ESTRO 2025 - Abstract Book

S1071

Clinical – Head & neck

ESTRO 2025

3227

Poster Discussion Prospective evaluation of Next Generation Sequencing (NGS) plasma HPVDNA assay for treatment response estimation in head and neck cancer Shreerang Bhide 1,2 , Monisha Dewan 3 , Jen Lee 4 , Nuria Porta 3 , Kevin Harrington 1,2 , Rosalind Cutts 5 , Rosemary Bowers 6 , Mark Sydenham 3 , Marie Emson 3 , Karen Poole 3 , Christina Wilson 7 , Emma De Winton 8 , Matthew Ward 9 , Tom Roques 10 , Ramkumar Shanmugasundaram 11 , Anoop Haridass 12 , Judith Christian 13 , Aung Tin 14 , Satya Garikipati 15 , Matthew Beasley 16 , Kee Howe Wong 1 , Maggie Chong U Cheang 3 1 Clinical Oncology, The Royal Marsden Hospital NHS Trust, London, United Kingdom. 2 Radiotherapy and Imaging, The Institute of Cancer Research, London, United Kingdom. 3 CTSU, The Institute of Cancer Research, London, United Kingdom. 4 Targeted Therapy, The Institute of Cancer Research, London, United Kingdom. 5 Molecular Oncology Group, The Institute of Cancer Research, London, United Kingdom. 6 CMP, The Royal Marsden Hospital NHS Trust, Sutton, United Kingdom. 7 Clinical Oncology, The Beatson West of Scotland cancer Centre, Glasgow, United Kingdom. 8 Clinical Oncology, The royal United Hospitals, Bath, United Kingdom. 9 Clinical Oncology, Portsmouth Hospitals NHS Trust, Portsmouth, United Kingdom. 10 Clinical Oncology, Norfolk and Norwich Hospital NHS Trust, Norwich, United Kingdom. 11 Clinical Oncology, The University Hospital Southhampton, Southampton, United Kingdom. 12 Clinical Oncology, The Clatterbridge Cancer Centre, LIverpool, United Kingdom. 13 Clinical Oncology, Nottingham University Hospitals, Nottingham, United Kingdom. 14 Clinical Oncology, James Cook University Hospital, Middlesborough, United Kingdom. 15 Clinical Oncology, Weston Park Cancer Centre, Sheffield, United Kingdom. 16 Clinical Oncology, UHB NHS Trust, Bristol, United Kingdom Purpose/Objective: We developed a NGS assay for the detection of circulating HPV16 DNA, “HPV-detect”, which demonstrated >90% sensitivity and specificity in a pilot study (1). For assay validation, we conducted a multi-centre prospective sample collection study to investigate circulating HPV-DNA (cHPV-DNA) as a marker of residual disease in people with locally advanced HPV-positive (p16 InK4A IHC/ISH) oropharyngeal cancer undergoing curative chemoradiation/radiotherapy (RT/CRT). Primary endpoint was the specificity of cHPV-DNA at 11-20 weeks post-RT/CRT, compared to 18F-FDG-PET CT. Here, we present the primary end-point analysis of this study. Material/Methods: Diagnostic tissue samples were collected to confirm HPV status using RNA/DNA polymerase chain reaction (PCR). Blood samples were collected at baseline, weekly during treatment, weekly up to 4 weeks post-RT/CRT, and at week 6, 3 months(M), 6M, 9M and 12M. All patients underwent 18F-FDG-PET-CT post-RT/CRT for the primary endpoint evaluation. Patients with positive/equivocal 18F-FDG-PET-CT underwent repeat imaging as per the decision by the local multidisciplinary team . Patient outcome data were collected up to 12 months post-RT/CRT.

Results: