Evaluating the heterogeneity of hippocampal avoidant whole brain radiotherapy treatment effect: A secondary analysis of NRG CC001

BACKGROUND

Hippocampal avoidant whole brain radiotherapy (HA-WBRT) is the standard of care for patients needing WBRT for brain metastases. This study, using existing data from NRG Oncology CC001 including baseline tumor characteristics and patient-reported MD Anderson Symptom Inventory-Brain Tumor (MDASI-BT) scores, sought to identify subgroups of patients that demonstrate differential neuroprotective treatment response to HA-WBRT.

METHODS

An exploratory analysis of NRG CC001, a phase 3 trial in which 518 patients were randomly assigned to WBRT plus memantine or HA-WBRT plus memantine, was performed. Rates of neurocognitive function failure (NCFF) were estimated between subgroups and stratified by arm. Covariate and subgroup interaction with differential treatment response were calculated.

RESULTS

The benefit of HA-WBRT on decreasing NCFF was seen in patients living ≥ 4 months (HR 0.75, 95% CI: 0.58-0.97, P = .03), whereas patients living < 4 months derived no significant neurocognitive benefit. A significant association between baseline MDASI-BT cognitive factor and treatment response (interaction P = .03) was identified. Patients with lower MDASI-BT scores (less patient-reported cognitive impairment) derived significantly greater benefit (HR = 0.64, 95% CI: 0.48-0.85, P = .002) compared to those with highest MDASI-BT scores (HR = 1.24, 95% CI: 0.76-2.04, P = .39). Tumor histology also had a significant interaction (P = .01) with treatment response. Primary lung histology patients derived cognitive failure risk reduction (HR = 0.58, 95% CI: 0.43-0.77, P = .0007) from HA-WBRT, in contrast to nonlung primary histology patients (HR = 1.15, 95% CI: 0.78-1.50, P = .48).

CONCLUSIONS

Differential neuroprotective response to HA-WBRT was identified in this analysis. Patients surviving ≥ 4 months derived benefit from HA-WBRT. There is evidence of heterogeneity of treatment effect for patients with less severe patient-reported cognitive impairment at baseline and those with primary lung histology.

Immunotherapy and Radiotherapy Combinations for Sarcoma

Sarcomas are a heterogeneous group of bone and soft tissue tumors. Survival outcomes for advanced (unresectable or metastatic) disease remain poor, so therapeutic improvements are needed. Radiotherapy plays an integral role in the neoadjuvant and adjuvant treatment of localized disease as well as in the treatment of metastatic disease. Combining radiotherapy with immunotherapy to potentiate immunotherapy has been used in a variety of cancers other than sarcoma, and there is opportunity to further investigate combining immunotherapy with radiotherapy to try to improve outcomes in sarcoma. In this review, we describe the diversity of the tumor immune microenvironments for sarcomas and describe the immunomodulatory effects of radiotherapy. We discuss studies on the timing of radiotherapy relative to immunotherapy and studies on the radiotherapy dose and fractionation regimen to be used in combination with immunotherapy. We describe the impact of radiotherapy on the tumor immune microenvironment. We review completed and ongoing clinical trials combining radiotherapy with immunotherapy for sarcoma and propose future directions for studies combining immunotherapy with radiotherapy in the treatment of sarcoma.

Evaluating the sensitivity of EQ-5D-5L in patients with brain metastases: a secondary analysis of NRG CC001

BACKGROUND

EuroQoL EQ-5D is a commonly used measure of health-related quality of life (HRQOL) in clinical trials given the use of its index score as a measure of health utilities. It is unclear whether EQ-5D is sensitive to changes in neurocognitive function and progression that occur following brain radiation. This study sought to evaluate the sensitivity of EQ-5D-5L in reflecting these changes.

PATIENTS AND METHODS

A secondary analysis of NRG Oncology CC001 was performed. Mean EQ-5D-5L index and visual analog scale (VAS) score changes from baseline between groups of patients stratified by neurocognitive function and intracranial progression status were assessed. MD Anderson Symptom Inventory for brain tumor (MDASI-BT) symptom and interference items were also analyzed between groups.

RESULTS

EQ-5D-5L index and VAS score changes between patients who had cognitive failure and those that had preserved cognition showed no significant differences at any time point. In contrast, VAS changes at 4 (1.61 vs -5.13, P = .05) and 6 months (8.17 vs -0.14, P = .04) were significantly improved in the patients who survived without intracranial progression.MDASI-BT cognitive factor scores were significantly improved in the cohort of patients with preserved neurocognitive function at 2 (1.68 vs 2.08, P = .05) and 4 months (1.35 vs 1.83, P = .04). MDASI-BT symptom interference was significantly associated with intracranial progression at 4 months, but not with neurocognitive status.

CONCLUSION

EQ-5D-5L index and VAS scores were not sensitive to neurocognitive changes that patients experienced, but VAS scores were sensitive to progression. This study challenges the routine use of EQ-5D as a QoL metric in brain metastases clinical trials that are focused on preventing neurocognitive dysfunction.

TRIAL REGISTRATION

NCT# 02360215.

A multi-institutional phase I study of acetazolamide with temozolomide in adults with newly diagnosed MGMT-methylated malignant glioma

Background

A significant unmet need exists for the treatment of glioblastoma, IDH-wildtype (GBM). Preclinical work shows that acetazolamide sensitizes GBM to temozolomide (TMZ) by overcoming TMZ resistance due to BCL-3-dependent upregulation of carbonic anhydrase. Acetazolamide is Food and Drug Administration-approved for the treatment of altitude sickness. Drug repurposing enables the application of drugs to diseases beyond initial indications. This multi-institutional, open-label, phase I trial examined a combination of acetazolamide and TMZ in patients with MGMT promoter-methylated high-grade glioma.

Methods

A total of 24 patients (GBM, IDH-wildtype = 22; Grade 4 astrocytoma, IDH-mutant = 1; Grade 3 astrocytoma, IDH-mutant = 1) were accrued over 17 months. All patients received oral acetazolamide (250 mg BID for 7 days increased to 500 mg BID for Days 8-21 of each 28-day cycle) during the adjuvant phase of TMZ for up to 6 cycles.

Results

No patient had a dose-limiting toxicity. Adverse events were consistent with known sequelae of acetazolamide and TMZ. In the 23 WHO Grade 4 patients, the median overall survival (OS) was 30.1 months and the median progression-free survival was 16.0 months. The 2-year OS was 60.9%. In total 37% of the study population had high BCL-3 staining and trended toward shorter OS (17.2 months vs N.R., P = .06).

Conclusions

The addition of acetazolamide is safe and tolerable in GBM patients receiving standard TMZ. Survival results compare favorably to historical data from randomized trials in patients with MGMT promoter-methylated GBM and support examination of acetazolamide in a randomized trial. BCL-3 expression is a potential biomarker for prognosis in GBM or for patients more likely to benefit from TMZ.

Sustained Preservation of Cognition and Prevention of Patient-Reported Symptoms With Hippocampal Avoidance During Whole-Brain Radiation Therapy for Brain Metastases: Final Results of NRG Oncology CC001

PURPOSE

Initial report of NRG Oncology CC001, a phase 3 trial of whole-brain radiation therapy plus memantine (WBRT + memantine) with or without hippocampal avoidance (HA), demonstrated neuroprotective effects of HA with a median follow-up of fewer than 8 months. Herein, we report the final results with complete cognition, patient-reported outcomes, and longer-term follow-up exceeding 1 year.

