ESTRO 2025 - Abstract Book

S1167

Clinical – Lower GI

ESTRO 2025

Oncology, University Hospitals Coventry and Warwickshire, Coventry, United Kingdom. 18 Clinical Oncology, University Hospitals Plymouth NHS Trust, Plymouth, United Kingdom. 19 Clinical Oncology, Guys and St Thomas NHS Foundation Trust Hospitals Sussex NHS Foundation Trust, London, United Kingdom. 20 Clinical Oncology, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom. 21 (NOTCH), The National Oncology Trainees Collaborative for Healthcare Research, National, United Kingdom. 22 Patient and Public Involvement Trial Representative, (PPI), London, United Kingdom. 23 Leeds Institute of Medical Research, St James University Hospital, Leeds, United Kingdom. 24 Clinical Oncology, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom Purpose/Objective: Patients with frailty and co-morbidity are often unable to tolerate standard-of-care chemoradiotherapy (CRT) for non-metastatic anal squamous cell carcinoma (ASCC) and are frequently excluded from clinical trials. Further research is required to determine the best management strategies for these patients. We aimed to quantify the cohort of patients treated in the United Kingdom (UK) who did not receive standard CRT and describe the range of practice and the treatment outcomes to inform future trials in this patient population. Material/Methods: A UK national retrospective multi-centre service evaluation to determine the demographics, treatment procedures and outcomes of patients treated with de-escalated treatment for non-metastatic ASCC over a 3-year period between 1/7/2017 and 30/06/2020. De-escalated treatment was defined as reduced dose radiotherapy or chemotherapy that was omitted or reduced from the outset. Data for patients receiving de-escalated treatment was collected at local centres and submitted anonymously using REDCap software. Clinical frailty was assessed retrospectively using a modified G8 score, threshold adjustments were used to account for missing data. Co morbidity was graded using ACE-27 score. Results: 21 UK cancer centres participated. A total of 338 patients with non-metastatic ASCC received de-escalated treatment; 17% of 1946 patients treated during the period studied. Modified G8 scores identified 195/338 (58%) patients who may have benefited from a comprehensive geriatric assessment (Frail) compared to 143/338 (42%) who did not (Not frail).