ESTRO 2022 - Abstract Book

S1169

Abstract book

ESTRO 2022

Materials and Methods Between October 2012 and June 2021, 15 patients with locally recurrent prostate cancer after brachytherapy (BQ) with biopsy-proven local-only recurrence and uroflowmetry test measure QMax > 12 ml/s and IPSS < 12, were planned to receive Salvage-EBRT: 60Gy +/- 55,2Gy (24 fractions at 5/weeks) to the prostate and seminal vesicles respectively; VMAT/IMRT technology with daily IGRT, previously urinary catheterization throughout the all treatment; The target volume consisted of the CTVp: prostate and CTVv: seminal vesicles; PTVp: CTVp + 3-5mm and PTVv: CTVv + 3-5mm and finally, the organs at risk (OARs) were delimited Bladder, urethra, rectum, femoral-heads, penis bulb. We evaluated biochemical failure (BF) was definited as PSA < post-treatment nadir+2, overall survival (OS), and acute/late gastrointestinal-urinary toxicities (CTCAE v 4.03) weekly during radiotherapy treatment and monthly after completion of treatment. Results The median age of 67 years (range 59-74). 47% (7/15) were low risk, 27% (4/15) intermediate risk, 6%(1/15) high risk and 20% (3/15) not specified. Median follow-up was 13 months (range 1-101,9m). Patients were treated in IMRT/VMAT (10/5). All patients received 60Gy (2.5 Gy/fraction) to the prostate and 27% (4/15) 55.2Gy (2,3 Gy/fr) to the seminal vesicles. Furthermore, 33,3% (5/15) received androgen deprivation therapy (ADT) concurrent for a median 6 months, starting 2 months prior RT. All patients completed EBRT. No patient has presented BF since the end of treatment with a median PSA nadir 0,18ng/mL (0,01-0,40), in an unspecified nadir PSA patient due to short follow-up period. All patients are alive at the present time. And acute/late gastrointestinal-urinary toxicities (CTCAE v 4.03): 33,3% (5/15) patients had acute urinary toxicities Grade > 3. In addition, Rectitis Grade > 2 were observed in 13,3% (2/15); No acute grade 4/5 toxicities were noted. Chronic toxicity, no grade Grade > 3 toxicities were noted. Conclusion Our data suggest that the treatment of locally recurrent prostate cancer with salvage External Beam Radiotherapy could provide adequate disease control and result in a safe technique that provides the patient with an alternative in the natural history of their disease. 1 Pontificia Universidad Católica de Chile, Departamento de Hemato-oncología, Santiago, Chile; 2 Red de Salud UC Christus, Servicio de radioterapia, Santiago, Chile Purpose or Objective We designed a hypofractionated radiotherapy protocol for adjuvant or salvage treatment after radical prostatectomy. In this first report we present the implementation of this protocol in the context of a COVID-19 pandemic. Materials and Methods Patients meeting the inclusion criteria (high-risk features on histopathology or biochemical recurrence) received radiotherapy to the prostate bed 51 Gy in 17 fractions, elective treatment of the pelvis at a dose of 36 Gy in 12 fractions was permited. Acute gastrointestinal (GI) and genitourinary (GU) toxicity was evaluated according to the National Cancer Institute Common Terminology Criteria for Adverse Events versión 4.03. The disease-related quality of life, urinary, gastrointestinal, sexual and hormonal function were evaluated with the Expanded Prostate Cancer Index Composite (EPIC), QLQc30 and PR25 questionnaires at baseline before the start of radiotherapy and at one month after radiotherapy, then every six monts for two years. In addition, the incidence of COVID-19 cases was reported in the patients recruited in the trial and in those who underwent standard fractionation treatment (1.8-2.0 Gy per fraction), and in health personnel involved in the treatment of patients in study period. Results From August 2020 to March 2021, 22 patients have been registered. Fourteen patients have completed treatment and are included in this report. The median age was 64 years and most had a Gleason 3 + 4 (50%), with a pT3a (35.7%) and negative surgical margins (71.4%). Three patients (21.4%) were staged as pN1. Most patients were treated for salvage (57.1%), with an median PSA prior to the start of RT of 0,29 ng/ml. Most patients report minimal or low acute radiation effects in terms of GI and GU toxicity, with an acute toxicity grade 2 GI and GU of 50% and 14.3%, respectively. Without Grade 3 or higher GI / GU toxicity. Of the 14 patients who received the trial protocol, none had a clinical of COVID-19 infection, while one patient who received treatment with conventional fractionation development a COVID-19 infection. Conclusion We present the implementation of an protocol of hypofractionated schedule of postoperative prostate radiotherapy in an academic center in a developing country in the context of a COVID-19 pandemic. Preliminary results show the absence of COVID infection in the included patients, and low GU and GI toxicity. PO-1379 Moderate hypofractionated radiotherapy after prostatectomy in the context of the COVID19 J. Canales 1 , T. Merino 1 , P. Reyes 2

PO-1380 Response evaluation with 68GA-PSMA-PET/CT in prostate cancer patients treated with radiotherapy

C. Onal 1 , O. Guler 1 , E. Oymak 2 , N. Torun 3 , M. Reyhan 1