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Abstract Background 90% of glioblastomas (GBM) relapse within two years of diagnosis. In contrast to the initial setting, there is no standard management for recurrent disease and options include hypofractionated stereotactic re-irradiation (re-mHSRT). The aims of this study were to investigate re-mHSRT practice in Swiss neuro-oncology centres. Methods A survey of 18 questions regarding re-irradiation for GBM was created and distributed electronically (SurveyMonkey, USA) to 11 radiation oncologists in Switzerland specialising in brain tumours. We evaluated the clinical outcomes of a multicentre series of patients treated with an established re-mHSRT schedule to benchmark these against the literature and investigated the radiological patterns of relapse after re-mHSRT. Results 8 of 11 (73%) radiation oncologists responded to the survey and re-irradiation practice was heterogeneous. The 10 × 3.5 Gy schedule (RTOG 1205, BRIOChe trials) was used by 5/8 respondents and 47/50 patients with recurrent GBM treated with re-mHSRT with this schedule in daily practice were included in the analysis. The median time to re-mHSRT following completion of adjuvant RT was 23.3 (7-224) months. The median PTV at re-mHSRT was 22.0 cm3 (0.9–190). Combined CTV + PTV margins ranged from 0 to 10 mm and median prescription isodose was 80% (67–100). 14/47 (30%) patients received temozolomide and four (8.5%) continued bevacizumab concomitantly. On multivariable analysis, concomitant systemic therapy predicted for progression-free survival (PFS), HR 2.87 (95% CI 1-03-7.96), p = 0.042. Median PFS following re-mHSRT was 6.6 (0.2–92.5) months and 26/47 patients (55%) received subsequent systemic therapy. The median overall survival (OS) following recurrence was 11.8 months (1.5–92.5), similar to the 10.8 months in the literature with the same schedule. The six-month OS rate was 37/47 (79%), which compares well with the 73% reported in a meta-analysis of 50 publications employing various schedules. In a subgroup analysis of 36/47 (79%) patients with MR follow-up after re-mHSRT, 8/36 (22%) had no radiological evidence of tumour progression at a median follow-up of 9.4 months. 21/28 (75%) radiological relapses were in-field, two were marginal and five were out of field. Conclusions Re-mHSRT with 10 × 3.5 Gy can achieve local control in selected patients with recurrent GBM.

Abstract Background and introduction Increasing evidence suggests that a subgroup of patients with oligometastatic cancer might achieve a prolonged disease-free survival through local therapy for all active cancer lesions. Our aims are to investigate the impact of brain metastases on the classification, treatment, and outcome in these patients. Materials and methods We analyzed a total of 7,000 oncological positron emission tomography scans to identify patients with extracranial oligometastatic disease (defined as ≤ 5 intra- or extra-cranial metastases). Concurrent magnetic resonance imaging brain was assessed to quantify intracranial tumor burden. We investigated the impact of brain metastases on oligometastatic disease state, therapeutic approaches, and outcome. Predictors for transitioning from oligo- to polymetastatic states were evaluated using regression analysis. Results A total of 106 patients with extracranial oligometastases and simultaneous brain metastases were identified, primarily originating from skin or lung/pleura cancers (90%, n = 96). Brain metastases caused a transition from an extracranial oligometastatic to a whole-body polymetastatic state in 45% (n = 48) of patients. While oligometastatic patients received systemic therapy (55% vs. 35%) more frequently and radiotherapy for brain metastases was more often prescribed to polymetastatic patients (44% vs. 26%), the therapeutic approach did not differ systematically between both sub-groups. The oligometastatic sub-group had a median overall survival of 28 months compared to 10 months in the polymetastatic sub-group (p

