ESTRO 2021 Abstract Book

S1129

ESTRO 2021

However, the morbidity profile following pelvic radiotherapy (RT) is not well described. The aim of this study was therefore to assess morbidity in high-risk PC patients receiving whole pelvic RT in the setting of a national clinical trial. Materials and Methods A total of 88 patients with adenocarcinoma of the prostate and high-risk parameters were enrolled and followed from 2011-2018. Patients were divided into two cohorts: 35 patients (cohort A) had no nodal staging (N x ) while 53 patients (cohort B) had metastasis to 1-2 pelvic lymph node(s) confirmed by nodal staging (N1). All patients received 39 fractions of RT delivering simultaneously 78 Gy to the prostate and 56 Gy to the seminal vesicles and pelvic lymph nodes. Radiotherapy was delivered with intensity modulated RT and daily image-guidance. Patients received three years of androgen deprivation therapy starting three months before RT. The primary endpoint was late morbidity. Physician reported morbidity was scored by the CTCAE v.4.0 while patient reported outcomes (PROs) were registered for gastro-intestinal (GI) by single items from the RT- ARD score, genito-urinary (GU) by the DAN-PSS, sexual and hormonal by the EPIC-26 and quality of life (QoL) by the EORTC C30 questionnaires. Prevalence of morbidities after RT were compared at different time points using the X 2 -test. Results Median follow-up (FU) time was 4.6 years. CTCAE grade 2+ GI morbidities varied from 0-6.0% from baseline throughout FU time, except for diarrhoea which was reported in 19.3% of the patients post-RT, declining to 2.3% at three months and remaining low thereafter. The prevalence of faecal incontinence was unaffected. Prevalences (≥ 1 monthly episode) of PRO symptoms varied between 0-17.8% at baseline. The prevalence of incontinence for liquid and solid stools, urgency, tenesmus, unproductive call to stool, mucus and blood in stool all increased significantly during FU (Fig. 1). No differences were observed for soiling, ≥4 bowel movements, nocturnal bowel movements, clustering, obstructive sensation, strain to defecate, pain at defecation, abdominal pain or defaecation assistance. CTCAE grade 2+ GU and sexual scores were unchanged. PROs revealed significant increase in both GU obstructive and irritative related items post-RT, although declining to pretreatment level at 24 months and thereafter. No clinical significant differences were found in sexual, hormonal and overall QoL scores compared to baseline. Conclusion Whole pelvic RT in high-risk PC patients is associated with a moderate risk of late GI morbidity with impact on patients' QoL. The prevalence of morbidities was clearly demonstrated by PRO scoring systems and not by physician administrated scorings. This underlines the importance of using PROs for morbidity assessment following pelvic RT.

PO-1380 Adjuvant radiotherapy of prostate cancer: a risk stratification system based on prognostic factors S. Bisello 1,2 , A. Arcelli 1,2 , F. Deodato 3,4 , N. Dominsky 2 , G. Tarantino 2,5 , M. Ntreta 1 , S. Cilla 6 , G. Siepe 1 , L. Cavallini 1,2 , D. Pezzulla 3 , A.R. Alitto 7,8 , A. Re 3 , S. Cammelli 1,2 , A. Cortesi 9 , A. Romeo 9 , G.P. Frezza 10 , A.G. Morganti 1,2 , G. Macchia 3 , M. Buwenge 1,2 1 Radiation Oncology, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy; 2 Department of Experimental, Diagnostic, and Specialty Medicine - DIMES, Alma Mater Studiorum Bologna University, Bologna, Italy; 3 Radiation Oncology Unit, Gemelli Molise Hospital – Università Cattolica del Sacro Cuore, Campobasso, Italy; 4 Istituto di Radiologia, Università Cattolica del Sacro Cuore, Roma, Italy; 5 Dana Farber Cancer Institute, Harvard Medical School, Boston, MA, USA; 6 Medical Physics Unit, Gemelli Molise Hospital – Università Cattolica del Sacro Cuore, Campobasso, Italy; 7 Istituto di Radiologia, Università Cattolica del Sacro Cuore, Roma, Italy; 8 Fondazione Policlinico Universitario A. Gemelli, IRCCS, UOC di Radioterapia, Dipartimento di Scienze Radiologiche, Radioterapiche ed Ematologiche, Roma, Italy; 9 Radiotherapy Unit, IRCCS Istituto Romagnolo per lo Studio dei Tumori (IRST) "Dino Amadori", Meldola, Italy; 10 Radiotherapy Department, Ospedale Bellaria, Bologna, Italy