ESTRO 2021 Abstract Book

S1093

ESTRO 2021

Medical Physics and Radiologic Protection , L’Hospitalet, Barcelona, Spain; 4 Catalan Institute of Oncology, Radiation Oncology Department, L’Hospitalet. Barcelona, Spain; 5 Catalan Institute of Oncology, Radiation Oncology, L’Hospitalet. Barcelona, Spain; 6 Catalan Institute of Oncology, Radiation Oncology, L’Hospitalet. Barcelona, Spain; 7 Catalan Institute of Oncology, Radiation Oncology Department, L’Hospitalet. Barcelona, Spain; 8 Catalan Institute of Oncology, Radiation Oncology Department, L’Hospitalet, Barcelona, Spain; 9 Catalan Institute of Oncology, Radiation Oncology, L’Hospitalet, Barcelona, Spain; 10 Catalan Institute of Oncology , Radiation Oncology, L’Hospitalet. Barcelona, Spain; 11 Bellvitge Hospital, Urology, L’Hospitalet, Barcelona, Spain; 12 Intstitute for diagnostic with images (IDI), MRI, L’Hospitalet ,Barcelona, Spain; 13 Bellvitge Hospital, Urology, L'Hospitalet. Barcelona, Spain; 14 Catalan Institute of Oncology, Medical Physics and Radiologic Protection, L’Hospitalet, Barcelona, Spain; 15 2 Institut Municipal d'Investigacions Mèdiques, Health Services Research Unit, Barcelona, Spain Purpose or Objective To evaluate the feasibility and toxicity of a regimen of a single dose hypofractionated prostate stereotactic boost. To obtain selfreported quality of life (QOL) measures in order to better define the possible deleterious effect of treatment. Materials and Methods Patients included were diagnosed of prostate cancer with T3aN0M0 Gleason score 8 or less (N+risk<25%) and IPSS 0-12. Hormonal-therapy was prescribed according to risk classification. Image Guided RT with Cone Beam CT was mandatory. Dose SBRT was delivered at a prescribed planning target volume (PTV) 9 Gy after 60 Gy 2 Gy per fraction in 30 days, using with RapidArc VMAT, with 6 MV FFF photons. Equivalence of dose at 2 Gy per fraction, using Linear Quadratic Model is round 87Gy. RTOG-EORTC and CTCAE v4.0 morbidity scores were used to assess toxicities. Health-related quality of life questionnaire was administered centrally by telephone interview before treatment and during follow-up (at 3, 6 12 months and every 12 months). Study was planned following a Simon’s 2-stage design. Patient’s recruitment continued because non toxicity limiting criteria was reached. Included patients in this report signed trial informed consent before 30-september-2019.> Results Forty two patients included in the study were analyzed. Mean age was 70.48 years old. Median follow-up was 37 months (4-83) with more than 90% having at least 12 months of followup. According to D’Amico risk classification for trial and inclusion criteria all of them were high risk. All patients completed the treatment as programmed with good tolerance. No toxicity greater than grade 2 was observed. EPIC urinary values decreased from 87.56 before treatment, to 80.37 at 36 months. EPIC hormonal was 77 before radiation and decreased to 61.11 at 12 months. EPIC bowel values for these points in time were 98.04 and 88.69. Non PSA relapse was seeing during this short follow-up. Acute GI and GU grade 2 toxicities were respectively 2.4 and 9.5 % at the 1st month after SBRT 9 Gy delivery. At the 3rd month GI and GU Grade 2 were both 4.8%. At 6 months GI grade 2 toxicity was 2.4 % and GU reached 7.1%. At the last follow-up late GU Grade 2 toxicity was 9.1%, whereas GI persisted in 2.4%. Conclusion SBRT regime of 9 Gy to the prostate after normofracionated 60 Gy for high risk prostate cancer is feasible and well tolerated in selected patients. Decline in QoL values are seen EPIC hormonal QLQ measures are related to prolonged hormonal treatment in high-risk patients. Long-term follow-up is needed for assessment of late toxicity and outcomes. T. Hölscher 1 , M. Baumann 2 , J. Kotzerke 3 , M. Wirth 4 , C. Thomas 4 , D. Zips 5 , S. Löck 6 , M. Krause 7,9,10 , F. Lohaus 8 1 Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany; 2 _, German Cancer Research Center (DKFZ), Heidelberg, Germany; 3 Department of Nuclearmedicine, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden , Dresden, Germany; 4 Department of Urology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden , Dresden, Germany; 5 Department of Radiation Oncology, Universität Tübingen, Tübingen, Germany; 6 OncoRay – National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Dresden, Germany; 7 Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden , Dresden, Germany; 8 Department of Radiotherapy and Radiation Oncology,, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany; 9 National Center for Tumor Diseases (NCT), Partner Site Dresden, Germany: German Cancer Research Center (DKFZ), Heidelberg, Germany, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany, and; Helmholtz Association / Helmholtz-Zentrum Dresden – Rossendorf (HZDR), Dresden, Germany; 10 German Cancer Consortium (DKTK), Partner Site Dresden, German Cancer Research Center (DKFZ), Heidelberg, Germany Purpose or Objective PSA-progression after curative primary therapy is common in patients with prostate cancer. Modern imaging methods, like PSMA-PET hybrid imaging, may detect patients with oligometastastic disease at low PSA-levels. Metastases-directed local ablative radiotherapy (aRT) is a safe option in this situation. Local control and the pattern of progression is evaluated for this prospective clinical phase II trial. Materials and Methods At two German centers, patients with PSA progression after local curative treatment had PSMA-PET-CT imaging. Patients with up to four PSMA-PET positive metastases (MET) were included in the clinical trial. Patients had no ongoing androgen deprivation therapy (ADT), a PSA <10 ng/ml and no severe comorbidity. The patients were treated with 3 x 10 Gy (SABR) or 25 x 2.0 Gy to all PSMA-PET positive MET (involved lesions). The primary endpoint was toxicity within two years after aRT. Here we report secondary endpoints including PO-1332 OLI-P trial: pattern of progression after radiotherapy in PSMA-PET positive METs of prostate cancer