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Monday, October 20, 2014
The human papilloma virus (HPV) is a well-known cause of genital and anal cancers in men and women, but it has become clear over the last decade that the virus is also a cause of cancers of the head and neck. Specifically, these cancers are located in the mouth and throat, including the:
These mouth and throat cancers have historically been known to be caused by tobacco use, but recent studies have shown that HPV may now be responsible for 70-80% of these malignancies.1 2 While the decreased use of tobacco, and therefore the decreased incidence of tobacco-associated cancers, has been observed over the last few decades, the rate of head and neck cancer has actually continued to rise.
HPV is the most common sexually transmitted infection, with 50% of all sexually active individuals becoming infected with the virus in their lifetime. In the same way that genital HPV is known to be transmitted during vaginal sex, HPV infection of the mouth and throat is thought to be transmitted during oral sex, with increasing greater risk of infection found in individuals with more oral sex partners.
The majority of cases of HPV infection are cleared by the body's immune system, so if your immune system isn't working well, it's harder to fight infection. Factors known to reduce immune function such as smoking and infection with the human immunodeficiency virus (HIV) are known to increase the risk of HPV-associated head and neck cancer. Oral HPV infection is also known to increase with age, suggesting that the body has more difficulty fighting off infection as it ages, or old infections are becoming active again.
11,500 cases of these HPV-associated mouth and throat cancer are diagnosed every year in the U.S., with the majority of cases, over 9,300, diagnosed in men. It is also unknown why men have more than double the risk of HPV-associated head and neck cancer, but some evidence suggests that vaginal or cervical HPV infections may be more easily transmitted to sexual partners than penile infections. It is presently unclear whether HPV is transmitted by acts such as open-mouth kissing or from mother to child at birth.
Prevention of oral HPV infection is likely to decrease the risk of head and neck cancer. HPV-16 has been found to be responsible for nearly 87% of all HPV-positive head and neck cancers, and the vaccines Gardasil and Cervarix both have been shown to prevent infection of this particularly dangerous strain of HPV in genital sites.
Gardasil, which provides immunity to 2 cancer-causing strains and 2 wart-causing strains of HPV, is recommended for use by the Advisory Committee of Immunization Practices in all females ages 11-12 and up to age 26 for the prevention of cervical and other genital cancers.
As of 2011, the ACIP recommends use of the HPV vaccine Gardasil for boys at age 11 or 12 - the same level of recommendation issued for girls of the this age group. It is also recommended that young men age 13-21 who have not previously received the full 3 doses of the vaccine be vaccinated. Gardasil is also currently approved for use in men aged 22-26 - a "permissive" recommendation that differs from females of the same age group. Permissive use means that the vaccine is recommended, but not considered to be of sufficient priority to include on routine vaccination schedules.
These recommendations were not able to take into account head and neck cancer risk, which is significantly higher for males, as studies adequately assessing the progression of oral HPV infection to head and neck cancer or the effectiveness of the vaccine in preventing oral HPV infection are lacking. It should be taken into account that vaccination is safe and effective in prevention of other health issues important to men, including risk of anal cancer, genital warts, and potentially putting female partners at risk for cervical and other cancers.
Prepared in partnership with Kyle Scarberry, MD, Class of 2013, Case Western Reserve University School of Medicine.
1The epidemic of HPV-associated oropharyngeal cancer is here: is it time to change our treatment paradigms?, AU Sturgis EM, Ang KK J Natl Compr Canc Netw. 2011;9(6):665.
2Human papillomavirus and rising oropharyngeal cancer incidence in the United States., Chaturvedi AK, Engels EA, Pfeiffer RM, Hernandez BY, Xiao W, Kim E, Jiang B, Goodman MT, Sibug-Saber M, Cozen W, Liu L, Lynch CF, Wentzensen N, Jordan RC, Altekruse S, Anderson WF, Rosenberg PS, Gillison ML, J Clin Oncol. 2011;29(32):4294.
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Last Reviewed: Mar 06, 2013
Pierre Lavertu, MD, FRCS(C), FACS
Professor of Otolaryngology-Head and Neck Surgery
School of Medicine
Case Western Reserve University