Aims: Multidisciplinary tumor boards (MDTs) are an integral part of ensuring high-quality, evidence-based and personalized cancer care. In this study, we aimed to evaluate the adherence to and implementation of MDT recommendations in patients with oligometastatic disease (OMD). Methods: We screened all oncologic positron emission tomography (PET) scans conducted at a single comprehensive cancer center in 2020. Patients were included if they had evidence of imaging-based OMD from a solid organ malignancy on the index scans, had their OMD case discussed at an MDT, and were treated and followed up at the same center. A switch away from the MDT-recommended treatment modalities was classified as a major deviation; non-MDT-mandated adjustments to a recommended treatment modality were coded as minor deviation. Clinical data was obtained via chart review; statistical calculations were computed using the R software. Results: After review of PET and/or concurrent brain scans, 787 cases of OMD were identified. Thereof, 347 (44.1 %) cases were discussed at MDT, of which 331 (42.1 %) were therapeutically managed and subsequently followed. The three most commonly recommended therapies were systemic therapy (35.6 %), multimodality treatment including definitive local therapy (17.8 %), and radiotherapy (13.9 %). A major deviation was recorded in 16.3 % of cases (most commonly: none of the MDT-recommended treatment modalities were performed: 19 (35.2 %); not all MDT-planned treatment modalities were performed: 12 (22.2 %); and additional treatment modality was performed: 11 (20.3 %). A minor deviation was found in 1.5 % of cases. On multivariable regression, number of distant metastases (n > 1) was associated with a major deviation (OR: 1.85; 95 % CI, 1.0–3.52). Major deviations were associated with a significantly worse OS (p = 0.0034). Conclusions: Adherence to and implementation of MDT recommendations in OMD patients was generally high (83.7%). Major deviations might be further reduced by more careful and elaborate discussions of OMD patient characteristics s and patient preferences.

Abstract Background Stereotactic arrhythmia radioablation (STAR) is delivered with a planning target volume (PTV) prescription dose of 25 Gy, mostly to the surrounding 75–85% isodose line. This means that the average and maximum dose received by the target is less than 35 Gy, which is the minimum threshold required to create a homogenous transmural fibrosis. Similar to catheter ablation, the primary objective of STAR should be transmural fibrosis to prevent heterogenous intracardiac conduction velocities and the occurrence of sustained ventricular arrhythmias (sVA) caused by reentry. We hypothesize that the current dose prescription used in STAR is inadequate for the long-term prevention of sVA and that a significant increase in dose is necessary to induce transmural scar formation. Objective A single arm, multi-center, phase II, dose escalation prospective clinical trial employing the i3 + 3 design is being conducted to examine the safety of a radiation dose-escalation strategy aimed at inducing transmural scar formation. The ultimate objective of this trial is to decrease the likelihood of sVA recurrence in patients at risk. Methods Patients with ischemic or non-ischemic cardiomyopathy and recurrent sVA, with an ICD and history of ≥ 1 catheter ablation for sVA will be included. This is a prospective, multicenter, one-arm, dose-escalation trial utilizing the i3 + 3 design, a modified 3 + 3 specifically created to overcome limitations in traditional dose-finding studies. A total of 15 patients will be recruited. The trial aims to escalate the ITV dose from 27.0 Gy to an ITV prescription dose-equivalent level of maximum 35.1 Gy by keeping the PTV prescription dose constant at 25 Gy while increasing the dose to the target (i.e. the VT substrate without PTV margin) by step-wise reduction of the prescribing isodose line (85% down to 65%). The primary outcome of this trial is safety measured by registered radiation associated adverse events (AE) up to 90 days after study intervention including radiation associated serious adverse events graded as at least 4 or 5 according to CTCAE v5, radiation pneumonitis or pericarditis requiring hospitalization and decrease in LVEF ≥ 10% as assessed by echocardiography or cardiac MRI at 90 days after STAR. The sample size was determined assuming an acceptable primary outcome event rate of 20%. Secondary outcomes include sVA burden at 6 months after STAR, time to first sVA recurrence, reduction in appropriate ICD therapies, the need for escalation of antiarrhythmic drugs, non-radiation associated safety and patient reported outcome measures such as SF-36 and EQ5D. Discussion DEFT-STAR is an innovative prospective phase II trial that aims to evaluate the optimal radiation dose for STAR in patients with therapy-refractory sVA. The trial has obtained IRB approval and focuses on determining the safe and effective radiation dose to be employed in the STAR procedure. Trial registration NCT05594368.

