ESTRO 2022 - Abstract Book

S75

Abstract book

ESTRO 2022

Figure 1. Xerostomia by Salivary scintigraphy for ipsilateral parotid

Conclusion Addition of brachytherapy to IMRT for early stage oropharyngeal cancers results in significant reduction in xerostomia and should be considered as the standard of care in suitable cases.

OC-0101 First results of FAST-Forward phase 3 RCT nodal substudy: 3-year normal tissue effects

D. Wheatley 1 , J. Haviland 2 , J. Patel 2 , M. Sydenham 2 , A. Alhasso 3 , C. Chan 4 , S. Cleator 5 , C. Coles 6 , E. Donovan 7 , A. Kirby 8 , C. Kirwan 9 , Z. Nabi 10 , E. Sawyer 11 , N. Somaiah 8 , I. Syndikus 12 , K. Venables 13 , J. Yarnold 14 , A.M. Brunt 15 , J. Bliss 2 1 Royal Cornwall Hospital, Sunrise Cancer Centre, Truro, United Kingdom; 2 The Institute of Cancer Research, ICR-CTSU, London, United Kingdom; 3 NHS Greater Glasgow and Clyde, The Beatson West of Scotland Cancer Centre , Glasgow, United Kingdom; 4 Nuffield Health, Breast Surgery, Cheltenham, United Kingdom; 5 Imperial College Healthcare NHS Trust, Oncology, London, United Kingdom; 6 Cambridge University Hospitals NHS Foundation Trust, Oncology, Cambridge, United Kingdom; 7 University of Surrey, Centre for Vision, Speech and Signal Processing, Guildford, United Kingdom; 8 The Royal Marsden NHS Foundation Trust, Academic Radiotherapy, Sutton, United Kingdom; 9 University Hospital of South Manchester, Breast Surgery, Manchester, United Kingdom; 10 The Hillingdon Hospitals NHS Foundation Trust, RTTQA , London, United Kingdom; 11 Guy’s and St Thomas’ NHS Foundation Trust, Oncology, London, United Kingdom; 12 The Clatterbridge Cancer Centre NHS Foundation Trust, Radiotherapy, Clatterbridge, United Kingdom; 13 The Hillingdon Hospitals NHS Foundation Trust, Medical Physics, London, United Kingdom; 14 The Institute of Cancer Research, Academic Radiotherapy, London, United Kingdom; 15 University of Keele, School of Medicine, Stoke on Trent, United Kingdom Purpose or Objective The FAST-Forward main trial showed that a radiotherapy (RT) schedule of 26Gy in 5 fractions (Fr) delivered in 1 week to the breast/chest wall is as safe and effective as a standard 15Fr regimen after primary surgery for early breast cancer. The findings have changed international clinical practice following publication in April 2020. Here, we present interim results of the nodal substudy up to 3-year follow-up. Formal hypothesis testing will await the 5-year primary analysis. Materials and Methods The FAST-Forward nodal substudy (ISRCTN19906132) randomised patients with invasive breast cancer (pT1-3 pN1-3a M0) after breast conservation or mastectomy to 40Gy/15Fr over 3 weeks, 27Gy or 26Gy/5Fr over 1 week (1:1:1) to level I-IV axilla. The level was specified by the clinician for each patient. A protocol amendment in 12/2017 closed recruitment to 27Gy/5Fr. Centres pre-specified tumour bed boost if required. Main objective was to assess non-inferiority in patient- reported arm/hand swelling (primary endpoint) and function for 5Fr vs 15Fr. Design assumed 5-year 10% moderate/marked arm/hand swelling (EORTC QLQ-BR23) in 40Gy/15Fr with non-inferiority defined as 10% absolute excess in 5Fr schedules (1- sided α =0.05). NTE are assessed by clinicians (annually) and by patients (3, 6, 12, 24, 60m). Results 467 patients were randomised 04/2016-10/2018 from 50 UK centres (181 40Gy, 182 26Gy, 104 27Gy). Median age was 60yrs; 7%, 53% & 40% were tumour grade 1, 2 & 3 respectively; 26% received a boost (of which 13% 16Gy/8Fr, 58% 10Gy/5Fr, 29% other). Data returns/expected (excluding deaths & withdrawals) were 89% (367/414) 2-year patient questionnaires and 89% (375/420) 3-year clinical follow-up. Patients reported 2-year moderate/marked arm/hand swelling in 13/127 (10%) for 40Gy, 10/134 (7%) for 26Gy and 12/89 (13%) for 27Gy; estimated absolute differences: -2.8% (90%CI -8.6, 3.0) for 26Gy and 5.1% (90%CI -2.9, 13.2) for 27Gy vs 40Gy. 2-year prevalence of other patient-reported NTE were comparable for 26Gy and 40Gy (table). Clinicians reported arm lymphoedema at 3 years in 11/130 (8%) for 40Gy, 15/123 (12%) for 26Gy, 9/85 (11%) for 27Gy.