bluuebunny/crossref_metadata_2025_split huggingface dataset:
RADT-30. PROTON THERAPY FOR RE-IRRADIATION OF RECURRENT GLIOMA
Authors: Barbour Andrew , Halasz Lia 
Published: November 2023

Abstract

BACKGROUND
Proton therapy may improve the side effect profile of re-irradiation for recurrent glioma by limiting the overlap with previous radiation dose received by the brain. Limited data exist regarding the outcomes or side effects after proton re-irradiation.

METHODS
We retrospectively reviewed the charts of 43 consecutive adult patients with glioma treated with uniform scanning or pencil beam scanning proton re-irradiation from June 2014-June 2022. Outcomes were estimated utilizing Kaplan-Meier analysis.

RESULTS
Median age of the cohort was 45 years (range 19-74). Initial histologic diagnosis was glioblastoma for 18 (42%), astrocytoma for 16 (37%), oligodendroglioma for 8 (19%) and diffuse glioma NOS for 1 (2%) patient. The median initial prescription dose was 60 Gy (range 54-61.2 Gy) with 86% receiving concurrent temozolomide. The median interval between initial radiation therapy (RT) and re-irradiation was 51 months (range 6-185 months). The median re-irradiation dose delivered was 37.5 cobalt gray equivalent (CGE) in 15 fractions (range 6-50.4 CGE in 2-28 fractions) with 34 patients receiving this dose fractionation. Concurrent systemic therapy included bevacizumab (8), chemotherapy (5), immunotherapy (2) or none (28). Overall, 40 (93%) finished the planned course and three stopped early given progression. Median survival was 11.5 months for the full cohort (95% confidence interval: 6.8-13.6 months). For patients with glioblastoma, median survival was 6.4 months (95%CI 5.0-13.5 months). For patients without glioblastoma, median survival was 11.6 months (95%CI 9.2-34.3 months). Twelve patients (28%) developed symptomatic pseudoprogression/radiation necrosis, with ten requiring increased steroids and four requiring bevacizumab.

CONCLUSIONS
Proton re-irradiation was well tolerated in patients with recurrent glioma, with 6.4 and 11.6 month median survival estimates for glioblastoma and non-glioblastoma histologies, respectively. Symptomatic pseudoprogression/radiation necrosis was common. Further study is needed to determine whether proton re-irradiation has improved tolerability compared to photons.
RADT-33. ANALYSIS OF PATIENTS DIAGNOSED WITH ATYPICAL TERATOID RHABDOID TUMOR OF BRAIN AT TERTIARY CARE CENTER
Authors: Shah Setu , Mehta Maitrik , Pandya Akash , Parikh Ankita 
Published: November 2023

Abstract
Atypical Teratoid Rhabdoid Tumor (ATRT) of brain is highly malignant neoplasm with incidence of 1-2% among all pediatric CNS tumors characterized by mutations and subsequent inactivation of SMARCB1 (INI1, hSNF5) gene with dismal prognosis of about 6-18 months. On retrospective analysis of patients between 2010-2021 from Medical Record Department, only five cases of ATRT brain were retrieved. All patients were of pediatric age group (6 yr/F, 2yr/M, 6yr/F, 4yr/F, and 1yr/M – Median 4 yrs). On radiological findings, in four patients lesion was primarily in brain and in one patient with diffuse leptomeningeal enhancement. Three patients underwent craniotomy and gross total excision, and, in 2 patients only biopsy was done. In molecular analysis immunohistochemistry (IHC) markers were as follows. In all patients Vimentin and Synaptophysin were positive. EMA was positive in 3 patients, GPAP was positive in 3 patients, CD99 was positive in 2 patients, AE1 was positive in 2 patients. A specific marker for ATRT (INI1 loss) was seen in 3 patients. In other patients INI1 assessment could not be done. In two patients CSF cytology was negative, and, in all patients bone marrow examination was normal. One patient (4yr/F) received local radiotherapy with concurrent Vincristine based chemotherapy and lost to follow up (after 1 year of treatment). One patient (6yr/F) received vincristine based chemotherapy and local palliative radiotherapy and expired (after 1 month of treatment). One patient (6yr/F) received St Jude HR/IRS III protocol chemotherapy and craniospinal irradiation (CSI) and is still on follow up (total follow up period – 9 years). Two patients did not take any kind of treatment in whom one patient expired, another lost to follow up. Looking at rarity of tumors and with the review of literature, multiagent chemotherapy and Craniospinal irradiation seems to be promising approach for treatment of ATRT brain.
RADT-38. DOSE ESCALATED RADIOTHERAPY IS ASSOCIATED WITH IMPROVED OUTCOMES FOR HIGH GRADE MENINGIOMA
Authors: Liang Zeng K , Soliman Hany , Myrehaug Sten , Tseng Chia-Lin , Detsky Jay , Chen Hanbo , Lim-Fat Mary-Jane , Ruschin Mark , Atenafu Eshetu G , Keith Julia , Lipsman Nir , Heyn Chris , Maralani Pejman , Das Sunit , Pirouzmand Farhad , Sahgal Arjun 
Published: November 2023