METHODS AND MATERIALS

Adult patients with brain metastases were randomized to HA-WBRT + memantine or WBRT + memantine. The primary endpoint was time to cognitive function failure, defined as decline using the reliable change index on the Hopkins Verbal Learning Test-Revised (HVLT-R), Controlled Oral Word Association, or the Trail Making Tests (TMT) A and B. Patient-reported symptom burden was assessed using the MD Anderson Symptom Inventory with Brain Tumor Module and EQ-5D-5L.

RESULTS

Between July 2015 and March 2018, 518 patients were randomized. The median follow-up for living patients was 12.1 months. The addition of HA to WBRT + memantine prevented cognitive failure (adjusted hazard ratio, 0.74, P = .016) and was associated with less deterioration in TMT-B at 4 months (P = .012) and HVLT-R recognition at 4 (P = .055) and 6 months (P = .011). Longitudinal modeling of imputed data showed better preservation of all HVLT-R domains (P < .005). Patients who received HA-WBRT + Memantine reported less symptom burden at 6 (P < .001 using imputed data) and 12 months (P = .026 using complete-case data; P < .001 using imputed data), less symptom interference at 6 (P = .003 using complete-case data; P = .0016 using imputed data) and 12 months (P = .0027 using complete-case data; P = .0014 using imputed data), and fewer cognitive symptoms over time (P = .043 using imputed data). Treatment arms did not differ significantly in overall survival, intracranial progression-free survival, or toxicity.

CONCLUSIONS

With median follow-up exceeding 1 year, HA during WBRT + memantine for brain metastases leads to sustained preservation of cognitive function and continued prevention of patient-reported neurologic symptoms, symptom interference, and cognitive symptoms with no difference in survival or toxicity.

Final Analysis of a Phase III Controlled Randomized Study of Stereotactic Body Proton Therapy or Conventionally Fractionated Proton Therapy for Early Prostate Cancer: PCG GU002

PURPOSE/OBJECTIVE(S)

To determine if stereotactic body proton therapy (SBPT) is non-inferior to conventionally fractionated proton therapy (CFPT) in patients with early prostate cancer.

MATERIALS/METHODS

Multicenter, randomized, controlled, open-label, non-inferiority phase 3 trial that included patients with histologically confirmed low-risk prostate adenocarcinoma defined by Gleason score ≤6, PSA <10 ng/mL, and clinical stage T1-2a N0 M0 by AJCC 7th Ed. Eligible participants were randomly assigned (initially 1:1 and later 2:1 ratio) to CFPT (79.2 Gy in 44 fractions for 9 weeks) or SBPT (38 Gy in 5 fractions for 1 week). Concurrent or adjuvant androgen deprivation therapy was not allowed. The primary endpoint was freedom from failure (FFF) at 2 years, defined as the first occurrence of local, regional, or distant recurrence, biochemical failure by the Phoenix definition (increase of PSA ≥2 ng/mL over the nadir PSA), or the start of salvage therapy including ADT. Secondary endpoints included GI and GU grade ≥2 toxicity according to CTCAE v4 criteria, as well as health-related quality of life (HRQoL) metrics assessed by AUASI and EPIC scores. Non-inferiority would be declared if the 1-sided 95% confidence interval limit for the difference in 2-year FFF rate was below 4.2% between both groups by Clopper-Pearson exact method.

RESULTS

Between November 2010 and September 2020, 133 patients were enrolled and randomly assigned to CFPT (n = 45) or SBPT (n = 88). Median follow-up was 5 years (IQ 3.9-5.2), with the last patient enrolled followed for at least 2 years. The 2-year FFF was 100% for both groups, fulfilling the pre-specified criteria for non-inferiority of SBPT compared to CFPT. By KM estimates, 5-year FFF was 97.4% and 100% (P = 0.1), and the 5-year OS was 97.1% and 95.5% (P = 0.46) for patients treated with CFPT and SBPT, respectively. The cumulative incidence of any grade ≥3 toxicities at 5 years was 0% and 5.7% (P = 0.14) for patients treated with CFPT and SBPT, respectively. The frequency of GI grade ≥2 toxicity at 6 months was of 0% and 2.3% (P = 0.55), and at 2 years was of 6.7% and 3.4% (P = 0.69) for patients treated with CFPT and SBPT, respectively. The frequency of GU grade ≥2 toxicity at 6 months was of 2.2% and 5.7% (P = 0.42), and at 2 years was of 8.9% and 5.7% (P = 0.54) for patients treated with CFPT and SBPT, respectively. Changes in HRQoL scores at 2 years were similar between groups (Table).

CONCLUSION

SBPT is non-inferior to CFPT regarding FFF and associated with similar long-term toxicity rates and HRQoL metric scores.

National Cancer Institute Collaborative Workshop on Shaping the Landscape of Brain Metastases Research: challenges and recommended priorities

Brain metastases are an increasing global public health concern, even as survival rates improve for patients with metastatic disease. Both metastases and the sequelae of their treatment are key determinants of the inter-related priorities of patient survival, function, and quality of life, mandating a multidimensional approach to clinical care and research. At a virtual National Cancer Institute Workshop in September, 2022, key stakeholders convened to define research priorities to address the crucial areas of unmet need for patients with brain metastases to achieve meaningful advances in patient outcomes. This Policy Review outlines existing knowledge gaps, collaborative opportunities, and specific recommendations regarding consensus priorities and future directions in brain metastases research. Achieving major advances in research will require enhanced coordination between the ongoing efforts of individual organisations and consortia. Importantly, the continual and active engagement of patients and patient advocates will be necessary to ensure that the directionality of all efforts reflects what is most meaningful in the context of patient care.

Building Team Medicine in the Management of CNS Metastases

CNS metastases are often terminal for cancer patients and occur at an approximately 10-fold higher rate than primary CNS tumors. The incidence of these tumors is approximately 70,000-400,000 cases annually in the US. Advances that have occurred over the past two decades have led to more personalized treatment approaches. Newer surgical and radiation techniques, as well as targeted and immune therapies, have enanled patient to live longer, thus increasing the risk for the development of CNS, brain, and leptomeningeal metastases (BM and LM). Patients who develop CNS metastases have often been heavily treated, and options for future treatment could best be addressed by multidisciplinary teams. Studies have indicated that patients with brain metastases have improved survival outcomes when cared for in high-volume academic institutions using multidisciplinary teams. This manuscript discusses a multidisciplinary approach for both parenchymal brain metastases as well as leptomeningeal metastases implemented in three academic institutions. Additionally, with the increasing development of healthcare systems, we discuss optimizing the management of CNS metastases across healthcare systems and integrating basic and translational science into our clinical care to further improve outcomes. This paper summarizes the existing therapeutic approaches to the treatment of BM and LM and discusses novel and emerging approaches to optimizing access to neuro-oncologic care while simultaneously integrating multidisciplinary teams in the care of patients with BM and LM.

Exposure to radon and heavy particulate pollution and incidence of brain tumors

BACKGROUND

Global incidence for brain tumors varies substantially without explanation. Studies correlating radon exposure and incidence are inconclusive. Particulate pollution has been linked to increased tumor incidence. Particulates may disrupt the blood-brain barrier allowing intracranial exposure to oncogenic radon. We investigated the relationship between exposure to residential radon, particulate pollution, and brain tumor incidence in the United States (US).

