Preliminary Results from Retrospective Correlation of Circulating Tumor DNA (ct-DNA) with Imaging for HPV-positive Oropharyngeal Squamous Cell Carcinoma.

The role of molecular markers is increasingly being recognized for head and neck tumors ranging from benign lesions like paragangliomas to malignancies like squamous cell carcinomas (SCCa). Multiple studies have recently validated blood tests for circulating tumor tissue modified viral- human papillomavirus DNA (HPV ct-DNA) (NavDx, Naveris Laboratories) for posttreatment surveillance of HPV-driven oropharyngeal SCCa. This technology quantifies fragments of circulating DNA that are shed into the blood stream with very high (>95%) positive and negative predictive values and are also highly sensitive in distinguishing tumor HPV-DNA from a non-cancerous source. This study has a cohort of 34 patients with HPV-driven oropharyngeal SCCa, having at least three sequential imaging studies and ct-DNA values. The study showed a strong positive correlation between the imaging findings and ct-DNA level in recurrent HPV positive oropharyngeal SCCa. Findings also include 100% negative predictive value of HPV ct-DNA tests to rule out tumor recurrence. At our institution, we are now routinely performing the ct-DNA assay for surveillance of treated HPV-oropharyngeal SCCa. Correlation between clinical, radiological, and biomarker findings are now part of routine discussions during the multidisciplinary tumor boards.ABBREVIATIONS: ct-DNA=circulating tumor deoxyribonucleic acid; HPV=Human Papilloma virus;OPC=Oropharyngeal SCCa=Squamous cell carcinomas; PCR= Polymerase chain reaction.