Association of Night Snacking and Screen Time on Sleep Behavior in Japanese Toddlers: A Cross-Sectional Study.

BACKGROUND/OBJECTIVES: Irregular lifestyles, such as sleep deprivation and disordered eating, disrupt the circadian clock and are linked to health issues. This study investigates the relationship among chronotypes, social jet lag, night-snacking habits, and screen time in toddlers. METHODS: A survey of 6177 mothers of children aged 3-8 years was conducted in June 2022. Means comparison and multiple regression analyses were used to analyze the data. RESULTS: Toddlers who consumed night snacks were more likely to be evening types and experienced longer social jet lag. Longer screen time during night snacking correlated with evening-type tendencies. Juice and ice cream were identified as evening-type snacks. CONCLUSIONS: We suggest that stopping snacks after dinner is crucial to prevent evening-type eating. Especially, high-sugar and high-fat night snacks like juice and ice cream may contribute to nocturnal habits and disrupt circadian rhythms in children.

Diaphragm Tracking System That Superimposes Planned Diaphragm Contours on Kilovolt Cine Images During Multiple Breath-Hold Volumetric Modulated Arc Therapy for Abdominal Tumors.

We recently published a phantom validation of our diaphragm tracking system, DiaTrak, on an Elekta linear accelerator with an integrated cone-beam computed tomography (CBCT) unit for multiple breath-hold volumetric modulated arc therapy of abdominal tumors, where the diaphragm position was compared between digitally reconstructed radiography (DRR) and kilovolt (kV) projection streaming images by template matching. In the present report, the visual feedback of the diaphragm position was added to the reported system. DICOM-RT diaphragm contour data were additionally exported from a treatment planning system to the DiaTrak PC. Following phantom localization by registering the CBCT to the planning CT images, a projected diaphragm contour was overlaid on each DRR image, whereas another two projected diaphragm contours were superimposed on each kV projection cine image every 180 ms after shifting ±5 mm (set as breath-hold tolerance) in the craniocaudal direction during gantry rotation. It was visually confirmed that the projected diaphragm surface was observed within the two contour lines on the kV cine window. The diaphragm registration errors of the localized phantom were also calculated based on image cross-correlation between the DRR and the projection cine images every 180 ms. It was found that the mean diaphragm registration error was -0.29 mm with a standard deviation of 0.32 mm during the gantry rotation. In conclusion, a new interface for the 5 mm tolerance check was proposed to provide direct visual feedback, thereby giving a sense of assurance to the attending radiotherapy technologists. The calculated diaphragm registration errors were relatively small compared to the tolerance of 5 mm, and therefore it is considered clinically acceptable.

Stereotactic Ablative Radiation Therapy for Sacral Bone Metastasis in Recurrent Type A Thymoma: A Two-Year Follow-Up Demonstrating Pain Reduction and Local Control.

A 74-year-old Asian man presented with sacral bone metastasis-related pain caused by a metastatic thymoma. Computed tomography revealed an approximately 6-cm sacral mass, which was confirmed as a metastatic thymoma. The patient was referred to our department and underwent stereotactic ablative radiation therapy (SABR) using volumetric modulated arc therapy and received a total dose of 35 Gy in five fractions. One year after SABR, the sacral lesion had decreased in size, and the pain medication was reduced. After two years, the patient no longer required pain medication, indicating successful management of bone metastases in recurrent Type A Thymoma.

First clinical experience of total body irradiation using volumetric modulated arc therapy technique in Japan.

ABSTRACT: In recent years, advances in radiotherapy technology have led to the use of high-precision radiotherapy such as volumetric modulated arc therapy (VMAT). Total body irradiation using VMAT technique (VMAT-TBI) was performed for the first time in our hospital. A 56-year-old male patient diagnosed with B-cell acute lymphoblastic leukemia was performed TBI as pretreatment for haploidentical-related peripheral blood stem-cell transplantation. The prescribed dose was 4 Gy for planning target volume in two fractions. The treatment plan was divided into two plans: upper body and lower body with three and two isocenters, respectively. The overall treatment time with VMAT-TBI was approximately 55 min, and it was not significantly longer than that of moving couch techniques. VMAT-TBI is a less burdensome and more accurate treatment for patients, and it may be a useful treatment for TBI.

