Persistent infection with oral human papillomavirus (HPV) 16 is believed to drive the development of most head and neck cancers. Now, researchers have discovered that prevalent oral HPV-16 infections in men persist longer than newly acquired infections. In addition, they found that persistence increases with age. The findings may help explain the high prevalence of oral HPV observed at older ages.

Oral HPV-16 persistence for up to four years was evaluated in 1,626 males originally enrolled in the Human Papillomavirus Infection in Men Study, an ongoing multinational cohort study of the natural history of HPV infections in men.

Over the course of the study, 23 oral gargle samples tested positive for oral HPV 16. In ten participants, HPV 16 was detected at enrollment. Among these prevalent infections, nine lasted for one year or longer, eight lasted for two years or longer, and two lasted for four years or longer. Among the remaining 13 incident infections, four lasted for one year or longer, one lasted for two years or longer, and none lasted for three or more years.

The study also showed that persistence of incident infections increased significantly with age. The researchers reported that all incident infections among men older than 45 persisted for one year or longer and 50 percent of those infections among men aged 31–44 persisted for one year or longer. However, none of the incident infections detected among men aged 18–31 persisted for as long as a year.

The findings of the study indicate that some oral HPV-16 infections persist in men for four years or more. However, the researchers do not yet know the necessary duration of persistent oral HPV infection to increase the risk of head and neck cancer, but the data suggest that oral HPV infections may be more likely to persist than genital HPV infections, which are generally believed to increase the risk of cervical cancer if such infections persist for two years.

Further studies are needed to provide a better understanding of oral HPV-16 persistence, and this could greatly benefit identification of men at high risk of developing HPV-related oropharyngeal cancer, the researchers concluded.

The study, titled “Long-Term Persistence of Oral Human Papillomavirus Type 16: The HPV Infection in Men (HIM) Study,” was published online on Jan. 9 in the Cancer Prevention Research journal ahead of print. It was carried out at the Moffitt Cancer Center and Research Institute in Tampa.

Original Source: The Dental Tribune.com