NIMG-03. TUMOR HABITAT ANALYSIS BY MAGNETIC RESONANCE IMAGING DISTINGUISHES TUMOR PROGRESSION FROM RADIATION NECROSIS IN BRAIN METASTASES AFTER STEREOTACTIC RADIOSURGERY

Abstract OBJECTIVES Identification of viable tumor after stereotactic radiosurgery (SRS) is important for future targeted therapy. This study aimed to determine whether tumor habitat on structural and physiologic MRI can distinguish viable tumor from radiation necrosis of brain metastases after SRS. METHOD Multiparametric contrast-enhanced T1-and T2-weighted imaging, apparent diffusion coefficient (ADC), and cerebral blood volume (CBV) were obtained from 52 patients with 69 metastases, showing enlarging enhancing masses after SRS. Voxel-wise clustering identified three structural MRI habitats (enhancing, solid low-enhancing, and nonviable) and three physiologic MRI habitats (hypervascular cellular, hypovascular cellular, and nonviable). Habitat-based predictors for viable tumor or radiation necrosis were identified by logistic regression. Performance was validated using the area under the curve (AUC) of the receiver-operating-characteristics curve in an independent dataset with 24 patients. RESULTS None of the physiologic MRI habitats were indicative of viable tumor. Viable tumor was predicted by a high-volume fraction of solid low-enhancing habitat (low T2-weighted and low CE-T1-weighted values; odds ratio [OR] 1.74, P< .001) and a low-volume fraction of nonviable tissue habitat (high T2-weighted and low CE-T1-weighted values; OR, 0.55, P< .001). Combined structural MRI habitats yielded good discriminatory ability in both development (AUC 0.85, 95% confidence interval [CI]: 0.77–0.94) and validation sets (AUC 0.86, 95% CI:0.70–0.99), outperforming single ADC (AUC 0.64) and CBV (AUC 0.58) values. The site of progression matched with the solid low-enhancing habitat (72%, 8/11). CONCLUSION Solid low-enhancing and nonviable tissue habitats on structural MRI can help to localize viable tumor in patients with brain metastases after SRS.

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MLTI-15. A CASE SERIES OF PRE-OPERATIVE GAMMA-KNIFE RADIOSURGERY FOR RESECTABLE BRAIN METASTASES

Neuro-Oncology Advances ◽

10.1093/noajnl/vdz014.074 ◽

2019 ◽

Vol 1 (Supplement_1) ◽

pp. i17-i17

Author(s):

Tatsuya Takezaki ◽

Haruaki Yamamoto ◽

Naoki Shinojima ◽

Jun-ichiro Kuroda ◽

Shigeo Yamashiro ◽

...

Keyword(s):

Brain Metastases ◽

Stereotactic Radiosurgery ◽

Gamma Knife ◽

Systemic Treatment ◽

Radiation Necrosis ◽

Gamma Knife Radiosurgery ◽

Case Series ◽

Phase 3 ◽

Optimal Sequence ◽

Median Margin

Abstract Recent advances in the systemic treatment of various cancers have resulted in longer survival and higher incidence of brain metastases. Phase 3 trials in north America and in Japan have demonstrated that stereotactic radiosurgery will be a standard adjuvant modality following surgery for resectable brain metastases. However, we don’t know the optimal sequence of this combination therapy. We hypothesized that pre-operative stereotactic radiosurgery for resectable brain metastases provides favorable rates of local control, overall survival, leptomeningeal dissemination and symptomatic radiation necrosis. We have experienced 4 cases of resected brain metastases within 1–7 days after Gamma-knife surgery (median margin dose:22Gy) and have been following their clinical course. We will show the repressive cases.

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31. RADIATION NECROSIS IN STEREOTACTIC RADIOSURGERY AND CHECKPOINTS INHIBITORS FOR BRAIN METASTASES FROM LUNG ADENOCARCINOMA

Neuro-Oncology Advances ◽

10.1093/noajnl/vdaa073.019 ◽

2020 ◽

Vol 2 (Supplement_2) ◽

pp. ii5-ii5

Author(s):

James Jurica ◽

Shraddha Dalwadi ◽

David Baskin ◽

Eric Bernicker ◽

Brian Butler ◽

...

