ESTRO 38 Abstract book

S133 ESTRO 38

patients did not translate into significantly higher IBR rates (HR 2.12, p=0.14). Conclusion After 10 years long term follow up, WBI after BCS of hormonal receptor positive “low-risk” breast cancer maintained significantly better local control as well as disease free survival rates compared to AH alone. In patients after sentinel node exstirpation only, DFS was significantly improved after WBI. In this trial, the omission of WBI and tumor grading Gx, respectively, turned out to be the only negative predictors for IBR. OC-0271 First randomized study of Hafnium nanoparticles activated by radiotherapy in soft tissue sarcoma S. Bonvalot 1 , P. Rutkowski 2 , J. Thariat 3 , S. Carrere 4 , M. Sunyach 5 , E. Saada-Bouzid 6 , P. Agoston 7 , A. Hong 8 , A. Mervoyer 9 , M. Rastrelli 10 , C. Le Pechoux 11 , V. Moreno 12 , R. Li 13 , B. Tiangco 14 , A. Casado Herraez 15 , A. Gronchi 16 , L. Mangel 17 , P. Hohenberger 18 , M. Delannes 19 , Z. Papai 20 1 Insitut Curie, Surgery, Paris, France ; 2 The Maria Skłodowska Curie Memorial Cancer Centre and Institute of Oncology MCMCC, Soft Tissue/Bone Sarcoma and Melanoma, Warsaw, Poland; 3 Cancer center Baclesse, Radiation Oncology, Caen, France ; 4 Centre Regional De Lutte Contre Le Cancer Paul Lamarque, Surgerical Oncology, Montpellier, France; 5 Centre Leon Berard, Radiation Oncology, Lyon, France; 6 Centre Antoine Lacassagne, Medical Oncology, Nice, France; 7 Országos Onkológiai Intézet, Radiation Oncology Budapest, Hungary; 8 Chris O'Brien Lifehouse, Radiation Oncology, Sidney, Australia; 9 Centre Rene Gauducheau- CLCC Nantes Atlantique, Radiation Oncology, Saint Herblain, France ; 10 Institute of Oncology Veneto IOV, Surgical Oncology, Padova, Italy; 11 Institut Gustave Roussy, Radiation Oncology, Villejuif, France; 12 Hospital Fundación Jimenez Diaz, Medical Oncology, Madrid, Spain ; 13 St. Luke’s Medical Center, Medical Oncology, Quezon City, Philippines; 14 The Medical City Cancer Center, Medical Oncology, Pasay City, Philippine; 15 Hospital Clinico Universitario San Carlos, Medical Oncology, Madrid, Spain; 16 Fondazione IRCCS - Istituto Nazionale dei Tumori, Surgery, Milan, Italy; 17 University of Pecs, Oncotherapy, Pècs, Hungary; 18 Universitätsklinikum Mannheim, Surgical Oncology and Thoracic Surgery, Mannheim, Germany; 19 Institut Claudius Regaud, Radiation Oncology, Toulouse, France; 20 Hungarian Defence Forces, Medical Centre, Budapest, Hungary Purpose or Objective Preoperative radiotherapy (RT) is an option for a subset of patients with locally advanced primary or relapsed tumors. Yet, its impact on efficacy in terms of pathological response is limited, highlighting the need for novel multimodal therapies aimed at local control with low toxicity. NBTXR3 is made of hafnium oxide nanoparticles which, injected intratumorally (IT) and activated by ionizing radiation, yield a tumor-localized high energy deposit and increase cell death compared to the same dose of RT alone. We report here the results of a phase II/III randomized clinical trial of NBTXR3 given as preoperative treatment to patients with locally advanced soft tissue sarcoma (STS) of the extremity and trunk wall [NCT02379845]. Material and Methods Act.In.Sarc is an international, multicenter, open-label, active-controlled phase II/III trial in which patients (pts) with locally advanced STS of the extremity or trunk wall were randomized 1:1 to receive a single IT NBTXR3 injection and RT (Arm A) or RT alone (Arm B), followed by surgical resection. RT consisted of Intensity Modulated RT or 3D-RT of 2Gy*25 fractions (total 50 Gy) over 5 weeks.

