Background
HPV-related oropharyngeal cancer (HPV-OPC) incidence is increasing but the natural history of the precursor, oral HPV, has not been well described.
Methods
This observational cohort study of people living with HIV and at-risk HIV uninfected people evaluated participants semi-annually using 30-second oral rinse/gargle specimens over 7 years. Initially, 447 subjects were followed for four years as part of the POPS Study, and a subset of 128 showing persistent infections at the last POPS visit had an additional visit, as part of MOUTH Study, on average 2.5 years later. Extracted DNA from oral rinse/gargle specimens were amplified using PCR and type-specification of 13 oncogenic HPV types. Risk factors for oncogenic oral HPV clearance were evaluated using Cox models.
Results
The majority of oncogenic oral HPV infections cleared quickly with median time to clearance of 1.4 years [IQR=0.5-3.9]. After 7 years of follow-up, 97% of incident and 71% of prevalent infections had cleared. Lower HPV16 viral load was statistically significantly associated with clearance (Per 10-fold decrease in copy number: adjusted hazard ratio [HR]=2.51, 95% confidence interval [CI]=1.20-5.26, p=.01) Adjusted analyses showed oncogenic oral HPV clearance was lower among prevalent than incident detected infections (aHR=0.44, 95%CI=0.35-0.55), among men than women (aHR=0.74, 95%CI=0.60-0.91), for older participants (aHR per 10 years increasing age=0.81, 95%CI=0.74-0.89), and among people living with HIV (aHR=0.76, 95% CI = 0.60-0.95). One participant who had oral HPV16 consistently detected at 10 study visits over 4.5 years was subsequently diagnosed with HPV-OPC.
Conclusions
This prospective study of oncogenic oral HPV infection is the longest and largest quantification of oral HPV16 infections to date.