Background and Purpose: The feasibility of acquiring diffusion-weighted imaging (DWI) images on an MR-Linac for quantitative response assessment during radiotherapy was explored. DWI data obtained with a Spin Echo Echo Planar Imaging sequence adapted for a 0.35 T MR-Linac were examined and compared with DWI data from a conventional 3 T scanner. Materials and Methods: Apparent diffusion coefficient (ADC) measurements and a distortion correction technique were investigated using DWI-calibrated phantoms and in the brains of seven volunteers. All DWI utilized two phase-encoding directions for distortion correction and off-resonance field estimation. ADC maps in the brain were analyzed for automatically segmented normal tissues. Results: Phantom ADC measurements on the MR-Linac were within a 3 % margin of those recorded by the 3 T scanner. The maximum distortion observed in the phantom was 2.0 mm prior to correction and 1.1 mm post-correction on the MR-Linac, compared to 6.0 mm before correction and 3.6 mm after correction at 3 T. In vivo, the average ADC values for gray and white matter exhibited variations of 14 % and 4 %, respectively, for different selections of b-values on the MR-Linac. Distortions in brain images before correction, estimated through the off-resonance field, reached 2.7 mm on the MR-Linac and 12 mm at 3 T. Conclusion: Accurate ADC measurements are achievable on a 0.35 T MR-Linac, both in phantom and in vivo. The selection of b-values significantly influences ADC values in vivo. DWI on the MR-Linac demonstrated lower distortion levels, with a maximum distortion reduced to 1.1 mm after correction.

Objective: To evaluate the impact of metastases-directed stereotactic body radiotherapy (SBRT) on health-related quality of life (HRQoL) in men with oligometastatic prostate cancer (PCa) using real-world data from the OligoCare cohort. Materials and methods: OligoCare is a pragmatic, observational cohort designed to assess the impact of metastases-directed SBRT on patients with oligometastatic disease (OMD). We report an interim analyses of the secondary endpoint HRQoL, assessed using the EORTC QLQ-C30, within six months of metastases-directed SBRT for oligometastatic disease in men with PCa among the first 1600 registered patients. HRQoL data collection was optional within the OligoCare cohort. To compare HRQoL between baseline and first follow-up assessment, a Wilcoxon signed-rank test was used. A multiple linear regression model was used to explore the HRQoL associations with predefined factors. Results: Out of the 1600 registered patients, 658 were treated for oligometastatic PCa, of which 233 had baseline QoL data and 132 patients had both baseline and follow-up HRQoL data. At baseline, most patients had a WHO performance status of 0 or 1 (87 %), were de-novo oligometastatic (79 %), had one metastasis (90 %), and had a good overall global health status (mean 80.81, SD16.11, IQR 75–92). 51 % received hormonal therapy as concomitant systemic treatment. Patients with comorbidities as assessed by the Charlson Comorbidity index had a worse global health status at baseline (-4.88, 95 % CI:-9.35, −0.42). No clinically meaningful significant difference in global health status was observed at first assessment following SBRT (median 3.0 months) compared with baseline (mean difference 2.27, 95 % CI:-1.54, 6.08). Upon evaluating the proportions, meaningful clinically important differences (a 10-point or more difference) was observed in, 17 % and 11 % of the patients reporting deterioration and improvement of global health status, respectively. Conclusion: Metastases-directed stereotactic body radiotherapy had no negative impact on global HRQoL within the first six months after treatment.

