Background:Following chemo-radiotherapy (CCRT) for human papilloma virus positive (HPV+) locally advanced head and neck cancer, patients frequently undergo unnecessary neck dissection (ND) and/or repeated biopsies for abnormal PET-CT, which causes significant morbidity. We assessed the role of circulating HPV DNA in identifying ‘true’ residual disease.Methods:We prospectively recruited test (n=55) and validation (n=33) cohorts. HPV status was confirmed by E7 RT-PCR. We developed a novel amplicon-based next generation sequencing assay (HPV16-detect) to detect circulating HPV DNA. Circulating HPV DNA levels post-CCRT were correlated to disease response (PET-CT).Results:In pre-CCRT plasma, HPV-detect demonstrated 100% sensitivity and 93% specificity, and 90% sensitivity and 100% specificity for the test (27 HPV+) and validation (20 HPV+) cohorts, respectively. Thirty-six out of 37 patients (test and validation cohort) with complete samples-set had negative HPV-detect at end of treatment. Six patients underwent ND (3) and repeat primary site biopsies (3) for positive PET-CT but had no viable tumour. One patient had positive HPV-detect and positive PET-CT and liver biopsy, indicating 100% agreement for HPV-detect and residual cancer.Conclusions:We demonstrate that HPV16-detect is a highly sensitive and specific test for identification of HPV DNA in plasma at diagnosis. HPV DNA post-treatment correlates with clinical response.

Caphosol did not reduce the incidence or duration of severe OM during and after radiotherapy in HNC.

Fewer significant differences in PG saliva analytes >12 months after IMRT indicate good functional recovery. Residual xerostomia after IMRT will only be further reduced by addressing the sparing of subsites of the PG or other salivary gland tissues, in addition to the PG.