ESTRO 2020 Abstract book

S657 ESTRO 2020

Ninety-six consecutive patients were analyzed fulfilling the following inclusion criteria: histopathological confirmed adenocarcinoma of the prostate, MRI-staging of localized (T1-2) or locally advanced (T3a-b) prostate cancer (N0 M0), radiotherapy of prostate according to ESTRO guideline without pelvis. Prostate cancer risk features (low LR, intermediate IR and high HR) were stratified in accordance with D'Amico Classification. Clinical endpoints were calculated from start of radiotherapy. Results Ninety-six patients (mean age: 73 years) were treated from September 2010 to November 2017. Two low risk, 27 intermediate risk and 67 high-risk prostate cancer patients according to D’Amico risk classification were included. CovP was given in step-and-shoot - or VMAT-IMRT with 6/15 MV in 39 fractions to 78 Gy. Mean CTV-volume reached 68.5 ccm (range: 36.0-143.0 ccm). Mean initial PSA (Prostate-specific antigen)-level reached 8.9 ng/mL (range: 1.15-36.0 ng/mL). Concomitant androgen deprivation therapy (ADT) was recommended and given in 89% patients for a median time of 11 months (HR: 13 months, range: 0-40, IR: 5.4 months, range 0-24, LR: 0 months). At the time of last follow-up ADT was finished in 69% patients. After a median follow-up of 26 months (range: 3-73 months) estimated PSA-control (n=96) reached 100% (Phoenix). In one high-risk patient a local recurrence was detected by PET/CT and MRI 54 months after treatment in the ipsilateral lobe, rescue brachytherapy was performed. Prostate cancer-specific survival and the distant metastasis-free survival after 2 years reached both 100 %. Conclusion Coverage probability radiotherapy in mainly intermediate and high-risk prostate cancer patients demonstrated excellent short-term biochemical control. PO-1158 Mobile app of individualized Patient Decision Aid for prostate cancer based on predictive models. I. Halilaj 1 1 Maastricht University, Precision Mediicine, Maastricht, The Netherlands Purpose or Objective Patient Decision Aids (PDAs) supports the decision making process between multiple treatment options and increased patient involvement in Shared Decision-Making (SDM). PDAs have shown the increase of patients’ knowledge, involvement in decision-making and preventive behavior, and they lead to more appropriate use of tests and treatments. Our aim was to build a user-friendly progressive web app for a new generation of PDA called individualized PDA (iPDA) in prostate cancer. We implemented predictive models from predictcancer.org which provide individualized risks of recurrence, toxicity and death for different treatment options in the app. This app can provide the patients with specific actionable information such as treatment option side effects, advantages and disadvantages of each treatment option, and clarification of the patient’s preferences for each option. We hypothesize that this will aid the patient in making an informed treatment choice. Material and Methods The progressive web app was built in accordance with the International PDA (IPDA) Standards (ipdas.ohri.ca). In a single-center pilot study the iPDA was tested with male volunteers in the appropriate age group. All respondents filled in a System Usability Scale (SUS) questionnaire with 10 questions regarding the usability and user-friendliness of the app. SUS consists of a 10 item questionnaire with five response options for respondents; from Strongly agree to Strongly disagree. The maximum score on the SUS is 100.

Results The mean SUS score obtained from the volunteers was 84 (Figure 2). Given that the SUS final score is 84 and the maximum is 100 we can conclude that all the respondents were satisfied with the app. They found the app easy to use. All of them agreed that they felt confident using the app and they think most people will be able to use it without assistance.

Conclusion We have shown that it is possible to integrate prediction models into a PWA based patient decision aid for prostate cancer. The scores on the SUS indicate that this is a useful tool to provide tailored information to patients and facilitate the SDM process. Future studies will focus on implementation of this tool in the clinic. As individual health information is abundantly available, patient decision aids should integrate and use this information, moving away from guideline-based general advice, to a more patient-centered, tailored approach. We strongly believe that the future lies in the iPDA. PO-1159 Toxicity Profile in Postoperative Radiotherapy for Prostate Cancer with Moderate Hypofractionation P. Pacifico 1,2 , E.M. Bonetto 1 , R.M. Niespolo 1 , E. De Ponti 2,3 , S. Vukcaj 1 , S. Arcangeli 1,2 1 S.C. di Radioterapia Oncologica presso Azienda Ospedaliera San Gerardo - Monza, S.C Radioterapia Oncologica, Monza, Italy ; 2 Università degli Studi di Milano-Bicocca, Facoltà di Medicina e Chirurgia, Milano, Italy ; 3 Azienda Ospedaliera San Gerardo - Monza, S.C. Fisica Sanitaria, Monza, Italy

Purpose or Objective