Impact of Circulating Cell Free Tumor Tissue Modified Viral-HPV DNA Testing on Post-Treatment Imaging Surveillance Protocol in Oropharyngeal Carcinoma

Harleen K. Sethi, DO

Nayel Khan, MD

Varsha Jain, MD, PhD

Melanie Nordlinger, MD

Leila J. Mady, MD, PhD, MPH

Christopher E. Fundakowski, MD Thomas Jefferson University

Post-treatment surveillance imaging recommendations for oropharyngeal squamous cell carcinoma (OPSCC) lack level I evidence, with significant variability in protocols by institution and providers. In addition to cross-sectional imaging (CSI), peripheral blood testing is available to detect circulating, cell free tumor tissue modified viral (TTMV)-HPV DNA in >90% of OPSSC. Given the paucity of data regarding radiologic surveillance with circulating tumor DNA (ctDNA) blood testing,1 our study aims to evaluate a novel post-treatment serologic surveillance pathway.

We performed a retrospective review of post-treatment imaging in HPV-associated OPSCC over 2-years at a single site. Institutional review board approval was obtained. Frequency of CSI was compared between 2 groups: 1-year prior to ctDNA (control) versus 1-year after ctDNA (experimental) integration (Table 1, Table 2). Eligible participants

Figures/Tables included patients treated for primary HPVassociated OPSCC with no evidence of disease on 3-month, post-treatment PET/ CT following the completion of definitive treatment. In-office exam and point of care ultrasound (POCUS) was used at each surveillance visit for all participants to assess for regional recurrence. The control group received CT neck with contrast every 6-months and CT chest at 6-12

Abbreviations: BOT, base of tongue; GT, glossotonsillar a US Preventative Services Task Force (USPSTF) defines high-risk smokers as adults aged 50 to 80 years who have a 20 pack-year smoking history and currently smoke or have quit within the past 15 years and recommends annual low dose computed tomography (CT) scans. b Low risk smokers were defined as patients whose tobacco history fell below USPSTF recommendations for annual CT surveillance c Stages are based on the American Joint Committee on Cancer staging manual, 8th edition