Kwasny 9 , D. Heck 10 , V. Bjelic-Radisic 11 , M. Balic 12 , H. Stöger 12 , U. Wieder 13 , R. Zwrtek 14 , D. Semmler 14 , W. Horvath 15 , E. Melbinger-Zeinitzer 16 , M. Wiesholzer 17 , V. Wette 18 , M. Gnant 19 1 Paracelsus Medical University- University Hospital Salzburg- Landeskrankenhaus, Radiotherapy and Radio- Oncology, Salzburg, Austria ; 2 Medical University of Vienna, Radiation Oncology, Vienna, Austria ; 3 Wiener Neustadt Hospital, Radiooncology and Radiotherapy, Wiener Neustadt, Austria ; 4 Ordensklinikum Barmherzige Schwestern Linz, Radiation Oncology, Linz, Austria ; 5 Comprehensive Cancer Center CCC- Medical University of Graz, Therapeutic Radiology and Oncology, Graz, Austria ; 6 Austrian Breast and Colorectal Cancer Study Group, Biostatistics, Vienna, Austria; 7 Paracelsus Medical University- University Hospital Salzburg- Landeskrankenhaus, Medical Oncology, Salzburg, Austria ; 8 Austrian Breast and Colorectal Cancer Study Group, Vienna Study Centre, Vienna, Austria ; 9 Wiener Neustadt Hospital, Surgery, Wiener Neustadt, Austria; 10 Ordensklinikum Barmherzige Schwestern Linz, Surgery, Linz, Austria; 11 Medical University of Graz, Gynecology, Graz, Austria ; 12 Medical University of Graz, Internal Medicine- Division of Oncology, Graz, Austria ; 13 Hanusch Spital, Surgery, Vienna, Austria ; 14 Mistelbach Hospital, Surgery, Mistelbach, Austria; 15 Guessing Hospital, Surgery, Guessing, Austria; 16 Wolfsberg Hospital, Surgery, Wolfsberg, Austria ; 17 University Hospital St. Poelten- Karl Landsteiner University of Health Sciences, Internal Medicine I- Division of Nephrology and Hematology, St. Pölten, Austria ; 18 Krankenhaus der Barmherzigen Brüder St. Veit an der Glan, Surgery, St. Veit an der Glan, Austria; 19 Medical University of Vienna, Surgery and Comprehensive Cancer Center, Vienna, Austria Purpose or Objective To investigate long term results of hormonal receptor positive breast cancer patients with a favorable risk profile after breast conserving surgery (BCS) and consecutive antihormonal treatment (AH) with or without whole breast irradiation (WBI). Material and Methods Within the 8 A trial of the Austrian Breast and Colorectal Cancer Study Group (ABCSG), altogether 869 patients received AH after BCS which was randomly followed by WBI (n=439) or observation (n=430). All patients were defined as “low-risk” with grading G1 or 2, small tumor sizes (< 3 cm) and a node negative status. WBI was applied up to mean total dosages of 50 Gy in conventional fractionation. 71% received an additional tumor bed boost with a 10 Gy mean dose. Of the whole study cohort, 251 (30%) and 519 (60%) were consecutively included in ABCSG–trial 16 and the PAM50 gene expression assay trial, respectively. Results After a median follow-up (FUP) of 9.89 years, 10 in-breast recurrences (IBR) were observed after WBI (group 1) and 31 with AH only (group 2), resulting in 10-years local control rates (LCR) of 97.5% after radiotherapy versus 92.4% (p<0.01) without, respectively. This translated into significantly higher disease free survival (DFS) rates: 94.5% group 1 vs 88.4% group 2, p=0.01. Advantage in DFS after WBI was also observed after sentinel-node exstirpation only (n=258) (HR 0.25, p=0.007) but not after axillary dissection (HR 0.7, p=0.2; n=590). For MFS and OS, respective 10-year rates amounted 96.7% and 86.6% for group 1 versus 96.4% and 87.6%, for group 2 (ns). For development of IBR, WBI (HR 0.27, p<0.01) and Gx tumor grading (HR 3.76, p= 0.03) were detected as significant predictors in multiple cox regression analysis. For the 519 patients of the PAM50 trial where gene expression information was available, a biological high-risk constellation (KI67>20 and/or positive for Her-2 neu) of This abstract is part of the media ogramme and will be released on the day of its presentation