The proteomic landscape of glioblastoma recurrence reveals novel and targetable immunoregulatory drivers.

Glioblastoma (GBM) is characterized by extensive cellular and genetic heterogeneity. Its initial presentation as primary disease (pGBM) has been subject to exhaustive molecular and cellular profiling. By contrast, our understanding of how GBM evolves to evade the selective pressure of therapy is starkly limited. The proteomic landscape of recurrent GBM (rGBM), which is refractory to most treatments used for pGBM, are poorly known. We, therefore, quantified the transcriptome and proteome of 134 patient-derived pGBM and rGBM samples, including 40 matched pGBM-rGBM pairs. GBM subtypes transition from pGBM to rGBM towards a preferentially mesenchymal state at recurrence, consistent with the increasingly invasive nature of rGBM. We identified immune regulatory/suppressive genes as important drivers of rGBM and in particular 2-5-oligoadenylate synthase 2 (OAS2) as an essential gene in recurrent disease. Our data identify a new class of therapeutic targets that emerge from the adaptive response of pGBM to therapy, emerging specifically in recurrent disease and may provide new therapeutic opportunities absent at pGBM diagnosis.

The technique and cost of radiosurgery for the treatment of 1-3 brain metastases.

BACKGROUND: Radiosurgery can be delivered through a variety of modalities including robotic and fixed gantry Linac-based systems. They appear equally effective and safe. Thus, community need and costs remain the main determinants for choosing a given modality. We performed an economic evaluation to identify settings in which one modality could be preferred over the other. METHODS: Using local estimates of resource volumes and unit prices, we computed the incremental cost/patient of robotic radiosurgery compared to fixed-gantry radiosurgery from a payer's perspective. By varying parameters of resource volumes, we performed a probabilistic analysis stratified by number of brain lesions. in addition, we performed sensitivity analyses to examine the effect of patient volume on cost/patient. RESULTS: The cost of robotic radiosurgery was $4,783/patient, and cost of fixed-gantry radiosurgery was $5,166/patient. The mean incremental cost was $-383 (95% interval: $-670, $110) for all lesions, $78 ($23, $123) for solitary lesions, and $-610 ($-679, $-534) for multiple lesions. The cost/patient of robotic radiosurgery varied from $5,656 (low volume setting) to $4,492 (high volume setting). CONCLUSION: in settings of moderate to high volume (6-10 hours of daily operation), and in multiple lesions, robotic radiosurgery is more cost effective than fixed-gantry radiosurgery.Technique utilisée et coût de la radiochirurgie pour le traitement de 1 à 3 métastases cérébrales.

Fractionated Stereotactic Radiation for Central Nervous System Lymphoma: Retrospective Analysis of Initial Cases.

Primary central nervous system lymphoma (PCNSL) is primarily treated with combination chemotherapy, while whole-brain radiotherapy (WBRT) can be used as consolidative treatment or as a salvage option for central nervous system (CNS) relapse. We investigated whether fractionated stereotactic radiosurgery (fSRS) could replace WBRT in cases where patients had poor performance status or minimal disease at the time of consolidation, to spare patients the adverse effects of WBRT. We retrospectively identified 10 patients who completed 14 courses of fSRS for PCNSL or for CNS relapse of systemic lymphoma. Of 14 fSRS treatments, there were 10 distant brain recurrences among 6 patients, occurring on average 13.6 months after fSRS. A total of 4 of the 10 recurrences were treated with further fSRS, and 4 were treated with WBRT. There was one late in-field recurrence after both fSRS and WBRT, which occurred 27 months after fSRS. The median survival after fSRS was 36 months, and side effects after fSRS were minimal. This case series represents a potential treatment option for patients with CNS lymphoma, for whom WBRT is indicated but where the toxic effects of this treatment would be prohibitive.

Association of circulating markers with cognitive decline after radiation therapy for brain metastasis.

