ESTRO 2025 - Abstract Book

S1263

Clinical – Lower GI

ESTRO 2025

Conclusion: This study highlights the significant impact of late GI toxicity on the QoL of anal cancer survivors, with better functioning scales and fewer symptoms observed in patients without severe toxicity. PROs align with CROs reflecting the severity and grade of toxicity. The findings emphasize the importance of preventing and managing late toxicities to improve survivorship outcomes. The use of the specific EORTC QLQ-ANL27 module provides a foundation for standardized PRO assessment and targeted interventions to improve survivorship outcomes.

Keywords: Anal Canal Cancer, QOL, PRO

3895

Proffered Paper Long term toxicity results of ACT4 RCT: evaluating reduced dose and standard dose chemoradiotherapy in early-stage anal cancer (ISRCTN:88455282) Alexandra Gilbert 1 , Joanne Webster 2 , Sarah Brown 2 , Joanne Copeland 2 , Sharon Ruddock 2 , Duncan Gilbert 3 , Maria Hawkins 4 , Rebecca Muirhead 5 , Andrew Renehan 6 , Natalie Abbott 7 , Lindy Berkman 8 , Chloe Gaul 2 , Rob Glynne-Jones 9 , Vicky Goh 10 , Sheela Rao 11 , Susan Richman 1 , Alexandra Smith 2 , Richard Adams 12 , Mark Harrison 9 , David Sebag Montefiore 1 1 Leeds Institute of Medical Research at St James’s, University of Leeds, Leeds, United Kingdom. 2 Clinical Trials Research Unit, Leeds Institute of Clinical Trials Research,, University of Leeds, Leeds, United Kingdom. 3 Sussex Cancer Centre, Royal Sussex County Hospital, Brighton, United Kingdom. 4 Dept of Medical Physics & Biomedical Engineering, University College London, London, United Kingdom. 5 Department of Oncology, Oxford University Hospitals NHS Trust, Oxford, United Kingdom. 6 Division of Cancer Sciences, University of Manchester, Manchester, United Kingdom. 7 National Radiotherapy Trials QA (RTTQA) Group, National Radiotherapy Trials QA (RTTQA) Group, Cardiff, United Kingdom. 8 Patient advocate, n/a, London, United Kingdom. 9 Mount Vernon Centre for Cancer Treatment, Mount Vernon Hospital, Northwood, United Kingdom. 10 School of Biomedical Engineering & Imaging Sciences, King's College London, London, United Kingdom. 11 Institute of Cancer Research, Royal Marsden, London, United Kingdom. 12 Centre for Trials Research, Cardiff University, Cardiff, United Kingdom Purpose/Objective: To evaluate acute and late toxicity associated with chemoradiotherapy for early-stage anal cancer within the ACT4 RCT. Material/Methods: ACT4 is a phase II prospective, multi-centre, two-arm non-comparative RCT. Patients with T1-2(≤4cm) N0/xM0 anal cancer were randomised 1:2 to standard dose (sd) IMRT: 50.4Gy in 28fractions (F) versus reduced dose (rd) IMRT: 41.4Gy in 23F with concurrent chemotherapy. The primary endpoint is 3-year locoregional failure with a sample size of 162. Secondary outcomes included acute toxicities and patient reported outcomes (PROs). Adverse reactions (CTCAEv5) were collected weekly during treatment. PROs were collected on paper or electronically via validated EORTC QLQ-C30 and QLQ-ANL27 questionnaires at baseline, end of treatment (EoT), 6-weeks, and 12, 24 and 36 months post EoT. Changes in mean scores of 5-10 points are classified as small; moderate: 10-20 points, and large changes >20 points(1). Results: 163 patients were randomised from 28 UK sites (sd-IMRT n=55; rd-IMRT n=108) between April 2017-November 2020; 3 patients were excluded from the modified intention-to-treat analysis. Chemotherapy and radiotherapy compliance are reported previously(2). Primary endpoint results are submitted in a companion abstract. ≥Grade 3 was reported in 45.5% sd-IMRT (n=25) versus 35.2% rd-IMRT (n=37)(Table 1). PRO compliance was high; 97.5% at baseline, ranging from 80.8% (EoT) to 91.6% (36-months). There was a moderate to large deterioration in pain, fatigue, bowel function, overall quality of life (QOL), physical, role and social function