Neurological prognosis prediction for cardiac arrest patients using quantitative imaging biomarkers from brain computed tomography.

PURPOSE: We aimed to predict the neurological prognosis of cardiac arrest (CA) patients using quantitative imaging biomarkers extracted from brain computed tomography images. METHODS: We retrospectively enrolled 86 CA patients (good prognosis, 32; poor prognosis, 54) who were treated at three hospitals between 2017 and 2019. We then extracted 1131 quantitative imaging biomarkers from whole-brain and local volumes of interest in the computed tomography images of the patients. The data were split into training and test sets containing 60 and 26 samples, respectively, and the training set was used to select representative quantitative imaging biomarkers for classification. In univariate analysis, the classification was evaluated using the p-value of the Brunner-Munzel test and area under the receiver operating characteristic curve (AUC) for the test set. In multivariate analysis, machine learning models reflecting nonlinear and complex relations were trained, and they were evaluated using the AUC on the test set. RESULTS: The best performance provided p = 0.009 (<0.01) and an AUC of 0.775 (95% confidence interval, 0.590-0.960) for the univariate analysis and an AUCof0.813 (95% confidence interval, 0.640-0.985) for the multivariate analysis. Overall, the gray level with the maximum gradient in the histogram of the three-dimensionally low-pass-filtered image was an important feature for prediction across the analyses. CONCLUSIONS: Quantitative imaging biomarkers can be used in neurological prognosis prediction for CA patients. Relevant biomarkers may contribute to protocolized computed tomography image acquisition to ensure proper decision support in acute care.

descSPIM: an affordable and easy-to-build light-sheet microscope optimized for tissue clearing techniques.

Despite widespread adoption of tissue clearing techniques in recent years, poor access to suitable light-sheet fluorescence microscopes remains a major obstacle for biomedical end-users. Here, we present descSPIM (desktop-equipped SPIM for cleared specimens), a low-cost ($20,000-50,000), low-expertise (one-day installation by a non-expert), yet practical do-it-yourself light-sheet microscope as a solution for this bottleneck. Even the most fundamental configuration of descSPIM enables multi-color imaging of whole mouse brains and a cancer cell line-derived xenograft tumor mass for the visualization of neurocircuitry, assessment of drug distribution, and pathological examination by false-colored hematoxylin and eosin staining in a three-dimensional manner. Academically open-sourced ( https://github.com/dbsb-juntendo/descSPIM ), descSPIM allows routine three-dimensional imaging of cleared samples in minutes. Thus, the dissemination of descSPIM will accelerate biomedical discoveries driven by tissue clearing technologies.

Prognostic value of radiomic features in patients with esophageal cancer treated with chemoradiotherapy.

BACKGROUND: The aim of the present study was to evaluate the prognostic value of radiomic features in patients who underwent chemoradiotherapy for esophageal cancer. METHODS: In this retrospective study, two independent cohorts of esophageal cancer patients treated with chemoradiotherapy were included. Radiomics features of each patient were extracted from pre-treatment computed tomography (CT) images. Radiomic features were selected by employing univariate and multivariate analyses in the test cohort. Selected radiomic features were verified in the validation cohort. The endpoint of the present study was overall survival. RESULTS: A total of 101 esophageal cancer patients were included in our study, with 71 patients in the test cohort and 30 patients in the validation cohort. Univariate analysis identified 158 radiomic features as prognostic factors for overall survival in the test cohort. A multivariate analysis revealed that root mean squared and Low-High-High (LHH) median were prognostic factors for overall survival with a hazard ratio of 2.23 (95% confidence interval [CI]: 1.16-4.70, P = 0.017) and 0.26 (95% CI: 0.13-0.54, P < 0.001), respectively. In the validation cohort, root mean squared high/LHH median low group had the most preferable prognosis with a median overall survival of 73.30 months (95% CI: 32.13-NA), whereas root mean squared low/LHH median low group had the poorest prognosis with a median overall survival of 9.72 months (95% CI: 2.50-NA), with a P value of < 0.001. CONCLUSIONS: We identified two radiomic features that might be independent prognostic factors of overall survival of esophageal cancer patients treated with chemoradiotherapy.

