ESTRO 37 Abstract book

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ESTRO 37

observed. Overall survival, local control, and colostomy- free survival at 3 years were 85 %, 93 %, and 91 %, respectively. Conclusion In this monocenter consecutive cohort comprising a selected patient cohort of patients suitable for BT, radiochemotherapy combined with image guided PDR-BT seem to compare favourably with published results. A dose-volume-response analysis including patient reported outcomes is ongoing. PV-0253 Importance of DCE- MRI for targeting biopsy and salvage treatments after prostate cancer recurrence J. Mason 1 , E. Adiotomre 2 , B. Carey 2 , P. Bownes 1 , A. Henry 3 1 Leeds Cancer Centre, Medical Physics & Engineering, Leeds, United Kingdom 2 Leeds Cancer Centre, Radiology, Leeds, United Kingdom 3 Leeds Cancer Centre, Clinical Oncology, Leeds, United Kingdom Purpose or Objective In men with non-metastatic prostate cancer who develop biochemical failure following radiation, multi-parametric MRI (mp-MRI) has an increasing role in targeting biopsies and localising target volumes to allow partial gland salvage treatments. T2 weighted MRI (T2W) and diffusion weighted imaging (DWI) are usually preferred for planning primary treatment but may be less useful after radiotherapy due to radiation induced fibrosis. For I-125 seed implant patients the brachytherapy seeds may create artefact that further reduces the value of DWI. Dynamic contrast enhanced MRI (DCE) demonstrates cancer induced neo-angiogenesis and may be of more value. This study compares T2W, DWI and DCE in patients previously treated with radiotherapy in terms of their usefulness for localising areas of prostate cancer recurrence. Material and Methods From a cohort of 37 patients with template biopsy confirmed local recurrence who were treated with whole or partial gland salvage brachytherapy between 2010- 2017, 19 patients who received mp-MRI scans locally using a consistent imaging protocol were retrospectively assessed. The original primary treatments were either I- 125 seed implant monotherapy (n=15, between 2002- 2013) or radical external beam radiotherapy (EBRT) (n=4, between 2007-2012). A radiologist with >20 years experience of prostate MRI reviewed imaging on two occasions blinded to clinical and biopsy information. At first review the T2W and DWI sequences were assessed for likely presence of tumour and at second review the additional DCE sequence was assessed. Results were recorded and compared on a prostate diagram divided into 12 sectors (quadrants at each of base, mid-gland and apex) plus seminal vesicles (SV). Following this review, results were validated against biopsy information. Results For seed patients, recurrence was visible in 6/15 patients for T2W, 5/15 for DWI and 15/15 for DCE-MRI. For EBRT patients, recurrence was visible in 1/4 patients for T2W, 3/4 for DWI and 4/4 for DCE-MRI. 5/19 patients had recurrence involving the SV and in 2/5 of the cases where recurrence was visible in DWI, the recurrence was in the SV alone. From the sector based analysis, excluding two patients with SV only recurrence, the recurrence involved median 2/12 prostate sectors (range 1/12-5/12) for seed patients and median 6/12 sectors (range 2/12-12/12) for EBRT patients. Combining the results for the 15 seed patients, 12 out of the 27 sectors in which recurrence was detected were at the anterior base of the prostate gland. An example is shown in the figure. Tumour locations

determined in this review were later successfully validated against targeted biopsy results.

Conclusion DCE-MRI is superior to T2W and DWI MRI in defining areas of recurrence within the prostate gland in patients previously treated with radiotherapy, particularly i125 permanent seed implant patients. DCE-MRI should be used to target biopsy and in treatment planning for partial gland salvage therapies. PV-0254 Matched-paired analysis of radical radiotherapy vs. prostatectomy in high-risk prostate cancer M. Cambeiro 1 , F. Diez-Caballero 2 , M. Gimeno Morales 1 , M. Basterra 1 , J. Aristu Mendioroz 1 , M. Moreno-Jimenez 1 , L. Arbea 1 , R. Martinez-Monge 1 1 Clinica Universitaria de Navarra, Radiation Oncology, Pamplona, Spain 2 Clinica Universitaria de Navarra, Urology, Pamplona, Spain Purpose or Objective The aim of the study was to compare oncologic outcomes, postoperative complications and late radiation toxicity in patients with initial PSA ≥20 ng/ml or Gleason >8 in trans-rectal biopsy or both in patients treated with radical radiotherapy (RR) or radical prostatectomy (RP). Material and Methods From 2001 to 2012 two prospective studies with RR were applied in high risk prostate cancer (HRPC) achieving prostate doses Eq2Gy (α/β = 1.2) of 89 & 110 Gy respectively through high dose rate brachytherapy combined with external beam radiotherapy & 2-3 years of androgen deprivation therapy (ADT). These patients were matched 1:1 with those whom underwent RP during the same period. Matching criteria were initial PSA ≥20 ng/ml, trans-rectal diagnostic biopsy Gleason ≥8 and age. Biochemical failure was defined as Phoenix criteria (nadir plus 2) in RR and PSA > 0,2 ng/ml in RP. Acute and late radiation toxicity was evaluated according to RTOG scoring system and also early postoperative severe complications were documented in RP cohort. Cox regression, Kaplan-Meier curves and log-rank tests were performed to assess differences in different end points and toxicity. Results Records of 401 patients in RR and 157 patients in RP cohort were reviewed. Finally, 126 patients that meet matching criteria were analyzed 63 in RR and 63 in RP cohort. The median follow up was 93 months (range 15- 180m), 88 months for radical RR (range 75-93m) and 106 for RP cohort (96-117m) (p=0.017). The 5-10 years actuarial biochemical, pelvic and distant control rates in RR vs. RP cohorts were (87%, 69% vs. 45%, 39% p=<0.001), (96%, 94% vs. 86%, 83% p=0.078) and (82%, 82% vs. 90%, 88% p=0.924) respectively. The 5-10 years actuarial overall and specific survival rates in RR vs. RP cohorts were (96%, 81% vs. 95%, 88% p=0.382) and (93%, 81% vs. 79%, 77% p=0.249) respectively. Postoperative radiotherapy (PORT) due to positive margins, extracapsular extension or both it would be indicate in 40 patients (63%). However, pelvic radiotherapy (PRT) was delivered in 24 (38%), 13 as PORT (20.6%) and 11 as salvage due to biochemical failure (17.5%) reaching a 5-year biochemical control rate in PRT of 22%.