Introduction and background: Metastatic disease has been proposed as a continuum, with no clear cut-off between oligometastatic and polymetastatic disease. This study aims to quantify tumor burden and patterns of spread in unselected metastatic cancer patients referred for PET-based staging, response assessment of restaging. Materials and methods: All oncological fluorodeoxyglucose (FDG-) and prostate-specific membrane antigen (PSMA-) positron emission tomography (PET) scans conducted at a single academic center in 2020 were analyzed. Imaging reports of all patients with metastatic disease were reviewed and assessed. Results: For this study, 7,000 PET scans were screened. One third of PET scans (n = 1,754; 33 %) from 1,155 unique patients showed presence of metastatic disease from solid malignancies, of which 601 (52 %) and 554 (48 %) were classified as oligometastatic (maximum 5 metastases) and polymetastatic (>5 metastases), respectively. Lung and pleural cancer, skin cancer, and breast cancer were the most common primary tumor histologies with 132 (23.8 %), 88 (15.9 %), and 72 (13.0 %) cases, respectively. Analysis of the number of distant metastases showed a strong bimodal distribution of the metastatic burden with 26 % of patients having one solitary metastasis and 43 % of patients harboring >10 metastases. Yet, despite 43 % of polymetastatic patients having >10 distant metastases, their pattern of distribution was restricted to one or two organs in about two thirds of patients, and there was no association between the number of distant metastases and the number of involved organs. Conclusion: The majority of metastatic cancer patients are characterized by either a solitary metastasis or a high tumor burden with >10 metastases, the latter was often associated with affecting a limited number of organs. These findings support both the spectrum theory of metastasis and the seed and soil hypothesis and can support in designing the next generation of clinical trials in the field of oligometastatic disease.

Background: Oligoprogression is defined as cancer progression of a limited number of metastases under active systemic therapy. The role of metastasis-directed therapy, using stereotactic body radiotherapy (SBRT), is controversial as is the continuation versus switch of systemic therapy. We report outcomes of oligoprogressive patients after SBRT, and compare those patients that continued or switched their current line of systemic therapy. Material/Methods.: We included patients who developed up to 5 progressive extracranial metastases under systemic therapy for any solid organ malignancy and were treated with SBRT to all lesions at our institution between 01/2014 and 12/2019. Overall survival (OS) and progression-free survival (PFS) were analyzed using the Kaplan-Meier method, and the interval to the next systemic therapy line determined using cumulative incidence functions. Multivariable Cox regression models were used to analyze the influence of baseline and post-progression variables on OS, PFS and survival with the next systemic therapy after SBRT. Results: Among 135 patients with oligoprogressive disease of which the most common primary tumor was lung cancer (n = 46, 34.1 %), 96 continued their current line of systemic therapy after oligoprogression. Among 39 who switched systemic therapy, 28 (71.8 %) paused or discontinued, while 11 (28.2 %) immediately started another systemic treatment. After a median follow-up of 27.2 months, patients that switched and those who continued systemic therapy after oligoprogression had comparable median OS (32.1 vs. 38.2 months, p = 0.47) and PFS (4.3 vs. 3.4 months, p = 0.6). The intervals to the next systemic therapy line were comparable between both cohorts (p = 0.6). An ECOG performance status of 2 and immediately starting a new systemic therapy after oligoprogression were associated with a poorer survival without next systemic therapy, while the de-novo OMD state was associated with better survival without next systemic therapy compared to the induced state. Conclusion: Oncological outcomes of patients that continued or switched systemic therapy after SBRT for oligoprogression were comparable, potentially indicating that further lines of treatment may be safely delayed in selected cases.

Background and introduction: Growing evidence supports a combined modality treatment strategy for patients with oligometastatic disease. However, lack of phase III trial data and uncertainties around patient selection highlight the importance of multidisciplinary tumor boards (MDT) in therapeutic decision-making. This study aimed to analyze the recognition of and treatment recommendations for oligometastatic patients by MDTs at a large comprehensive cancer center in order to better understand current treatment patterns of oligometastasis. Materials and methods: For this retrospective single-center cross-sectional study, oligometastatic patients were identified by screening oncological PET and concurrent brain MRI scans conducted at our center in 2020. MDT discussions and recommendations within four weeks of the imaging diagnosis of oligometastasis were analyzed. Logistic regression analysis was used to identify predictors for the addition of local therapy to standard-of-care. Results: A total of 787 oligometastatic cases were identified. Lung cancer and mesothelioma, skin cancer, and prostate cancer were the most common histologies with 231 (29 %), 160 (20 %), and 84 (11 %) cases, respectively. Almost half of the cases (46 %) had one distant metastasis on imaging only. More than half (56 %) of all oligometastatic cases were discussed at an MDT. In 47 % of cases, for which a therapeutic recommendation was reached in an MDT, local therapy was part of the therapeutic strategy. On logistic regression analysis, oligometastatic skin cancer was significantly associated with a recommendation for local therapy (p