Abstract

BACKGROUND
The optimal modern radiotherapy (RT) approach after surgery for atypical and malignant meningioma is unclear. We present results of dose-escalation.

METHODS
Consecutive patients with histopathologic grade 2 or 3 meningioma treated with RT were reviewed. A dose-escalation cohort [≥ 66Gy equivalent dose in 2 Gy fractions using an a/b = 10 (EQD2)], was compared to a standard dose cohort (&lt; 66Gy). Outcomes were progression-free survival (PFS), cause-specific survival (CSS), overall survival (OS), local failure (LF) and radiation necrosis.

RESULTS
118 patients (111 Grade 2, 94.1%) were identified; 54/118 (45.8%) received dose-escalation and 64/118 (54.2%) standard dose. Median follow-up was 45.4 months (IQR: 24.0 - 80.0 months) and median OS was 9.7 years (Q1: 4.6 years, Q3: not reached). All dose-escalated patients had residual disease vs. 65.6% in the standard dose cohort (p &lt; 0.001). PFS at 3-, 4- and 5-years in the dose-escalated vs. standard dose cohort were 78.9%, 72.2% and 64.6% vs. 57.2%, 49.1% and 40.8%, respectively, (p = 0.030). On multivariable (MVA) analysis, dose-escalation (HR: 0.544,p = 0.042) was associated with improved PFS, whereas ≥ 2 surgeries (HR: 1.989, p = 0.035) and older age (HR: 1.035, p &lt; 0.001) were associated with worse PFS. The cumulative risk of LF was reduced with dose-escalation (p = 0.016). MVA confirmed dose-escalation protective for LF (HR: 0.483, p = 0.019), whereas ≥ 2 surgeries prior to RT predicted for LF (HR: 2.145, p = 0.008). A trend was observed for improved CSS and OS in the dose-escalation cohort (p &lt; 0.1). Seven patients (5.9%) developed symptomatic radiation necrosis (RN) with no significant difference between the two cohorts.

CONCLUSIONS
Dose-escalated radiotherapy with ≥ 66Gy for high grade meningioma is associated with improved local control and PFS with an acceptable risk of RN.
RADT-39. CYBERKNIFE: THE CURRENT STATE OF LINAC AS TREATMENT FOR VESTIBULAR SCHWANNOMAS
Authors: Brown Nolan , Musmar Basel , Nguyen Oanh , Neil Zachery , Kuo Cathleen , Gendreau Julian 
Published: November 2023

Abstract

INTRODUCTION
In the present study, we systematically review the extant literature describing CyberKnife radiosurgery (CKRS) as treatment for vestibular schwannoma (VS). We then perform pooled meta-analysis of long-term tumor control and hearing preservation rates reported across all retrospective observational series describing the efficacy of CKRS.

