ESTRO 38 Abstract book

S455 ESTRO 38

while sixty three patients (59%) received 68 Gy to the tumor bed as boost. With a median followup of 26 months, 3-year locoregional control (LRC), disease-free survival (DFS), and overall survival (OS) were 74.3%, 62.9%, and 67.7% respectively. 82% retained a disease-free bladder, while another 8.5% had non muscle invasive recurrences managed conservatively. Patients receiving dose escalation to 68 Gy showed no difference in OS and DFS compared to those receiving <68 Gy. Acute and late Radiation Therapy Oncology Group (RTOG) grade III/IV genitourinary (GU) toxicity was seen in 7.5% and 6.5% patients respectively. Acute and late RTOG grade III gastrointestional (GI) toxicity was seen in 0% and 3.8% patients respectively. The incidence of grade III/IV acute or late GU or GI toxicity was not found to be associated with dose escalation. Conclusion Dose escalation with adaptive plan-of-the-day approach for bladder irradiation is clinically safe and effective. A high bladder preservation rate can be achieved without compromising on survival or toxicities using plan of the day ART. PO-0864 Normal tissue sparing with diffusion weighted MRI informed tumour boost in bladder radiotherapy K. Chan 1 , K. Warren-Oseni 2 , H. Abdel-Aty 3 , A. Dunlop 2 , D. McQuaid 2 , M. Koh 3 , A. Sohaib 3 , R. Huddart 3 , S. Hafeez 3 1 The Royal Marsden NHS Foundation Trust, Radiotherapy and Imaging, London, United Kingdom ; 2 The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, Joint Department of Physics, London, United Kingdom ; 3 The Institute of Cancer Research - The Royal Marsden NHS Foundation Trust, Radiotherapy and Imaging, London, United Kingdom Purpose or Objective Partial bladder radiotherapy for the radical treatment of muscle invasive bladder cancer (MIBC) can be utilized with no adverse effect on local control [1, 2]. Studies however have failed to show improved toxicity. This may be due in part to uncertainty in CT based GTV delineation. DWI has an established diagnostic role in local MIBC staging with improved accuracy over CT. Here we evaluate the use of DWI to inform GTV delineation and its impact on ) using in-house software (Adept, Institute of Cancer Research, London), was imported into the TPS (Raystation 6.99, RaySearch Laboratories, Stockholm, Sweden) and registered to the radiotherapy planning CT scan (using anatomical information from T2 and b0 image). The GTV and CTV (whole bladder) was expanded anisotropically (1.5cm anteriorly and superiorly, 1.0cm posteriorly and 0.5cm laterally and inferiorly) to create PTV boost_CT, PTV boost_DW-MRI , and PTV bladder . Two VMAT plans were created (for five patients), each treating PTV Bladder to 52Gy and PTV boost to 70Gy in 32 fractions using the two different PTV boost volumes. Target volumes and dose to normal structures between were compared using Wilcoxon signed rank test where possible. Results All tumours seen on T2 image were identified on DWI. In 3 patients no tumour was seen on either T2 or DWI. Mean GTV CT was 34.1cm 3 (SD 21.1; range 6.7-78.7). Mean GTV DW-MRI was 15.6cm 3 (SD 23.4; range 0-104.4). GTV DW-MRI was significantly smaller than GTV CT (p=0.001). normal tissue sparing. Material and Methods Twenty-one patients with unifocal T2-T3N0M0 MIBC recruited to an ethics approved phase I dose escalation radiotherapy protocol (NCT01124682) were evaluated. For treatment the tumour boost volume (GTV) was delineated on the radiotherapy planning CT (GTV CT ). Pre-radiotherapy DWI was performed on a 1.5T system using b values 0, 50,100, 250, 500 and 750s/mm 2 . GTV was drawn on 750 s/mm 2 image (GTV DW- MRI

circumference [cm]) and Functional Fitness [2 minute step test and 30 second sit-to-stand test]). Patient were recruited at planning CT scan and randomised at fraction 6 of EBRT. Assessments were conducted at baseline (planning CT), mid EBRT, end of EBRT, and at 1 month post EBRT. Results From 02/2014 to 04/2014, 24 pts were recruited (12 per arm). All pts were evaluable. The overall MVPA-WEI adherence rate in the intervention group was 81.8%. 33% of pts in the control group increased their average daily step count. When compared to baseline, pts allocated to the intervention group experienced at 1 month post EBRT, greater and persistent improvements in 1) fatigue [mean Fatigue score difference: -20.17 vs. +5.75], 2) quality of life [Improved FACT-P score only noted in the intervention group], 3) anthropometric measurements [mean weight difference: -1.7 Kg vs. + 1.7 Kg, mean % body fat difference: – 1.1% vs. +1.1%, mean waist circumference difference: -0.9 cm vs. + 3.4 cm, mean % muscle mass difference: +0.5% vs. – 0.8%] and 4) physical performance [2min step performance difference: +55.8% vs. + 30%, Sit- to-stand test performance difference: +25.3% vs. 9.0%] Conclusion This preliminary evidence suggests that a pragmatic home- based MVPA-WEI is feasible and has potential clinical benefits in pts treated by EBRT+ADT, and thus provides a strong rational for a Phase 3 randomised trial. PO-0863 Adaptive radiotherapy for carcinoma of the urinary bladder: Long term outcomes with dose escalation P. Gupta 1 , V. Murthy 1 , K. Baruah 1 , R. Krishnatry 1 , G. Bakshi 1 , G. Prakash 2 , M. Pal 2 , A. Joshi 3 , K. Prabhash 3 1 Tata Memorial Centre, Dept of Radiation Oncology, Mumbai, India ; 2 Tata Memorial Centre, Dept of Urology, Mumbai, India ; 3 Tata Memorial Centre, Dept of Medical Oncology, Mumbai, India Purpose or Objective This study was done to assess the clinical outcomes with dose escalated, image guided adaptive radiation therapy (ART) in patients of muscle invasive bladder cancer (MIBC), as a part of trimodality treatment approach for Patients with non-metastatic MIBC treated with ART were analysed. After maximal resection of bladder tumor, they were treated with radical chemoradiation. For ART, 3 anisotropic planning target volumes were concentrically grown (PTVs small, medium and large) around the bladder. A library of intensity modulated radiotherapy (IMRT) plans was created for each patient. A dose of 64 Gy in 32 fractions to the whole bladder and 55 Gy to the pelvic nodes was planned. In selected patients with solitary tumor or two tumors in close proximity, without any in situ carcinoma component, dose escalation to tumor bed to 68 Gy (equivalent dose for 2-Gy fractions assuming α/β of 10 [EQD2] 10 = 68.7 Gy) was planned. Simultaneous integrated boost was used for dose escalation and these patients were treated with a comfortably full bladder. On-board daily megavoltage imaging was used every day to choose the most appropriate PTV encompassing the bladder (‘Plan-of-the-day’ approach) for each fraction. Results A total of 106 patients were analysed. Most patients had T2 (68%) or T3 (19%) disease. Twenty three patients (22%) received neoadjuvant chemotherapy and 76% received concurrent weekly chemotherapy (platinum-based in 63%, gemcitabine-based in 35%). Ninety two patients (87%) completed the planned dose of 64 Gy to the whole bladder bladder preservation. Material and Methods Poster: Clinical track: Urology-non-prostate