ESTRO 36 Abstract Book

S713 ESTRO 36 2017 _______________________________________________________________________________________________

beams. The treatment schedule was 35 Gy in five fractions delivered on alternate days. The PTV included the prostate for low risk and prostate plus seminal vesicles for intermediate risk, with a 5 mm margin in all other directions. Toxicity was recorded according to CTCAE criteria v4.0. Biochemical failure was calculated according to the Phoenix definition. The Expanded Prostate Cancer Index Composite questionnaire was used to record health- related quality of life. Results From May 2012 to April 2016, 50 patients were enrolled. Twenty-five patients were classified in low risk group and 25 in intermediate risk group. Mean age was 78 years old (range 75 – 84); Gleason score was 6 in 26 and 7 in 24 patients. Median initial PSA was 6,43 (range 2,6 – 17). Median follow-up was 26 months. Acute toxicity was mild. Rectal toxicity was reported as grade 1 in 5 (10%) cases and grade 2 in 1 (2%) cases; grade 1 and grade 2 genitourinary toxicity was described in 13 (26%) and 14 (28%) patients, respectively. In the late setting, 3 (6%) patients reported rectal grade 1 toxicity. Genitourinary late effects were reported as grade 1 in 13 (26%) patients and grade 2 in 2 (4%) patient. Regarding outcome, median nadir PSA was 0.51 ng/ml (range 0.01 – 3.12). Trend of PSA is reported in Figure 1. No biochemical relapses were observed during follow-up and all patients are alive at the moment of the analysis.

Conclusion Gantry-based SBRT with VMAT and FFFs can be considered an effective, non-invasive and safe approach for elderly patients affected by prostate cancer at low and intermediate risk. Randomized trials comparing SBRT with other approaches in this setting are necessary. EP-1344 Long-term quality of life after high-dose-rate brachytherapy boost for prostate cancer W. Busser 1 , I. Korfage 2 , S. Aluwini 1 1 Erasmus MC Cancer Institute, Radiation Oncology, Rotterdam, The Netherlands 2 Erasmus Medical Center, Public Health, Rotterdam, The Netherlands Purpose or Objective Quality of life (QoL) of patients treated for prostate cancer (PCa) is relevant because of the long survival of these patients. We aimed to report late toxicity incidences and generic and PCa-specific health-related QoL and to investigate associations between toxicity and QoL in patients treated with high-dose-rate brachytherapy (HDR-BT) boost combined with external beam 264 low- and intermediate risk PCa patients were treated between 2000-2007 with single implant HDR-BT boost (3x6 Gy) combined with EBRT (25x1.8 Gy). Of these, 171 patients with QoL data available with 6-10 years follow-up (FU) were included. Late grade ≥2 gastrointestinal (GI) or genitourinary (GU) toxicity was evaluated using physicians charts and EORTC-RTOG toxicity questionnaire at 3, 6 and radiotherapy (EBRT). Material and Methods

Conclusion SBRT is safe and offers excellent in-field control. At 2 years after SBRT, 1 out of 3 patients is progression-free. Further investigation is warranted to identify patients who may benefit most from SBRT and to define the optimal combination with ADT EP-1343 Is stereotactic body radiation therapy a viable option for elderly patients with prostate cancer? C. Franzese 1 , G. D'agostino 1 , L. Di Brina 1 , L. Cozzi 1 , T. Comito 1 , D. Franceschini 1 , F. De Rose 1 , P. Navarria 1 , E. Clerici 1 , A. Ascolese 1 , A. Tozzi 1 , C. Iftode 1 , S. Tomatis 1 , M. Scorsetti 1 1 Istituto Clinico Humanitas, Radiotherapy and Radiosurgery, Rozzano Milan, Italy Purpose or Objective Data regarding the treatment of elderly patients with prostate cancer show that Radiotherapy (RT) is associated with a cancer specific mortality risk reduction of 2.6% at 10 years, even after adjusting for several confounders including 12 comorbid conditions. The aim of the present study is to evaluate the efficacy and toxicity of Stereotactic body radiation therapy (SBRT) in a group of elderly patients affected by low and intermediate risk prostate cancer. Material and Methods Patients aged ≥ 75 years, with biopsy-confirmed prostate cancer were enrolled. Inclusion criteria were: initial prostate-specific antigen (PSA) ≤ 20 ng/ml, Gleason Score ≤ 7, International Prostate Symptom Score ≤ 7. Gantry- based SBRT was performed with Volumetric Modulated Arc Therapy in its RapidArc form and flattening filter free