Abstract Book

S841

ESTRO 37

EP-1559 Quality of Life Results of a Phase II Study of SBRT for Prostate Cancer in an Asian population Y. Li 1 , J.K.L. Tuan 1,2 , T.W.K. Tan 1,2 , M.L.C. Wang 1,2 , J. Teh 1,2 , M.L.K. Chua 1,2 1 National Cancer Center Singapore, Department of Radiation Oncology, Singapore, Singapore 2 Duke-NUS Medical School, Oncology Academic Clinical Programme, Singapore, Singapore Purpose or Objective There is substantial evidence on clinical and patient- reported quality of life (QOL) outcomes after prostate stereotactic body radiotherapy (SBRT) in the Caucasian population. However, limited evidence is available in the Asian population, and it is unclear if demographic differences exist with regard to QOL outcomes following such profound hypofractionation. We, therefore, conduct a single-institution prospective phase II trial of prostate SBRT in favourable intermediate-risk prostate cancers (fIR-Pca) treated at an Asian tertiary cancer centre. Material and Methods We recruited patients with biopsy-proven prostate adenocarcinoma who were classified as fIR-PCa by the NCCN Zumsteg-Spratt classification. We adopted a prostate SBRT schema of 36.25 Gy in 5 fractions on alternate days delivered using Linac-based RapidArc. Clinical target volume included only the prostate. Planning margins of 5 mm (circumferential) and 3 mm (posterior) were applied. Adverse events (AEs) were assessed using CTCAE v4.0; QOL was assessed using the EPIC instrument at baseline, 1 and 2-year post-SBRT. Results Between 2014-2016, 47 patients were recruited to the study. Median follow-up duration was 30 months; median age was 68 years. Acute gastrointestinal (GI) toxicities peaked at 1 week post-SBRT, with 8 patients reporting G1 and G2 AEs. 7 patients reported G2 acute genitourinary (GU) AEs. 3 late G2 GU AEs were recorded, and there was no late G2 GI toxicity. Mean EPIC scores across GI, GU and sexual domains did not differ significantly post-SBRT from baseline. However, 8 (17%) patients reported worsened scores in the GU irritative/obstructive domain, and 9 (19%) patients had worsened GI scores across all items. A third of cases reported worsened sexual EPIC scores; 9 (19%) due to erectile function and 12 (26%) expressed sexual dissatisfaction. Conclusion Prostate SBRT is well tolerated in our Asian cohort of fIR- PCa. While conventional GU and GI AEs rates did not differ between our Asian and other Caucasian SBRT cohorts, specific QOL domains, in particular sexual dissatisfaction, appear to be more common in our Asian population. This may suggest intrinsic genetic and epigenetic demographic differences in normal tissue responses to prostate SBRT. EP-1560 Clinical results of a moderately hypofractionated radiotherapy in postoperative prostate carcinoma M. Ntreta 1 , G. Siepe 1 , F. Bertini 1 , M. Ferioli 1 , S. Ciabatti 1 , I. Capocaccia 1 , G. Macchia 2 , F. Deodato 2 , S. Cilla 3 , M. Ferro 2 , E. Arena 2 , M. Buwenge 1 , A. Arcelli 1,4 , A.F.M. Kamal Uddin 5 , S. Cammelli 1 , G.P. Frezza 4 , A.G. Morganti 1 1 Radiation Oncology Center, Diagnostic and Specialty Medicine – DIMES- University of Bologna S. Orsola- Malpighi Hospital, Bologna, Italy 2 Radiotherapy Unit, Fondazione di Ricerca e Cura "Giovanni Paolo II", Campobasso, Italy 3 Medical Physic Unit, Fondazione di Ricerca e Cura

"Giovanni Paolo II" Catholic University of Sacred Heart, Campobasso, Italy 4 Radiation Oncology Unit, Bellaria Hospital, Bologna, Italy 5 Radiation Oncology Department, United Hospital Limited Gulshan, Dhaka, Bangladesh Purpose or Objective Purpose/Objective. To report the outcome of moderately hypo-fractionated radiation therapy in patients with prostate cancer after radical prostatectomy using intensity-modulated radiation treatment with simultaneous integrated boost (IMRT-SIB). Material and Methods Material/Methods. From April 2011 to April 2016, 121 high risk patients were included in this study. High risk was defined by positive surgical margins, pathological stage T3b, positive lymph nodes and/or detectable PSA after surgery. All patients underwent adjuvant treatment and were treated at Sant’Orsola-Malpighi Hospital in Bologna. All patients received 66 Gy to the prostate bed in 30 fractions (2.2 Gy per fraction). Pelvic nodes irradiation was prescribed to 62.8% of patients (54 Gy in 30 fractions). Acute toxicity was recorded and evaluated according to RTOG (Radiation Therapy Oncology Group) criteria and late toxicity according to the RTOG-EORTC (European Organization for Research and Treatment of Cancer) scale. Results Results. No cases of grade ≥ 3 acute gastrointestinal and genitourinary toxicity were recorded. Grade 2 acute gastrointestinal and genitourinary toxicity was recorded in 3.3% and 6.6% of patients, respectively. Five-year grade 3 late gastrointestinal and genitourinary toxicity was 0% and 2.1%, respectively. Overall 5-year biochemical relapse-free survival (bRFS) was 87.4%. Conclusion Conclusions. Adjuvant moderately hypofractionated IMRT- SIB treatment, enabling a reduction in the overall treatment time, shows a favorable acute and late toxicity profile and promising results in terms of relapse-free survival. EP-1561 A systematic review on postoperative hypofractionated radiation therapy in prostate carcinoma G. Siepe 1 , M. Buwenge 1 , A. Arcelli 1,2 , M. Ntreta 1 , F. Bertini 1 , M. Ferioli 1 , S. Ciabatti 1 , C.M. Donati 1 , I. Capocaccia 1 , G. Macchia 3 , F. Deodato 3 , S. Cilla 4 , M. Ferro 3 , E. Arena 3 , A.F.M. Kamal Uddin 5 , S. Cammelli 1 , G.P. Frezza 2 , A.G. Morganti 1 1 Radiation Oncology Center, Department of Experimental- Diagnostic and Specialty Medicine - DIMES University of Bologna, Bologna, Italy 2 Radiation Oncology Unit, Bellaria Hospital, Bologna, Italy 3 Radiotherapy Unit, Fondazione di Ricerca e Cura "Giovanni Paolo II", Campobasso, Italy 4 Medical Physic Unit, Fondazione di Ricerca e Cura "Giovanni Paolo II" Catholic University of Sacred Heart, Campobasso, Italy 5 Radiation Oncology Department, United Hospital Limited Gulshan, Dhaka, Bangladesh Purpose/Objective While several randomized studies tested hypofractio- nated radiotherapy (HFRT) as exclusive treatment of prostate cancer (PCa), high level evidences on safety and efficacy of HFRT in postoperative setting are lacking.