METHODS

County-level median radon testing results and annual air quality index values were obtained and divided into tertiles. Counties without both values were excluded. Four groups of counties were generated: high particulate/high radon (high/high), high/low, low/high, and low/low. Using incidence data from the Central Brain Tumor Registry of the US (provided by CDC's National Program of Cancer Registries and NCI's SEER), annual age-adjusted incidence rates (AAAIRs) by group were generated by behavior. Incidence rate ratios were calculated to examine for significant differences (α = .05). Poisson regression accounting for possible confounders was conducted.

RESULTS

Counties with available data included 83% of the US population. High/high exposure was significantly associated with increased AAAIR of all non-malignant tumors (up to 26% higher, including most meningiomas) even after accounting for potential confounders. An increased AAAIR was noted for all malignant tumors (up to 10% higher), including glioblastoma, but was negated after accounting for demographic/socioeconomic differences.

CONCLUSIONS

We present the first report suggesting increased non-malignant brain tumor incidence in regions with high particulate and radon exposure. These findings provide insight into unexplained variation in tumor incidence. Future studies are needed to validate these findings in other populations.

CTNI-49. EARLY SIGNAL OF ACTIVITY FROM A PHASE 2 STUDY OF ST101, A FIRST-IN-CLASS PEPTIDE ANTAGONIST OF CCAAT/ENHANCER-BINDING PROTEIN Β (C/EBPΒ), IN RECURRENT GLIOBLASTOMA (GBM)

BACKGROUND

C/EBPβ is a transcription factor that is active during embryofetal development but held in an inactive state in most mature cells (Zahnow 2009). C/EBPβ activates a proliferation/survival gene signature in multiple cancers, where it inversely correlates with disease prognosis and survival. ST101 is a cell-penetrating peptide antagonist of C/EBPβ. ST101 exposure leads to selective tumor cell death in multiple human cancer cell lines, including GBM, without impacting normal cell viability. In vivo, ST101 displays rapid uptake into multiple organs, the ability to cross the blood-brain barrier, and a long plasma half-life due to its resistance to degradation. It has potent anti-tumor activity in multiple GBM models, as a single agent or in combination, which supported moving into clinical development. TRIAL DESIGN: This phase 2 study is enrolling adult patients with GBM that has recurred or progressed after one standard treatment regimen (surgery, radiotherapy +/-temozolomide). Patients require measurable disease at baseline and at least 3 months from prior radiotherapy. Subjects receive the recommended phase 2 dose of ST101 (500mg IV weekly). Recruitment in the phase 2 portion of this trial began in January, 2022.

RESULTS

As of June 1, 2022, 14 GBM patients were enrolled. One patient has a confirmed mRANO partial response (PR) after 18 weeks of therapy, seven patients have not reached the first on-study assessment and six patients progressed. The median duration of therapy was 5 weeks. ST101 has a favorable safety profile with minor infusion related reactions being the most common adverse event. Based on the confirmed PR, the GBM cohort will be expanded.

CONCLUSION

This first-in-class C/EBPβ inhibitor, ST101, showed an early signal of activity in recurrent GBM. More extensive follow-up and clinical experience will be presented as this trial expands and matures.

NCOG-03. IMPACT OF THE RATE OF RADIOGRAPHIC RESPONSE (RR) OF BRAIN METASTASES (BM) TO WHOLE BRAIN RADIATION THERAPY (WBRT) ON NEUROCOGNITIVE FUNCTION (NCF) ON NRG-CC001

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.

Deep Learning-Based Automatic Detection of Brain Metastases in Heterogenous Multi-Institutional Magnetic Resonance Imaging Sets: An Exploratory Analysis of NRG-CC001

PURPOSE

Deep learning-based algorithms have been shown to be able to automatically detect and segment brain metastases (BMs) in magnetic resonance imaging, mostly based on single-institutional data sets. This work aimed to investigate the use of deep convolutional neural networks (DCNN) for BM detection and segmentation on a highly heterogeneous multi-institutional data set.

METHODS AND MATERIALS

A total of 407 patients from 98 institutions were randomly split into 326 patients from 78 institutions for training/validation and 81 patients from 20 institutions for unbiased testing. The data set contained T1-weighted gadolinium and T2-weighted fluid-attenuated inversion recovery magnetic resonance imaging acquired on diverse scanners using different pulse sequences and various acquisition parameters. Several variants of 3-dimensional U-Net based DCNN models were trained and tuned using 5-fold cross validation on the training set. Performances of different models were compared based on Dice similarity coefficient for segmentation and sensitivity and false positive rate (FPR) for detection. The best performing model was evaluated on the test set.

RESULTS

A DCNN with an input size of 64 × 64 × 64 and an equal number of 128 kernels for all convolutional layers using instance normalization was identified as the best performing model (Dice similarity coefficient 0.73, sensitivity 0.86, and FPR 1.9) in the 5-fold cross validation experiments. The best performing model demonstrated consistent behavior on the test set (Dice similarity coefficient 0.73, sensitivity 0.91, and FPR 1.7) and successfully detected 7 BMs (out of 327) that were missed during manual delineation. For large BMs with diameters greater than 12 mm, the sensitivity and FPR improved to 0.98 and 0.3, respectively.

CONCLUSIONS

The DCNN model developed can automatically detect and segment brain metastases with reasonable accuracy, high sensitivity, and low FPR on a multi-institutional data set with nonprespecified and highly variable magnetic resonance imaging sequences. For large BMs, the model achieved clinically relevant results. The model is robust and may be potentially used in real-world situations.

Radiotherapy for elderly patients with glioblastoma: an assessment of hypofractionation and modern treatment techniques

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.

SPCR-01 RAPIDPLAN HIPPOCAMPAL SPARING WHOLE BRAIN MODEL VERSION 2 - HOW FAR CAN WE REDUCE THE DOSE?

BACKGROUND

Whole-brain radiotherapy (WBRT) has been the standard palliative treatment for patients with brain metastases due to its effectiveness, availability, and ease of administration. Recent clinical trials have shown that limiting radiation dose to the hippocampus is associated with decreased cognitive toxicity. In this study, we updated an existing Knowledge Based Planning (KBP) model to further reduce dose to the hippocampus and improve other dosimetric plan quality characteristics.

METHODS

42 clinical cases were contoured according to NRG-CC001 guidelines. A new dosimetric scorecard was created as an objective measure for plan quality. The new Hippocampal Sparing Whole Brain Version 2 (HSWBv2) model adopted a complex recursive training process and was validated with five additional cases. HSWBv2 treatment plans were generated on the Varian HalcyonTM and TrueBeamTM systems and compared against plans generated from the existing (HSWBv1) model released in 2016.

RESULTS

On the HalcyonTM platform, 42 cases were re-planned. Hippocampal D100% from HSWBv2 and HSWBv1 models had an average dose of 5.75 Gy and 6.46 Gy, respectively (p&lt;0.001). HSWBv2 model also achieved a hippocampal Dmean of 7.49 Gy, versus 8.10 Gy in HSWBv1 model (p&lt;0.001). Hippocampal D0.03CC from HSWBv2 model was 9.86 Gy, in contrast to 10.57 Gy in HSWBv1 (p&lt;0.001). For PTV_3000, D98% and D2% from HSWBv2 model were 28.27 Gy and 31.81 Gy, respectively, compared to 28.08 Gy (p=0.020) and 32.66 Gy from HSWBv1 (p&lt;0.001). Among several other dosimetric quality improvements, there was a significant reduction in PTV_3000 V105% from 35.35% (HSWBv1) to 6.44% (HSWBv2) (p&lt;0.001). On five additional validation cases, dosimetric improvements were also observed on TrueBeamTM.

