ESTRO 36 Abstract Book

S295 ESTRO 36 _______________________________________________________________________________________________

Conclusion Preliminary results of this trial demonstrate for both study arms the feasibility, tolerance, and acceptable toxicity profile of this treatment approach. Longer follow-up is needed to assess the impact of OTT and urethra-sparing on outcome, late toxicity, and QoL. PV-0553 Prognostic significance of Testosteron Level in prostate carcinoma patients treated with TAB and RT G. Ozyigit 1 , F. Akyol 1 1 Hacettepe University- Faculty of Medicine, Department of Radiation Oncology, Ankara, Turkey Purpose or Objective The aim of this study is to evaluate the prognostic significance of testosterone levels measured during total androgen blockade (TAB) in intermediate risk (IR) and high risk (HR) non-metastatic prostate adenocarcinoma patients treated with three dimensional conformal radiotherapy (3D-CRT) or intensity modulated radiation therapy (IMRT). Material and Methods The clinical data of 329 eligible T1-3N0M0 (AJCC 2010) prostate adenocarcinoma patients treated at our department between 1996-2011 with either 3D-CRT or IMRT were evaluated. The median age was 67 years. D'Amico 1998 risk classification was used, and 80 patients were in IR, as 249 patients were in HR group, respectively. The total 3D-CRT and IMRT dose was 70 Gy, 76 Gy respectively in 2 Gy daily fraction doses. All patients received TAB (combined LHRH agonist and bicalutamide), and 61% of patients were given less than 12 months of TAB. Total testosteron levels were measured in every 3 months during hormonal therapy. The castration level for testosteron was accepted as ≤20 ng/dL according to the European Association of Urology (EAU) criteria; and patients were categorized as castrated group (C) and non- castrated group (nC), accordingly. Log-rank test was used for univariate analyses (UVA), and Cox-regression model was used for multivariate analyses (MVA). Results Median follow-up was 9.2 years. There were no statistically significant differences between C and nC groups in terms of age, RT technique, TAB duration, risk group, Gleason score, PSA levels, T stage and RT dose. Five and 10 year overall survival (OS) rates were 97%, 91% for C group, and 90%, 75% for nC group (p<0.001). Five and 10 year biochemical relapse free survival rates (BRFS) were 87%, 83 % for C , and 71%, 51% for nC group (p<0.001). MVA revealed that testosteron level above 20 ng/dL (p=0.001) and Gleason score of 8-10 (p0.01) were found to be independent significant poor prognostic factors in predicting OS and BRFS. Conclusion The prognostic significance of testosteron levels was previously demonstrated in metastatic prostate cancer patients receiving hormonal therapy, but not for non- metastatic patients receiving TAB and radiotherapy . In a median follow-up of 9.2 years, we found that non-castrate levels of testosteron (>20 ng/dL) measured during TAB had significant detrimental effects both on overall and biochemical relapse free survival in intermediate-high risk non-metastatic prostate cancer patients. Thus, we recommend to continuously monitor testosteron levels during TAB in order to measure the efficacy of castration. PV-0554 Patient-reported outcomes from the phase III prostate HYPRO trial: urinary toxicity R.C. Wortel 1 , L. Incrocci 1 , F.J. Pos 2 , R.J. Smeenk 3 , A.D.G. Krol 4 , S. Aluwini 1 , M.G. Witte 2 , B.J.M. Heijmen 1 , W.D. Heemsbergen 2 1 Erasmus MC Cancer Institute, Radiation Oncology, Rotterdam, The Netherlands 2 Netherlands Cancer Institute, Radiation Oncology,

PV-0552 Urethra-sparing SBRT for prostate cancer: acute toxicity results from a randomized phase II trial T. Zilli 1 , S. Jorcano 2 , S. Bral 3 , C. Rubio 4 , A. Bruynzeel 5 , A. Oliveira 6 , U. Abacioglu 7 , H. Minn 8 , Z. Symon 9 , R. Miralbell 1,2 1 Hôpitaux Universitaires de Genève, Radiation Oncology, Geneva, Switzerland 2 Teknon Oncologic Institute, Radiation Oncology, Barcelona, Spain 3 Onze-Lieve-Vrouwziekenhuis, Radiation Oncology, Aalst, Belgium 4 Hospital Universitario Sanchinarro, Radiation Oncology, Madrid, Spain 5 VU University Medical Center, Radiation-Oncology, Amsterdam, The Netherlands 6 Portuguese Institut of Oncology, Radiation Oncology, Porto, Portugal 7 Neolife Medical Center, Radiation Oncology, Istanbul, Turkey 8 University Hospital Turku, Radiation Oncology, Turku, Finland 9 Sheba Medical Center, Radiation Oncology, Ramat Gan, Israel Purpose or Objective To present the acute toxicity results from a prospective multicenter phase II randomized trial of short or protracted urethra-sparing stereotactic body radiotherapy (SBRT) for localized prostate cancer (PCa). Material and Methods From 08/2012 to 12/2015, 170 patients (pts) from nine European centers with cT1c-3a N0 M0 PCa and a low risk of nodal involvement (≤20%, according to Roach et al.) were recruited and randomized according to two different overall treatment time (OTT) schedules: either 9 days (arm A, 84 pts), or 28 days, once-a-week, the same week- day (arm B, 86 pts). The prescribed dose was 36.25 Gy in 5 fractions of 7.25 Gy to the prostate ± seminal vesicles in both arms. The prostatic urethra, with a surrounding margin of 3 mm, received a lesser dose of 5 x 6.5 Gy = 32.5 Gy. All patients were treated either with a VMAT or IMRT technique under stereotactic conditions using Novalis linacs and ExacTrac image-guided technology. Genitourinary (GU) and gastrointestinal (GI) toxicity (CTCAE v4.0 grading scale), IPSS, and QoL scores (EORTC QLQ-PR25) were assessed at baseline, at the 5 th fraction (5fx), and 12 th weeks (12W) since SBRT start. Results 82 (median age 70 years) and 83 (median age 69 years) pts, respectively, from arms A and B, were retained for this analysis. Low-, intermediate-, and high-risk presentation was respectively 22%, 63%, and 15% (arm A) and 22%, 64%, and 14% (arm B). A 6-months androgen deprivation was used in 44% and 45% of the pts in arm A and B, respectively. The toxicity stopping rule of the study during the first 3-months was never activated. In both arms, Grade 1 GI toxicity increased from baseline to 5fx (from 19.5% to 38% and from 23% to 32% for arms A and B, respectively) returning back to baseline by W12 (18% for Arm A and 25% for Arm B). Only 2 cases of grade 2 GI toxicity (2.5%) were observed at 5fx in arm A. Grade 2 GU toxicity rates at baseline, 5fx, and W12 were 2%, 17%, and 11% vs. 5%, 19% and 6% in arms A and B, respectively (mainly moderate irritative and voiding symptoms). Only one grade 3 GU toxicity was observed at W12 in arm B (desobstructive TURP in a patient with a preexisting history of acute urinary retention). Median IPSS scores at the same endpoints were 6, 10, and 6 vs. 6, 10, and 7 for arms A and B, respectively, with similar IPSS-based QoL rates at baseline and W12 (80% of pts satisfied). No changes in EORTC QLQ-PR25 scores for GU, GI, and sexual domains were observed in both arms between baseline and W12.