ESTRO 2020 Abstract Book

S615 ESTRO 2020

Material and Methods From 2002 to 2016, we retrospectively evaluate 448 patients with histologically confirmed high-risk prostate cancer defined by National Comprehensive Cancer Network (NCCN) risk group were included. All patients received RT and ADT. Biochemical relapse was established by Phoenix criteria (PSA concentration superior than nadir plus 2 ng/ml) and the presence of metastasis was radiographically confirmed. We analyze survival using Kaplan-Meier method. Results Demographic characteristics of patients are showed in Table 1. Median follow-up was 88 months. At 5 and 10 years DSS was 98.7% and 96.9%, BFFS was 86.7% and 75%, DFFS was 93% and 84.8% while RFFS was 91.5% and 87.9, respectively. Pelvic node radiation provides a significant improvement in RFFS at 88 months versus no pelvis radiation (97% versus 85%; p= 0.00) but not a better OS (84.2% versus 81%; p=0.2). Acute genital-urinary and gastro-intestinal toxicity was acceptable (only 1.3% and 1.8% ≥ grade 3, respectively) and also chronic toxicity was limited (5,6% and 1.6% ≥ grade 3, respectively). Conclusion Overall, in our experience combination of WPRT with ADT provides an excellent local control with high DSS rate and tolerable toxicity. Finally, patients treated with nodal pelvis radiation showed best outcomes. PO-1169 Influence of localisation of PSMA-positive oligo-metastases on efficacy of metastasis-directed EBRT N. Schmidt-Hegemann 1 , S. Kroeze 2 , C. Henkenberens 3 , M. Vogel 4 , S. Kirste 5 , J. Becker 6 , I. Burger 7 , T. Derlin 8 , P. Bartenstein 9 , M. Eiber 10 , M. Mix 11 , C. Lafougere 12 , A. Müller 6 , A. Grosu 5 , S. Combs 4 , H. Christiansen 3 , M. Guckenberger 2 , C. Belka 1 1 Department of Radiation Oncology, University Hospital LMU Munich, München, Germany ; 2 Department of Radiation Oncology, University Hospital Zürich, Zürich, Switzerland ; 3 Department of Radiotherapy and Special Oncology, Medical School Hannover, Hannover, Germany ; 4 Department of Radiation Oncology, Technical University of Munich, Munich, Germany ; 5 Department of Radiation Oncology, University of Freiburg, Freiburg, Germany ; 6 Department of Radiation Oncology, University Hospital Tübingen, Tübingen, Germany ; 7 Department of Nuclear Medicine, University Hospital Zürich, Zürich, Switzerland ; 8 Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany ; 9 Department of Nuclear Medicine, University Hospital LMU Munich, Munich, Germany ; 10 Department of Nuclear Medicine, Technical University Munich, Munich, Germany ; 11 Department of Nuclear Medicine, University of Freiburg, Freiburg, Germany ; 12 Department of Nuclear Medicine, University Hospital Tübingen, Tübingen, Germany Purpose or Objective Approximately 40-70% of biochemically persistent or recurrent prostate cancer (PCa) patients after radical prostatectomy (RPE) are oligo-metastatic in 68 Gallium- prostate-specific membrane antigen positron emission tomography ( 68 Ga-PSMA PET). Those lesions are frequently not cured by the current standards of care like external- beam radiotherapy (EBRT) of the prostatic fossa. This retrospective study analyses the influence of oligo- metastases’ site on outcome after metastasis-directed radiotherapy (MDR). Material and Methods Retrospectively, 359 patients with PSMA PET-positive PCa recurrences after RPE all treated with MDR were analyzed. Patients with prior salvage treatments were excluded. Biochemical recurrence-free survival (BRFS) (PSA < post- radiotherapy nadir + 0.2ng/mL) was assessed using Kaplan-

Meier survival. Cox regression analysis was performed to determine factors influencing BRFS. Results All patients were initially cM0 with mostly high-risk PCa (342/359; 95%). Seventy-five patients had local recurrence within the prostatic fossa, 32 patients pelvic nodal plus local recurrence, 117 patients pelvic nodal recurrence, 51 patients paraaortic lymph node metastases with/without locoregional recurrence and 84 patients had bone or visceral metastases with/without locoregional recurrence. Median PSA before MDR was 1.2 ng/ml (range, 0.04 - 47.5). MDR was either applied as stereotactic body or normo- fractionated EBRT to macroscopic tumor lesions. Additive androgen deprivation therapy (ADT) was given in 35% (125/359) of patients with ongoing ADT at last follow-up in 51% (64/125) of those patients. Median PSA nadir after MDR was 0.23 ng/mL (range, <0.03 - 18.30). After a median follow-up of 16 months (1 - 57), 239/351 (68%) patients had no biochemical recurrence. Patients with distant lymph node and/or distant metastases, the so-called oligo- body cohort, had an overall in-field control of 90/98 (91%) but at the same time an ex-field progress of 44/96 (46%). In comparison, an ex-field progress was detected in 28/154 (18%) patients with local and/or pelvic nodal recurrence (oligo-pelvis group). Compared to the oligo-pelvis group, there was a significantly lower BRFS in oligo-body patients at last follow-up. Conclusion Overall, BRFS was dependent on patterns of metastatic disease. Thus, MDR of PSMA PET-positive oligo-metastases can be offered considering that about one-third of the patients progressed within a median follow-up of 16 months. PO-1170 Long-Term testosterone levels and its influence in treatment outcomes in prostate cancer patients J.L. Munoz Garcia 1 , F. Ropero Carmona 1 , B. Ortiz Sierra 1 , Y. Rios Kavadoy 1 , J. Quiros Rivero 1 , J. Cabrera Rodriguez 1 , P. Simon Silva 1 , B. Baños Perez 1 , C. Corral Fernandez 1 1 Badajoz University Hospital, Radiation Oncology Department, Badajoz, Spain Purpose or Objective Low testosterone levels (LTL) is an objective during ADT but long-term LTL increase the causes of death not related to prostate cancer (PCa). Our objective was to analyse the influence of long-term LTL in treatment outcomes in patients with PCa who underwent External Beam Radiation Therapy (EBRT) and androgen deprivation therapy (ADT). Material and Methods Retrospective comparative study of 536 patients with PCa treated with EBRT+ADT in our hospital from October 2001 to June 2012. In the last follow-up 263 (49%) patients had LTL and 273 (51%) normal testosterone level (NTL). The baseline characteristics of the patients in the sample were significantly different between patients with LTL and NTL. LTL were elderly patients, with higher PSA, more advanced primary tumour stage, risk group, Gleason score, positive cylinder percentage, longer ADT and personal history of diabetes mellitus and cardiovascular disease. The median doses of EBRT doses was 78 Gy for LTL and NTL. Overall survival (OS), Disease free survival (DFS) and Cause specific survival (CSS) were estimated with Kaplan-Meier and compared with Log Rank test. Prognostics factors as age, initial PSA, primary tumour stage, risk group of tumours, Gleason score, positive cylinder percentage, EBRT doses, ADT duration and personal history of mellitus diabetes and cardiovascular disease were related to survivals using Cox regression.