial local failure rate was 4.1%, and the 3-year OS rate was 96%. After 3 years, progression occurred in 2 additional patients: 1 patient with recurrent WHO Grade I meningioma and 1 patient with WHO Grade II disease; both remain alive. Among 52 evaluable patients who received protocol treatment, 36 (69.2%) had WHO Grade II tumors and underwent GTR, and 16 (30.8%) had recurrent WHO Grade I tumors. There was no significant difference in PFS between these subgroups (p = 0.52, HR 0.56, 95% CI 0.09–3.35), validating their consolidation. Of the 52 evaluable patients, 44 (84.6%) received IMRT, and 50 (96.2%) were treated per protocol or with acceptable variation. AEs (definitely, probably, or possibly related to protocol treatment) were limited to Grade 1 or 2, with no reported Grade 3 events.CONCLUSIONSThis is the first clinical outcomes report from NRG Oncology RTOG 0539. Patients with intermediate-risk meningioma treated with RT had excellent 3-year PFS, with a low rate of local failure and a low risk of AEs. These results support the use of postoperative RT for newly diagnosed gross-totally resected WHO Grade II or recurrent WHO Grade I meningioma irrespective of resection extent. They also document minimal toxicity and high rates of tumor control with IMRT.Clinical trial registration no.: NCT00895622 (clinicaltrials.gov).

The proper treatment of brain metastases continues to be a challenge for oncologists given the variability of individual patients' prognoses and the variety of treatment options available to address brain metasteses. There have been efforts since the 1990s to develop prognostic indices and nomograms to help clinicians determine the best approach for individuals with secondary malignant neoplasms of the central nervous system. A literature search was performed to identify the existing prognostic tools published between January 1995 and January 2017. While there have been several reported indices, many are limited by the number of patients analyzed or lack of generalizability. The most robust prognostic tools available are the Disease Specific Graded Prognostic Assessment and the Barnholtz-Sloan nomogram, both of which have online tools available to help clinicians. While these tools are helpful in stratifying different patients' outcomes, they are limited by their retrospective nature and likely underestimate survival in the modern era, where there is a rapidly growing arsenal of systemic agents available to patients with metastatic disease.

PURPOSE: RTOG 0933 demonstrated benefits to memory following HA-WBRT, supporting the hypothesis of hippocampal radiosensitivity and associated memory specificity. However, some patients demonstrated cognitive decline, suggesting mechanisms outside hippocampal radiosensitivity playing a role. WMI has been implicated in RT-induced cognitive decline. This secondary analysis explored the relationship between pre-treatment WMI and memory following HA-WBRT. METHODS AND MATERIALS: 113 patients received HA-WBRT. Standardized cognitive assessments were performed at baseline, 2, 4, and 6 months. The primary endpoint was Hopkins Verbal Learning Test Delayed Recall (HVLT-DR) at 4 mos. Secondary endpoints included HVLT Total Recall (HVLT-TR) and Recognition (HVLT-Recog). Of 113 patients, 34 underwent pre-treatment and 4-month post-treatment HVLT testing and pre-treatment post-contrast volumetric T1 and axial T2/FLAIR MRI. Volumetric analysis of metastatic disease burden and disease-unrelated WMI was conducted on the pre-treatment MRI. Correlational analyses were performed examining the relationship between pre-treatment WMI and HVLT outcomes following HA-WBRT. RESULTS: Correlation was found between larger volumes of pre-treatment WMI and decline in HVLT-Recog (r=.54, p< .05) and a correlational trend was observed between larger volume of pre-treatment WMI and decline in HVLT-DR (r=.31, p=.08). Patients with higher pre-treatment disease burden experienced a greater magnitude of stability or positive shift in HVLT-recall and –delayed recall following HA-WBRT. (r=-.36 and r=-.36, p’s < .05), compared to the magnitude of stability/positive shift in those with lesser disease burden. CONCLUSION: In patients receiving HA-WBRT, pre-treatment-WMI predicts memory decline, suggesting white matter integrity pre-treatment contributes to the pathogenesis of post-WBRT cognitive toxicity independent of hippocampal stem cell radiosensitivity. Less decline or improvement in HVLT following HA-WBRT for patients with higher pre-treatment intracranial metastatic burden supports the importance of WBRT-induced intracranial control on cognition. These imaging biomarkers for cognitive toxicity will be further explored on NRG CC001 and CC003, phase III trials of WBRT with or without HA.

