S27 ESTRO 33, 2014 Only through comparison with a large control dataset could a statistically significant dose dependence be detected. Conclusions: Consistent with previous analyses of our low and low- tier intermediate risk patients, commonly used whole-prostate dose metrics were not predictive of biochemical relapse in the 2000 patient cohort, nor were they predictive of local relapse. In addition, significant under- dosage of the ASQ relative to other regions of the prostate was not predictive of relapse. Dose to the AIQ was predictive of local relapse, while doses to the PSQ and PIQ, which were consistently high, were not. OC-0071 Salvage reirradiation for recurrent prostate cancer patients: three fractions of high-dose-rate brachytherapy P. Wojcieszek 1 , M. Fijalkowski 1 , S. Kellas-Sleczka 1 , B. Bialas 1 1 Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Brachytherapy, Gliwice, Poland Purpose/Objective: To evaluate HDR BT (high-dose-rate brachytherapy) in management of recurrent prostate cancer. Materials and Methods: Prospective pilot study on salvage HDR was started in our centre in 2008. Main inclusion criteria were: localised prostate cancer relapse after EBRT (alone or with BT-boost), no prior radical prostatectomy and histopathological confirmation of recurrence. Included patient was planned for three fractions of HDR BT, 10 Gy each, every two weeks in 28 days. There were 68 patients treated from 2008 to 2012. We excluded patients from analysis if: average V100 was below 80%, third fraction of HDR BT was canceled. Acute and late toxicity were evaluated in EORTC/RTOG scale. Biochemical relapse was defined according to Phoenix consensus. Results: 61 men were included in analysis. Median age was 70 years (55 – 80). Median primary peak PSA was 13,7 ng/ml. Median time to relapse from first irradiation was 63 months (21 – 128 months). Median relapse peak PSA was 3,1 ng/ml (0,065 – 19,9 ng/ml). Median follow – up time was 33 months (10 – 60 months). Only one patient suffered from grade 3 acute urinary toxicity. Three patients had acute rectal toxicity grade 1. 55 patients had late urinary toxicity grade 2 or below. 4 patients developed late urinary toxicity grade 4. 4 patients had late rectal toxicity grade 1. Median PSA at last follow – up was 0,106 ng/ml (0,008 – 2470,74 ng/ml). There were 13 biochemical relapses. 8 patients suffered from metastases. Median time to failure was 16 months. 3 – year disease – free survival was 69%. 3 and 5 – year OS was 98% and 83%, respectively. Conclusions: Salvage HDRBT is a good option for patients with localised relapse of prostate cancer. Toxicity of this modality is acceptable, however patients should be selected carefully due to risk of distant failures. OC-0072 Focal salvage Iodine-125 brachytherapy for recurrent prostate cancer after primary radiotherapy M. Peters 1 , M. Maenhout 1 , J.R.N. Van der Voort van Zyp 1 , M.A. Moerland 1 , M. Moman 2 , U.A. Van der Heide 3 , L.M.G. Steuten 4 , J.J. Battermann 1 , M.J.H. Van Deursen 1 , M. Van Vulpen 1 1 UMC Utrecht, Radiotherapy, Utrecht, The Netherlands 2 UMC Utrecht, Radiology, Utrecht, The Netherlands 3 The Netherlands Cancer Institute, NKI, Amsterdam, The Netherlands 4 University of Twente, Department of Health Technology and Services Research, Enchede, The Netherlands Purpose/Objective: Whole gland salvage treatments such as radical prostatectomy, cryotherapy and brachytherapy for recurrent prostate cancer (PCa) after primary irradiation show high failure and severe toxicity rates. High failure rates are probably associated with inadequate patient selection. The significant toxicity rates are due to a high cumulative dose to the organs at risk (OAR) after salvage irradiation to the entire prostatic volume. Early and adequate localization of recurrences enables focal salvage, thereby potentially improving functional treatment outcomes, while maintaining biochemical control rates. This study describes toxicity, biochemical outcome and quality of life for focal salvage Iodine-125 (I125) brachytherapy. Materials and Methods: A total of 20 patients with locally recurrent PCa after primary radiotherapy (external beam radiotherapy or brachytherapy) underwent focal salvage I-125 brachytherapy. Tumor was defined by multiparametric MRI (T2, dynamic contrast enhanced and diffusion weighted imaging) and confirmed through systematic transrectal prostate biopsies. Dosimetry data was obtained intra- operatively for all patients (figure 1). Toxicity was scored by the Common Terminology Criteria for Adverse Events (CTCAE-4).Biochemical failure (BF) was determined with the Phoenix criteria (PSA-nadir+2.0 ng/ml). Quality of Life (QoL)was measured by SF-36 Health Survey, European Organization of Research and Treatment of Cancer (EORTC) C30+3 and PR25 questionnaires. Results: Nearly all patients met the dosimetry prescription limits for the GTV (D90 > 145Gy) and the surrounding OAR. With a median follow-up of 36 (range 10-45) months, six patients experienced BF. Three patients had no response to focal salvage treatment, while three patients failed between 24 and 36 months. The biochemical disease free survival rates were 70% (including non-responders) and 82% (excluding non- responders). Severe (grade 3) genitourinary (GU) and gastrointestinal (GI) toxicity did not occur after focal salvage treatment. One patient required an endoscopic intervention due to urethral stricture. This was not scored as grade 3 toxicity since there was no hydronephrosis or renal dysfunction. Overall, toxicity was mild (grade 1-2) and manageable with medication. Grade 3 erectile dysfunction did not occur in the five potent patients before salvage therapy. During the entire follow-up, QoL remained significantly decreased with regard to urinary symptoms as compared to baseline. Physical functioning and general physical discomfort also deteriorated after a median follow-up of 3 years. This was probably due to increasing age and co-morbidities. Conclusions: Focal salvage I-125 brachytherapy showed no severe (grade 3) toxicity in the first 20 treated patients, with an acceptable biochemical response and QoL OC-0073 Preservation of erectile function after prostate permanent implantation for localized prostate cancer R. Oismueller 1 , K. Poljanc 2 , C. Somay 1 , S. Schuch 1 , M. Rauchenwald 3 , S.T. Madersbacher 3 , R. Hawliczek 1 1 SMZ-Ost Donauspital, Radiooncology, Vienna, Austria 2 TU Vienna, Atomic Institute, Vienna, Austria 3 SMZ-Ost Donauspital, Urology, Vienna, Austria Purpose/Objective: To prospectively investigate the impact of permanent prostate interstitial brachytherapy (PPI) on erectile function using a validated patient-administered questionnaire to analyze maintaining potency two years and five years after treatment. Materials and Methods: 529 patients underwent permanent prostate brachytherapy from July 1999 to October 2013. For this analysis patients were required to have a minimum of two years of follow-up and to be off androgen deprivation therapy (ADT). 285 patients remained eligible. Median age of patients was 67.4years. 57 patients received Pd-103 as monotherapy. 228 patients received I-125, 9 of them combined with external beam radiotherapy (EBRT). 74.5% of Pd-103 patients and 21.8% of I-125 patients received androgen deprivation therapy (ADT) prior to