Relationship between hydrogel spacer distribution and dosimetric parameters in linear-accelerator-based stereotactic body radiotherapy for prostate cancer.

PURPOSE: To explore the potential of quantitative parameters of the hydrogel spacer distribution as predictors for separating the rectum from the planning target volume (PTV) in linear-accelerator-based stereotactic body radiotherapy (SBRT) for prostate cancer. METHODS: Fifty-five patients underwent insertion of a hydrogel spacer and were divided into groups 1 and 2 of the PTV separated from and overlapping with the rectum, respectively. Prescribed doses of 36.25-45 Gy in five fractions were delivered to the PTV. The spacer cover ratio (SCR) and hydrogel-implant quality score (HIQS) were calculated. RESULTS: Dosimetric and quantitative parameters of the hydrogel spacer distribution were compared between the two groups. For PTV, D99% in group 1 (n = 29) was significantly higher than that in group 2 (n = 26), and Dmax, D0.03cc, D1cc, and D10% for the rectum were significantly lower in group 1 than in group 2. The SCR for prostate (89.5 ± 12.2%) in group 1 was significantly higher (p < 0.05) than that in group 2 (74.7 ± 10.3%). In contrast, the HIQS values did not show a significant difference between the groups. An area under the curve of 0.822 (95% confidence interval, 0.708-0.936) for the SCR was obtained with a cutoff of 93.6%, sensitivity of 62.1%, and specificity of 100%. CONCLUSIONS: The SCR seems promising to predict the separation of the rectum from the PTV in linear-accelerator-based SBRT for prostate cancer.

Initial validation of a diaphragm tracking system for multiple breath-hold volumetric modulated arc therapy of abdominal tumors: A phantom study.

BACKGROUND: The breath-hold radiotherapy has been increasingly used to mitigate interfractional and intrafractional breathing impact on treatment planning and beam delivery. Previous techniques include body surface measurements or radiopaque metal markers, each having known disadvantages. PURPOSE: We recently proposed a new markerless technique without the disadvantages, where diaphragm was registered between DRR and fluoroscopic x-ray projection images every 180 ms during VMAT delivery. An initial validation of the proposed diaphragm tracking system (DiaTrak) was performed using a chest phantom to evaluate its characteristics. METHODS: Diaphragm registration was performed between DRR and projection streaming kV x-ray images of a chest phantom during VMAT delivery. Streaming data including the projection images and the beam angles were transferred from a linac system to an external PC, where the diaphragm registration accuracy and beam-off latency were measured based on image cross correlation between the DRR and the projection images every 180 ms. RESULTS: It was shown that the average of the beam-off latency was 249.5 ms and the average of the diaphragm registration error was 0.84 mm CONCLUSIONS: Initial validation of the proposed DiaTrak system for multiple breath-hold VMAT of abdominal tumors has been successfully completed with a chest phantom. The resulting beam-off latency and the diaphragm registration error were regarded clinically acceptable.

Cone-beam computed-tomography-based delta-radiomic analysis for investigating prognostic power for esophageal squamous cell cancer patients undergoing concurrent chemoradiotherapy.