CONCLUSION

In comparison to published data in addition to the HSWBv1 model, the HSWBv2 model achieved higher quality HA-WBRT treatment plans through further reductions in hippocampal dose while improving target coverage and dose conformity/homogeneity. HSWBv2 model is shared publicly.

CLRM-10 METIS (EF-25): A PIVOTAL, RANDOMIZED CONTROLLED STUDY OF TUMOR TREATING FIELDS IN PATIENTS WITH 1–10 BRAIN METASTASES FROM NON-SMALL CELL LUNG CANCER

BACKGROUND

Tumor Treating Fields (TTFields) are electric fields that disrupt cancer cell division. TTFields treatment showed efficacy in preclinical non-small cell lung cancer (NSCLC) models. Furthermore, TTFields therapy improved survival with a tolerable safety profile in patients with glioblastoma. The objective of the pivotal METIS trial [NCT02831959] is to evaluate the efficacy and safety of TTFields therapy in NSCLC patients with brain metastases.

METHODS

NSCLC patients (N=270) with 1–10 brain metastases will be randomized 1:1 to stereotactic radiosurgery (SRS) followed by continuous TTFields therapy using NovoTTF-200M (150 kHz, recommended &gt;18 h/day) with best standard of care (BSC) or SRS followed by BSC alone. Follow-ups will be conducted every 2 months until second intracranial progression. Key inclusion criteria are: Karnofsky Performance Status ≥70, new diagnosis of 1 inoperable or 2–10 supra- and/or infratentorial brain metastases from NSCLC amenable to SRS, and optimal therapy for extracranial disease. Key exclusion criteria are: prior whole brain radiotherapy, single operable, or recurrent brain metastases. Primary endpoint is time to first intracranial progression. Secondary endpoints include time to neurocognitive failure, overall survival, radiological response rate (RANO-BM and RECIST V1.1), quality of life, adverse events, time to first/second intracranial progression for patients with 1–4 and 5–10 brain metastases, bi-monthly intracranial progression rate from 2–12 months, and time to second intracranial and distant progression. The study is powered at 80% (2-sided alpha of 0.05) to detect a hazard ratio of 0.57. In July 2021, an independent Data Monitoring Committee (DMC) reviewed the study data and recommended continuation as planned. The trial is currently recruiting at 92 sites in North America, Europe, Israel, mainland China and Hong Kong.

Radiation Therapy for Brain Metastases: An ASTRO Clinical Practice Guideline

PURPOSE

This guideline provides updated evidence-based recommendations addressing recent developments in the management of patients with brain metastases, including advanced radiation therapy techniques such as stereotactic radiosurgery (SRS) and hippocampal avoidance whole brain radiation therapy and the emergence of systemic therapies with central nervous system activity.

METHODS

The American Society for Radiation Oncology convened a task force to address 4 key questions focused on the radiotherapeutic management of intact and resected brain metastases from nonhematologic solid tumors. The guideline is based on a systematic review provided by the Agency for Healthcare Research and Quality. Recommendations were created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

Strong recommendations are made for SRS for patients with limited brain metastases and Eastern Cooperative Oncology Group performance status 0 to 2. Multidisciplinary discussion with neurosurgery is conditionally recommended to consider surgical resection for all tumors causing mass effect and/or that are greater than 4 cm. For patients with symptomatic brain metastases, upfront local therapy is strongly recommended. For patients with asymptomatic brain metastases eligible for central nervous system-active systemic therapy, multidisciplinary and patient-centered decision-making to determine whether local therapy may be safely deferred is conditionally recommended. For patients with resected brain metastases, SRS is strongly recommended to improve local control. For patients with favorable prognosis and brain metastases receiving whole brain radiation therapy, hippocampal avoidance and memantine are strongly recommended. For patients with poor prognosis, early introduction of palliative care for symptom management and caregiver support are strongly recommended.

CONCLUSIONS

The task force has proposed recommendations to inform best clinical practices on the use of radiation therapy for brain metastases with strong emphasis on multidisciplinary care.

The Cognitive Effects of Radiotherapy for Brain Metastases

Brain metastases are the most common intracranial neoplasm and are seen in upwards of 10-30% of patients with cancer. For decades, whole brain radiation therapy (WBRT) was the mainstay of treatment in these patients. While WBRT is associated with excellent rates of intracranial tumor control, studies have demonstrated a lack of survival benefit, and WBRT is associated with higher rates of cognitive deterioration and detrimental effects on quality of life. In recent years, strategies to mitigate this risk, such as the incorporation of memantine and hippocampal avoidance have been employed with improved results. Furthermore, stereotactic radiosurgery (SRS) has emerged as an appealing treatment option over the last decade in the management of brain metastases and is associated with superior cognitive preservation and quality of life when compared to WBRT. This review article evaluates the pathogenesis and impact of cranial irradiation on cognition in patients with brain metastases, as well as current and future risk mitigation techniques.

Radiation Therapy for Brain Metastases: ASCO Guideline Endorsement of ASTRO Guideline

PURPOSE

American Society of Radiation Oncology (ASTRO) has developed a guideline on appropriate radiation therapy for brain metastases. ASCO has a policy and set of procedures for endorsing clinical practice guidelines that have been developed by other professional organizations.

METHODS

"Radiation Therapy for Brain Metastases: An ASTRO Clinical Practice Guideline"² was reviewed for developmental rigor by methodologists. An ASCO Endorsement Panel subsequently reviewed the content and the recommendations.

RESULTS

The ASCO Endorsement Panel determined that the recommendations from the ASTRO guideline, published May 6, 2022, are clear, thorough, and based upon the most relevant scientific evidence. ASCO endorses "Radiation Therapy for Brain Metastases: An ASTRO Clinical Practice Guideline."².

RECOMMENDATIONS

Within the guideline, stereotactic radiosurgery (SRS) is recommended for patients with Eastern Cooperative Oncology Group performance status of 0-2 and up to four intact brain metastases, and conditionally recommended for patients with up to 10 intact brain metastases. The guideline provides detailed dosing and fractionation recommendations on the basis of the size of the metastases. For patients with resected brain metastases, radiation therapy (SRS or whole-brain radiation therapy [WBRT]) is recommended to improve intracranial disease control; if there are limited additional brain metastases, SRS is recommended over WBRT. For patients with favorable prognosis and brain metastases ineligible for surgery and/or SRS, WBRT is recommended with hippocampal avoidance where possible and the addition of memantine is recommended. For patients with brain metastases, limiting the single-fraction V_12Gy to brain tissue to ≤ 10 cm³ is conditionally recommended.Additional information is available at www.asco.org/neurooncology-guidelines.

Dose-escalated accelerated hypofractionation for elderly or frail patients with a newly diagnosed glioblastoma

BACKGROUND

The standard of care for elderly glioblastoma patients is 40 Gy in 15 fraction radiotherapy with temozolomide (TMZ). However, this regimen has a lower biologic equivalent dose (BED) compared to the Stupp regimen of 60 Gy in 30 fractions. We hypothesize that accelerated hypofractionated radiation of 52.5 Gy in 15 fractions (BED equivalent to Stupp) will have superior survival compared to 40 Gy in 15 fractions.