Keyword(s):

Overall Survival ◽

Multivariate Analysis ◽

Brain Metastases ◽

Lung Adenocarcinoma ◽

Stereotactic Radiosurgery ◽

Median Survival ◽

Radiation Necrosis ◽

Concomitant Treatment ◽

Prognostic Assessment ◽

Graded Prognostic Assessment

Abstract PURPOSE Treatment with stereotactic radiosurgery (SRS) and immune checkpoint inhibitors (ICI) is increasingly common for brain metastases (BM) from lung adenocarcinoma. Rates of radiation necrosis (RN) with SRS in the setting of ICIs is an ongoing area of research. We investigated rates of RN in patients with BM from lung adenocarcinoma treated with SRS with or without concurrent ICIs. METHODS We identified 39 patients at a single institution who underwent SRS treatment for BM from lung adenocarcinoma. Of these, 19 (49%) received SRS without ICIs and 20 (51%) patients received ICIs within a month of SRS. The rate of RN, defined by MRI features and histology when available, was compared between each group using multivariate analysis. Kaplan Meier survival estimates were calculated based on overall survival and compared to median survival predicted by the graded prognostic assessment. RESULTS Overall survival for all patients from diagnosis of brain metastases was 16.6 months (range 3.6–45.9) and median survival predicted by the graded prognostic assessment was 13.7 months (range 6.9–26.5). In total 11 (28%) patients developed MRI and/or histologic evidence for RN during the follow-up period; 5 of 20 (25%) from the SRS with ICI group and 6 of 19 (31%) from the SRS without ICI group. In multivariate analysis, ICI treatment had no significant impact on rates of RN between groups (OR 0.72 [95% CI: 0.17–2.93]; p=0.65) while bevacizumab treatment was associated with a decreased RN risk (OR 0.88 [95% CI: 0.43–0.99]; p=0.02). CONCLUSION Retrospective analysis of patients with BM from lung adenocarcinoma treated with SRS suggested that administration of ICIs does not increase risk for development of RN. Further, concomitant treatment with bevacizumab may decrease risk of RN. These findings suggest that patients with BM from lung adenocarcinoma can be treated with combination therapy without increased risk of neurologic toxicity.

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Gamma Knife versus Frameless Linear Accelerator Based Stereotactic Radiosurgery for Brain Metastases: Clinical Outcomes and Factors Associated with Local Failure and Radiation Necrosis

10.21203/rs.3.rs-885725/v1 ◽

2021 ◽

Author(s):

Gregory S. Alexander ◽

Jill S. Remick ◽

Emily S. Kowalski ◽

Kai Sun ◽

Yannick Poirer ◽

...

Keyword(s):

Brain Metastases ◽

Stereotactic Radiosurgery ◽

Clinical Outcomes ◽

Gamma Knife ◽

Linear Accelerator ◽

Radiation Necrosis ◽

Univariate Analysis ◽

Local Failure ◽

Rank Test ◽

Chi Square Analysis

Abstract BackgroundSingle-fraction stereotactic radiosurgery (SF-SRS) for the treatment of brain metastases can be delivered with either a Gamma-Knife platform (GK-SRS) or with a frameless linear accelerator (LA-SRS) which vary based on patterns of prescribing, patient setup and radiation delivery. Whether these differences affect clinical outcomes is unknown. MethodsPatients treated for metastatic brain cancer treated with SF-SRS from 2014-2020 were retrospectively reviewed and clinical outcomes were recorded on a per lesion basis. Covariates between groups were compared using a Chi-square analysis for dichotomous variables and t-test for continuous variables. Median follow up was calculated using the reverse Kaplan Meier (KM) method. Primary endpoints of local failure (LF) and symptomatic radiation necrosis (RN) were estimated using the KM method with salvage WBRT used as a censoring event. Outcome estimates were compared using the log-rank test. Multivariate analysis (MVA) and Cox proportional hazards modeling were used for statistical analyses. Propensity score (PS) adjustments were used to reduce the effects confounding variables.ResultsOverall, 119 patients with 287 lesions were included for analysis which included 57 patients (127 lesions) treated with LA-SRS compared to 62 patients (160 lesions) treated with GK-SRS. On both multivariate and univariate analysis, there was no statistically significant differences between GK-SRS and LA-SRS for LF, RN, or the combined endpoint of either LF or RN (multivariate p-value=0.17).ConclusionsIn our retrospective cohort, we found no statistically significant differences in the incidence of RN or LF in patients treated with GK-SRS when compared to LA-SRS.Trial Registration: Retrospectively registered

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ML-4 A case of primary CNS lymphoma diagnosed 5 years after stereotactic radiosurgery

Neuro-Oncology Advances ◽

10.1093/noajnl/vdab159.087 ◽

2021 ◽

Vol 3 (Supplement_6) ◽

pp. vi23-vi23

Author(s):

Yusuke Tabei ◽

Ichirou Nakazato ◽

Kenichi Ooyama ◽

Masatou Kawashima ◽

Akira Matsuno ◽

...

