Circulating HPVDNA in patients undergoing transoral robotic surgery for oropharyngeal cancer: liquid biopsy could identify molecular residual disease

Objectiveswe evaluated the hypothesis that level of ctHPVDNA on the first postoperative day (POD-1); and at 15 days (POD-15) could be associated with the need for adjuvant therapy and the presence of recurrence.Materials and methodsthis is a prospective observational study on biomarkers, focusing on the longitudinal monitoring of ctHPVDNA in a cohort of HPV-OPSCC patients undergoing TORS. Blood samples were collected according to the following schema: (1) pretreatment; (2) on first postoperative day (POD 1); and (3) at 15 days (POD 15). Plasma samples were analyzed with ddPCR assay comprising E6 of HPV16, HPV 33 and HPV 35.ResultsPresent study was conducted on 44 OPSCC patients and revealed a ctHPVDNA sensitivity of 100% (95%CI: 89-100%) in blood samples at first diagnosis. Data demonstrated a significant different of ctHPVDNA levels at POD-1 among patients who received observation vs. adjuvant treatment and among patients who remained disease-free at the last follow-up, compared to those who experienced recurrence. In the next years, studies on larger patients’ surgical cohorts focused on ctHPVDNA levels at POD-1 and continued improvements in assay methodology could allow the implementation of ctHPVDNA in routine clinical use.ConclusionLiquid biopsy could identify residual molecular disease after surgery and guide clinicians choosing adjuvant treatment.