METHODS

Elderly patients (≥ 65 years old) who received hypofractionated radiation with TMZ from 2010 to 2020 were included in this analysis. Overall survival (OS) and progression free survival were defined as the time elapsed between surgery/biopsy and death from any cause or progression. Baseline characteristics were compared between patients who received 40 and 52.5 Gy. Univariable and multivariable analyses were performed.

RESULTS

Sixty-six newly diagnosed patients were eligible for analysis. Thirty-nine patients were treated with 40 Gy in 15 fractions while twenty-seven were treated with 52.5 Gy in 15 fractions. Patients had no significant differences in age, sex, methylation status, or performance status. OS was superior in the 52.5 Gy group (14.1 months) when compared to the 40 Gy group (7.9 months, p = 0.011). Isoeffective dosing to 52.5 Gy was shown to be an independent prognostic factor for improved OS on multivariable analysis.

CONCLUSIONS

Isoeffective dosing to 52.5 Gy in 15 fractions was associated with superior OS compared to standard of care 40 Gy in 15 fractions. These hypothesis generating data support accelerated hypofractionation in future prospective trials.

Secondary CNS myeloma with remission after systemic CNS-penetrating agents

Background

CNS myeloma is a rare manifestation of multiple myeloma and is often associated with a dismal prognosis; however, cases are increasing in frequency as overall survival improves for MM. There is currently no standardized treatment for CNS myeloma; however, different chemotherapy and radiotherapy regimens have been described.

Methods

We had previously reported on the efficacy of proton-based craniospinal irradiation in a patient with CNS myeloma; here we present a patient with a history of extramedullary plasmacytoma, 10 years in remission status post standard systemic chemotherapy, with biopsy-proven CNS myeloma successfully treated with systemic chemotherapy as a first-line treatment.

Results

The patient achieved clinical and radiographic remission on 2 separate occasions with systemic chemotherapy alone.

Conclusions

This case demonstrates that systemically administered agents may have activity in CNS myeloma. Further investigations are necessary to establish the optimal combination of agents and treatment schedules.

Treatment for Brain Metastases: ASCO-SNO-ASTRO Guideline

PURPOSE

To provide guidance to clinicians regarding therapy for patients with brain metastases from solid tumors.

METHODS

ASCO convened an Expert Panel and conducted a systematic review of the literature.

RESULTS

Thirty-two randomized trials published in 2008 or later met eligibility criteria and form the primary evidentiary base.

RECOMMENDATIONS

Surgery is a reasonable option for patients with brain metastases. Patients with large tumors with mass effect are more likely to benefit than those with multiple brain metastases and/or uncontrolled systemic disease. Patients with symptomatic brain metastases should receive local therapy regardless of the systemic therapy used. For patients with asymptomatic brain metastases, local therapy should not be deferred unless deferral is specifically recommended in this guideline. The decision to defer local therapy should be based on a multidisciplinary discussion of the potential benefits and harms that the patient may experience. Several regimens were recommended for non-small-cell lung cancer, breast cancer, and melanoma. For patients with asymptomatic brain metastases and no systemic therapy options, stereotactic radiosurgery (SRS) alone should be offered to patients with one to four unresected brain metastases, excluding small-cell lung carcinoma. SRS alone to the surgical cavity should be offered to patients with one to two resected brain metastases. SRS, whole brain radiation therapy, or their combination are reasonable options for other patients. Memantine and hippocampal avoidance should be offered to patients who receive whole brain radiation therapy and have no hippocampal lesions and 4 months or more expected survival. Patients with asymptomatic brain metastases with either Karnofsky Performance Status ≤ 50 or Karnofsky Performance Status < 70 with no systemic therapy options do not derive benefit from radiation therapy.Additional information is available at www.asco.org/neurooncology-guidelines.

Association of Pretreatment Hippocampal Volume With Neurocognitive Function in Patients Treated With Hippocampal Avoidance Whole Brain Radiation Therapy for Brain Metastases: Secondary Analysis of NRG Oncology/RTOG 0933

Purpose

Hippocampal volume (HV) is an established predicting factor for neurocognitive function (NCF) in neurodegenerative disease. Whether the same phenomenon exists with hippocampal-avoidant whole brain radiation therapy is not known; therefore, we assessed the association of baseline HV with NCF among patients enrolled on RTOG 0933.

Methods and Materials

Hippocampal volume and total brain volume were calculated from the radiation therapy plan. Hippocampal volume was correlated with baseline and 4-month NCF scores (Hopkins Verbal Learning Test-Revised [HVLT-R] Total Recall [TR], Immediate Recognition, and Delayed Recall [DR]) using Pearson correlation. Deterioration in NCF was defined per the primary endpoint of RTOG 0933(mean 4-month relative decline in HVLT-R DR). Comparisons between patients with deteriorated and nondeteriorated NCF were made using the Wilcoxon test.

Results

Forty-two patients were evaluable. The median age was 56.5 years (range, 28-83 years), and 81% had a class II recursive partitioning analysis. The median total, right, and left HVs were 5.4 cm³ (range, 1.9-7.4 cm³), 2.8 cm³ (range, 0.9-4.0 cm³), and 2.7 cm³ (range, 1.0-3.7 cm³), respectively. The median total brain volume was 1343 cm³ (range, 1120.5-1738.8 cm³). For all measures of corrected HV, increasing HV was associated with higher baseline HVLT-R TR and DR scores (ρ: range, 0.35-0.40; P-value range, .009-.024) and 4-month TR and DR scores (ρ: range, 0.29-0.40; P-value range, .009-.04), with the exception of right HV and 4-month DR scores (ρ: 0.29; P = .059). There was no significant association between HV and NCF change between baseline and 4 months. Fourteen patients (33.3%) developed NCF deterioration per the primary endpoint of RTOG 0933. There was no significant difference in HV between patients with deteriorated and nondeteriorated NCF, although in all instances, patients with deteriorated NCF had numerically lower HV.

Conclusions

Larger HV was positively associated with improved performance on baseline and 4-month HVLT-R TR and DR scores in patients with brain metastases undergoing hippocampal-avoidant whole brain radiation therapy but was not associated with a change in NCF.

CTIM-12. A PHASE 1 TRIAL OF IMMUNORADIOTHERAPY WITH THE IDO ENZYME INHIBITOR (BMS-986205) AND NIVOLUMAB IN PATIENTS WITH NEWLY DIAGNOSED MGMT PROMOTER UNMETHYLATED IDHwt GLIOBLASTOMA

BACKGROUND

IDHwt glioblastoma with unmethylated MGMT gene promoter carries a poor prognosis. Preclinical studies have shown that combination of radiotherapy and dual immunotherapy with nivolumab and IDO inhibition significantly prolongs survival of mice with an orthotopic glioblastoma [Ladomersky, et al. CCR 2018;24(11):2559-2573]. In a clinical trial in patients with newly diagnosed glioblastoma with unmethylated MGMT we substituted temozolomide for dual immunotherapy combination.

