ESTRO 2023 - Abstract Book

S1293

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ESTRO 2023

tumor settings. However, the optimal dose and fractionation of SFRT are yet to be explored. Therefore, a prospective, multicenter, dose-escalation trial was initiated. We are proposing a new treatment methodology, (called Stereotactic Centralized Ablative Radiation Therapy, (SCART), for bulky or metastatic tumors, which is based on the principles of SFRT, by using SBRT methods to deliver an ablative radiation dose to the central portion of the target while keeping the dose to surrounding normal tissue to a relatively low level. We performed a prospective dose escalation study of SCART for bulky metastatic or recurrent cancer. The purpose of the study was to determine dose-limiting toxicities (DLTs) and the Maximum Tolerated Dose (MTD) of SCART. Materials and Methods Methods and Materials: This study was registered at ClinicalTrials.gov Identifier: NCT0488198, and approved at Foshan Chancheng Hospital. Patients with unresectable solid "bulky" nonhematological malignancies with limited treatment options were enrolled and received SCART with a prescription to the central spot in the tumor with a peripheral dose to the tumor edge at around 20% isodose line of the prescription dose. Five dose levels were proposed. The primary endpoint was the maximum tolerated dose (MTD), defined as the highest dose where zero of three or one of six patients experienced grade 3 dose-limiting toxicity (DLT), scored according to the Common Toxicity Criteria for Adverse Events v. 4.03, up to 6 months after SCART. Results Results: A total of 21 patients received SCART and have eligible data for study follow-up. Radiotherapy was well tolerated with all treatment completed as scheduled. The dose was escalated for two patients to 24GyX3. No grade 3 toxicity was observed in any of the enrolled patients. The median SCART dose was 18Gy (range: 15 - 24). Six out of the 18 patients with data for overall survival (OS) died, and the median time to death was 16.29 months (range: 0.99 - 25.58). Three patients out of the 15 patients with available data for local recurrence (LR) were found to have an LR and the median time to LR was 16.01 months (range: 0.99 - 25.58). There appears to be a trend of tumors decreasing from the patient's first visit date, or pre-SCART, to their final volume post-SCART. The mean percent change for tumor shrinkage between first visit volumes and post-SCART volumes was 49.49% (SD: 40.89, p-value:0.009). Conclusion Conclusion: SCART dose was safely dose escalated to 24 X 3 fractions, which is the maximum Tolerated Dose (MTD) for SCART. This regimen will be used in future phase II trials. 1 Varian, a Siemens Healthineers Company, Global Evidence and Value, Palo Alto, USA; 2 Nordic Healthcare Group, NHG Finland, Advisory Business Unit, Helsincki, Finland; 3 Nordic Healthcare Group, NHG Finland, Advisory Business Unit, Helsinki, Finland; 4 Tampere University Hospital and University of Tampere, Department of Oncology, Tays Cancer Center, and Faculty of Medicine and Health Technology, Tampere, Finland Purpose or Objective Prospective randomized trials have demonstrated that ePRO usage can improve outcomes for those receiving systemic therapy, but few data exist regarding its utilization in patients receiving radiation therapy (RT) as part of their care. The aim of this study is to better understand the experiences of these patients Materials and Methods Participants (n=1309) were Tampere University Hospital cancer patients that received radiotherapy (RT) or RT + systemic treatment between 2015 and 2021 and also used the app to respond to symptom module questionnaires. All symptom modules ask patients to report their overall distress via an 11-point scale (0=none,10=Worst Possible) and functioning using an ECOG-based item. Additionally, patients can report treatment-related symptoms using a Common Terminology Criteria for Adverse Events (v5) response framework. The CCT administers the questionnaire on a regular cadence throughout active treatment. When a patient reports moderate or severe symptoms a real-time electronic alert is generated which prompts the CCT to offer clinical recommendations via the app. Patients’ electronic health record data along with ePRO usage were matched and analyzed descriptively Results Participants were predominantly female (n=1026,78.4%) and middle-aged (M=63.0,SD=11.3). The majority of patients had a primary diagnosis of either breast (72.6%) or prostate cancer (15.3%). Most received standard-of-care RT + some form of systemic therapy (n=1047;80%;Table 1) and were in active treatment longer. The mean number of questionnaires administered was 10.0 (SD=12.9) and the overall response rate of 87.9%. Table 2 indicates that RT patients generally reported low distress and adequate performance status (patient-reported ECOG performance status grade of 0 or 1; Table 2), but it should be noted that 27.1% of patients reported moderate-to-severe distress at least one time. The three RT treatment symptoms that patients reported the highest levels of moderate-to-severe symptomatology, at least one time, were “other” (64.6%), pain (60.3%), and fatigue (28.0%). Patients receiving RT + systemic therapy reported, comparatively, higher levels of distress, worse physical performance, and higher reports of moderate and severe pain (76.7%), “other” (62.6%), and fatigue (39.0%). PO-1593 Real-world electronic patient reported outcome utilization in patients receiving radiation therapy I. Kudel 1 , H. Curry 1 , P. Pennanen 2 , M. Lahelma 3 , J. Vuorio 2 , R. Leskelä 2 , Z. Shamsi 1 , M. Bärlund 4