PURPOSE: To investigate the prognostic power of cone-beam computed-tomography (CBCT)-based delta-radiomics in esophageal squamous cell cancer (ESCC) patients treated with concurrent chemoradiotherapy (CCRT). METHODS: We collected data from 26 ESCC patients treated with CCRT. CBCT images acquired at five time points (1st-5th week) per patient during CCRT were used in this study. Radiomic features were extracted from the five CBCT images on the gross tumor volumes. Then, 17 delta-radiomic feature sets derived from five types of calculations were obtained for all the cases. Leave-one-out cross-validation was applied to investigate the prognostic power of CBCT-based delta-radiomic features. Feature selection and construction of a prediction model using Coxnet were performed using training samples. Then, the test sample was classified into high or low risk in each cross-validation fold. Survival analysis for the two groups were performed to evaluate the prognostic power of the extracted CBCT-based delta-radiomic features. RESULTS: Four delta-radiomic feature sets indicated significant differences between the high- and low-risk groups (p < 0.05). The highest C-index in the 17 delta-radiomic feature sets was 0.821 (95 % confidence interval, 0.735-0.907). That feature set had p-value of the log-rank test and hazard ratio of 0.003 and 4.940 (95 % confidence interval, 1.391-17.544), respectively. CONCLUSIONS: We investigated the potential of using CBCT-based delta-radiomics for prognosis of ESCC patients treated with CCRT. It was demonstrated that delta-radiomic feature sets based on the absolute value of relative difference obtained from the early to the middle treatment stages have high prognostic power for ESCC.

Intrafractional Diaphragm Variations During Breath-Hold Stereotactic Body Radiotherapy for a Liver Tumor Based on Real-Time Registration Between Kilovoltage Projection Streaming and Digitally Reconstructed Radiograph Images: A Case Report.

In liver stereotactic body radiotherapy (SBRT), precise image guidance is paramount, serving as the foundation of this treatment approach. The accuracy of SBRT in liver cancer treatment heavily relies on meticulous imaging techniques. The diaphragm, situated adjacent to the liver, is a crucial anatomical structure susceptible to positional and motion variations, which can potentially impact the accuracy of liver tumor targeting. This study explores the application of real-time kilovoltage projection streaming images (KVPSI) in comparison to digitally reconstructed radiography (DRR) for assessing diaphragm position deviations during breath-hold liver tumor SBRT. A 76-year-old male diagnosed with cholangiocarcinoma underwent breath-hold SBRT using split arc volumetric modulated arc therapy (VMAT), where a full arc was split into six sub-arcs, each spanning 60 degrees. The diaphragm dome positions were continuously monitored through KVPSI during treatment. The intrafractional position deviations of the diaphragm were calculated and analyzed for each split arc. The case report revealed a mean diaphragm dome deviation of 0.47 mm (standard deviation: 4.47 mm) in the entire arc. This pioneering study showcases the feasibility of intrafractional diaphragm position variation assessment using real-time KVPSI during the breath-hold liver tumor VMAT-SBRT. Integrating real-time imaging techniques enhances our comprehension of the intra-breath-hold variations, thereby guiding adaptive treatment strategies and potentially improving treatment outcomes. Clinical validation through further research is essential.

Virtual cone-beam computed tomography simulator with human phantom library and its application to the elemental material decomposition.

PURPOSE: The purpose of this study is to develop a virtual CBCT simulator with a head and neck (HN) human phantom library and to demonstrate the feasibility of elemental material decomposition (EMD) for quantitative CBCT imaging using this virtual simulator. METHODS: The library of 36 HN human phantoms were developed by extending the ICRP 110 adult phantoms based on human age, height, and weight statistics. To create the CBCT database for the library, a virtual CBCT simulator that simulated the direct and scattered X-ray on a flat panel detector using ray-tracing and deep-learning (DL) models was used. Gaussian distributed noise was also included on the flat panel detector, which was evaluated using a real CBCT system. The usefulness of the virtual CBCT system was demonstrated through the application of the developed DL-based EMD model for case involving virtual phantom and real patient. RESULTS: The virtual simulator could generate various virtual CBCT images based on the human phantom library, and the prediction of the EMD could be successfully performed by preparing the CBCT database from the proposed virtual system, even for a real patient. The CBCT image degradation owing to the scattered X-ray and the statistical noise affected the prediction accuracy, although these effects were minimal. Furthermore, the elemental distribution using the real CBCT image was also predictable. CONCLUSIONS: This study demonstrated the potential of using computer vision for medical data preparation and analysis, which could have important implications for improving patient outcomes, especially in adaptive radiation therapy.

