ESTRO 2025 - Abstract Book

S1218

Clinical – Lower GI

ESTRO 2025

2788

Proffered Paper Assessment of Quality of Life in Patients Participating in OPERA Randomized Trial : long-term Results. Syrine Ben Dhia 1 , Arthur Sun Myint 2 , Tanguy Pace-loscos 3 , Christopher Rao 4 , David Baron 1 , Jean Pierre Gérard 1 , Nicolas Barbet 5 , Jerome Doyen 1 1 radiation oncology, Antoine Lacassagne, Nice, France. 2 radiation oncology, Clatterbridge Cancer center, Liverpool, United Kingdom. 3 Department of Epidemiology, Biostatistics, and Health Data (DEBDS), Antoine Lacassagne, Nice, France. 4 Department of Surgery and Cancer, Imperial College London, London, United Kingdom. 5 radiation oncology, Centre Leon Blum, Lyon, France Purpose/Objective: The OPERA trial showed that adding a contact X-ray brachytherapy (CXB) boost increased the 3-year organ preservation (OP) rate in cT2-T3a/b, cN0 M0 rectal adenocarcinoma from 59% to 81%. At 5 years, OP remained higher in the CXB arm (56% vs 79%). This study reports on quality of life (QoL) and bowel function. Material/Methods: A total of 141 patients (pts) were included. All pts received external beam radiotherapy (EBRT): 45 Gy in 25 fractions with capecitabine. Pts were randomized 1:1 to receive either a boost of EBRT in group A (9 Gy/5 fractions) or a boost with CXB (90 Gy/3 fractions) in group B. A total of 116 pts (A: 46, B: 70) followed a Watch & Wait approach. QoL was evaluated using the EORTC QLQ-C30 (Baseline: 140 pts; years 1, 2, and 3: 78, 57, 43 pts) and QLQ-CR29 (Baseline: 125 pts; years 1, 2, and 3: 80, 58, 44 pts). Bowel function was evaluated using the LARS score in 86 pts who preserved their rectum after 1 year (arm A: 34, arm B: 52) and in 45 pts after 5 years (A: 18, B: 27). Rectal bleeding was assessed in patients preserving their rectum and when present, scored using CTCAE version 4.03. It was assessed each year for up to 5 years (year 1: 87 pts, year 5: 46 pts). Results: For the QLQ-C30, no significant differences were observed between group A and group B in any of the items, including global QoL, social functioning, and cognitive functioning. Similarly, for the QLQ-CR29, no significant differences were observed between the two groups. At 5 years, LARS scores ≥30 were seen in 12% (A) and 18% (B), with no significant difference. Mild rectal bleeding (Grade 1–2) due to radiation telangiectasia occurred more in group B (63% vs. 12%, p < 0.0001) at 1 year but resolved by 3 years. Conclusion: Although a high dose of radiation was delivered in a small volume using the CXB boost, QoL was comparable to the EBRT boost, with satisfactory bowel function in over 80% of patients. CXB caused more telangiectasia and mild rectal bleeding at 1 year, which resolved by 3 years. QoL data comparing patients with and without TME will be presented at the time of the meeting, along with detailed tables and figures for all results.

Keywords: rectal cancer, organ preservation, quality of life

2950

Digital Poster CBCT-based online Adaptive Radiotherapy in rectal cancer: workflow and decision pathways. Patricia Lorenzana 1 , Maribel Martínez 1 , Mario Martín 2 , Víctor De la Llana 3 , Mikel Rico 1 , Naiara Fuentemilla 2 , Sonia Flamarique 1 , Amaya Sola 1 , Erkuden Burillo 1 , Libe Amondarain 1 , Ujué Ruiz 1 , Darwin E. Pozo 1 , Santiago Pellejero 2 , Lucía Biscari 1 , Sara López 1 , Laura Casaña 1 , Elena Villafranca 1