Abstract book - ESTRO meets Asia

S46 ESTRO meets Asia 2018

4 University Hospital S-H- Campus Lübeck, Interdisciplinary Brachytherapy Unit- University of Lübec k, Lübeck, Germany Purpose or Objective Brachytherapy (BT) is a consolidate method to create dose-escalation and steep dose gradients between target and organs at risks (OAR). HDR boost complementary to external beam treatment provides good results in local control and survival rates as confirmed in several case series and randomized trial. The aim of this multicentric study was the evaluation of acute and late genitourinary (GU) and gastrointestinal (GI) toxicity in patients with prostate cancer treated with high dose rate-BT (HDR-BT) plus intensity modulated radiation therapy (IMRT), comparing to patients treated with Helical Tomotherapy Patients consecutive treated in three European Radiation Oncology Departments (Rome, Lübeck and Perugia) were evaluated retrospectively in matched-pair analysis. High- risk or intermediate-risk features and no metastatic disease were common selection criteria. All patients assumed androgen deprivation therapy. Patients treated in Rome underwent exclusive IMRT or IMRT complementary to BT. IMRT alone was performed in 40 daily fractions for a total dose of 80 Gy delivered to whole prostate and 72 Gy delivered to seminal vesicles (EQD2 80 Gy). HDR-BT + IMRT was performed with one 15 Gy single fraction of HDR-BT on high-risk zone followed by IMRT (46 Gy/23 daily fractions) after two weeks (EQD2 100 Gy). Two fractions HDR-BT (fraction dose 15 Gy) plus IMRT (50 Gy) resulting in a total nominal dose of 80 Gy (EQD2 158 Gy in six weeks total treatment time) was performed in Lübeck. In Perugia HT was performed with a total dose delivered to whole prostate of 74.25 Gy in 33 daily fractions or 67.50 Gy in 25 daily fractions (EQD2 78 Gy) and 62 Gy or 56.25 Gy to seminal vesicles. The Common Toxicity Criteria for Adverse Event (Version 4.03) were used to collect acute and late toxicity. Results Data of 51 selected and matched patients, treated from January 2013 to June 2017 were analyzed retrospectively. Seventeen patients were treated by HT in Perugia; 17 patients underwent IMRT alone in Rome and 17 patients underwent IMRT plus BT of whom 9 patients in Lubeck and 8 patients Rome. Mean FUP time was 22 months, none of the 51 patients showed local recurrence (LR) at last FUP. G1 GU late toxicity was shown in two patients treated with two fractions HDR-BT plus IMRT and in one patient treated with IMRT alone; no late G2-3-4 toxicity was reported. One patient treated with HT showed G3 GU acute toxicity; G1- 2 toxicity was shown in 7 patients treated with BT plus IMRT, 10 patients treated with IMRT and 13 patients treated with HT. In one patient treated with IMRT alone G1 GI late toxicity. 4 patients treated with BT plus IMRT showed acute G1-2 GI toxicity versus 7 patients treated with HT and 8 patients treated with IMRT (see tab.1). (HT) or exclusive IMRT. Material and Methods

Results Between March 2014 and March 2018, 121 patients (76% intermediate, 24% high-risk) with a median age of 70 years (53–85) have been treated across 5 centres. Short course (≤6 m) ADT was used in 36%, long course in 18%. Rectal displacement method was SpaceOAR in 56% and Rectafix in 44%. 42 and 79 patients were treated at the 19 Gy and 20 Gy dose levels respectively. Median follow-up was 18 months, maximal follow-up 42 months. Acute G2 GI and GU toxicity occurred in 3% and 24% with no cases of acute G3 toxicity. Late ≥G2 GI toxicity was 3%, 1% and 0% at 12, 24 and 36 months respectively. Only one G3 GI toxicity occurred (18 months post-RT). Late ≥G2 GU toxicity at 6,12,18, 24 and 36 months was 1%, 9%, 14%, 7% and 7% respectively with only two G3 events (18 months post RT). For patients not receiving ADT the median PSA value pre- treatment was 7.6 ug/L (1.1 – 20) and at 12, 24 and 36 months post-treatment was 0.87, 0.37 and 0.15 ug/L respectively. Conclusion Delivery of linac-based SBRT boost is feasible and well tolerated with low rates of early toxicity and promising PSA responses. A second transient peak in GU toxicity was observed at 18 months, similar to that observed in men treated with brachytherapy boost. Longer term follow-up is required to document late toxicity and tumour control with this approach. OC-119 BIT-ART: Brachytherapy, IMRT, Tomotherapy for prostate cancer Advanced Radiation Therapy. L. Tagliaferri 1 , A. D'Aviero 2 , A.R. Alitto 1 , V. Frascino 1 , F. Catucci 1 , V. Lancellotta 3 , C. Staackmann 4 , C. Aristei 3 , V. Valentini 2 , G. Mantini 2 , G. Kovács 4 1 Fondazione Policlinico Universitario A. Gemelli IRCCS, UOC Radioterapia, Rome, Italy 2 Fondazione Policlinico Universitario A. Gemelli IRCCS- U

niversità Cattolica del Sacro Cuore, Istituto di Radiologia, Rome, Italy

Conclusion LR and tolerance in HDR-BT boost plus IMRT appeared to be comparable to exclusive IMRT and HT. Less GU and GI acute toxicity was showed in patients undergoing HDR-BT

3 University of Perugia and Perugia General Hospital, Radiation Oncology Section- Department of Surgery and Biomedical Sciences, Perugia, Italy