BACKGROUND: A recent phase III trial (NCT01372774) comparing use of stereotactic radiosurgery [SRS] versus whole-brain radiation therapy [WBRT] after surgical resection of a single brain metastasis revealed that declines in cognitive function were more common with WBRT than with SRS. A secondary endpoint in that trial, and the primary objective in this secondary analysis, was to identify baseline biomarkers associated with cognitive impairment after either form of radiotherapy for brain metastasis. Here we report our findings on APOE genotype and serum levels of associated proteins and their association with radiation-induced neurocognitive decline. METHODS: In this retrospective analysis of prospectively collected samples from a completed randomized clinical trial, patients provided blood samples every 3 months that were tested by genotyping and enzyme-linked immunosorbent assay, and results were analyzed in association with cognitive impairment. RESULTS: The APOE genotype was not associated with neurocognitive impairment at 3 months. However, low serum levels of ApoJ, ApoE, or ApoA protein (all P < .01) and higher amyloid beta (Aß 1-42) levels (P = .048) at baseline indicated a greater likelihood of neurocognitive decline at 3 months after SRS, whereas lower ApoJ levels were associated with decline after WBRT (P = .014). CONCLUSIONS: Patients with these pretreatment serum markers should be counseled about radiation-related neurocognitive decline.

Outcomes in Elderly Patients with Glioblastoma Multiforme Treated with Short-Course Radiation Alone Compared to Short-Course Radiation and Concurrent and Adjuvant Temozolomide Based on Performance Status and Extent of Resection.

(1) Background: Studies in elderly patients over the age of 65 with glioblastoma have shown survival benefits of short-course radiation therapy with concurrent and adjuvant temozolomide, making it the standard of care adopted at Juravinski Cancer Center. Our study retrospectively examines patients with GBM aged ≥ 70 at the JCC treated with short-course radiation alone compared to those treated with short-course radiation and concurrent and adjuvant TMZ, to determine if there is a difference in outcomes based on performance status. (2) Methods: A retrospective chart review was conducted at JCC using patients diagnosed with GBM in 2014-2017 (treated with the old protocol of short-course RT alone) versus those diagnosed in 2017-2019 (treated with the new protocol of short-course radiation and TMZ). Patient demographics, treatments, outcomes, and baseline KPS were analyzed. (3) Results: No clear benefit and more neurologic decline post treatment were seen in patients with borderline performance status and subtotal resection who underwent concurrent treatment with temozolomide and radiation. The addition of temozolomide was most helpful in patients with good performance status and a gross total resection. Variable outcomes were seen in patients with mixed traits. (4) Conclusions: This study suggests that performance status and extent of resection are significant determinants of patient response to treatment. In the case of elderly patients with borderline performance status and GTR or those with good performance status and STR, also described as "mixed traits", it may be beneficial to pursue single modality treatment, ideally based on MGMT promoter methylation status as opposed to bimodality treatment in order to maintain the best QOL.

Hypofractionated Stereotactic Radiotherapy for the Treatment of Benign Intracranial Meningiomas: Long-Term Safety and Efficacy.

INTRODUCTION: Hypofractionated stereotactic radiotherapy (hSRT) has emerged as an alternative to single-fraction stereotactic radiosurgery (SRS) and conventionally fractionated radiotherapy for the treatment of intracranial meningiomas (ICMs). However, there is a need for data showing long-term efficacy and complication rates, particularly for larger tumors in sensitive locations. METHODS: A retrospective review was conducted on adult patients with ICMs seen at a tertiary care center. Eligible patients were treated with the CyberKnife platform and had a planned treatment course of 3-5 fractions from 2011-2020. The local control was assessed based on radiographic stability and the late toxicity/radionecrosis rates were recorded. Radiographic progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. RESULTS: In total, 62 patients (age 26-87) with 67 treated tumors were included in this study with a median follow-up of 64.7 months. RT was delivered as the primary treatment in 62.7% of cases and for recurrence in 37.3%. The most common tumor locations were the convexity of the brain and the base of the skull. The tumor sizes ranged from 0.1-51.8 cc and the median planning target volume was 4.9 cc. The most common treatment schedule was 18 Gy in 3 fractions. The five-year PFS and OS were 85.2% and 91.0%, respectively. The late grade III/IV toxicity rate was 3.2% and the radionecrosis rate was 4.8%. CONCLUSIONS: Based on our data, hSRT remains an effective modality to treat low-grade ICMs with acceptable long-term toxicity and radionecrosis rates. hSRT should be offered to patients who are not ideal candidates for SRS while preserving the benefits of hypofractionation.

