ESTRO 2023 - Abstract Book

S334

Sunday 14 May 2023

ESTRO 2023

OC-0433 GETUG-AFU 22 phase II randomized trial : final results on clinical outcomes with immediate SRT I. Latorzeff 1 , S. Guerif 2 , F. Castan 3 , E. Meyer 4 , S. Supiot 5 , E. Lagneau 6 , E. Deniaud-Alexandre 7 , P. Ronchin 8 , A. Benyoucef 9 , L. Cartier 10 , H. Hamidou 11 , A. Hasbini 12 , G. Crehange 13 , P. Pommier 14 , A. Bareille Saint Gaudens 15 , M. Zibouche 16 , E. Gross 17 , G. Ploussard 18 , L. Salomon 19 , P. Sargos 20 1 Groupe ONCORAD Garonne, Pasteur Clinic, Radiation Oncology, Toulouse, France; 2 Poitiers University Hospital, Radiation Oncology, Poitiers, France; 3 ICM Regional Cancer Institute of Montpellier, Statistics, Montpellier, France; 4 Francois Baclesse Institute, Radiation Oncology, Caen, France; 5 René Gauducheau Cancer Center, Radiation Oncology, Saint Herblain, France; 6 Oncology and Radiotherapy Center, Radiation Oncology, Dijon, France; 7 Hospital Center of Vendée, Radiation Oncology, La Roche Sur Yon, France; 8 Azuréen Cancer Center, Radiation Oncology, Mougins, France; 9 Henri Becquerel Cancer Center, Radiation Oncology, Rouen, France; 10 Sainte Catherine Institute, Radiation Oncology, Avignon, France; 11 Paul Papin Cancer Center, Radiation Oncology, Angers, France; 12 Pasteur Clinic, Radiation Oncology, Brest, France; 13 Georges François Leclerc Cancer Center, Radiation Oncology, Dijon, France; 14 Léon Bérard Cancer Center, Radiation Oncology, Lyon, France; 15 University Institute of Cancerology and Hematology, Radiation Oncology, Saint Etienne, France; 16 Unicancer, Clinical research, Paris, France; 17 Ramsay Générale de santé, Private hospital Clairval, Radiation Oncology, Marseille, France; 18 Croix du Sud Clinic, Urology, Toulouse, France; 19 Henri Mondor Hospital - APHP, Urology, Creteil, France; 20 Bergonié Institute, Radiation Oncology, Bordeaux, France Purpose or Objective The standard of care for patients with localized prostate cancer is radical prostatectomy (RP) but no recommendations exist for patients with persistently elevated prostate-specific antigen (PSA) after RP. The aim of this trial was to compare immediate salvage radiation therapy (iSRT) with or without short-term androgen deprivation therapy (ADT) in these patients and to select the most effective arm. Materials and Methods RP patients with non metastatic PCa on conventional preoperative imaging, and with a post-RP PSA level between 0.2 and 2 ng/mL were randomized (1:1) to iSRT alone (iSRT arm) or 6 months of ADT (degarelix) with iSRT (iSRT+ADT arm). ISRT consisted of pelvic irradiation (46 Gy in 23 Fr) with a boost on the prostate bed (66 Gy in 33 Fr). The primary endpoint was event-free survival (EFS). Biochemical progression-free survival (bPFS), metastates-free survival (MFS), overall survival (OS), quality of life, and toxicities were evaluated as secondary endpoints. With a pick the winner design, 122 pts were required to select the most effective arm with the probability > 80% (82% according to Liu's formula) for a 20% reduction in the instantaneous risk ratio (HR=0.80) Results From Jan-2013 to Sept-2015, 125 pts were included (iSRT arm: 64 pts; iSRT+ADT arm: 61). Median follow up was 74.94 months (95% CI: 74.1-76.6). Median PSA was 0.6 ng/mL (0.12-3.65) at randomization. At 5 years. EFS rate was 62.3% (95% CI: 48.9-73.2) in iSRT arm and 63.5% (95% CI: 49.9-74.2) in iSRT+ADT arm (HR=0.83; 95%CI: 0.47-1.47; p=0.528). bPFS rate was 62.3% (95% CI: 48.9-73.2) in iSRT arm and 66% (95% CI: 52.3-76.6) in iSRT+ADT arm (HR=0.76; 95%CI: 0.44-1.31; p=0.322). MFS was in favor of the iSRT+ADT arm with HR=0.51 (95% CI: 0.26-0.99; p=0.048). OS data were not mature at the time of analysis. In a multivariate analysis, PSA level <0.6 ng/ml at randomization and tumor ≤ pT3a were were significant good prognostic factors for bPFS (HR=0.56; 95%CI: 0.31-1.01; p=0.05 and HR=0.33; 95%CI: 0.19-0.58; p=0.0002, respectively). ISRT alone and PSA level <0.6 ng/ml at randomization were good prognostic factors for MFS (HR=0.39; 95%CI: 0.16-0.93; p=0.03 and HR=0.36; 95%CI: 0.14-0.88; p=0.019, respectively) in multivariate analysis. No grade 4 toxicities were observed. Overall, no difference in acute toxicity were observed between the 2 arms and more late toxicities ( ≥ 6 months after iSRT) were observed in the iSRT+ADT than the iSRT arm (53.1% vs 70.5%; p=0.046). At 12 months ADT-related symptoms were more important in the iSRT+ADT arm (QLQ-PR25; p=0.04). At 24 months, no difference in QLQ-C30 or QLQ-PR25 analysis was reported. After an initial 25-fold decrease in blood testosterone level, all patients recovered to normal level 12 months after starting ADT Conclusion This study demonstrated that iSRT+ADT is the most effective arm and improved MFS with good tolerance for patients with persistently elevated PSA after RP. iSRT+ADT may be used as reference arm for a phase III study. OC-0434 Long -term results of OLIGOPELVIS, a Phase II Trial of pelvic RT in Oligorecurrent Prostate Cancer S. Supiot 1 , L. Vaugier 2 , D. Pasquier 3 , X. Buthaud 4 , N. Magné 5 , D. Peiffert 6 , P. Sargos 7 , G. Crehange 8 , P. Pommier 9 , G. Loos 10 , A. Hasbini 11 , I. Latorzeff 12 , M. Silva 13 , F. Denis 14 , J. Lagrange 15 , C. Morvan 16 , L. Campion 17 , A. Blanc-Lapierre 18 , J. Paul 19