ESTRO 36 Abstract Book

S961 ESTRO 36 2017 _______________________________________________________________________________________________

Patients treated with Iodine-125 BT with post-implant dosimetry after at least 5 years of follow-up were retrospectively assessed. Patients who received combination therapy (EBRT and BT) and salvage BT were excluded. Results From 616 patients treated between March 2001 and November 2010, 406 of them were included in the study. 65.5% were low-risk; 30%, intermediate-risk; 4.5%, high- risk. After a median follow-up of 87.5 months, 61 (15.0%) patients developed biochemical recurrence. BFFS at 5 and 10 years was 90.6% and 82.2% respectively. There were no significant differences in the BFFS among the risk groups (p = 0.294). Nadir ≥ 1 ng/ml was associated with higher risk of biochemical failure (HR = 5.81; CI 95%: 3.39 to 9.94; p ≤ 0.001). MFS at 5 and 10 years was 98.3% and 94% respectively. Three patients (0.3%) died from prostate cancer during follow-up. OS at 5 and 10 years was 96.2% and 85.1% respectively. Acute and late grade ≥ 2 and grade ≥ 3 gastrointestinal toxicity were observed in 5.6% and 0.5% and 4.6% and 0.5%, respectively. Acute and late grade ≥ 2 and grade ≥ 3 genitourinary toxicity were 57.3%, 3.6% and 28%, 3.1%, respectively. Conclusion Iodine-125 LDR-BT is a safety and efficient treatment for well-selected prostate cancer patients. EP-1772 HDR Brachytherapy in the treatment of Prostate Cancer – the Vienna Experience O. Komina 1 , C. Seitz-Kästner 1 , J. Hofbauer 1 , M. Kuntner 1 , J. Wimmer 1 , T. Knocke-Abulesz 1 , E. Nechvile 1 1 KH Hietzing mit Neurologischem Zentrum Rosenhügel, Sonderabteilung für Strahlentherapie, Wien, Austria Purpose or Objective Radiation Therapy (RT) plays a crucial role in the treatment of prostate cancer. The advantage of high dose rate brachytherapy (HDR-BT) as monotherapy or boost to deliver high radiation dose to the tumor and to spare organs at risk (OAR) was recently shown in clinical studies. Material and Methods We summarized the overall patient data collected in our institution since 2010 when we implemented the real time planning system based on 3D ultrasound imaging. Between 2010 and 2015 a total of 256 patients were treated and 584 implants being performed. 47% of the patients with local disease received HDR-BT alone (4 x 9 Gy on a weekly basis [n= 22], after 2012 3 x 10,5 Gy every other week [n= 99]). 53% of the patients received combination therapy for treatment of intermediate or high-risk prostate cancer. These patients received one or two fractions of HDR-BT with the doses of 9 or 10,5 Gy respectively combined with local external beam RT of the prostate only or additional pelvic lymph node irradiation. 17 patients were treated in terms of salvage therapy after radical prostatectomy (RPE), external beam or brachytherapy. Results Median age was 69,2 years (range 44,8 - 87,5). The majority of patients (37%) had Gleason 6 histology, 29% Gleason 7a, and 9% 7b. High risk patients receiving exclusively combination therapy had Gleason 8 in 13%, Gleason 9 in 11% and Gleason 10 in 1% of the cases. The median V100 for the prostate was 93,7%. No acute grade ≥3 toxicity was observed in the whole cohort of the patients. Late rectal toxicity was observed predominantly in the patients receiving additional external beam therapy. Conclusion The feasibility of HDR-BT as a treatment option in low, intermediate and high grade prostate carcinoma was confirmed. As previously expected, HDR-BT patients treated in a monotherapy setting showed a more favorable profile of detected side effects. In our experience HDR-BT can be implemented within a

radiooncological department of a community hospital.

EP-1773 Clinical outcomes in localized prostate cancer treated with HDR Brachytherapy as single fraction L. Larrea 1 , E. López-Muñoz 1 , P. Antonini 1 , V. Gonázlez 1 , M.C. Baños 2 , J. Bea 2 , M.A. García 2 1 Clinica Virgen del Consuelo, Radiation Oncology, Valencia, Spain 2 Clinica Virgen del Consuelo, Radiophysics Department, Valencia, Spain Purpose or Objective To describe the technique and analyze early outcomes in patients with low and intermediate risk prostate cancer treated with high dose rate brachytherapy (HDR) as monotherapy. Material and Methods From January to December 2015, 8 low and 8 intermediate prostate cancer patients were treated with 20 Gy HDR (Ir 192) as monotherapy, in one fractionation. At diagnosis, mean PSA was 7,42 ng/mL (range 6-16) and mean Gleason score was 6 (range 4-7). Any patient received androgen deprivation therapy. Mean prostate volume was 49 cc (range 21-67,3). Under rachianesthesia the patient is placed in a dorsal lithotomy position. A balloon catheter is placed into the bladder to correctly visualization of the urethra in transrectal ultrasonography (TRUS). Using a template, plastic needles are placed into the prostate through the perineal skin to the inside of the bladder. The template has needles holes at 5 mm intervals. Mean number of needles inserted was 13 (range 12-15). After implantation of needles TRUS 2 mm spaced axial images are taken for 3D treatment planning. Prostate delination was done as clinical target volume (CTV) and to evaluate dose constraints. PTV includes the whole prostate gland with a 2 mm posterior wall rectal margin and 5 mm all margins. Urethra was always defined. Dose constraints were: urethra total dose less than 120% and rectal dose less than 70% of the prescription dose. Prescription dose to prostate was 20 Gy. The minimal dose achieved to the 95% of the volume (D95) was 21-23 Gy (105-110%). All the procedure expends about 1-2 hours. Patients stay in hospital for 12 hours with urethral catheter. Genitourinary and gastrointestinal toxicity was evaluated in agreement with Common Terminology Criteria for Adverse Events (CTCAE v4.03). For sexual function the International Index of Erectil Function Questionnaire was used. The global cost is a forfait for all the procedure. Results With a median follow-up of 15,1 months (range 10-21) all patient survive without progression. Mean PSA after treatment was 1,4 ng/mL (range 0,21-3,37). Three patients presented acute disuria and one patient urinary urgency (grade 1) that were resolved in less that 3 weeks. Erectil function preservation was 87,5%. No gastrointestinal toxicity was observed. One patient was diagnosed of lung cancer two months after brachytherapy treatment. The overall cost treatment was among €- 10.000 per patient (€-9.000-14.000). Conclusion In our experience, HDR brachytherapy using extreme hypofractionation is a safe and well tolerated alternative to permanent-seed implants with a high local control disease and low toxicity rates. Some advantages as “in vivo” prescription, short surgical time and no radioactive procedure were confirmed. However, long-term follow-up is needed to confirm our initial results. EP-1774 Randomized phase II trial of IGRT with or without HDR boost in intermediate-risk prostate cancer E. Vigneault 1 , G. Morton 2 , W. Perulekar 3 , T. Niazi 4 , G. Springer 5 , M. Barkati 6 , P. Chung 7 , W. Koll 8 , A. Kamran 9 , M. Montreal 3 , K. Ding 3 , A. Loblaw 2