METHODS
We queried three databases to identify all primary retrospective studies reporting local tumor control and hearing preservation rates following CKRS for treatment of vestibular schwannoma. All studies returned across the three databases were subject to systematic screen according to pre-defined inclusion and exclusion criteria in a multi-step process performed by two investigators.

RESULTS
Following a comprehensive systematic search, a total of 15 studies comprising 2018 vestibular schwannoma patients were included. The proportion of females ranged from 30% to 60.3%, and the mean age of all 2,018 patients was 60.2 years. There were 64 patients who had neurofibromatosis type 2 (NF-2). Additionally, 309 patients had previously undergone surgical resection and/or radiosurgery for VS. In regard to CKRS treatment parameters, the marginal dose ranged from 1.9-25.78 Gy. The mean follow-up duration across the included studies was 40.0 months. Pooled rate of tumor control using the random effects model was 96% (95% CI: 95%-98%), and that of hearing preservation was 73% (95% CI: 66%-81%). The most common major complications following CKRS were trigeminal neuralgia, facial neuropathy, and hydrocephalus.

CONCLUSIONS
As studies on CyberKnife radiosurgery, one of the SRS modalities administered via LINAC, are far less common than studies on Gamma Knife radiosurgery for treatment of VS, more studies are needed in order to solidify the findings reported in the present meta-analysis. Although there are currently only 15 single-institution retrospective studies available in the neurosurgical literature, this study provides the most comprehensive and up-to-date analysis of highly relevant outcomes of interest in treatment of vestibular schwannoma via CyberKnife.
RADT-41. PREDICTION OF TREATMENT OUTCOME IN GAMMA KNIFE RADIOSURGERY OF BENIGN MENINGIOMAS
Authors: Yang Hye Jeong , Kim Tae Hoon , Seo Youngchan , Chung Hyun-Tai 
Published: November 2023

Abstract

Objective
This study aimed to assess the predictability of machine learning (ML) ensemble models for the success of Gamma Knife radiosurgery (GKRS) on non-skull base benign meningiomas.

METHODS
A total of 331 non-skull base benign meningiomas treated primarily with GKRS between 1997 and 2015 were retrospectively analyzed. When a tumor remained not larger than 125% of the initial volume at the last imaging follow-up and no significant change in the high signal intensity area around the tumor, it was classified as 'treatment success (TS).' Univariate correlation and multivariate logistic regression analyses were performed to identify statistically significant prognostic factors. Four ensemble algorithms were trained to predict the outcome of GKRS. The importance of features related to TS was analyzed.

RESULTS
The median MR imaging follow-up period was 8.6 years. The tumor control and signal change rates were 91.5% and 16.3%, respectively, and the TS rate was 77.6%. The conventional multivariate logistic regression model showed 83.7% accuracy and 37.8% specificity. The ML models had accuracies between 78.0% and 82.2% and specificities between 30.3% and 80.7%, and they were similar to those of conventional logistic regression analyses. The smaller brain volume absorbed more than 14 Gy, and the absence of signal change before GKRS was a favorable prognostic factor for TS in all models. The bagging algorithm with selected features showed the best specificity of 80.7% and the most significant AUC of 0.723.

CONCLUSION
A bagging ensemble algorithm with selected features had better specificity with similar accuracy than conventional multivariate logistic regression in predicting GKRS outcomes for non-skull base meningiomas.
RADT-42. STRATEGIES FOR TREATING RECURRENT GERM CELL TUMORS IN PATIENTS WHO HAVE UNDERGONE PRIOR CHEMORADIOTHERAPY AGAINST PRIMARY GERMINOMA
Authors: Yamasaki Fumiyuki , Kinoshita Yasuyuki , Takayasu Takeshi , Yonezawa Ushio , Taguchi Akira , Onishi Shumpei , Ozono Iori , Khairunnisa Novita Ikbar , Dowaki Ryosuke , Horie Nobutaka 
Published: November 2023

Abstract

BACKGROUND
Germinoma patients are thought to have a favorable prognosis due to their high sensitivity to chemotherapy and radiotherapy. However, it is also known that germinoma is at risk of recurrence after a long course of disease. Despite excellent sensitivity to chemotherapy and radiotherapy, there is no established standard treatment for patients with recurrent germinoma.

