ESTRO 2020 Abstract book

S678 ESTRO 2020

each time point from baseline: soon after the end of RT, at one month after RT and at 12 ad 24 months. Results Overall, patients’ tolerance was assessed as satisfactory across all the considered time points, with no residual toxicity exceeding G2 at 6 months after the end of treatment, except for one patient who developed G3 GI symptoms. The most relevant deterioration in IPSS from baseline was reported after 1 month from the end of treatment, although a sizable recovery towards baseline value was assessed at 12 months. Boxplots reporting IPSS modification are shown in Figure 1. The QLQ-PR25 Urinary Symptoms score was also analyzed to evaluate the urinary function. A deterioration of GU symptoms from baseline was observed already after the end of RT and maintained at one month after, with a recovery towards baseline value at 12 months. Interestingly patients with a bladder volume under the median showed a worsening of symptoms after RT, whereas patients with a volume equal or greater than the median reported a significant decreasing trend of deterioration of symptoms with a median complete recovery at 12 months (Figure 2). The analysis of QLQ-C30 and IIEF-5 showed a non-statistically significant change of QoL from baseline. Only one patient out of the 65 patients died and not for disease-relating cause, leading to an OS of 98%. Biochemical progression-free survival (b-PFS) was of 97% at 2-years. Since 2014, only 2 patients experienced biochemical and clinical relapse.

Actuarial probability of remaining free from biochemical progression was 85% at 3 years and 79% at 5 years. Actuarial probability of freedom from local or pelvic nodal relapse / intra-pelvic nodal relapse at 5 years was 96% / 97% respectively. The majority (15 of 18) biochemical relapses occurred in the GS 8 and above group. Actuarial probability of biochemical control / freedom from distant metastases at 5 years was 90% / 93% for GS 7 or less vs 70% / 75% for GS 8 and above. (Log rank p 0.015 and 0.043 respectively). Actuarial probability of biochemical control / freedom from distant metastases at 5 years was 90% / 96% for Orchidectomy vs 70% / 75% for Medical ADT. (Log rank p 0.009 and 0.009 respectively). Gleason score and ADT method remained independent predictors of outcomes on multivariate analysis. Actuarial probability of freedom from occurrence of grade 2 + GI toxicity was 98% at 2 years and 90% at 5 years post RT. 35% of patients had undergone transurethral resection of the prostate (TURP) prior to RT. TURP was a statistically significant predictor of late GU toxicity: The actuarial probability of freedom from occurrence of grade 2+ GU toxicity at 2 years and 5 years was 82% and 61% for those who had undergone TURP prior to RT versus 94% and 87% for those who had not. (log rank p =0.001) Conclusion Long term outcomes with HypoRT are at par with reported outcomes with standard fractionation in high risk disease. Failures were driven by distant metastases. Gleason score and method of ADT were predictors of outcomes. Late GI morbidity rates were on par with reported literature. Patients who had undergone TURP prior to RT had worse late urinary morbidity. PO-1197 Short-term high precision RT for early PCa with SIB to the DIL: QoL assessment (AIRC IG 13218) G. Marvaso 1 , S.G. Gugliandolo 1 , G. Corrao 1 , S. Volpe 1 , G. Riva 1 , D.P. Rojas 1 , D. Zerini 1 , M. Pepa 1 , P. Pricolo 2 , S. Alessi 2 , G. Petralia 2 , F. Cattani 3 , O. De Cobelli 4 , R. Orecchia 5 , B.A. Jereczek-Fossa 1 1 IEO- European Institute of Oncology IRCCS, Division of Radiotherapy, Milan, Italy ; 2 IEO- European Institute of Oncology IRCCS, Division of Radiology, Milan, Italy ; 3 IEO- European Institute of Oncology IRCCS, Medical Physics Unit, Milan, Italy ; 4 IEO- European Institute of Oncology IRCCS, Division of Urology, Milan, Italy ; 5 IEO- European Institute of Oncology IRCCS, Scientific Directorate, Milan, Italy Purpose or Objective As part of the AIRC IG-13218, registered at ClinicalTrials.gov as NCT01913717, we analyzed data from 65 prospectively enrolled patients with low and intermediate risk prostate cancer treated with extremely hypofractionated radiotherapy (RT) to identify clinically meaningful information through the analysis of validated questionnaires testing gastrointestinal (GI) and genitourinary (GU) RT related toxicity and their impact on After the end of RT treatment, clinical assessment and prostate-specific antigen (PSA) measurements were performed every 3 months for at least 2 years. GI and GU toxicities were scored according to Radiation Therapy Oncology Group and European Organization for Research and Treatment of Cancer (RTOG/EORTC) scoring criteria. QoL of enrolled patients was assessed by the International Prostatic Symptoms Score (IPSS), Quality Life Questionnaire - Core 30 (QLQ-C30), QLQ for prostate specific (QLQ-PR25) and sexual activity by the International Index of Erectile Function (IIEF-5). Within- patient score changes of questionnaires were calculated at quality of life (QoL). Material and Methods

Conclusion The median follow-up is still too short to make our data about the oncological outcomes consistent, but the toxicity results and the relative assessed QoL appear to be encouraging. The increasing dose to the DIL does not compromise the RT toxicity and at the same time opens the question about the possibility of an even more escalate treatment. PO-1198 Comparison between built custom linked seeds and loose seeds in prostate brachytherapy L. Ollivier 1 , F. Lucia 1 , C. Lucas 2 , V. Bourbonne 1 , J. Marolleau 2 , N. Boussion 1 , G. Goasduff 1 , G. Fournier 2 , G. Dissaux 1 , O. Pradier 1 , A. Valeri 2 , U. Schick 1 1 Radiation Oncology department- University Hospital- Brest- France-, Radiation Oncology department- University Hospital- Brest- France-, Brest, France ; 2 Urology Department - CHU Brest - Brest - France, Urology Department - CHU Brest - Brest - France, Brest, France

Purpose or Objective