Post-Treatment Circulating Free HPV DNA As a Marker of Treatment Outcome in Patients with HPV-Related Propharyngeal Cancer After Radio(chemo)therapy

Abstract

Circulating cell-free HPV16 DNA (cfHPV DNA) assessed after treatment completion was tested as a prognostic marker of treatment failure in patients with HPVrelated oropharyngeal cancer (OPC) treated with radiotherapy alone (RT) or radiotherapy combined with chemotherapy (CHRT). Fifty-five patients with OPC in whom cfHPV DNA was found prior to RT/CHRT were included into the study. cfHPV DNA was subsequently assessed after treatment completion. cfHPV DNA remission (cfHPVrem) was defined as the absence of cfHPV DNA after treatment completion. The association between cfHPVrem and the risk of local, nodal or distant failure was calculated. Survival curves were calculated according to the Kaplan-Meier technique and compared according to cfHPVrem after treatment completion with the log-rank test. Thirteen (24%) patients presented no cfHPVrem after treatment completion. For these patients, the risk of nodal failure was significantly higher (HR=9.38, 95% CI: 1.63-53.97, p=0.009) than for patients with cfHPVrem. The probability of dissemination was comparable in patients with cfHPVrem and with no cfHPVrem (p=0.95). For patients with HPV related OPC, who has no cfHPVrem after RT/CHRT completion stricter follow up is proposed due to higher risk of nodal failure.