Pretreatment Volume of MRI-Determined White Matter Injury Predicts Neurocognitive Decline After Hippocampal Avoidant Whole-Brain Radiation Therapy for Brain Metastases: Secondary Analysis of NRG Oncology Radiation Therapy Oncology Group 0933.

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 < .05), and a correlational trend was observed between larger volume of pretreatment WMI and decline in HVLT-R delayed recall (r = 0.31, P = .08). Patients with higher pretreatment disease burden experienced a greater magnitude of stability or positive shift in HVLT-R recall and delayed recall after HA-WBRT (r = -0.36 and r = -0.36, P < .05), compared to the magnitude of stability or positive shift in those with lesser disease burden. CONCLUSIONS: In patients receiving HA-WBRT for brain metastases, extent of pretreatment WMI predicts posttreatment memory decline, suggesting a mechanism for radiation therapy-induced neurocognitive toxicity independent of hippocampal stem cell radiosensitivity. Stability or improvement in HVLT after HA-WBRT for patients with higher pretreatment intracranial metastatic burden supports the importance of WBRT-induced intracranial control on neurocognition.

The Technique, Resources and Costs of Stereotactic Body Radiotherapy of Prostate Cancer: A Comparison of Dose Regimens and Delivery Systems.

Robotic system has been used for stereotactic body radiotherapy (SBRT) of prostate cancer. Arc-based and fixed-gantry systems are used for hypofractionated regimens (10-20 fractions) and the standard regimen (39 fractions); they may also be used to deliver SBRT. Studies are currently underway to compare efficacy and safety of these systems and regimens. Thus, we describe the technique and required resources for the provision of robotic SBRT in relation to the standard regimen and other systems to guide investment decisions. Using administrative data of resource volumes and unit prices, we computed the cost per patient, cost per cure and cost per quality adjusted life year (QALY) of four regimens (5, 12, 20 and 39 fractions) and three delivery systems (robotic, arc-based and fixed-gantry) from a payer's perspective. We performed sensitivity analyses to examine the effects of daily hours of operation and in-room treatment delivery times on cost per patient. In addition, we estimated the budget impact when a robotic system is preferred over an arc-based or fixed-gantry system. Costs of SBRT were $6333/patient (robotic), $4368/patient (arc-based) and $4443/patient (fixed-gantry). When daily hours of operation were varied, the cost of robotic SBRT varied from $9324/patient (2 hours daily) to $5250/patient (10 hours daily). This was comparable to the costs of 39 fraction standard regimen which were $5935/patient (arc-based) and $7992/ patient (fixed-gantry). In settings of moderate to high patient volume, robotic SBRT is cost effective compared to the standard regimen. If SBRT can be delivered with equivalent efficacy and safety, the arc-based system would be the most cost effective system.

Brain metastases in non-small-cell lung cancer.

Up to 50% of patients with advanced non-small-cell lung cancer will develop brain metastases at some point during their illness. These metastases cause a substantial burden in morbidity and mortality, which has motivated research and technological innovation over the past 2 decades. Surgery, radiotherapy, and systemic therapies have each played a role in management, with the greatest changes associated with the popularization of stereotactic radiosurgery. In this review, the evidence behind each modality used in the management of brain metastases for non-small-cell lung cancer patients is examined, and recommendations regarding the current standards of care and areas of future research focus are provided.

Preservation of memory with conformal avoidance of the hippocampal neural stem-cell compartment during whole-brain radiotherapy for brain metastases (RTOG 0933): a phase II multi-institutional trial.

