Radiotherapy dosing in intracranial ependymoma using the national cancer database.

PURPOSE: To determine the dose-dependent effect of adjuvant radiotherapy on survival for pediatric intracranial ependymomas and explore patient and disease characteristics that experience survival benefit from higher doses. METHODS: Data was accessed from the National Cancer Database. Inclusion criteria was comprised of a diagnosis of non-metastatic intracranial ependymoma, World Health Organization (WHO) grade 2 or 3, surgical resection, adjuvant radiotherapy between 4500-6300 cGy, and non-missing survivorship data. Crude and adjusted Cox proportional hazard ratios (HRs) were calculated to estimate the associations of patient, tumor, and treatment characteristics with overall survival (OS). Kaplan-Meier (KM) estimations were used to visualize survival curves for dosing for the general cohort and by subgroups (age, resection extent, and grade). RESULTS: Of the 1154 patients who met inclusion criteria, 405 received ≤ 5400 cGy and 749 received > 5400 cGy. We found no difference in OS crude (0.95, 95% CI 0.72-1.06) or adjusted (0.88, 95% CI 0.46-1.69) HR for those receiving ≤ 5400 cGy. KM curves showed no difference in OS for dosing for the general cohort based on age, surgical extent, and grade. However, there was better OS in those with WHO grade 2 tumors compared to grade 3 regardless of dose received. CONCLUSIONS: There was no difference in OS between patients who received ≤ 5400 cGy compared to > 5400 cGy. We found improved OS in those with grade 2 tumors compared to grade 3, however there was no difference in OS based on dose received by tumor grade, age, or resection extent. Limitations in data available prevent exploring other outcomes or toxicity.

Systematic Review and Meta-Analysis of Adjuvant Radiation Dose for Pediatric Patients (≤22 years) with Nonmetastatic Intracranial Ependymomas.

PURPOSE: Ependymomas are the third most common brain tumors in children. Standard of care is surgery followed by adjuvant radiation therapy. Controversy in the literature still exists over optimal radiation therapy dose. We completed a systematic review and meta-analysis to determine the optimal dose for local control (LC), event-free survival (EFS), and overall survival (OS) in pediatric patients. METHODS AND MATERIALS: We searched MEDLINE (PubMed), Cochrane Database of Systematic Reviews, and Web of Science through January 2024. We included cohort studies that compared adjuvant radiation therapy of ≤54 Gy with >54 Gy in pediatric patients (≤22 years) with nonmetastatic intracranial ependymomas. We assessed study quality using the Newcastle-Ottawa Quality Assessment Scale of Cohort Studies. We pooled studies using a random effects meta-analysis for hazard ratios (HR), 95% confidence intervals (CI), and assessed statistical heterogeneity via I2. When HRs were unavailable, we transformed risks using established methods. We narratively summarized qualitative outcomes. RESULTS: Seven studies met our inclusion criteria, covering a combined 1321 patients. Studies included a range of doses from 45 to 66.6 Gy. Compared with >54 Gy, we found no difference in LC for those receiving ≤54 Gy (HR, 0.83; 95% CI, 0.56-1.24; I2, 49.1%), in EFS (HR, 1.02; 95% CI, 0.95-1.09; I2, 0.00%), and OS (HR, 0.99; 95% CI, 0.82-1.20; I2, 37.5%). Two studies reported on subtotal resection by radiation therapy dose, neither study reporting statistical differences in LC, EFS, or OS, although the number of patients was small (n ≤ 30). Five studies reported on late effects, with brainstem radionecrosis, radiation-induced vasculopathy, and secondary tumors being the most frequent. Overall study quality was high, although lower scores were consistently seen in comparability of cohorts. To our knowledge, no studies reported on molecular subgroups. CONCLUSIONS: We found no difference in LC, EFS, or OS for those treated with ≤54 Gy compared with >54 Gy. There were insufficient data to complete a subgroup meta-analysis on radiation therapy dosing based on extent of resection or molecular subgroups.

One Year of Clinic-Wide Cherenkov Imaging for Discovery of Quality Improvement Opportunities in Radiation Therapy.

PURPOSE: Cherenkov imaging is clinically available as a radiation therapy treatment verification tool. The aim of this work was to discover the benefits of always-on Cherenkov imaging as a novel incident detection and quality improvement system through review of all imaging at our center. METHODS AND MATERIALS: Multicamera Cherenkov imaging systems were permanently installed in 3 treatment bunkers, imaging continuously over a year. Images were acquired as part of normal treatment procedures and reviewed for potential treatment delivery anomalies. RESULTS: In total, 622 unique patients were evaluated for this study. We identified 9 patients with treatment anomalies occurring over their course of treatment, which were only detected with Cherenkov imaging. Categorizing each event indicated issues arising in simulation, planning, pretreatment review, and treatment delivery, and none of the incidents were detected before this review by conventional measures. The incidents identified in this study included dose to unintended areas in planning, dose to unintended areas due to positioning at treatment, and nonideal bolus placement during setup. CONCLUSIONS: Cherenkov imaging was shown to provide a unique method of detecting radiation therapy incidents that would have otherwise gone undetected. Although none of the events detected in this study reached the threshold of reporting, they identified opportunities for practice improvement and demonstrated added value of Cherenkov imaging in quality assurance programs.