METHODS

Phase 1 trial [NCT04047706] using a 3 + 3 dose-escalation design. All received standard radiotherapy (30 x 2 Gy) with addition of once daily oral BMS-986205 and intravenous nivolumab (240mg every 2 weeks) begining on day 1 of radiotherapy and continuing until disease progression or intolerance. BMS-986205 dosing was increased from 50 mg to 100 mg. DLT period encompasses 6 weeks of radiotherapy and the 4 subsequent weeks. Immunocorrelatives being conducted before and after treatment include mass spectrometry for tryptophan and kynurenine levels, immunohistochemistry of resected tumor, and RNA-sequencing and flow cytometric analysis of PBMCs.

RESULTS

Twelve patients were treated on 2 dose levels of BMS-986205 (50, 100 mg). Treatment-emergent toxicity was as expected for this population. Three (25%) treatment-related SAEs were reported. Dose limiting toxicity of grade 3 transaminase elevation was observed in 2 patients at the 100 mg dose level, while at lower doses of BMS-986205 no substantial alterations of liver enzymes was observed. No other relevant treatment related toxicity occured. Ongoing immunocorrelative profiling and preliminary outcome data (all patients minimal follow-up &gt;12 months) will be available at the time of the meeting.

CONCLUSIONS

Dose limiting toxicity of BMS-986205 in combination with nivolumab and radiotherapy is hepatic (reversible) transaminitis. The recommended dose for further investigation is 50 mg. Accrual is ongoing for the MGMT promoter methylated cohort using the same regimen without withholding temozolomide. A randomized phase 2/3 trial is approved within the NRG network.

Advances in radiotherapy for brain metastases

As novel systemic therapies yield improved survival in metastatic cancer patients, the frequency of brain metastases continues to increase. Over the years, management strategies have continued to evolve. Historically, stereotactic radiosurgery has been used as a boost to whole-brain radiotherapy (WBRT) but is increasingly being used as a replacement for WBRT. Given its capacity to treat both macro- and micro-metastases in the brain, WBRT has been an important management strategy for years, and recent research has identified technologic and pharmacologic approaches to delivering WBRT more safely. In this review, we outline the current landscape of radiotherapeutic treatment options and discuss approaches to integrating radiotherapy advances in the contemporary management of brain metastases.

Radiotherapy intensification for glioblastoma: enhancing the backbone of treatment

Given the impact of radiotherapy on survival outcomes for patients with glioblastoma (GBM), intensification of radiotherapy through dose-escalation and/or dose-per-fraction escalation has been an important area of ongoing investigation. Prior to the introduction of temozolomide, radiotherapy intensification beyond 60-Gy conventionally fractionated radiotherapy did not yield a survival benefit. With the emergence of temozolomide and its radio-sensitizing properties, as well as greater understanding of the patterns of first progression after 60-Gy radiotherapy, hypotheses regarding the impact of radiotherapy intensification have arisen. This article will discuss ongoing and future investigations of radiotherapy intensification in the modern temozolomide era of GBM management. These efforts have focused on better radiotherapy delivery techniques and/or improved tumor imaging to identify high-risk regions of progression.

Case series of diffuse extraneural metastasis in H3F3A mutant high-grade gliomas: Clinical, molecular phenotype and literature review

H3K27M and H3.3G34R/V mutations have been identified in pediatric high-grade gliomas (pHGG), though extraneural metastases are rarely reported and poorly characterized. Three pHGG patients from two institutions were identified with extraneural metastasis, harboring histone mutations. Their clinical, imaging and molecular characteristics are reported here. A 17-year old female presented with supratentorial H3.3G34R-mutant glioma with metastatic osseous lesions in the spine, pelvis, bone marrow, pleural effusion and soft tissue of pelvis. Bone marrow biopsy and soft tissue of pelvis biopsy showed neoplastic cells positive for P53. A 20-year old female was diagnosed with H3F3A H3K27M-mutant thalamic glioma. She developed diffuse sclerotic osseous lesions. Biopsy of an osseous lesion was non-diagnostic. A 17-year old female presented with a H3F3A H3K27M-mutant diffuse midline glioma with diffuse spinal cord metastasis. She further developed multifocal chest lymphadenopathy, pleural effusions, and a soft tissue mass in the abdominal wall. The latter was positive for H3K27M mutation. We present the first case series of pHGG with H3F3A mutation and diffuse extraneural dissemination, describing their clinical and molecular profile.

Dose Escalated Radiation Therapy for Glioblastoma Multiforme: An International Systematic Review and Meta-Analysis of 22 Prospective Trials

PURPOSE

Limited evidence is available on the utility of dose-escalated radiation therapy (DE-RT) with or without temozolomide (TMZ) versus standard-of-care radiation therapy (SoC-RT) for patients with newly diagnosed glioblastoma multiforme. We performed a systematic review/meta-analysis to compare overall survival (OS) and progression-free survival (PFS) between DE-RT and SoC-RT.

METHODS AND MATERIALS

We used a Population, Intervention, Control, Outcomes, Study Design/Preferred Reporting Items for Systematic Reviews and Meta-analyses/Meta-analysis of Observational Studies in Epidemiology selection criterion to identify studies. The primary and secondary outcomes were 1-year OS and 1-year PFS, respectively. Outcomes and comparisons were subdivided based on receipt of TMZ and MGMT status. DE-RT was defined based on equivalent dose calculations. Random effects meta-analyses using the Knapp-Hartung correction, arcsine transformation, and restricted maximum likelihood method were conducted. Meta-regression was used to compare therapeutic (eg, DE-RT or TMZ) and pathologic characteristics (eg, MGMT methylation status) using the Wald-type test.

RESULTS

Across 22 published studies, 2198 patients with glioblastoma multiforme were included; 507 received DE-RT. One-year OS after DE-RT alone was higher than SoC-RT alone (46.3% vs 23.4%; P = .02) as was 1-year PFS (17.9% vs 5.3%; P = .02). No significant difference in 1-year OS (73.2% vs 64.4%; P = .23) or 1-year PFS (44.5% vs 44.3%; P = .33) between DE-RT + TMZ and SoC-RT + TMZ was noted. No difference in 1-year OS was noted between DE-RT + TMZ and SoC-RT + TMZ in either MGMT methylated (83.2% vs 73.2%; P = .23) or MGMT unmethylated (72.6% vs 50.6%; P = .16) patients.

CONCLUSIONS

DE-RT alone resulted in superior PFS and OS versus SoC-RT alone. DE-RT + TMZ did not lead to improved outcomes versus SoC-RT + TMZ. No differential benefit based on MGMT status was found. Future studies are warranted to define which subgroups benefit most from DE-RT.

Individualized quality of life benefit and cost-effectiveness estimates of proton therapy for patients with oropharyngeal cancer

Background

Proton therapy is a promising advancement in radiation oncology especially in terms of reducing normal tissue toxicity, although it is currently expensive and of limited availability. Here we estimated the individual quality of life benefit and cost-effectiveness of proton therapy in patients with oropharyngeal cancer treated with definitive radiation therapy (RT), as a decision-making tool for treatment individualization.

Methods and materials

Normal tissue complication probability models were used to estimate the risk of dysphagia, esophagitis, hypothyroidism, xerostomia and oral mucositis for 33 patients, comparing delivered photon intensity-modulated RT (IMRT) plans to intensity-modulated proton therapy (IMPT) plans. Quality-adjusted life years (QALYs) lost were calculated for each complication while accounting for patient-specific conditional survival probability and assigning quality-adjustment factors based on complication severity. Cost-effectiveness was modeled based on upfront costs of IMPT and IMRT, and the cost of acute and/or long-term management of treatment complications. Uncertainties in all model parameters and sensitivity analyses were included through Monte Carlo sampling.