Keyword(s):

Brain Metastases ◽

Stereotactic Radiosurgery ◽

Tumor Cells ◽

Temporal Lobe ◽

Radiation Necrosis ◽

B Cell Lymphoma ◽

Unknown Primary ◽

High Dose ◽

Left Temporal Lobe ◽

The Right

Abstract Central nervous system primary malignant lymphoma (PCNSL) is rarely diagnosed as multiple metastatic brain tumors. Almost tumors recure early after receiving stereotactic radiosurgery (SRS). Regardless of the fact, the following case report displays PCNSL, diagnosed five years after the initial treatment with SRS as brain metastases of unknown primary origin. This extraordinal case suggests long-term follow-up regarding PCNCL. The case was a 55-year-old woman with a history of a total hysterectomy for cervical cancer. She developed left paralysis. Brain MRI confirmed a 27 mm contrast-enhanced lesion in the right frontal lobe and three other lesions. SRS was performed as a diagnosis of multiple brain metastases for urgent symptom relief. No extra-cranial cancerous lesions were found. Unknown primary cancer was a probable diagnosis at that time. Two years after SRS, local regrowth of tumor of the right frontal primary motor area was discovered. Re-irradiation was performed. Cerebral edema, contrast enhancement, and left paralysis progressed following five months, taking an oral corticosteroid. Craniotomy and debulk. The pathological diagnosis was brain radiation necrosis due to no viable tumor cells. New lesions in the left temporal lobe and basal ganglia appeared three years after surgery. Awake craniotomy was performed for the left temporal lobe lesion. Histopathology showed diffuse growth of tumor cells with a high nucleo-cytoplasmic ratio and irregular nuclear shape. Immunohistochemistry revealed positive CD10, CD20, CD45 (LCA), MUM1, and negative CD3, CD5. The Ki- 67 labeling rate was as high as almost 100% to diagnose diffuse large B-cell lymphoma, PCNSL. Multidrug chemotherapy consisting of rituximab, high-dose methotrexate, procarbazine, and vincristine were performed. Complete remission was obtained without any serious adverse events. Considering the residual radiation necrosis, whole-brain irradiation was avoided. Moreover, consolidation therapy was performed only with high-dose cytarabine therapy.

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Staged Stereotactic Radiosurgery for Large Brain Metastases: Local Control and Clinical Outcomes of a One-Two Punch Technique

Neurosurgery ◽

10.1093/neuros/nyx355 ◽

2017 ◽

Vol 83 (1) ◽

pp. 114-121 ◽

Cited By ~ 11

Author(s):

Ammoren Dohm ◽

Emory R McTyre ◽

Catherine Okoukoni ◽

Adrianna Henson ◽

Christina K Cramer ◽

...

Keyword(s):

Overall Survival ◽

Brain Metastases ◽

Stereotactic Radiosurgery ◽

Radiation Necrosis ◽

Treatment Options ◽

Radiation Therapy Oncology Group ◽

Local Failure ◽

Median Dose ◽

Kaplan Meier ◽

Dosimetric Analysis

Abstract BACKGROUND Treatment options are limited for large, unresectable brain metastases. OBJECTIVE To report a single institution series of staged stereotactic radiosurgery (SRS) that allows for tumor response between treatments in order to optimize the therapeutic ratio. METHODS Patients were treated with staged SRS separated by 1 mo with a median dose at first SRS of 15 Gy (range 10-21 Gy) and a median dose at second SRS of 14 Gy (range 10-18 Gy). Overall survival was evaluated using the Kaplan-Meier method. Cumulative incidences were estimated for neurological death, radiation necrosis, local failure (marginal or central), and distant brain failure. Absolute cumulative dose–volume histogram was created for each treated lesion. Logistic regression and competing risks regression were performed for each discrete dose received by a certain volume. RESULTS Thirty-three patients with 39 lesions were treated with staged radiosurgery. Overall survival at 6 and 12 mo was 65.0% and 60.0%, respectively. Cumulative incidence of local failure at 6 and 12 mo was 3.2% and 13.3%, respectively. Of the patients who received staged therapy, 4 of 33 experienced local failure. Radiation necrosis was seen in 4 of 39 lesions. Two of 33 patients experienced a Radiation Therapy Oncology Group toxicity grade > 2 (2 patients had grade 4 toxicities). Dosimetric analysis revealed that dose (Gy) received by volume of brain (ie, VDose(Gy)) was associated with radiation necrosis, including the range V44.5Gy to V87.8Gy. CONCLUSION Staged radiosurgery is a safe and effective option for large, unresectable brain metastases. Prospective studies are required to validate the findings in this study.

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