Background: Patients who develop oligorecurrent disease may be treated with metastasis-directed stereotactic body radiotherapy (SBRT) to defer the start of systemic therapy and delay its potential side effects. We report oncological outcomes and patterns of failure in patients with oligorecurrent disease treated with SBRT and determine which factors impact the interval to initiation of systemic therapy. Material/Methods: This retrospective study included patients with oligorecurrent disease (≤5 lesions) from any solid organ malignancy, treated with SBRT to all metastases and no systemic therapy for a minimum one month after SBRT between 01/2014 and 12/2019. The Kaplan-Meier method was used to analyze overall survival (OS) and progression-free survival (PFS), and the cumulative incidence of initiation of systemic therapy was analyzed assuming death without systemic therapy as a competing risk. Univariable and multivariable analyses are used to assess predictors of the systemic therapy-free interval. Results: Among 545 patients treated with SBRT for oligometastatic disease, 142 patients were treated with SBRT only for oligorecurrent disease. The most common primary tumors were lung and gastrointestinal cancer in 47 (33.1 %) and 28 (19.7 %) patients, respectively. After a median follow-up of 25 months, the median PFS and OS was 6.1 months and 48.9 months, respectively. Distant metastases were the most common first failure, and oligometastatic distant failure occured in 86 patients (60.6 %). New metastases were treated with repeat SBRT in 48 patients (33.8 %). The 1- and 2-year cumulative incidence of initiation of systemic therapy was 24.6 % and 36.8 %, respectively. In multivariable analysis, the number of previous lines of systemic therapy and the cumulative volume of metastases were significantly associated with the interval to initiation of systemic therapy. Conclusion: Selected patients with oligorecurrence achieved favorable OS and low cumulative incidence of initiation of systemic therapy. Prospective studies are warranted to determine how the deferral of systemic therapy impacts OS compared with immediate systemic therapy in combination with SBRT.

Background and purpose: Radiomics offers great potential in improving diagnosis and treatment for patients with glioblastoma multiforme. However, in order to implement radiomics in clinical routine, the features used for prognostic modelling need to be stable. This comprises significant challenge in multi-center studies. The aim of this study was to evaluate the impact of different image normalization methods on MRI features robustness in multi-center study. Methods: Radiomics stability was checked on magnetic resonance images of eleven patients. The images were acquired in two different hospitals using contrast-enhanced T1 sequences. The images were normalized using one of five investigated approaches including grey-level discretization, histogram matching and z-score. Then, radiomic features were extracted and features stability was evaluated using intra-class correlation coefficients. In the second part of the study, improvement in the prognostic performance of features was tested on 60 patients derived from publicly available dataset. Results: Depending on the normalization scheme, the percentage of stable features varied from 3.4% to 8%. The histogram matching based on the tumor region showed the highest amount of the stable features (113/1404); while normalization using fixed bin size resulted in 48 stable features. The histogram matching also led to better prognostic value (median c-index increase of 0.065) comparing to non-normalized images. Conclusions: MRI normalization plays an important role in radiomics. Appropriate normalization helps to select robust features, which can be used for prognostic modelling in multicenter studies. In our study, histogram matching based on tumor region improved both stability of radiomic features and their prognostic value.

A novel quality assurance process for electroanatomical mapping (EAM)-to-radiotherapy planning imaging (RTPI) target transport was assessed within the multi-center multi-platform framework of the RAdiosurgery for VENtricular TAchycardia (RAVENTA) trial. A stand-alone software (CARDIO-RT) was developed to enable platform independent registration of EAM and RTPI of the left ventricle (LV), based on pre-generated radiotherapy contours (RTC). LV-RTC were automatically segmented into the American-Heart-Association 17-segment-model and a manual 3D-3D method based on EAM 3D-geometry data and a semi-automated 2D-3D method based on EAM screenshot projections were developed. The quality of substrate transfer was evaluated in five clinical cases and the structural analyses showed substantial differences between manual target transfer and target transport using CARDIO-RT.