Results

The incremental cost-effectiveness ratios (ICERs) showed considerable variability in the cost of QALYs spared between patients, with median $361,405/QALY for all patients, varying from $54,477/QALY to $1,508,845/QALY between individual patients. Proton therapy was more likely to be cost-effective for patients with p16-positive tumors ($234,201/QALY), compared to p16-negative tumors ($516,297/QALY). For patients with p16-positive tumors treated with comprehensive nodal irradiation, proton therapy is estimated to be cost-effective in ≥ 50% of sampled cases for 8/9 patients at $500,000/QALY, compared to 6/24 patients who either have p16-negative tumors or receive unilateral neck irradiation.

Conclusions

Proton therapy cost-effectiveness varies greatly among oropharyngeal cancer patients, and highlights the importance of individualized decision-making. Although the upfront cost, societal willingness to pay and healthcare administration can vary greatly among different countries, identifying patients for whom proton therapy will have the greatest benefit can optimize resource allocation and inform prospective clinical trial design.

RTID-01. RADIOSURGERY FOLLOWED BY TUMOR TREATING FIELDS FOR BRAIN METASTASES (1-10) FROM NSCLC IN THE PHASE 3 METIS TRIAL

BACKGROUND

Tumor Treating Fields (TTFields) are non-invasive, loco-regional, anti-mitotic treatment modality comprising alternating electric fields. TTFields have demonstrated efficacy in preclinical non-small cell lung cancer (NSCLC) models. TTFields treatment to the brain was safe and extended overall survival in newly-diagnosed glioblastoma. The objective of the METIS study [NCT02831959] is evaluation of the efficacy and safety of TTFields in NSCLC patients with brain metastases.

METHODS

NSCLC patients (N=270) with 1-10 brain metastases were randomized 1:1 to stereotactic radio surgery (SRS) followed by continuous TTFields ((150 kHz, &gt; 18 hours/day) within 7 days of SRS or supportive care. The portable device delivered TTFields to the brain using 4 transducer arrays, while patients received the best standard-of-care for systemic disease. Patients were followed every two months until second intracranial progression. Key inclusion criteria: KPS ≥70, new diagnosis of 1 inoperable or 2–10 supra- and/or infratentorial brain metastases from NSCLC amenable to SRS; and optimal therapy for extracranial disease. Prior WBRT, surgical resection of metastases, or recurrent brain metastases were exclusionary. Primary endpoint was time to 1st intracranial progression. Secondary endpoints included time to neurocognitive failure (HVLT, COWAT and TMT), overall survival, radiological response rate (RANO-BM and RECIST V1.1); quality-of-life; adverse events; time to first/second intracranial progression for patients with 1–4 and 5–10 brain metastases; bi-monthly intracranial progression rate from 2–12 months; and time to second intracranial and distant progression. The sample size (N=270) was calculated using a log-rank test (Lakatos 1988 and 2002) with 80% power at two sided alpha of 0.05 to detect a hazard ratio of 0.57. On September, 2019, an independent Data Monitoring Committee (DMC) reviewed METIS trial data collected to that point. The DMC concluded that no unexpected safety issues had emerged and recommended continuation of the METIS study as planned.

CTNI-50. NEUROCOGNITIVE FUNCTION (NCF) OF THE PHOTON COHORT IN NRG-BN001

NRG BN001 is an ongoing randomized phase II trial of dose-intense (DI-RT) versus standard dose photon-based radiation therapy (SD-RT) with temozolomide (TMZ) for newly diagnosed glioblastoma. We report preliminary results of Group 1, DI-RT delivered with IMRT while SD-RT could be 3DCRT or IMRT. Group 2, DI-RT delivered with proton therapy, continues to accrue. From 10/2014 to 7/2018, 229 patients were eligible and randomized. Differences in overall survival following DI-RT versus SD-RT were not significant. Patients were scheduled to complete NCF testing at baseline, cycle 3 (within 7 days of cycle 4), and cycle 12 (day 22–28 of cycle 12, or 60 weeks from completion of chemoradiation). At baseline, 93–94% of eligible patients completed NCF testing. Compliance for evaluable patients at cycle 3 and cycle 12 was 66–68% and 51–54%, respectively, across the battery of NCF tests. The most common reasons for missing data were patient refusal (cycle 3: 14%, cycle 12: 22–23%) and institutional error (cycle 3: 9–10%, cycle 12: 14–15%). A prespecified secondary endpoint analysis was conducted to evaluate differences in NCF between SD-RT and DI-RT based on the Clinical Trial Battery Composite (CTB COMP), which is the mean of the standardized scores from the NCF test battery (HVLT-R, TMT, COWA). There was no statistically significant between arm difference in change from baseline on the CTB COMP at cycle 3 (DI-RT vs SD-RT mean/SD, 0.0 +/- 1.3 vs -0.3 +/- 1.5, p=0.370, Cohen’s d=0.22) or cycle 12 (DI-RT vs SD-RT mean/SD, 0.2 +/- 1.7 vs 0.2 +/- 1.1, p=0.977, Cohen’s d=0.01). A mixed effects longitudinal model of the CTB COMP yielded a non-significant time by treatment effect interaction (p=0.216). There were no significant differences in change scores between arms on any NCF test at cycles 3 or 12. NCF outcomes were similar for photon-based SD-RT and DI-RT.

NCOG-04. PRETREATMENT VOLUME OF MR-DETERMINED WHITE MATTER INJURY (WMI) PREDICTS NEUROCOGNITIVE DECLINE AFTER HIPPOCAMPAL AVOIDANT (HA) WBRT+MEMANTINE FOR BRAIN METASTASES: SECONDARY ANALYSIS OF NRG ONCOLOGYCC001

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&lt; 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.

Improved neuropsychological outcomes following proton therapy relative to X-ray therapy for pediatric brain tumor patients

BACKGROUND

Survivors of pediatric brain tumors are at risk for impaired development in multiple neuropsychological domains. The purpose of this study was to compare neuropsychological outcomes of pediatric brain tumor patients who underwent X-ray radiotherapy (XRT) versus proton radiotherapy (PRT).

METHODS

Pediatric patients who underwent either XRT or PRT and received posttreatment age-appropriate neuropsychological evaluation-including measures of intelligence (IQ), attention, memory, visuographic skills, academic skills, and parent-reported adaptive functioning-were identified. Multivariate analyses were performed to assess differences in neuropsychological outcomes and included tests for interaction between treatment cohort and follow-up time.

RESULTS

Between 1998 and 2017, 125 patients with tumors located in the supratentorial (17.6%), midline (28.8%), or posterior fossa (53.6%) compartments received radiation and had posttreatment neuropsychological evaluation. Median age at treatment was 7.4 years. The PRT patient cohort had higher estimated SES and shorter median time from radiotherapy completion to last neuropsychological evaluation (6.7 vs 2.6 y, P < 0.001). On multivariable analysis, PRT was associated with higher full-scale IQ (β = 10.6, P = 0.048) and processing speed (β = 14.4, P = 0.007) relative to XRT, with trend toward higher verbal IQ (β = 9.9, P = 0.06) and general adaptive functioning (β = 11.4, P = 0.07). Planned sensitivity analyses truncating follow-up interval in the XRT cohort re-demonstrated higher verbal IQ (P = 0.01) and IQ (P = 0.04) following PRT, with trend toward improved processing speed (P = 0.09).

