Determinants of Circulating Tumor HPV DNA in Surgically Treated Oropharyngeal Cancer

Importance: Circulating tumor DNA (ctDNA) is a biomarker of disease status in patients with human papillomavirus (HPV)-mediated oropharyngeal squamous cell carcinoma (OPSCC). Objective: To assess clinicopathologic variables associated with circulating tumor human papillomavirus DNA (ctHPVDNA) before and after surgery. Design, Setting, and Participants: The retrospective review and cohort study was conducted at a tertiary academic medical center and included patients with HPV-mediated OPSCC who were treated with upfront surgery between September 2021 and April 2025. Data were analyzed between September 2025 and December 2025. Exposures: Clinicopathologic variables, including demographic characteristics, pathologic T and N stage, American Joint Committee on Cancer Staging Manual, 8th edition stage, tumor size, margin status, pathologic extranodal extension (pENE), and lymphovascular and perineural invasion. Main Outcomes and Measures: Multivariable negative binomial regression was used to identify clinicopathologic factors associated with preoperative ctHPVDNA, which was measured using tumor tissue-modified viral HPV DNA. Factors associated with detectable postoperative ctHPVDNA were evaluated using logistic regression. Results: A total of 104 patients (mean [SD] age, 59 [10] years; 20 female individuals [19%] and 84 male individuals [81%]; 3 Black individuals [3%] and 101 White individuals [97%]) with HPV-associated OPSCC who were treated with upfront surgery had preoperative ctHPVDNA measurements, and 74 patients had preoperative and postoperative assessments. The mean (SD) preoperative ctHPVDNA level was 2786 (9714) copies/mL. On multivariable negative binomial regression, higher estimated glomerular filtration rate (eGFR; rate ratio [RR], 1.05; 95% CI, 1.01-1.09) and higher pathologic N stage (RR, 12.30; 95% CI, 2.65-57.5) were independently associated with higher preoperative ctHPVDNA levels, whereas perineural invasion (PNI; RR, 0.23; 95% CI, 0.07-0.83) and pathologic extranodal extension (pENE; RR, 0.11; 95% CI, 0.04-0.28) were associated with lower levels. Detectable postoperative ctHPVDNA was observed in 15 of 74 patients (20.2%) and was associated with more than 4 positive lymph nodes (odds ratio [OR], 4.86; 95% CI, 1.39-19.49) higher preoperative ctHPVDNA levels (OR, 1.17; 95% CI, 1.04-1.36), PNI (OR, 2.95; 95% CI, 0.51- 15.51), and pENE (OR, 3.38; 95% CI, 0.84-13.29). Recurrence occurred for 3 of 15 patients (20.0%) with detectable postoperative ctHPVDNA compared with 8 of 59 patients (13.6%) with undetectable ctHPVDNA. Among patients with undetectable postoperative ctHPVDNA, 4 locoregional recurrences occurred in individuals who declined guideline-concordant adjuvant therapy. Conclusions and Relevance: The results of this cohort study illuminate the biological and clinical factors associated with ctHPVDNA shedding and clearance, potentially offering guidance for integrating ctHPVDNA into biomarker-driven clinical trials.