ESTRO 2023 - Abstract Book

S2031

Digital Posters

ESTRO 2023

Initial data review suggests there is limited independent displacement between LN relative to bony anatomy. This implies that bony anatomy could be used as a match surrogate for N1 prostate patients receiving nodal irradiation. As a result of this, the current IGRT protocol for these patients is under review, with a view to remove daily EFOV-CBCT. An EFOV-CBCT would instead be done on a weekly basis, with a CBCT at prostate/PLN level followed by a kV/kV pair at the level of superior nodal disease being done daily. The aim of this evaluation was to ensure that N1 prostate patients are receiving safe IGRT with concomitant doses that are ALARP. The new proposed protocol would decrease the imaging dose as well as treatment time. Data analysis will continue for the remaining 17 patients and if findings align, a new IGRT protocol will be implemented. K. Layer 1 , J.P. Layer 2 , A. Glasmacher 2 , G. Sarria 2 , A. Böhner 2 , Y. Layer 2 , P. Feyer 3 , B. Baumert 4 , A. Schendera 5 , R. Baumann 6 , D. Krug 7 , F. Giordano 8 , L.C. Schmeel 2 1 University Hospital Bonn, Department of Radiation Oncology , Bonn, Germany; 2 University Hospital Bonn, Department of Radiation Oncology, Bonn, Germany; 3 Vivantes Hospital Neukölln, Department of Radiation Oncology, Berlin, Germany; 4 Cantonal Hospital Graubünden, Institute of Radiation Oncology, Chur, Switzerland; 5 Community Hospital Mittelrhein, Department of Radiation Oncology, Koblenz, Germany; 6 St. Marien Hospital Siegen, Department of Radiation Oncology, Siegen, Germany; 7 University Medical Center Schleswig-Holstein, Department of Radiation Oncology, Kiel, Germany; 8 University Hospital Mannheim, Department of Radiation Oncology, Mannheim, Germany Purpose or Objective Radiation dermatitis (RD) represents the most frequent side effect in radiation therapy (RT). It considerably affects quality of life and may lead to treatment interruptions. Early recognition and prevention is crucial, but both risk assessment and preventive measures are not standardized in clinical routine. We sought to characterize surveillance and non- pharmaceutical preventive management of radiation dermatitis in German-speaking hospitals and private centers. Materials and Methods We conducted a survey on RD among German-speaking radiation oncologists inquiring for their evaluation of risk factors, assessment methods as well as non-pharmaceutical preventive management of radiation dermatitis. Results 244 health professionals from academic, non-academic and private centers in Germany, Austria and Switzerland participated. RT-dependent factors were deemed most relevant for RD onset, followed by lifestyle-depending factors, emphasizing the impact of treatment conceptualization and patient education. While a broad majority assesses RD at least once during RT, 59% of participants report RD at least partially subjectively and 17.4% stated to classify RD severity solely subjectively. 83.7% of all participants were unaware of any availability of patient-reported outcomes (PROs). While consensus exists on some non-pharmaceutical recommendations like avoidance of sun exposure and hot baths under RT, others like deodorant usage remain controversial.RD remains a relevant and challenging aspect of clinical routine. Its surveillance is widely lacking methodology and objectivity. Assessment and non-pharmaceutical prevention of RD fall short in evidence- or consensus-based practices. Intensifying outreach in the radiation oncology community is needed to improve practice patterns. Conclusion RD remains a relevant and challenging aspect of clinical routine. Its surveillance is widely lacking methodology and objectivity. Assessment and non-pharmaceutical prevention of RD fall short in evidence- or consensus-based practices. Intensifying outreach in the radiation oncology community is needed to improve practice patterns. 1 Kaohsiung Chang Gung Memorial Hospital, Proton Therapy Center Department , Kaohsiung, Taiwan; 2 Kaohsiung Chang Gung Memorial Hospital, Proton Therapy Center, Department, Kaohsiung, Taiwan; 3 Kaohsiung Chang Gung Memorial Hospital , Proton Therapy Center, Department, Kaohsiung, Taiwan Purpose or Objective The type of fixation mask and head supports used in SRS has a considerable impact on treatment accuracy. The CyberKnife robotic radiosurgery system is characterized by real-time image-guided positioning technology with a flexible robotic arm that can correct for the intrafractional motion of the patient.The aim of this study was to analyze the differences in patients’ cranial angle and treatment accuracy in CyberKnife robotic radiosurgery. Materials and Methods In this study, we retrospective collected 5240 records from 48 patients with brain tumors treated with CyberKnife robotic radiosurgery at our institution (No. 202200891B0). The median cranial angle was 10° with a range of 3-18°. There were 38 patients with a cranial angle ≤ 10° (Group A), and 28 patients with cranial angle >10° (Group B). The skull motions in X (superior-inferior), Y (right-left), Z (anterior-posterior) axes, 3D (three-dimensional) vector, roll, pitch, and yaw between the two groups were compared. The Friedman ANOVA test was used to analyze the change in error over each 10-minute period. Linear regression analysis was performed to assess differences between the two groups. All analyses were performed using IBM SPSS Statistics 22.0 software (IBM Corp., Armonk, NY, USA). PO-2258 Risk assessment, surveillance and non-pharmaceutical prevention of acute radiation dermatitis PO-2259 Analysis of Patient Cranial Angle and Intrafractional Stability in CyberKnife Robotic Radiosurgery Y. Huang 1 , C. Kang 2 , S. Tsai 2 , Y. Chen 3

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