ICHNO-ECHNO 2022 - Abstract Book

S84

ICHNO-ECHNO 2022

Conclusion Perineural Invasion in Head and Neck Cancers is found to be strongly associated with Depth of Invasion and Neck Node Metastases suggesting that presence of Perineural Invasion implies tumour biology aggressiveness. It can therefore also serve as an independent risk factor in Head and Neck Squamous Cell Cancers.

PO-0132 Personalised ctDNA analysis for detection of minimal residual disease and recurrence in HNSCC

S. Flach 1 , K. Howarth 2 , S. Hackinger 2 , C. Pipinikas 2 , P. Ellis 2 , K. McLay 2 , G. Marsico 2 , C. Walz 3 , C.A. Reichel 1 , O. Gires 1 , M. Canis 1 , P. Baumeister 1 1 LMU Klinikum, Department of Otorhinolaryngology, Head and Neck Surgery, Munich, Germany; 2 Inivata, Babraham Research Park, Cambridge, United Kingdom; 3 LMU Klinikum, Institute of Pathology, Munich, Germany Purpose or Objective Head and neck squamous cell carcinoma (HNSCC) remain a substantial burden to global health. Cell-free circulating tumour DNA (ctDNA) is an emerging biomarker available from blood which remains largely uncharacterised in the context of surgical treatment of patients with HNSCC. The aims of this study were firstly to determine whether post-operative ctDNA detection can act as a biomarker for surgical tumour clearance. Secondly, to evaluate the potential of personalised ctDNA analysis for early molecular-level detection of relapse prior to clinically confirmed recurrence with concomitant implications for therapy planning. Materials and Methods We conducted Liquid BIOpsy for MiNimal RESidual DiSease Detection in Head and Neck Squamous Cell Carcinoma (LIONESS), a single-centre prospective cohort study to investigate ctDNA in patients with p16-negative HNSCC who received primary surgical treatment with curative intent. Whole exome sequencing was performed on FFPE tissue obtained from 25 unique tumours. We utilised RaDaR™, a highly sensitive personalised assay using deep sequencing of up to 48 tumour- specific variants. The RaDaR™ assay demonstrated 95% sensitivity at 0.001% median variant allele frequency (AF) in analytical validation studies and was used to analyse serial pre- and post-operative plasma samples for evidence of minimal residual disease and recurrence. Results In a subset of 21 patients analysed, personalised panels were designed with between 20 and 52 somatic variants (median 48). Preliminary data shows 100% ctDNA detection in baseline samples taken prior to surgery. 131 longitudinal samples were assessed for evidence of ctDNA. In post-surgery samples, ctDNA could be detected at levels as low as 0.0005% AF. In all cases with clinical recurrence to date (6/6), ctDNA was detected prior to progression, with lead times ranging from 108 to 298 days. Conclusion This study illustrates the potential of ctDNA as a biomarker for monitoring of minimal residual disease as well as recurrence in patients with HNSCC and demonstrates the feasibility of personalised ctDNA assays for detection of disease post- treatment and with consequences for further therapy planning. 1 Cancer Research Institute, Tomsk National Research Medical Center, Laboratory of Cancer Progression Biology, Tomsk, Russian Federation; 2 Cancer Research Institute, Tomsk National Research Medical Center, Department of Head and Neck Cancer, Tomsk, Russian Federation Purpose or Objective Oral squamous cell carcinoma (OSCC) is considered a disease of the elderly. However, the incidence of OSCC has been increased in young (< 45 yrs) adults over the last years. The etiology and molecular mechanisms of early-onset OSCC remain largely unknown. Copy number alterations (CNA) are nearly ubiquitous in cancer and alter a greater portion of the cancer genome than any somatic genetic aberrations. Our study aimed to analyze the CNA landscape of OSCC in young adults compared with patients over 45 years of age. Materials and Methods Seven nonsmoking and HPV-negative OSCC patients (5 under 45 and 2 over 45 years old; T2-3N1M0) were enrolled. The primary tumor and peripheral blood samples were used to isolate DNA using DNeasy Blood & Tissue Kit (Qiagen, USA). DNA libraries were prepared using SureSelect XT v.7 (Agilent, USA) and sequenced on a NextSeq 500 (Illumina, USA). Results Three CNAs were detected in 3 out of 5 young patients (60%), and were not detected in elderly patients: amplification of 6q23.2-25.1 and deletion of 3p26.2-26.3 and 8p23.3 regions. The 6q23.2-25.1 region contains BCLAF1, IFNGR1, SGK1, and TNFAIP3 genes, which were previously described as cancer drivers genes. According to TCGA, 6q24.1-24.3 amplification occurs in 2.4% of young people with head and neck cancer. The 3p26.2-26.3 region includes genes of contactins 4 and 6, which belong to the immunoglobulin superfamily. CNTN4 and С NTN6 genes deletions are observed in 1.5% and 0.8%, respectively, in patients with head and neck cancer (TCGA). DLGAP2 and FBXO25 genes are located in 8p23.3 region and PO-0133 Copy number alterations in early-onset oral squamous cell carcinoma E. Kolegova 1 , R. Vorobev 1 , I. Fedorova 2 , T. Gerashchenko 1 , D. Kulbakin 2 , E. Denisov 1