CONCLUSIONS

PRT is associated with favorable outcomes for intelligence and processing speed. Combined with other strategies for treatment de-intensification, PRT may further reduce neuropsychological morbidity of brain tumor treatment.

30. RADIOSURGERY FOLLOWED BY TUMOR TREATING FIELDS FOR BRAIN METASTASES (1–10) FROM NSCLC IN THE PHASE 3 METIS TRIAL

BACKGROUND

Tumor Treating Fields (TTFields) are non-invasive, loco-regional, anti-mitotic treatment modality comprising alternating electric fields. TTFields have demonstrated efficacy in preclinical non-small cell lung cancer (NSCLC) models. TTFields treatment to the brain was safe and extended overall survival in newly-diagnosed glioblastoma. The objective of the METIS study [NCT02831959] is evaluation of the efficacy and safety of TTFields in NSCLC patients with brain metastases.

METHODS

NSCLC patients (N=270) with 1–10 brain metastases were randomized 1:1 to stereotactic radio surgery (SRS) followed by continuous TTFields ((150 kHz, > 18 hours/day) within 7 days of SRS or supportive care. The portable device delivered TTFields to the brain using 4 transducer arrays, while patients received the best standard-of-care for systemic disease. Patients were followed every two months until second intracranial progression. Key inclusion criteria: KPS ≥70, new diagnosis of 1 inoperable or 2–10 supra- and/or infratentorial brain metastases from NSCLC amenable to SRS; and optimal therapy for extracranial disease. Prior WBRT, surgical resection of metastases, or recurrent brain metastases were exclusionary. Primary endpoint was time to 1st intracranial progression. Secondary endpoints included time to neurocognitive failure (HVLT, COWAT and TMT), overall survival, radiological response rate (RANO-BM and RECIST V1.1); quality-of-life; adverse events; time to first/second intracranial progression for patients with 1–4 and 5–10 brain metastases; bi-monthly intracranial progression rate from 2–12 months; and time to second intracranial and distant progression. The sample size (N=270) was calculated using a log-rank test (Lakatos 1988 and 2002) with 80% power at two sided alpha of 0.05 to detect a hazard ratio of 0.57. On September, 2019, an independent Data Monitoring Committee (DMC) reviewed METIS trial data collected to that point. The DMC concluded that no unexpected safety issues had emerged and recommended continuation of the METIS study as planned.

Hippocampal Avoidance During Whole-Brain Radiotherapy Plus Memantine for Patients With Brain Metastases: Phase III Trial NRG Oncology CC001

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.

Multidisciplinary patient-centered management of brain metastases and future directions

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.

ACTR-50. PRESERVATION OF NEUROCOGNITIVE FUNCTION & PATIENT-REPORTED SYMPTOMS WITH HIPPOCAMPAL AVOIDANCE (HA) DURING WHOLE-BRAIN RADIOTHERAPY (WBRT) FOR BRAIN METASTASES: LONG-TERM RESULTS OF NRG ONCOLOGY CC001

BACKGROUND

NRG-CC001 sought to evaluate the neuro-protective effects of avoiding the peri-hippocampal stem cell niche using intensity-modulated radiotherapy during WBRT.

METHODS

Patients with brain metastasis were stratified by RPA class and prior radiosurgery/surgery and randomized to WBRT+M or HA-WBRT+ Memantine (M) (30Gy in 10 fractions). Standardized NCF tests and the M.D. Anderson Symptom Inventory Brain Tumor (MDASI-BT) were obtained at baseline, 2, 4, 6, and 12 months (mos). The primary endpoint was NCF failure defined using the reliable change index. Pre-specified secondary endpoints included patient-reported symptoms using the MDASI-BT. Time to NCF was reported as cumulative incidence (with death without NCF failure as a competing risk); between-arms differences were tested using Gray’s test. Deterioration at discrete time-points were tested using chi-square tests. MDASI-BT symptom burden, interference, and cognitive and neurologic burden were analyzed using mixed effects models and t-tests within the model using Hochberg’s multiplicity adjustment.

RESULTS

A total of 518 patients were randomized from 7/2016 to 3/2018. Median follow-up for alive patients was 12.1 mos, with no difference between arms in terms of toxicity, overall survival or intracranial progression-free survival. HA-WBRT+M was associated with lower risk of NCF failure (adjusted HR=0.739, 95% CI: 0.577–0.945, p=0.0.016), with differences first noted at 4 mos in Trail Making Test Part-B (23.3% vs. 40.4% deteriorated, p=0.012). Age did not dilute treatment effect. HA-WBRT+M was associated with reduced cognitive symptom burden in an imputed model (estimate=-0.29, p=0.0425), and also reduced overall symptom burden (p< 0.0001) and interference (p< 0.0016) at 6 mos.

CONCLUSIONS

The addition of HA to WBRT+M preserved NCF and reduced patient reported cognitive symptom burden, overall symptom burden and symptom interference and should be considered standard of care for any patient fit enough to have WBRT. Supported by grants UG1CA189867 (NCORP), U10CA180868 (NRG Oncology Operations), DCP from the National Cancer Institute.

RBTT-02. RADIOSURGERY FOLLOWED BY TUMOR TREATING FIELDS FOR BRAIN METASTASES (1–10) FROM NSCLC IN THE PHASE 3 METIS TRIAL

BACKGROUND: Tumor Treating Fields (TTFields) are non-invasive, loco-regional, anti-mitotic treatment modality comprising alternating electric fields. TTFields have demonstrated efficacy in preclinical non-small cell lung cancer (NSCLC) models. TTFields treatment to the brain was safe and extended overall survival in newly-diagnosed glioblastoma. The METIS study [NCT02831959] investigates the efficacy and safety of TTFields in NSCLC patients with brain metastases. Study Design: NSCLC patients (N=270) with 1–10 brain metastases are randomized 1:1 to stereotactic radio surgery (SRS) followed by continuous TTFields ((150 kHz, > 18 hours/day) within 7 days of SRS or supportive care. The portable device delivers TTFields to the brain using 4 transducer arrays, while patients receive the best standard-of-care for systemic disease. Patients are followed every two months until second intracranial progression. Key inclusion criteria: KPS ≥70, new diagnosis of 1 inoperable or 2–10 supra- and/or infratentorial brain metastases from NSCLC amenable to SRS; and optimal therapy for extracranial disease. Prior WBRT or surgical resection of metastases, a single resectable lesion or recurrent brain metastases were exclusionary. Primary endpoint was time to 1st intracranial progression. Secondary endpoints included time to neurocognitive failure (HVLT, COWAT and TMT), overall survival, radiological response rate (RANO-BM and RECIST V1.1); quality-of-life; adverse events; time to first/second intracranial progression for patients with 1–4 and 5–10 brain metastases; bi-monthly intracranial progression rate from 2–12 months; and time to second intracranial and distant progression. The sample size (N=270) was calculated using a log-rank test (Lakatos 1988 and 2002) with 80% power at two sided alpha of 0.05 to detect a hazard ratio of 0.57. In August 2018, an independent Data Monitoring Committee (DMC) performed a review of the METIS trial data collected to that point. The DMC concluded that no unexpected safety issues had emerged and recommended continuation of the METIS study as planned.