Circulating Tumor DNA Testing for Detection and Surveillance of Sinonasal HPV-Associated Cancers.

Background: The incidence of human papilloma virus (HPV)-mediated head and neck (H/N) cancers has risen dramatically. While most HPV-associated H/N cancers are oropharyngeal squamous cell carcinoma (OPSCC), sinonasal squamous cell carcinoma (SNSCC) is the second most common. Recent studies highlight an increasing incidence of HPV-positive SNSCC. Circulating tumor HPV DNA (ctDNA) is a noninvasive tool that has become increasingly utilized to detect high-risk HPV genotypes in the setting of OPSCC, with recent studies reporting high sensitivity and specificity in both pretreatment detection and posttreatment surveillance in OPSCC. Only one study exists reporting its use for SNSCC and nasopharyngeal carcinoma, which was successful in pretreatment detection and identification of recurrence posttreatment. Case Reports: We report two cases demonstrating the utility of ctDNA in HPV-mediated sinonasal malignancies. Case 1: 60-year-old male who presented with a large nasal cavity cancer. Pretreatment ctDNA testing yielded a positive tumor tissue modified viral (TTMV)-HPV DNA Score of 67, reflective of the normalized tumor tissue modified viral-HPV DNA fragments/mL of plasma, and pathology confirmed HPV+ SNSCC. Posttreatment surveillance with HPV ctDNA and endoscopy has shown no evidence of disease. Case 2 involves a 64-year-old male with HPV+ neuroendocrine carcinoma who developed recurrence. ctDNA testing, previously negative following initial treatment, scored 35 at recurrence, prompting salvage surgery and adjuvant chemoradiation. Conclusion: These cases, along with prior studies, underscore the potential of ctDNA as a diagnostic and surveillance tool for sinonasal malignancies. Further multi-institutional prospective trials with larger cohorts are needed to validate its role in detection and surveillance.