METHODS
Fourteen patients with recurrent germinoma treated in our institution from 1989 to 2022 were included in this retrospective study. All patients were treated for primary tumor with carboplatin-etoposide and 23.4 Gy of whole ventricle/whole brain irradiation. Twelve patients were treated at our institution at primary and first recurrence, and three patients were referred to our institutional for management against recurrent tumors. Medical records were examined to determine the course of the disease at the time of initial onset, the first recurrence, and the following course, including recurrence and survival.

RESULTS
There were 12 male and 2 female patients with recurrent germinoma, age at initial onset ranged from 11 to 29 years (median 18.5 years), and age at first recurrence ranged from 16 to 36 years (median 23.5 years). The time from the date of treatment initiation against primary tumor to first confirmed recurrence ranged from 4.2 to 272 months (median 79 months). Eleven patients had recurrences outside the irradiation field, with six experiencing spinal recurrence. Thirteen patients received chemotherapy, and 12 patients had radiotherapy, including eight patients treated with craniospinal irradiation (CSI). There were no reported cases of recurrence or mortality in the CSI-treated group. In contrast, the median PFS and OS in the group that did not receive CSI were 12 and 36 months, respectively, which were significantly different from the CSI-treated group (P &lt; 0.05).

CONCLUSION
Our findings suggest that CSI has an important role in reducing the likelihood of future recurrence.
RADT-43. LONG TERM OUTCOMES OF PEDIATRIC AND ADULT CENTRAL NEUROCYTOMA—THE ROLE OF SALVAGE RADIOTHERAPY AND CONSERVATIVE MANAGEMENT
Authors: Yang Yufan , Wadhwani Nitin , Zheng Shuhua , Chandler James , Lesniak Maciej , Tate Matthew , Sonabend Adam , Kalapurakal John , Horbinski Craig , Lukas Rimas , Stupp Roger , Kumthekar Priya , Sachdev Sean 
Published: November 2023

Abstract

INTRODUCTION
Central Neurocytoma (CN) is a rare, WHO grade 2 brain tumor that predominantly affects young adults. Gross total resection (GTR) is often curative for CN, but the optimal treatment paradigm following subtotal resection (STR) and or scarcer pediatric cases has yet to be established—including the role of radiation therapy (RT). Herein, we reviewed the long-term outcomes of CN patients at our institution.

METHODS
Patients between the years 2001 and 2021 with a pathologic diagnosis of CN were reviewed. Demographic, treatment, and tumor characteristics (histopathological and molecular) were recorded. Recurrence free survival (RFS) and overall survival (OS) were calculated according to the Kaplan Meier-method. Post-RT tumor volumetric regression analysis was performed.

RESULTS
Seventeen adults (≥ 18 years old) and 5 children (&lt; 18 years old) met the criteria for data analysis (n = 22). With a median follow-up of 6.9 years (range: 1.2-42.8 years), there was zero tumor-related mortality. Patients who received STR and/or had atypical tumors (criteria = Ki-67 &gt;4%) experienced decreased RFS compared to those who received GTR and/or were without atypical tumors. RFS at 5 years was 67% for typical CNs and 22% for atypical CNs. Every pediatric tumor was atypical and 3/5 recurred within 5 years. Salvage RT following tumor recurrence led to 100% tumor control, with no further recurrences (median post-RT follow-up = 5.79 years); volumetric analysis for 3 recurrent tumors (8.59 cumulative years of serial scans) revealed an ~80% reduction in tumor (range: 76.3%-81.1%), at a mean rate of 2.49% per month.

CONCLUSION
We provide encouraging evidence that (1) CNs have limited long-term risk of tumor-related mortality and (2) RT after tumor recurrence conveys strong long-term tumor control, including for potentially more aggressive pediatric CNs. Our institutional experience supports the conservative management of CN, including withholding RT until signs of recurrence regardless of resection extent or Ki-67.
RADT-45. TREATMENT OF ATYPICAL CENTRAL NEUROCYTOMA WITH PROTON THERAPY
Authors: Singh Pawan 
Published: November 2023

Abstract
Central neurocytoma is a rare intraventricular tumor often thought to be benign but can demonstrate aggressive behavior such as recurrence or CNS dissemination with elevated MIB1 index. This is a clinical case presentation of a 19 year old male who presented with increased intracranial pressure and was found to have atypical central neurocytoma with Ki-67 of 5%. Given residual disease after second craniotomy and high risk for recurrence, patient was treated with a six week course of proton therapy. Patient responded to radiation therapy with stable disease and improvement of cognitive function. Outcome of disease stability with proton therapy is consistent with reported literature. This case adds further evidence for use of proton therapy in patients with atypical central neurocytoma.
RADT-46. STEREOTACTIC RADIOSURGERY FOR CYSTIC AND SOLID INTRACRANIAL HEMANGIOBLASTOMAS: A SINGLE-INSTITUTION RETROSPECTIVE SERIES
Authors: Yoo Kelly , Park David , Marianayagam Neelan , Pollom Erqi , Soltys Scott , Meola Antonio , Chang Steven 
Published: November 2023

Abstract

INTRODUCTION
Intracranial hemangioblastoma is a rare neoplasm that poses significant challenges in clinical management. Hemangioblastomas are characterized by unique radiological features into cystic or solid tumors. Out study aims to evaluate the role of SRS in the management of cystic and solid hemangioblastomas in a single institution setting.

METHODS
We conducted a retrospective analysis of clinical and radiological outcomes of patients with intracranial hemangioblastomas treated with CyberKnife SRS at our institute between 1998 and 2023. The follow-up data were available for 93 intracranial hemangioblastomas in 23 patients. Ten (43.5%) patients presented with 23 (25.6%) cystic hemangioblastomas, while 13 (56.5%) patients had 70 (75.3%) solid hemangioblastomas at the time of SRS treatment. The median age was 36 years and the median tumor volume accounted for 0.43 cc. The SRS was administered with the median single-fraction equivalent dose (SFED) of 20 Gy at the 77% of the median isodose line.

RESULTS
At a one-year follow-up, 11 initially solid hemangioblastomas developed cystic formation, resulting in a total of 34 (36.6%) cystic hemangioblastomas and 59 (63.4%) solid hemangioblastomas across 13 and 10 patients, respectively. Among these, 84.6% exhibited peritumoral edema prior to the onset of cystic formation. For 37 solid hemangioblastomas accompanied by peritumoral edema, SRS was administered before cystic transformation, remaining solid throughout the latest follow-up. Over a median follow-up period of 59 months (range: 3-260), 6 (17.6%) cystic and 13 (22%) solid hemangioblastomas progressed. The 5-year local tumor control (LTC) rate for intracranial hemangioblastomas was 84.7%, with 97% and 76.9% in cystic and solid lesions, respectively.

CONCLUSION
Our study illustrates the largest single-institutional long-term retrospective analysis of intracranial hemangioblastomas treated with SRS to date. Early SRS treatment at the time of edema may prevent cystic hemangioblastoma development and provides durable treatment outcomes for patients with both cystic and solid hemangioblastomas in long-term.
RADT-50. EVIDENCE-BASED MULTIVARIATE NORMAL TISSUE COMPLICATION PROBABILITY (NTCP) STUDY OF DOMAIN-SPECIFIC COGNITIVE DECLINE AFTER PARTIAL BRAIN RADIATION (RT)
Authors: Hopper Austin , Connor Michael , Salans Mia , Karunamuni Roshan , Unnikrishnan Soumya , Huynh-Le Minh , Tibbs Michelle , Reyes Anny , Stasenko Alena , McDonald Carrie , Moiseenko Vitali , El-Naqa Issam , Hattangandi-Gluth Jona 
Published: November 2023

Abstract
Beyond the hippocampus, there are no evidence-based dose constraints for eloquent brain structures which subserve cognitive domains. We performed a multivariate NTCP analysis of post-RT neurocognitive decline, examining dosimetric predictors of eloquent brain regions in a prospective longitudinal clinical trial. 83 patients with primary brain tumors receiving fractionated RT completed comprehensive neurocognitive evaluation and high-resolution volumetric and diffusion MRI at baseline and 6 months post-RT. Image processing using robust, validated automated segmentation parcellated individual white matter (WM) tracts, cortical regions, and hippocampi. Well-validated neurocognitive tests evaluating multiple cognitive domains were assessed with negative reliable change indices adjusted for practice effects between timepoints scored as decline. Univariate logistic regression and multivariate model building were performed examining dose to eloquent structures and clinical variables. Univariate analysis showed mean dose to the bilateral caudal anterior cingulate cortex and WM were correlated with decline in executive function. Attention/processing speed decline was correlated with mean/max dose to the posterior corpus callosum (CC), volume getting &gt;20 Gy in the combined CC, as well as anti-epileptic use and chemotherapy. On multivariate analysis for attention automated bootstrapped logistic regression performance at nested cross-validation by AUC was 0.59 (0.54-0.65); LASSO model performance by AUC was 0.60 (0.54-0.66) with mean dose to combined CC being the most frequent variable in both. The top three most important variables in Random Forest by mean decrease in Gini coefficient were max dose to posterior and combined CC and mean dose to anterior CC. Model performance by AUC was 0.70 (0.64-0.75). Here we present the first, to our knowledge, NTCP model for decline in attention/processing speed, along with dosimetric predictors of executive function decline. We found that after partial brain RT, dose to several ROIs significantly correlated with post-RT impairment. These data can guide future cognitive-sparing strategies for brain RT.
RADT-51. RADIATION-INDUCED CEREBRAL CONTRAST ENHANCEMENTS STRONGLY SHARE RISK FACTORS WITH STROKE
Authors: Eichkorn Tanja , Lischalk Jonathan , Schwarz Robert , Bauer Lena Jasmin , Deng Maximilian , Regnery Sebastian , Jungk Christine , Herfarth Klaus , König Laila , Debus Jürgen 
Published: November 2023

Abstract

BACKGROUND AND PURPOSE
Radiation-induced cerebral contrast enhancements (RICE) are feared because frequent and potentially health-threatening. Risk factors are badly understood. Better understanding of RICE risk factors is critical to better face its risks by adapting therapy in the first place or patient care during follow-up.

MATERIALS AND METHODS
We analyzed consecutive 235 patients treated with proton radiotherapy (PRT; 54Gy RBE) for LGG from 2010 to 2020 and followed with serial clinical exams and magnetic resonance imaging for in median 5.6 years.

RESULTS
The risk of RICE was significantly higher in patients with vascular risk factors (VRF) (p = 0.02). Especially age ≥50 years (vs. adults &lt;50 years: two-fold risk; p = 0.02), hypertension (three-fold risk; p = 0.0001) and diabetes (6.7-fold risk; p = 0.007) were shown to be clearly associated to RICE occurrence. Dyslipidemia (2.4-fold), overweight (1.3-fold) and smoking (1.3-fold) was also more frequently observed in the cohort that developed RICE. History of previous stroke went along with a 1.7-fold risk for RICE but threshold for significance was not reached. If RICE occurred, Bevacizumab treatment was two-fold more frequently needed in the cohort with VRF, but RICE prognosis did not differ relevantly between the RICE subcohort with and without VRF.

CONCLUSIONS
These data firstly demonstrate that RICE strongly share risk factors with ischemic stroke which further enhances our vague understanding of multifactorial pathophysiology and opportunities of tackling RICE. Classical vascular risk factors, especially age, hypertension and diabetes correlated strongly with RICE risk. Risk-adapted screening and therapy can be directly derived from this data.