Association of Pretreatment Circulating Tumor Tissue-Modified Viral HPV DNA With Clinicopathologic Factors in HPV-Positive Oropharyngeal Cancer

IMPORTANCE Circulating tumor tissue-modified viral (TTMV) human papillomavirus (HPV) DNA is a dynamic, clinically relevant biomarker for HPV-positive oropharyngeal squamous cell carcinoma. Reasons for its wide pretreatment interpatient variability are not well understood. OBJECTIVE To characterize clinicopathologic factors associated with TTMV HPV DNA. DESIGN, SETTING, AND PARTICIPANTS This cross-sectional study included patients evaluated for HPV-positive oropharyngeal squamous cell carcinoma at Dana-Farber Cancer Institute in Boston, Massachusetts, between December 2019 and January 2022 and who were undergoing curative-intent treatment. EXPOSURES Clinicopathologic characteristics including demographic variables, tumor and nodal staging, HPV genotype, and imaging findings. MAIN OUTCOMES AND MEASURES Pretreatment circulating TTMV HPV DNA from 5 genotypes (16, 18, 31, 33, and 35) assessed using a commercially available digital droplet polymerase chain reaction-based assay, considered as either detectable/undetectable or a continuous score (fragments/mL). RESULTS Among 110 included patients, 96 were men (87%) and 104 were White (95%), with a mean (SD) age of 62.2 (9.4) years. Circulating TTMV HPV DNA was detected in 98 patients (89%), with a median (IQR) score of 315 (47-2686) fragments/mL (range, 0-60 061 fragments/mL). Most detectable TTMV HPV DNA was genotype 16 (n = 86 [88%]), while 12 patients (12%) harbored other genotypes. Circulating TTMV HPV DNA detection was most strongly associated with clinical N stage. Although few patients had clinical stage N0 disease, only 4 of these 11 patients (36%) had detectable DNA compared with 94 of 99 patients (95%) with clinical stage N1 to N3 disease (proportion difference, 59%; 95% CI, 30%-87%). Among patients with undetectable TTMV HPV DNA, more than half (7 of 12 [58%]) had clinical stage N0 disease. The TTMV HPV DNA prevalence and score increased with progressively higher clinical nodal stage, diameter of largest lymph node, and higher nodal maximum standardized uptake value on positron emission tomography/computed tomography. In multivariable analysis, clinical nodal stage and nodal maximum standardized uptake value were each strongly associated with TTMV HPV DNA score. Among 27 surgically treated patients, more patients with than without lymphovascular invasion had detectable TTMV HPV DNA (12 of 12 [100%] vs 9 of 15 [60%]). CONCLUSIONS AND RELEVANCE In this cross-sectional study, circulating TTMV HPV DNA was statistically significantly associated with nodal disease at HPV-positive OPSCC diagnosis. The few patients with undetectable levels had predominantly clinical stage N0 disease, suggesting assay sensitivity for diagnostic purposesmay be lower among patients without cervical lymphadenopathy. Mechanisms underlying this association, and the use of this biomarker for surveillance of patients with undetectable baseline values, warrant further investigation.