Abstract Background Main purpose was to describe procedures and identify challenges in the implementation process of adaptive and non-adaptive MR-guided radiotherapy (MRgRT), especially new risks in workflow due to the new technique. We herein report the single center experience for the implementation of (MRgRT) and present an overview on our treatment practice. Methods Descriptive statistics were used to summarize clinical and technical characteristics of treatment and patient characteristics including sites treated between April 2019 and end of March 2020 after ethical approval. A risk analysis was performed to identify risks of the online adaptive workflow. Results A summary of the processes on the MR-Linac including workflows, quality assurance and possible pitfalls is presented. 111 patients with 124 courses were treated during the first year of MR-guided radiotherapy. The most commonly treated site was the abdomen (42% of all treatment courses). 73% of the courses were daily online adapted and a high number of treatment courses (75%) were treated with stereotactic body irradiation. Only 4/382 fractions could not be treated due to a failing online adaptive quality assurance. In the risk analysis for errors, the two risks with the highest risk priority number were both in the contouring category, making it the most critical step in the workflow. Conclusion Although challenging, establishment of MRgRT as a routinely used technique at our department was successful for all sites and daily o-ART was feasible from the first day on. However, ongoing research and reports will have to inform us on the optimal indications for MRgRT because careful patient selection is necessary as it continues to be a time-consuming treatment technique with restricted availability. After risk analysis, the most critical workflow category was the contouring process, which resembles the need of experienced staff and safety check paths.

Abstract Purpose To assess the effects of daily adaptive MR-guided replanning in stereotactic body radiation therapy (SBRT) of liver metastases based on a patient individual longitudinal dosimetric analysis. Methods Fifteen patients assigned to SBRT for oligometastatic liver metastases underwent daily MR-guided target localization and on-table treatment plan re-optimization. Gross tumor volume (GTV) and organs at risk (OARs) were adapted to the anatomy-of-the-day. A reoptimized plan (RP) and a rigidly shifted baseline plan (sBP) without re-optimization were generated for each fraction. After extraction of DVH parameters for GTV, planning target volume (PTV), and OARs (stomach, duodenum, bowel, liver, heart) plans were compared on a per-patient basis. Results Median pre-treatment GTV and PTV were 14.9 cc (interquartile range (IQR): 7.7–32.9) and 62.7 cc (IQR: 42.4–105.5) respectively. SBRT with RP improved PTV coverage (V100%) for 47/75 of the fractions and reduced doses to the most proximal OARs (D1cc, Dmean) in 33/75 fractions compared to sBP. RP significantly improved PTV coverage (V100%) for metastases within close proximity to an OAR by 4.0% (≤ 0.2 cm distance from the edge of the PTV to the edge of the OAR; n = 7; p = 0.01), but only by 0.2% for metastases farther away from OAR (> 2 cm distance; n = 7; p = 0.37). No acute grade 3 treatment-related toxicities were observed. Conclusions MR-guided online replanning SBRT improved target coverage and OAR sparing for liver metastases with a distance from the edge of the PTV to the nearest luminal OAR