Dosimetric Comparison Study Between Free Breathing and Breath Hold Techniques in Patients Treated by Liver-Directed Stereotactic Body Radiation Therapy.

Background Breathing motion management is the key to delivering stereotactic body radiation therapy (SBRT) for liver lesions. This study aimed to compare the dosimetric parameters of liver SBRT using two different techniques: free breathing and breath hold. Method The study included 11 patients with liver metastases or hepatocellular carcinoma who underwent liver-directed SBRT. A dosimetric comparison was performed using dose-volume histogram analysis, evaluating parameters such as the maximum dose to 5 cc of bowel volume, mean liver dose (MLD), and liver V20 and V30. Statistical analyses were performed to compare results. Results The findings revealed that the breath hold technique resulted in significantly lower doses to the bowel and smaller volumes of normal liver tissue receiving 20 Gy (V20) and 30 Gy (V30) than the free breathing. Although there was no statistically significant difference in the MLD between the two techniques, the breath hold technique resulted in a lower MLD. Conclusion This dosimetric comparison study suggests that the breath hold technique is associated with lower radiation exposure to the bowel and normal liver tissues. Although this may not be feasible for all patients, it may be an appropriate procedure for selected individuals. Further research is needed to validate these findings in different patient populations and explore their impact on clinical outcomes and patient-reported quality of life.

Association of breakfast styles such as Japanese, Western, and cereals with sleeping habits, eating habits, and lifestyle in preschool and elementary school children.

Introduction: In Japan, breakfast styles are categorized into five groups; Japanese breakfast (JB; rice and miso soup), Western breakfast (WB; bread and milk), Japanese-Western breakfast (J-WB; alternative daily serving), cereal breakfast (CB), and breakfast skipping. In our recent studies, breakfast style was highly associated with the daily sleep-wake phase (chronotype), and healthy eating habits. In contrast with other breakfast style consumers, JB-consumers were positively associated with the morning chronotype and healthy eating habits such as a high consumption of a variety of protein sources, vegetables, and dietary fibers, and low consumption of sweetened juices. These previous studies included only adult participants; hence, in the current study, we investigated whether similar observations can be made in children. Methods: Preschool (aged 3-5 years) and elementary school children (6-8 years) (N = 6,104, 49.87% boys, 50.13% girls, mean body mass index 15.39 ± 0.03 kg/m2 for preschoolers and percentage of overweight -2.73 ± 0.22 for elementary school children) participated in this cross-sectional online survey on lifestyle, including eating and sleep habits, through their mother's responses. Results: The results showed that the morning-evening type index values (chronotype indicator, smaller indicates morning type) were negatively correlated with JB intake (-0.05, p < 0.01) and positively correlated with WB (0.03, p < 0.05) and CB intake (0.06, p < 0.01), suggesting that the JB group exhibited the morning chronotype and the WB and CB groups exhibited the evening chronotype. The JB group consumed a variety of protein sources (mean ± SE; days/week) with more frequency (fish 2.95 ± 0.038 p < 0.001, soy 3.55 ± 0.043 p < 0.001, egg 3.82 ± 0.044 p < 0.001) compared with the WB group (fish 2.58 ± 0.033, soy 3.00 ± 0.038, egg 3.49 ± 0.039). On the other hand, the JB group consumed snacks (5.48 ± 0.042 p < 0.001) and sweetened juice (2.50 ± 0.050 p < 0.001) less frequently than the WB group (snacks; 5.80 ± 0.037 and sweetened juice; 2.74 ± 0.049). Discussion: JB-eating children with a morning chronotype exhibited better sleep and eating habits than WB-eating children with an evening type pattern. The results suggest that JB eating habits may be associated with good eating and sleeping lifestyles, even among preschool and elementary school children.

