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PurposeNormal brain tissue doses have been shown to be strongly apparatus dependent for multi-target stereotactic radiosurgery. In this study, we investigated whether inter-target dose interplay effects across contemporary radiosurgical treatment platforms are responsible for such an observation.MethodsFor the study, subsets ([Formula: see text] and 12) of a total of 12 targets were planned at six institutions. Treatment platforms included the (1) Gamma Knife Perfexion (PFX), (2) CyberKnife, (3) Novalis linear accelerator equipped with a 3.0-mm multi-leaf collimator (MLC), and the (4) Varian Truebeam flattening-filter-free (FFF) linear accelerator also equipped with a 2.5 mm MLC. Identical dose-volume constraints for the targets and critical structures were applied for each apparatus. All treatment plans were developed at individual centers, and the results were centrally analyzed.ResultsWe found that dose-volume constraints were satisfied by each apparatus with some differences noted in certain structures such as the lens. The peripheral normal brain tissue doses were lowest for the PFX and highest for TrueBeam FFF and CyberKnife treatment plans. Comparing the volumes of normal brain receiving 12 Gy, TrueBeam FFF, Novalis, and CyberKnife were 180-290% higher than PFX. The mean volume of normal brain-per target receiving 4-Gy increased by approximately 3.0 cc per target for TrueBeam, 2.7 cc per target for CyberKnife, 2.0 cc per target for Novalis, and 0.82 cc per target for PFX. The beam-on time was shortest with the TrueBeam FFF (e.g., 6-9 min at a machine output rate of 1,200 MU/min) and longest for the PFX (e.g., 50-150 mins at a machine output rate of 350 cGy/min).ConclusionThe volumes of normal brain receiving 4 and 12 Gy were higher, and increased more swiftly per target, for Linac-based SRS platforms than for PFX. Treatment times were shortest with TrueBeam FFF.

The BC-brain questionnaire was developed by BC Cancer to detect health problems in patients with central nervous system (CNS) tumours in routine clinical care, treated with radiotherapy (RT), as part of the Prospective Outcomes and Support Initiative (POSI). This study aimed to present and validate the BC-brain questionnaire in patients with brain metastases (BrM) treated with RT. The BC-brain questionnaire was constructed with three subscales: mobility, thinking and CNS symptoms. Patients with BrM from five BC Cancer centres completed this questionnaire at first visit and subsequent follow-up appointments. A total of 365 patients finished the first and 105 finished the follow-up questionnaire. Summary scores of each subscale were calculated. Mobility, thinking and subtotal score showed good reliability with Cronbach's α > 0.7. Multitrait scaling analysis showed good convergent and divergent validity. The correlations between subscales ranged from 0.262 to 0.456 for baseline and from 0.378 to 0.597 for follow-up. Patients on dexamethasone had worse performance. Patients with a KPS of 70. In general, this BC-brain questionnaire has good reliability and validity, and is proper to use as an option for a patient-reported outcome (PRO) instrument to measure the quality of life in BrM patients treated with RT. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the feasibility of using volumetric modulated arc therapy (VMAT) to deliver whole brain radiotherapy (WBRT) with hippocampal avoidance and a simultaneous integrated boost (SIB) for one to three brain metastases. Methods and Materials: Ten patients previously treated with stereotactic radiosurgery for one to three brain metastases underwent repeat planning using VMAT. The whole brain prescription dose was 32.25 Gy in 15 fractions, and SIB doses to brain metastases were 63 Gy to lesions ≥2.0 cm and 70.8 Gy to lesions <2.0 cm in diameter. The mean dose to the hippocampus was kept at <6 Gy2. Plans were optimized for conformity and target coverage while minimizing hippocampal and ocular doses. Plans were evaluated on target coverage, prescription isodose to target volume ratio, conformity number, homogeneity index, and maximum dose to prescription dose ratio. Results: Ten patients had 18 metastases. Mean values for the brain metastases were as follows: conformity number = 0.73 ± 0.10, target coverage = 0.98 ± 0.01, prescription isodose to target volume = 1.34 ± 0.19, maximum dose to prescription dose ratio = 1.09 ± 0.02, and homogeneity index = 0.07 ± 0.02. For the whole brain, the mean target coverage and homogeneity index were 0.960 ± 0.002 and 0.39 ± 0.06, respectively. The mean hippocampal dose was 5.23 ± 0.39 Gy2. The mean treatment delivery time was 3.6 min (range, 3.3-4.1 min). Conclusions: VMAT was able to achieve adequate whole brain coverage with conformal hippocampal avoidance and radiosurgical quality dose distributions for one to three brain metastases. The mean delivery time was under 4 min. [Copyright &y& Elsevier]

Objectives The purpose of this study was to examine the impact of EGFR mutations on the incidence of brain metastases in patients with advanced non-small cell lung cancer (NSCLC). Materials and methods A retrospective, population-based study was conducted using a provincial cancer registry to identify patients with metastatic NSCLC. Patients with diagnostic EGFR mutation testing were divided into EGFR mutation positive (EGFR+) and EGFR wild type (WT) cohorts. The primary endpoint was the incidence of brain metastases. Cumulative incidence curves were estimated using the competing risk method. The secondary endpoint was overall survival. Results For 543 patients there were 121 EGFR+ and 422 EGFR WT. The cumulative incidence of brain metastases was 39.2% for EGFR+ patients compared to 28.2% for EGFR WT (p = 0.038; HR 1.4). In multivariate analysis, younger age and EGFR+ status were significant factors for developing brain metastases. The median survival for the EGFR+ and EGFR WT cohorts were 22.4 and 7.9 months (p < 0.001), respectively. In multivariate analysis, poor performance status and brain metastases were factors significant for worse survival. Conclusions There is a higher incidence of brain metastases for patients with EGFR+ metastatic NSCLC, even when adjusted for differences in survival, compared to EGFR WT. For patients with and without brain metastases, survival prognosis with stage IV NSCLC is much longer with EGFR+ disease. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: We conducted a retrospective population-based study to examine the survival outcomes in patients with brain metastases treated with salvage stereotactic radiosurgery (SRS), compared to boost SRS, after previous whole brain radiotherapy (WBRT). Methods and materials: From January 2000 to June 2011, 191 patients treated with WBRT and SRS for brain metastases in British Columbia were studied. Patients were divided into a boost cohort and a salvage cohort. The criteria used to determine eligibility for SRS were: 1–3 metastases, ⩽4cm size, Karnofsky performance status ⩾70, and control of extracranial disease. Results: Diagnosis by primary site was 84 lung, 47 breast, 15 melanoma, 12 renal, 9 colorectal, and 24 other. There were 113 patients (59%) in the boost cohort and 78 patients (41%) in the salvage cohort. The median overall survival from WBRT for the whole population was 17.7months: 12.1months for the boost cohort and 22.7months for the salvage cohort. There was no difference in median survival after SRS for the boost and salvage cohorts (11.2 vs. 11.2months, p =0.78). Conclusions: In selected patients with brain metastases treated with WBRT, survival following salvage SRS is as good as survival after WBRT+boost SRS. [Copyright &y& Elsevier]