ESTRO 2023 - Abstract Book

S706

Monday 15 May 2023

ESTRO 2023

We must remember that the way we interact with each person will have a profound effect on their imaging and treatment experience and will remain with them always. It has for me. Every patient is unique, and we need to ensure they are at the centre of their care. In the early 1990s I interviewed some patients on their experiences of having facial cancers. One lady retold the way her diagnosis was given to her 'he sat not looking at me, at right angles and with a desk between us’, and her strong feelings months later of how he had made her feel ‘we are people, not just bodies’. It is a phrase that is so powerful in its simplicity and one I have never forgotten … and never will! With ever increasing workload pressures and imaging and cancer targets we must take time to include our patients, to listen to their true voices and learn from them.

SP-0836 yESTRO update: what happened since last ESTRO S. Petit The Netherlands Abstract not available Award Lecture: Interdisciplinary Award

SP-0838 The flame of interdisciplinary research U. van der Heide The Netherlands Abstract not available Award Lecture: Donal Hollywood Award

SP-0839 Adaptive and dose redistributed radiotherapy in head and neck cancer: ARTFORCE RCT phase III results A. de Leeuw 1 , J. Giralt 2 , Y. Tao 3 , S. Benavente 2 , T.F. Nguyen 4 , F. Hoebers 5 , A. Hoeben 6 , C. Terhaard 7 , L.W. Lee 8 , S. Friesland 9 , R. Steenbakkers 10 , M.T. Kayembe 11 , S. van Kranen 1 , H. Bartelink 1 , C. Rasch 12 , J. Sonke 1 , O. Hamming-Vrieze 1 1 The Netherlands Cancer Institute, Department of Radiation Oncology, Amsterdam, The Netherlands; 2 Hospital General Vall d’Hebron, Department of Radiation Oncology, Barcelona, Spain; 3 Institut Gustave Roussy, Villejuif, Department of Radiation Oncology, Villejuif, France; 4 Institut Gustave Roussy, Department of Radiation Oncology, Villejuif, France; 5 GROW - School for Oncology and Developmental Biology, Maastricht University Medical Centre Department of Radiation Oncology (MAASTRO), Maastricht, The Netherlands; 6 GROW-School of Oncology and Developmental Biology Maastricht University Medical Center+, Division of Medical Oncology, Department of Internal Medicine, Maastricht, The Netherlands; 7 University Medical Center Utrecht, Department of Radiation Oncology, Utrecht, The Netherlands; 8 The Christie NHS Foundation Trust, Department of Radiation Oncology, Manchester, United Kingdom; 9 Karolinska University Hospital, Department of Radiation Oncology, Stockholm, Sweden; 10 University Medical Center Groningen, Department of Radiation Oncology, Groningen, The Netherlands; 11 The Netherlands Cancer Institute, Department of Bioinformatics and Statistics, Amsterdam, The Netherlands; 12 Leiden University Medical Center, Department of Radiation Oncology, Leiden, The Netherlands Purpose or Objective The multicentre randomized phase III Adaptive Radiation Treatment for Head and Neck Cancer (ARTFORCE) trial (NCT01504815) aimed to improve the locoregional control (LRC) in patients with locoregionally advanced head and neck cancer (LAHNSCC) by increasing dose to radioresistant tumor subvolumes using the fluorodeoxyglucose positron emission tomography (FDG-PET). Secondly, toxicity rates were aimed to be similar to conventional radiotherapy by decreasing dose to the primary tumor planning target volume (PTVp) borders and improving treatment accuracy using adaptive radiotherapy. Materials and Methods A sample of 268 was determined to find a LRC benefit of 15%, given a historic LRC of 65% (two-sided α =0.05, β =0.80). After including 221 eligible patients with LAHNSCC from 9 institutes since 2012, the trial closed in 2019 due to slow accrual. Patients were randomized (1:1) to receive either conventional radiotherapy with a homogeneous dose of 70Gy (cRT, n=112) or adaptive and FDG-PET guided dose redistributed radiotherapy (rRT, n=109). In rRT, dose was redistributed by escalating dose (min 70Gy, max 84Gy, mean 77Gy) in the PTVFDG (>50%SUVmax), and decreasing (min 64Gy) dose at PTVp borders. Both schedules were delivered in 35 fractions by simultaneous integrated boost and combined with concurrent three cycle high dose cisplatinum (100mg/m2). Anatomical adaptation was scheduled after the 10th fraction for patients treated by rRT. LRC, progression-free (PFS) and overall survival (OS) analyses were performed by the intention-to-treat principle using the Kaplan Meier (KM) method. Unadjusted hazard ratios were obtained using univariable Cox proportional hazards regression (CPH). Toxicities were scored using the CTCAE (v4.0). 2-year toxicity prevalence was evaluated by Fisher’s exact test for patients with complete and locoregional failure-free 2-year follow up. KM and CPH methods were used for 2-year late toxicity incidence analysis. The software R (version 4.1.1.) was used for analysis. Results Median follow up time was 4 years (IQR 2.4–5.1). 2 patients in both arms prematurely ended radiotherapy. 2-year LRC was not significantly different between trial arms, with control rates of 76.8% and 82.7% (log-rank p=0.426) for the cRT and rRT arm, respectively (fig. 1A). Neither was a significant difference found for 5-year PFS (p=0.626, fig. 1B) or OS (p=0.964, fig. 1C). 2-year toxicity prevalence was evaluable for 78 cRT and 79 rRT patients. Grade ≥ 2 or grade ≥ 3 toxicity prevalence (p ≥ 0.120, table 1) or incidence (p=0.898)