ADA Positions & Statements

ADA Council on Scientific Affairs

The ADA Council on Scientific Affairs recognizes the rising incidence of head and neck squamous cell carcinoma associated with human papillomavirus, or HPV.^1-3 According to a 2008 study, over 20 percent of all oral and oropharyngeal cancers, or more than 7300 cases of HPV-associated cancers, were diagnosed annually in the United States from 1998 through 2003.² The association of HPV infection and oral and oropharyngeal cancer is strongest for squamous cell carcinomas of the tonsils and the base of the tongue.^3,4

Researchers have identified over 100 types of humanpapilloma virus, some of which are known to infect mucosal surfaces. These give rise to a host of cutaneous or mucosal epithelial lesions, mostly benign hyperplasias such as warts or papillomas. Emerging studies have linked certain oral and oropharyngeal cancers with the presence of HPV-16 and HPV-18, two high-risk, aggressive HPV types that are also associated with 70% of cervical cancer cases, one of the most common cancers among women worldwide.^2,5-8 A recent analysis of U.S. oral cancer incidence data found that the proportion of oral cancers arising from sites typically associated with HPV significantly increased from 1973 to 2004, particularly in white males aged 40 to 59 years.¹ In addition, studies have demonstrated that the incidence of HPV-associated oropharyngeal cancers is three times higher among men than women,² higher among younger adults,³ and among persons with a higher lifetime number of sex partners (vaginal and oral).^8,9 These high-risk HPV types are primarily sexually transmitted.

Risk factors for oral and oropharyngeal cancer have typically been older age (median age 62 years at diagnosis) and the use of tobacco and excessive alcohol consumption.^1,10,11 However, based on the available evidence, oral HPV infection is now considered an important risk factor for oropharyngeal cancers for both men and women, even in the absence of smoking and alcohol consumption.^2,9,12 Given this emerging evidence, it has been suggested that use of prophylactic HPV vaccines directed against HPV-16 and HPV-18 may reduce oropharyngeal cancer incidence. Currently, the commercially available HPV vaccines are FDA approved for the prevention of HPV-associated cancers of the cervical, vulvar and vaginal mucosa. Studies are planned to investigate the efficacy of these vaccines for the prevention of HPV-associated oropharyngeal mucosal cancers.

Dentists are formally trained to perform thorough intra- and extra-oral soft tissue examinations, identify suspicious oral lesions, and perform, or refer for, scalpel/punch biopsies to determine a definitive diagnosis. The Council encourages clinicians to provide routine oral soft tissue examinations for all patients, not just those with the traditional tobacco use and alcohol consumption risk factors.¹³ Detection of oral cancer at an early stage significantly increases the five-year survival rate.¹⁰ Dentists should continue to provide advice and guidance to their patients regarding the known risks for oral cancer from smoking and heavy alcohol consumption. In addition, providers should be aware of the head and neck cancer-HPV relationship, especially the growing prevalence of oropharyngeal cancers in younger non-smokers and non-drinkers.

Before specific guidance regarding HPV can be provided to patients, considerable research remains to be done to answer questions related to the natural history of oral HPV, transmission risks, screening/testing, predictive value of a positive HPV test for the subsequent development of oropharyngeal cancer, and many other issues. The ADA will keep dentists informed as further information becomes available.

References

¹ Chaturvedi AK, Engals EA, Anderson WF, Gillison MF. Incidence trends for human papillomavirus–related and –unrelated oral squamous cell carcinomas in the United States. J Clin Oncol 2008;26:612–9.

² Ryerson AB, Peters ES, Coughlin SS et al. Burden of potentially human papillomavirus-associated cancers of the oropharynx and oral cavity in the US, 1998-2003. Cancer 2008 Nov 15;113(10 Suppl): 2901–9.

³ Shiboski CH et al. Tongue and tonsil carcinoma: increasing trends in the US population ages 20–44 years, Cancer;103:1843–1849.

⁴ Hobbs CGL, Sterne JAC, Bailey M, Heyderman RS, Birchall MA, Thomas SJ. Human papillomavirus and head and neck cancer: a systematic review and meta-analysis. Clinical Otolaryngology 2006;31: 259–266.

⁵ Gillison ML et al. Distinct risk factor profiles for human papillomavirus type 16–positive and human papillomavirus type 16–negative head and neck cancers. J Nat Cancer Inst 2008 100(6):407–420.

⁶ Schlect NF. Prognostic value of human papillomavirus in the survival of head and neck cancer patients: an overview of the evidence. Oncol Rep 2005;14:1239–47.

⁷ Agrawal Y, Koch WM, Xiao W, Westra WH, Trivett AL, Symer DE, Gillison ML. Oral human papillomavirus infection before and after treatment for human papillomavirus 16-positive and human papillomavirus 16-negative head and neck squamous cell carcinoma. Clin Cancer Res 2008 Nov 1;14(21):7143–7150.

⁸ Kreimer AR, Clifford GM, Boyle P, Franceschi S. Human papillomavirus types in head and neck squamous cell carcinomas worldwide: a systematic review. Cancer Epidemiology Biomarkers Prev 2005; 14(2):467–75.

⁹ D’Souza G, Kreimer AR, Viscidi R, Pawlita M, Fakhry C, Koch WM et al. Case-control study of human papillomavirus and oropharyngeal cancer. N Engl J Med 2007;356:1944–56.

¹⁰ Ries LAG, Melbert D, Krapcho M, Stinchcomb DG, Howlader N, Horner MJ, Mariotto A, Miller BA, Feuer EJ, Altekruse SF, Lewis DR, Clegg L, Eisner MP, Reichman M, Edwards BK (eds). SEER Cancer Statistics Review, 1975–2005, National Cancer Institute. Bethesda, MD, http://seer.cancer.gov/csr/1975_2005/ , based on November 2007 SEER data submission, posted to the SEER Web site, 2008.

¹¹ Hashibe M, Brennan P, Chuang SC, Boccia S et al. IARC, Lifestyle, Environment and Cancer Group, Genetics and Epidemiology Cluster, Lyon, France. Interaction between tobacco and alcohol use and the risk of head and neck cancer: pooled analysis in the International Head and Neck Cancer Epidemiology Consortium. Cancer Epidemiol Biomarkers Prev. 2009 Feb;18(2):541–50. Epub 2009 Feb 3.

¹² Lingen M, Sturgis EM, Kies MS. Squamous cell carcinoma of the head and neck in nonsmokers: clinical and biologic characteristics and implications for management. Curr Opin Oncol. 2001 May;13(3):176–82.

¹³ American Dental Association. Prevention and early oral cancer detection [policy statement]. Transactions, 1996; p. 681.

Posted April 2009