Novel breath-hold liver target stereotactic ablative radiotherapy using the intrafraction diaphragm registration of kilovoltage projection streaming image with digitally reconstructed radiography of the planning computed tomography.

Stereotactic ablative radiotherapy (SABR) is an emerging treatment option for patients with primary or metastatic liver tumors, particularly for those who are not eligible for surgery or transplantation. SABR is a high-precision radiation therapy that delivers a high dose of radiation to the tumor while minimizing the dose to the surrounding healthy tissues. However, the accurate targeting of the tumor is a crucial aspect of liver SABR, which requires real-time imaging and tracking of the liver and tumor motion during treatment. One of the motion management strategies for liver SABR is the repeated breath-hold technique, which involves the patient holding their breath multiple times during treatment delivery to reduce the movement of the liver and other organs due to breathing. This technique helps to improve the accuracy of the treatment and reduce the radiation dose to the healthy liver. The current study proposes a novel approach for multiple breath-hold volumetric modulated arc therapy (VMAT) stereotactic ablative radiotherapy for liver tumors, which uses the intrafraction diaphragm registration in real time to improve the accuracy and precision of the treatment. The proposed approach is based on real-time comparison of the diaphragmatic surface location between the digitally reconstructed radiography (DRR) and intrafraction kilovoltage projection streaming images (kV-PSI) having the same beam angles. The image cross-correlation between the DRR and the intrafraction kV-PSI provides a measure of the similarity between the two images and can be used to identify and track the diaphragm position during VMAT delivery. The proposed methodology consists of several steps, including planning CT and treatment planning, reference image reconstruction, and patient positioning and immobilization. The proposed approach has the potential to improve the accuracy and precision of liver cancer VMAT SABR, thereby increasing the efficacy of the treatment and reducing the risk of radiation exposure to surrounding healthy tissues.

Intractable Pleural Effusion After Stereotactic Ablative Radiotherapy for Early-Stage Lung Cancer.

Stereotactic ablative radiotherapy (SABR) is an effective and attractive treatment option for patients who are poor surgical candidates. This case report describes a rare but serious complication of intractable pleural effusion after SABR for early-stage lung cancer. The patient was an 89-year-old woman with a medical history of early-stage breast cancer who was treated with partial resection and postoperative radiotherapy of 50 gray (Gy) in 25 fractions. SABR using 55 Gy in four fractions was conducted for lung lesions. The patient developed a pleural effusion that was refractory to conservative management and required multiple interventions, including repeated thoracentesis. This case report emphasizes the importance of monitoring and managing pleural effusion in patients with lung cancer receiving radiotherapy.

An Invisible Skin Marker for External Beam Radiation Therapy: Utilization of Ultraviolet Fluorescent Marker Pens.

Radiation therapy plays an important role in cancer treatment along with surgery and systemic therapy. The total dose of radiation therapy is divided into small doses, and the treatment is typically delivered once a day. The total treatment period can need several weeks or more, and it is necessary to deliver the radiation dose to the target volume within the patient precisely each time. Therefore, the reproducibility of patient positioning is essential for the precision of the dose delivery. Although radiological technologies such as image-guided radiation therapy have also recently been widely used for positioning patients, skin marking is still widely used in many facilities. Skin marking is an inexpensive and universal positioning technique in patients undergoing radiation therapy; however, it is considered a major source of psychological stress. We propose the use of fluorescent ink pens, which are invisible in standard room lighting, as skin markers for radiotherapy. The primary technique of fluorescence emission is widely employed in molecular biological experiments and for assessing cleaning protocols for infection control. This technique may reduce the stress induced by skin markings during radiotherapy.

Establishment of a Prediction Model for Overall Survival after Stereotactic Body Radiation Therapy for Primary Non-Small Cell Lung Cancer Using Radiomics Analysis.