PURPOSE: Hippocampal neural stem-cell injury during whole-brain radiotherapy (WBRT) may play a role in memory decline. Intensity-modulated radiotherapy can be used to avoid conformally the hippocampal neural stem-cell compartment during WBRT (HA-WBRT). RTOG 0933 was a single-arm phase II study of HA-WBRT for brain metastases with prespecified comparison with a historical control of patients treated with WBRT without hippocampal avoidance. PATIENTS AND METHODS: Eligible adult patients with brain metastases received HA-WBRT to 30 Gy in 10 fractions. Standardized cognitive function and quality-of-life (QOL) assessments were performed at baseline and 2, 4, and 6 months. The primary end point was the Hopkins Verbal Learning Test-Revised Delayed Recall (HVLT-R DR) at 4 months. The historical control demonstrated a 30% mean relative decline in HVLT-R DR from baseline to 4 months. To detect a mean relative decline ≤ 15% in HVLT-R DR after HA-WBRT, 51 analyzable patients were required to ensure 80% statistical power with α = 0.05. RESULTS: Of 113 patients accrued from March 2011 through November 2012, 42 patients were analyzable at 4 months. Mean relative decline in HVLT-R DR from baseline to 4 months was 7.0% (95% CI, -4.7% to 18.7%), significantly lower in comparison with the historical control (P < .001). No decline in QOL scores was observed. Two grade 3 toxicities and no grade 4 to 5 toxicities were reported. Median survival was 6.8 months. CONCLUSION: Conformal avoidance of the hippocampus during WBRT is associated with preservation of memory and QOL as compared with historical series.

Technology resource planning in radiation oncology: application of a needs-based analytic framework to radiosurgery planning in Ontario.

PURPOSE: With the emergence of radiosurgery as a new radiotherapeutic technique, health care decision makers are required to allocate capital radiotherapy resources to meet both current and future radiosurgery requirements. The goal of this article is to demonstrate the feasibility of applying an explicit, needs-based model to resource planning in radiation oncology. METHODS: Using an analytic model that relates radiosurgery need to population size, epidemiology, level of service planned, and productivity, the current radiosurgical need for single brain metastases in Ontario was estimated. The model was populated using Ontario-specific data where possible and supplemented with information from the published literature. Multiway sensitivity analyses were performed to calculate the minimum and maximum technology requirements. RESULTS: The calculated number of full-time radiosurgical units required to treat patients with single brain metastases in Ontario was 5.9. Sensitivity analyses performed varying both level of service planned and productivity yielded a range of requirements from 2.5 to 12.2 full-time radiosurgery units. CONCLUSION: We have shown through the example of single brain metastases in Ontario that it is feasible to perform explicit, needs-based resource planning in radiation oncology. As the availability of new specialized technology increases, health care decision makers may use this approach to ensure the needs of their population are met while maximizing productivity and minimizing opportunity cost.

Selecting patients with extensive-stage small cell lung cancer for prophylactic cranial irradiation by predicting brain metastases.

INTRODUCTION: Prophylactic cranial irradiation has recently been reported to improve overall survival and quality of life in patients with extensive-stage small cell lung cancer. The generalizability of this treatment to an unselected population with extensive-stage small cell lung cancer is not clear, as the incidence of brain metastases is variably reported in the literature, ranging from 25 to 60%. METHODS: We completed a retrospective review of 130 consecutive patients with extensive-stage small cell lung cancer seen in consultation between January 1, 2004, and December 31, 2006. Our primary objective was to determine the incidence of brain metastases and to establish significant factors that were predictive of developing brain metastases, using both univariate and multivariate regression analysis. RESULTS: The median patient age was 68.0 years, and the median survival time was 25.6 weeks. The majority of patients (84.9%) received systemic therapy. Twenty-nine patients (22.3%) presented with brain metastases while an additional 21 patients (20.8%) developed brain metastases over their lifetime. Response to chemotherapy was a predictor of brain metastases using univariate (odds ratio [OR] 5.28, p = 0.03) and multivariate analysis (OR 5.49, p = 0.04). Weight loss more than 5 kg predicted for freedom from the development of brain metastases using univariate (OR 0.20, p = 0.01) and multivariate analysis (OR 0.69, p = 0.03). CONCLUSIONS: 20.8% of patients developed brain metastases after their initial presentation. This incidence is lower than that previously reported and may suggest that prophylactic cranial irradiation should be targeted to patients at highest risk. Response to chemotherapy and less than 5 kg baseline weight loss were independent predictors of future brain metastases.