ESTRO 2022 - Abstract Book

S533

Abstract book

ESTRO 2022

Grade ≥ 2 GU and GI late toxicities were found in 43 (12%) and 11 (3%) patients, respectively. A 5-year PFS benefit was highlighted for groups A, B and C (313 patients) when the MR dose was ≥ 72Gy: 72,8% (95%CI 64.6-79.4) versus 60.3% (95%CI 48,4-70,3), p=0.03. Conclusion SPIDER 01, a modern series integrating salvage radiotherapy guided by functional imaging data, we confirmed that sRT is effective in the event of MR inside the PB, with an acceptable toxicity profile. In addition, with the help of functional imaging, we found that dose escalated ≥ 72 Gy on the MR had a significant impact on PFS. Prospective data should further investigate the correlation between MR-targeted dose escalation and PFS.

OC-0608 Phase II trial of hypofractionated postoperative radiotherapy in prostate cancer: NCT02192788

A. Hervás 1 , A. Zapatero 2 , A.M. Carballo 3 , M. Barrado 4 , F. López-Campos 5 , C. Cano 6 , C. Martin de Vidales 7 , A. Rodríguez 8 , C. Eito 9 , A. Salinas 10 , P. Peleteiro 11 , I. Visus 4 , I. Rodríguez Melcón 12 , G. Vázquez 13 , A. Lazo 14 , F. Couñago 15 , L. Guerrero 16 , A. Otero 17 , W.A. Vasquez 18 , P. Samper 19 , B. Caballero 20 , G. Sancho 21 , R. Pérez 22 , J. Olivera 23 , A. del Rey 24 1 Hospital Universitario Ramón y Cajal, Radiation Oncology, Madrid, Spain; 2 Hospital Universitario La Princesa, Radiation Oncology, Madrid, Spain; 3 H, Universitario Santiago de Compostela, Radiation Oncology, Santiago de Compostela, Spain; 4 Complejo Hospitalario de Pamplona, Radiation Oncology, Pamplona, Spain; 5 H, Universitario Ramón y Cajal, Radiation Oncology, Madrid, Spain; 6 H. Universitario Torrecárdenas, Radiation Oncology, Almería, Spain; 7 H. Universitario La Princesa, Radiation Oncology, Madrid, Spain; 8 H. Ruber Internacional, Radiation Oncology, Madrid, Spain; 9 Instituto Oncológico IMQ, Radiation Oncology, Bilbao, Spain; 10 H. Universitario Virgen de la Candelaria, Radiation Oncology, Tenerife, Spain; 11 H. Universitario Santiago de Compostela, Radiation Oncology, Santiago de Compostela, Spain; 12 H. Universitario de Gran Canaria Dr. Negrín, Radiation Oncology, Las Palmas de Gran Canaria, Spain; 13 H. Universitario San Juan de Alicante, Radiation Oncology, Alicante, Spain; 14 H, Universitario Virgen de las Nieves, Radiation Oncology, Granada, Spain; 15 H. Quirón Madrid, Radiation Oncology, Madrid, Spain; 16 H. Quirón La Luz, Radiation Oncology, Madrid, Spain; 17 H. Universitario Virgen de la Victoria, Radiation Oncology, Málaga, Spain; 18 Fundación Jiménez Dñiaz, Radiation Oncology, Madrid, Spain; 19 H. Rey Juan Carlos de Móstoles, Radiation Oncology, Madrid, Spain; 20 H. Universitario de Fuenlabrada, Radiation Oncology, Madrid, Spain; 21 H, Santa Creu i Sant Pau, Radiation Oncology, Barcelona, Spain; 22 H, Carlos Haya, Radiation Oncology, Málaga, Spain; 23 Fundación Jiménez Díaz, Radiation Oncology, Madrid, Spain; 24 H, Universitario Ramón y Cajal, Bioinformatics Unit, Madrid, Spain Purpose or Objective HYPORT-ES (ClinicalTrials.gov Identifier: NCT04484038) is a collaborative (URONCOR, GICOR and SEOR) prospective multicenter phase II trial testing hypofractionated postoperative radiotherapy in prostate cancer. We presented the first results of acute gastrointestinal (GI) and genitourinary (GU) toxicity. Materials and Methods Moderate hypofractionated postoperative radiotherapy (adjuvant and salvage radiotherapy indication according to international guidelines definition) was administered in order to evaluate the feasibility (efficacy and safety) of this scheme. The radiation dose used was 62.5 Gy in 25 fractions of 2.5 Gy/fraction, EQD2= 70 Gy. The inclusion criteria included the presence of unfavourable pathological factors (pT3 and/or positive surgical margins) and/or biochemical failure (PSA ≥ 0.2 and ≤ 2 ng/mL) and/or early salvage (PSA<0.2 ng/mL). Prophylactic nodal irradiation was not allowed. IMRT and IGRT was mandatory. Risk adapted androgen deprivation therapy was permitted. The main outcome measure was acute and late genitourinary (GU) and gastrointestinal (GI) toxicity according to CTCAE. v5 criteria. For acute toxicity we analized patients who had at least 3 months of follow-up from the end of radiotherapy treatment. Secondary outcomes were biochemical control, metastasis-free survival, overall survival and quality of life (EPIC-26, I-PSS and QLQ-30 questionnaires). Results From 07/2019 to 09/2021 288 patients from 24 Spanish centers were recruited. Median follow-up was 11 months (range 2- 26 months). Median age was 68 years (range 48-83 years), 42% of the patients were pT3 and 62% had positive margins. The indication for postoperative RT was adjuvant in 7% and salvage in 93% of the cases. Median PSA pre-RT was 0.28 ng/ml (0- 1.81 ng/ml). 46% of the patients were treated with concomitant androgen deprivation therapy. Acute GU toxicity grade II was observed in 4% of patients, with no cases of acute grade ≥ III GU toxicity; moreover, only 14% of patients developed acute grade II GI toxicity and there were no reported cases of acute GI toxicity ≥ grade III. Conclusion Hypofractionated postoperative radiotherapy in prostate cancer is a safe treatment with excellent acute GU and GI toxicity profile. Longer follow-up is needed to evaluated chronic toxicity and oncologic outcomes.

OC-0609 Radiotherapy quality assurance of the PEACE-1 trial: Initial results of individual case reviews

N. Alyamani 1 , P. Sargos 2 , P. Blanchard 3 , S. Supiot 4 , P. Ronchin 5 , P. Pommier 6 , T. Duberge 7 , M. Silva 8 , Y. Hammoud 9 , A. Hasbini 10 , J. Khalifa 11 , K. Gnep 12 , C. Scrase 13 , J. Saez 14 , L. Vieillevigne 15 , M. Christiaens 16 , T. Zilli 17 , H. Ribault 18 , A. Bossi 19 , K. Fizazi 20 , N. Andratschke 21