TPS8578 Background: Multiple clinical trials have shown that prophylactic cranial irradiation (PCI) prevents brain metastases and may prolong survival in small cell lung cancer (SCLC). However,prophylactic cranial irradiation can lead to decline in cognitive function. Preclinical evidence suggests that the pathogenesis of this toxicity includes inflammatory injury to proliferating neuronal progenitor cells in the peri-hippocampal stem cell niches. We hypothesized that conformal avoidance of the hippocampal neural stem cell compartment during brain irradiation using intensity-modulated radiotherapy (IMRT) would decrease the likelihood and/or severity of this toxicity. This hypothesis was recently validated by positive results from NRG Oncology CC001, a phase III trial of hippocampal avoidance during whole-brain radiotherapy for patients with brain metastases. NRG Oncology CC003 is an ongoing randomized phase II/III trial of hippocampal avoidance during prophylactic cranial irradiation (HA-PCI) for small cell lung cancer, conducted in parallel with NRG Oncology CC001. Methods: The primary endpoints of the phase IIR and III components are 12-month intracranial relapse rate and 6-month deterioration in Hopkins Verbal Learning Test-Revised (HVLT-R) Delayed Recall, respectively. This is a seamless phase IIR/III trial, with the phase IIR designed to demonstrate non-inferiority. If the non-inferiority margin of the phase IIR component is not exceeded, then the trial would transition to the phase III component. Following accrual of 182 of planned 172 patients on the phase IIR component, the trial closed to accrual on 10/13/17 to assess the phase IIR primary endpoint. The DSMB evaluated the IIR outcomes, and on 1/9/19, the trial was reactivated to accrue an additional 122 patients to the phase III component. Eligibility criteria include: 1) small cell lung cancer with at least partial response to chemotherapy; 2) contrast-enhanced thin-slice volumetric MRI scan; and, 3) Zubrod performance status 0-2. Supported by grant UG1CA189867 (NCORP) from the National Cancer Institute. Clinical trial information: NCT02635009.

BACKGROUND AND PURPOSE: Patients with recurrent glioblastoma often exhibit regions of diffusion restriction following the initiation of bevacizumab therapy. Studies suggest that these regions represent either diffusion-restricted necrosis or hypercellular tumor. This study explored postmortem brain specimens and a population analysis of overall survival to determine the identity and implications of such lesions. MATERIALS AND METHODS: Postmortem examinations were performed on 6 patients with recurrent glioblastoma on bevacizumab with progressively growing regions of diffusion restriction. ADC values were extracted from regions of both hypercellular tumor and necrosis. A receiver operating characteristic analysis was performed to define optimal ADC thresholds for differentiating tissue types. A retrospective population study was also performed comparing the overall survival of 64 patients with recurrent glioblastoma treated with bevacizumab. Patients were separated into 3 groups: no diffusion restriction, diffusion restriction that appeared and progressed within 5 months of bevacizumab initiation, and delayed or stable diffusion restriction. An additional analysis was performed assessing tumor O6-methylguanine-DNA-methyltransferase methylation. RESULTS: The optimal ADC threshold for differentiation of hypercellularity and necrosis was 0.736 × 10−3mm2/s. Progressively expanding diffusion restriction was pathologically confirmed to be coagulative necrosis surrounded by viable tumor. Progressive lesions were associated with the worst overall survival, while stable lesions showed the greatest overall survival (P CONCLUSIONS: Progressive diffusion-restricted lesions were pathologically confirmed to be coagulative necrosis surrounded by viable tumor and associated with decreased overall survival. Stable lesions were, however, associated with increased overall survival. All lesions were associated with O6-methylguanine-DNA-methyltransferase unmethylated tumors.