Human Papillomavirus HPV & Oral Cancer

Human Papillomavirus (HPV) is the most common STD in the United States.  There are 6.2 million new infections each year.  Most HPV infections spontaneously clear on their own, 70% within one year and 90% within two years.    Over 40 different types of HPV infect the mucosal areas of the body. 


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The skin can also become infected, for example plantar warts are caused a variety of the HPV virus.  In this case, only skin to skin contact or walking on an unclear surface can result in an infection.

Substantial evidence is mounting that the Human Papillomavirus or HPV is playing an increasing important role in oral cancer.  On the rise are cancers of the tonsils and base of tongue.  Infections with HPV-6 and HPV-11 are known causes of genital warts and cervical cancer(1) .  It has been shown that 70% of cervical cancers are caused by HPV-16 and HPV-18.  Frisch and Biggar (2)  reported that patients with anogenital squamous cell carcinoma had a 4.5 increased risk of developing tonsillar cancer.  
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Of the 29,627 cases of oral cancer in 2003, up to 12% were caused by HPV.  The incidence is approximately, one-third of the 11.820 cases of vaginal cancer caused by HPV in the same year.  
 
Sexual transmission is associated with infection of the upper respiratory tract.   D'Souza, et. al. (4) found that HPV associated oral pharyngeal cancer was associated with greater than 25 life-time vaginal-sex partners and greater than 6 life-time oral sex partners.  However, they could not rule out transmission by direct mouth to mouth contact.

D'Souza (4) demonstrated that HPV is by far the major risk factor for developing oropharyngeal carcinoma.  He demonstrated HPV-16 in 72% of 100 pathology specimens studied.  He found that patients who developed HPV had an odds ratio of developing oropharyngeal cancer of 32.2, as heavy alcohol use had an odds ratio of 2.5, and heavy smoking (greater than 20 pack year) had an odds ratio of 2.8.  The interaction between HPV, tobacco and alcohol is unclear. 

Chemock et. al (5) found Human Papilloma Virus in 63.5% of oropharyngeal squamous cell carcinoma tumors in Whites and 11.5% of tumors in African Americans.

Haddad (6) reports that HPV associated oral carcinoma occurs in a higher proportion of men, at a younger age and at a more advanced stage than non-HPV associated oral carcinoma.  He also states that HPV oral carcinomas are believed to have a better prognosis. 

A new vaccine, Gardasil, protects against four of the most common HPV viruses which causes genital warts and cervical cancer.  Since the cancer risk for men for oropharyngeal cancer, anorectal cancer and penile cancer is about the same incidence as for cervical cancer, some doctors are now considering giving   the vaccine to men (6).