Stereotactic body radiation therapy (SBRT) for early-stage non-small cell lung cancer (NSCLC) leads to recurrence in approximately 18% of patients. We aimed to extract the radiomic features, with which we predicted clinical outcomes and to establish predictive models. Patients with primary non-metastatic NSCLC who were treated with SBRT between 2002 and 2022 were retrospectively reviewed. The 358 primary tumors were randomly divided into a training cohort of 250 tumors and a validation cohort of 108 tumors. Clinical features and 744 radiomic features derived from primary tumor delineation on pre-treatment computed tomography were examined as prognostic factors of survival outcomes by univariate and multivariate analyses in the training cohort. Predictive models of survival outcomes were established from the results of the multivariate analysis in the training cohort. The selected radiomic features and prediction models were tested in a validation cohort. We found that one radiomic feature showed a significant difference in overall survival (OS) in the validation cohort (p = 0.044) and one predicting model could estimate OS time (mean: 37.8 months) similar to the real OS time (33.7 months). In this study, we identified one radiomic factor and one prediction model that can be widely used.

Quality of life after definitive linear accelerator-based stereotactic radiotherapy for prostate cancer: a longitudinal study.

BACKGROUND: Prostate cancer is the second most common malignancy worldwide, and the majority of patients are diagnosed with localized disease. We examined patients' quality of life after stereotactic body radiation therapy (SBRT) for prostate cancer. METHODS: We included patients who were treated between 2016 and 2020. Inclusion criteria were adenocarcinoma of the prostate; class risk of low, intermediate, and high; and a World Health Organization performance status of 0-2. Quality of life was measured using the Functional Assessment of Cancer Therapy-Prostate (FACT-P). RESULTS: A total of 439 patients were treated with SBRT, with a median age of 73 years old. The median follow-up period was 34 months. FACT-P Trial Outcome Index (p < 0.0001), FACT-General (p = 0.0003), and FACT-P-Total (p < 0.0001) scores declined at 1 month post-SBRT, then recovered and returned to the same level as before treatment at 3-4 months post-SBRT. The decrease in quality of life in the first month was particularly remarkable in patients who received long-term hormone injections (36%). One month after the end of SBRT, about 22% of patients experienced "quite a bit" or more troubling side effects. CONCLUSIONS: This study showed longitudinal changes in quality of life by FACT-P after SBRT for prostate cancer. Overall, prostate SBRT was well tolerated.

High Dose Radiosurgery Targeting the Primary Tumor Sites Contributes to Survival in Patients With Skull Base Chordoma.

PURPOSE: Skull base chordoma (SBC) is a rare, aggressive bone tumor and a challenging therapeutic target. The efficacy of stereotactic radiosurgery (SRS) for SBC remains unclear. We aimed to elucidate therapeutic factors for favorable outcomes and establish a novel therapeutic approach for SBC. METHODS AND MATERIALS: This single-center retrospective study examined 47 SBCs treated with SRS. Treatment factors affecting local control rates (LCRs), remote control rates (RCRs), and overall survival (OS) were evaluated. Initially, we applied "localized-field SRS," wherein the irradiated volume accurately included recurrent/residual tumors on the radiographic images. Since 2015, we systematically applied "extended-field SRS," wherein the irradiated volume included the tumor location on the radiographic images and the preoperative tumor location with 2-mm margins. RESULTS: Tumor progression was observed in 23 SBCs (49%) after SRS. Higher marginal doses ≥20 Gy resulted in a higher LCR than lower-dose treatments (92% at 2 years and 73% at 5 years vs 43% at 2 years and 21% at 3 years, P = .001). Twenty-four patients underwent extended-field SRS, and 23 underwent localized-field SRS. While the LCRs were not significantly different, extended-field SRS improved RCRs (extended-field SRS: 100% vs localized-field SRS: 46% at 5 years; P = .001) without radiation-induced adverse events. Multivariate analysis demonstrated that extended-field SRS was associated with better RCRs (P = .001) and OS (P = .001). CONCLUSIONS: Extended-field SRS achieved LCRs comparable to previous studies and excellent OS without increasing the risk of radiation-induced adverse events.