Abstract Background Radiotherapy treatment of head and neck cancer affects local arteries and increases the risk of stroke. This study aimed at a closer characterization of this damage and its development in time with a longitudinal study set up. Methods Male patients treated between 2011 and 2016 for hypopharyngeal carcinoma were identified from the in-house clinical data base. They were included into the study if besides the planning CT at least one additional CT image was available from follow-up (13 patients) or at least two MRI scans (16 patients of which 2 were already included). All patients received radiotherapy, and chemotherapy was administered to 16 patients. The time from the beginning of radiotherapy to the last available image ranged from 2 months to 4.5 years. For six segments of the carotid arteries, the number and volume of atherosclerotic plaques were determined from the CT scans, and the intima media thickness from the MRI scans. Information on comorbid cardiovascular disease, hypertension and diabetes mellitus was retrieved from medical records. Results Total plaque volume rose from 0.25 cm3 before to 0.33 cm3 after therapy but this was not significant (p = 0.26). The mean number of plaques increased from 5.7 to 8.1 (p = 0.002), and the intima media thickened from 1.17 mm to 1.35 mm (p = 0.002). However, the mean intima media thickness practically did not change in patients with comorbid diabetes mellitus (p-value for homogeneity: 0.03). For patients without diabetes mellitus, dynamics of both plaque number and intima media thickness, was consistent with an increase until about one year after therapy and no further progression thereafter. Conclusion Our study confirmed the thickening of artery walls and the increase in the number of plaques. Results imply that definitive radiation damage to the artery walls can be determined not earlier than about one year after radiotherapy and there is no substantial deterioration thereafter. Reasons for the absence of an observable intima media thickening in patients with diabetes are unclear.

Abstract Purpose Pathogenesis of brain metastases/meningeal cancer and the emotional and neurological outcomes are not yet well understood. The hypothesis of our study is that patients with leptomeningeal cancer show volumetric differences in brain substructures compared to patients with cerebral metastases. Methods Three groups consisting of female breast cancer patients prior to brain radiotherapy were compared. Leptomeningeal cancer patients (LMC Group), oligometastatic patients (1–3 brain metastases) prior to radiosurgery (OMRS Group) and patients prior to whole brain radiation (WB Group) were included. All patients had MRI imaging before treatment. T1 MRI sequences were segmented using automatic segmentation. For each patient, 14 bilateral and 11 central/median subcortical structures were tested. Overall 1127 structures were analyzed and compared between groups using age matched two-sided t-tests. Results The average age of patients in the OMRS group was 60.8 years (± 14.7), 65.3 (± 10.3) in the LMC group and 62.6 (± 10.2) in the WB group. LMC patients showed a significantly larger fourth ventricle compared to OMRS (p = 0.001) and WB (p = 0.003). The central corpus callosum appeared smaller in the LMC group (LMC vs OMRS p = 0.01; LMC vs WB p = 0.026). The right amygdala in the WB group appeared larger compared with the OMRS (p = 0.035). Conclusions Differences in the size of brain substructures of the three groups were found. The results appear promising and should be taken into account for further prospective studies also involving healthy controls. The volumetrically determined size of the fourth ventricle might be a helpful diagnostic marker in the future.

Abstract Purpose/objective(s) Along with breast-conserving surgery (BCS), adjuvant radiotherapy (RT) of patients with early breast cancer plays a crucial role in the oncologic treatment concept. Conventionally, irradiation is carried out with the aid of tangentially arranged fields. However, more modern and more complex radiation techniques such as IMRT (intensity-modulated radio therapy) are used more frequently, as they improve dose conformity and homogeneity and, in some cases, achieve better protection of adjacent risk factors. The use of this technique has implications for the incidental- and thus unintended- irradiation of adjacent loco regional lymph drainage in axillary lymph node levels I-III and internal mammary lymph nodes (IMLNs). A comparison of a homogeneous “real-life” patient collective, treated with helical tomotherapy (TT), patients treated with 3D conformal RT conventional tangentially arranged fields (3DCRT) and deep inspiration breath hold (3DCRT-DIBH), was conducted. Materials/methods This study included 90 treatment plans after BCS, irradiated in our clinic from January 2012 to August 2016 with TT (n = 30) and 3D-CRT (n = 30), 3DCRT DIBH (n = 30). PTVs were contoured at different time points by different radiation oncologists (> 7). TT was performed with a total dose of 50.4 Gy and a single dose of 1.8 Gy with a simultaneous integrated boost (SIB) to the tumor cavity (TT group). Patients irradiated with 3DCRT/3DCRT DIBH received 50 Gy à 2 Gy and a sequential boost. Contouring of lymph drainage routes was performed retrospectively according to RTOG guidelines. Results Average doses (DMean) in axillary lymph node Level I/Level II/Level III were 31.6 Gy/8.43 Gy/2.38 Gy for TT, 24.0 Gy/11.2 Gy/3.97 Gy for 3DCRT and 24.7 Gy/13.3 Gy/5.59 Gy for 3DCRT-DIBH patients. Internal mammary lymph nodes (IMLNs) Dmean were 27.8 Gy (TT), 13.5 Gy (3DCRT), and 18.7 Gy (3DCRT-DIBH). Comparing TT to 3DCRT-DIBH dose varied significantly in all axillary lymph node levels and the IMLNs. Comparing TT to 3DCRT significant dose difference in Level I and IMLNs was observed. Conclusion Dose applied to locoregional lymph drainage pathways varies comparing tomotherapy plans to conventional tangentially arranged fields. Studies are warranted whether dose variations influence loco-regional spread and must have implications for target volume definition guidelines.

