ESTRO 2021 Abstract Book

S1106

ESTRO 2021

data. Prospective randomised trials comparing BT and SBRT are needed.

PO-1347 Prostate cancer RT pattern of practice in Italy between 2004-2011: an analysis by the AIRO database A. Bruni 1 , E. Mazzeo 1 , L. Triggiani 2 , L. Frassinelli 3 , A. Guarneri 4 , S. Bartoncini 5 , P. Antognoni 6 , S. Gottardo 7 , D. Greco 2 , S. Borghesi 8 , S. Nanni 8 , G. Ingrosso 9 , R.M. D'Angelillo 10 , B. Detti 11 , G. Francolini 11 , A. Magli 12 , A. Guerini 2 , S. Arcangeli 13 , L. Spiazzi 14 , U. Ricardi 15 , F. Lohr 1 , S.M. Magrini 2 1 University Hospital of Modena, Radiation Therapy Unit - Department of Oncology and Hematology, Modena, Italy; 2 University and "Spedali Civili" Hospital, Radiation Oncology Department, Brescia, Italy; 3 University Hospital of Modena, Radiation Therapy Unit - Department of Oncology and Hematology , Modena, Italy; 4 University Hospital "Città della salute e della scienza", Radiation Oncology - Department of Oncology, Turin, Italy; 5 University Hospital "Città della Scienza e della Salute", Radiation Oncology - Department of Oncology, Turin, Italy; 6 "ASST- Sette Laghi-Ospedale di Circolo and Fondazione Macchi", Radiotherapy Department, Varese, Italy; 7 Clinical Institute "S.Ambrogio", Service of Radiotherapy, Milan, Italy; 8 AUSL South Eastern Tuscany, Radiation Oncology Unit of Arezzo-Valdarno, Arezzo, Italy; 9 University of Perugia, Radiation Oncology Section - Department of Medicine and Surgery, Perugia, Italy; 10 "Tor Vergata" University of Rome, Department of Biomedicine and Prevention, Rome, Italy; 11 University Hospital "Careggi", Radiation Oncology Unit, Florence, Italy; 12 Udine General Hospital, Department of Radiation Oncology , Udine, Italy; 13 "S. Gerardo" Hospital - University of Milan "Bicocca", Department of Radiation Oncology, Milan, Italy; 14 "Spedali Civili" Hospital, Department of Medical Physics, Brescia, Italy; 15 University of Turin, Radiation Oncology - Department of Oncology, Turin, Italy Purpose or Objective Two previous “Patterns Of Practice” surveys (POP I and POP II) including more than 4000 patients affected by prostate cancer treated with radical external beam radiotherapy (EBRT) between 1980 and 2003 established a “benchmark” Italian data source for prostate cancer radiotherapy. This report (POP III) updates the previous studies Materials and Methods Data on clinical management and outcome of 2525 prostate cancer patients treated by EBRT from 2004 to 2011 were collected on behalf of the Uro-Oncology Study Group and then compared with POP II and, when feasible, also with POP I. This report provides data on clinical presentation, diagnostic workup, radiation therapy management and toxicity as collected within the framework of POP III. Results More than 50% of POP III patients were classified as low or intermediate risk using D’Amico risk categories as in POP II; 46% were classified as ISUP grade group 1. CT scan, bone scan and endorectal ultrasound were less frequently prescribed. Dose-escalated radiotherapy (RT), intensity modulated (IMRT) and image guided radiotherapy (IGRT), hypofractionated RT were more frequently offered during the study period. Delivered doses to prostate in patients submitted to conventionally fractionated treatments increased when compared to the previous series as 45% patients received more than 76 Gy in POPIII vs. 9% in POPII and <1% in POPI with a mean dose to the prostate (74.1 Gy) significantly higher (p<0.0001) than in POP II (71.6 Gy), and POP I (69 Gy). Less than 1% of patients treated with conventional fractionation received doses <70 Gy. Treatment was generally well tolerated since most patients experienced no or mild gastrointestinal (GI) or genitourinary (GU) clinically insignificant toxicity: grade 2 and 3 acute GU toxicity was reported in 343 patients (13%) and 30 patients (1.2 %) respectively, while Grade 4 GU acute toxicity was reported in only 3 patients. No Grade 4 acute GI toxicity was reported; G2 acute GI toxicity was observed in 260 patients (10%), while only 22 patients (<1%) experienced G3 toxicity. Late G2 and G3 GI toxicity was observed in 194 (7.7%) and 29 patients (1.1%), respectively; only 1 patient had G4 toxicity. Late G2, G3 and G4 GU toxicity was registered respectively in 164 (7.7%), 13 (0.5%) and 6 (0.2 %) patients. Five year overall survival, disease-specific survival and biochemical relapse free survival were 88%, 97% and 86% respectively. Intermediate (IR) and high risk (HR) patients (D’Amico classification) treated with a total dose (EqD2) ≥ 76Gy enjoyed an increased 5-year BRFS (95% vs 86% for IR patients – 84% vs 76% for HR patients, log-rank, p<0,0001). Conclusion This report highlights the improvements in radiotherapy planning and dose delivery among Italian Centers in the 2004-2011 period. Consequently, dose-escalated treatments resulted in better biochemical control with a reduction in acute toxicity and acceptable late toxicity, in line with the data obtained from randomized controlled studies. PO-1348 Urethral sparing increases the therapeutic ratio in dose escalated hypofractionated radiotherapy S. Spohn 1 , I. Sachpazidis 2 , R. Wiehle 2 , B. Thomann 2 , A. Sigle 3 , P. Bronsert 4 , J. Ruf 5 , M. Benndorf 6 , N. Nicolay 1 , T. Sprave 1 , A. Grosu 1 , D. Baltas 2 , C. Zamboglou 1 1 University Medical Centre, Department of Radiation Oncology, Freiburg, Germany; 2 University Medical Centre, Division of Medical Physics, Department of Radiation Oncology, Freiburg, Germany; 3 University Medical Centre, Department of Urology, Freiburg, Germany; 4 University Medical Centre, Institute for Surgical Pathology, Freiburg, Germany; 5 University Medical Centre, Department of Nuclear Medicine, Freiburg, Germany; 6 University Medical Centre, Department of Radiology, Freiburg, Germany Purpose or Objective Advanced imaging methods such as multiparametric magnetic resonance tomography (mpMRI) and prostate specific membrane antigen positron emission tomography (PSMA-PET/CT) are used for focal radiotherapy (RT) dose escalation guidance. These concepts intend to improve treatment effectiveness. Since maintenance of a good quality of life is essential, this planning study investigates whether urethral sparing in moderately