Much is known about the progression of human papillomavirus (HPV) in the genital tract. This includes the association of high-risk HPV with cervical cancer and its prevention by the newly available HPV vaccines. While long-term studies of the natural history of HPV within the oral cavity are not available, it is known that the acquisition of HPV occurs through open-mouthed kissing and oral sex.
Oral HPV infection, and especially infection with HPV-16, has been acknowledged as a risk factor for developing oropharyngeal cancer, particularly oropharyngeal squamous cell carcinoma (OSCC) by the International Agency for Research Against Cancer. A recently published study in the Journal of Emerging Infectious Diseases suggests that there is a slow epidemic of HPV infection-induced oral cancers, notably OSCC.
The incidence of these oral cancers, or number of new cases diagnosed, has increased significantly among persons between ages 20 and 39 in the U.S. Persons with prior HPV infections are 32 times more likely to develop oral cancers at the base of the tongue and tonsils than those who do not.
This is about 10 times greater than the risk associated with chronic alcohol or tobacco use.
Throughout the last decade, the age at diagnosis, incidence, location of oral and pharyngeal cancers, and risk factors have changed dramatically. From 1998 to 2003, differences in the type of oropharyngeal cancers, the location and regional variations have been determined from epidemiologic data obtained from national cancer registries and behavioral data. At least one published review of data demonstrates that the incidence, or newly diagnosed cases of oral cancer at the tonsillar area and base of the tongue are increasing.
Several research studies, including at least one case control study, have suggested that these changes might be attributed to the acquisition/transmission of HPV.
While the science is evolving, dentists should carefully consider their role in the prevention of oral cancers. This includes reviewing their oral cancer screening protocols periodically to include assessment of HPV infection in the oral cavity.
While there is limited data on oral practices, the highest-risk group is expected among young sexually active adults under the age of 25. Since many of these young people are otherwise healthy and do not regularly visit another primary care provider, dentists could play a significant role in the prevention of a growing subset of oral cancers.
Therefore, dentists should assess and expand their capacity to provide HPV screening, appropriate referral and counseling. They should be aware that open-mouthed kissing and oral sex carries some risk of HPV transmission. This is likely to be greater, especially when one partner is known to be infected with HPV, when either partner's HPV status is not known, and/or when one partner is not monogamous. Since at least one study shows that persons with more than six oral sex partners are nine times more likely to develop oral cancer than those who did not, dentists should evaluate their capacity to assess the patient's oral practices for risk of acquiring HPV infection.
Oral care providers should also determine their ability to provide appropriate training, counseling or referral on oral sex practices, including the use of proper barrier protection and partner reduction to reduce risk of HPV-associated oral cancers.
Oral HPV and the Dental Professional's Role in Public Health
by Margaret Scarlett, DMD: Captain, USPHS (ret.), Centers for Disease Control and Prevention CEO and President, Scarlett Consulting International