Ventricular tachycardia (VT) caused by myocardial scaring bears a significant risk of mortality and morbidity. Antiarrhythmic drug therapy (AAD) and catheter ablation remain the cornerstone of VT management, but both treatments have limited efficacy and potential adverse effects. Stereotactic body radiotherapy (SBRT) is routinely used in oncology to treat non-invasively solid tumors with high precision and efficacy. Recently, this technology has been evaluated for the treatment of VT. This review presents the basic underlying principles, proof of concept, and main results of trials and case series that used SBRT for the treatment of VT refractory to AAD and catheter ablation.

Abstract Background The cranial border of the target volume (TV) in rectal cancer patients treated with neoadjuvant chemoradiation (nCRT) is mostly defined at the level of L5/S1. However, current studies have shown that relapse cranially of the target volume after neoadjuvant nCRT and surgery is very rare. A reduction of cranial TV margins could be reasonable to reduce toxicity to the organs at risk (OAR). In this study we compared the dose distribution to the OAR for different cranial longitudinal margins using a dose-volume histogram (DVH) analysis. Methods Ten patients with loco regional advanced rectal cancer were analysed retrospectively. All patients were planned for Volumetric Arc Therapy Radiation Therapy (VMAT). Next to the original PTV (PTV0), three new planning target volumes (PTV) were defined for each patient: The PTV0 reduced by 1 cm, 2 cm and 3 cm on cranial extension. For each PTV a treatment plan with a total dose of 50.4 Gy with daily doses of 1.8 Gy was calculated. Dose to the OAR were evaluated and compared. Results For the bone marrow, the small bowel and the peritoneal space all clinically relevant relative dose parameters (V10-V50) as well as the Dmedian could be significantly reduced with every cranial target volume reduction of 1 cm. For V10 of the peritoneal space the dose could be nearly halved with a 3 cm shortened TV. After TV reduction of 3 cm also for the urinary bladder a significant dose reduction of the Dmedian could be achieved. Conclusions Considering the very low recurrence rates in the TME and IMRT era, the distribution patterns of these relapses as well as the relevant side effects of nCRT, we would agree with existing recommendations of reduction of the cranial target volume in nCRT treated rectal cancer patients.

Abstract Background The purpose of this study is to evaluate the tumor movement and accuracy of patient immobilization in stereotactic body radiotherapy of liver tumors with low pressure foil or abdominal compression. Methods Fifty-four liver tumors treated with stereotactic body radiotherapy were included in this study. Forty patients were immobilized by a vacuum couch with low pressure foil, 14 patients by abdominal compression. We evaluated the ratio of gross tumor volume/internal target volume, the tumor movement in 4D-computed tomography scans and daily online adjustments after cone beam computed tomography scans. Results The ratio of gross tumor volume/internal target volume was smaller with low pressure foil. The tumor movement in 4D-computed tomography scans was smaller with abdominal compression, the cranial movement even significantly different (p = 0.02). The mean online adjustments and their mean absolute values in the vertical, lateral and longitudinal axis were smaller with abdominal compression. The online adjustments were significantly different (p