HPV and Oropharyngeal Cancers

Human papillomavirus (HPV) is a member of the papillomavirus family of viruses that is capable of infecting humans. HPV is the virus known for causing cervical cancer in women.  While the majority of the nearly 200 known types of HPV cause no symptoms in most people, some types can cause warts (verrucae), while others can – in a minority of cases – lead to cancers of the cervix, vulva, vagina, and anus in women or cancers of the anus and penis  in men. In recent years, people have started acknowledging that it can also cause cancers of the head and neck (tongue, tonsils and throat).  A recent study finds half of all American men are infected with it. The virus is responsible for 32,000 new cancer cases in the U.S. every year, and according to few other reports, a growing number of men are being diagnosed with head and neck cancers.  But emerging research suggests that HPV-related throat cancer is poised to become the leading form of head and neck cancer in the U.S. A recent study found that, at its current rate, throat cancer will surpass cervical cancer as the leading HPV-associated cancer in the next decade.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3018627/?tool=pubmed

Doctors say the trend is worrisome because no screening test exists for HPV-related oral cancers, though the diagnosis is rising at a rate of 10 percent a year. HPV is so common that at least half of sexually active people contract it at some point in their lives. About 6 million people a year are newly infected with the virus each year, according to the Centers for Disease Control and Prevention. Almost all of the 12,000 cases of cervical cancer a year in the U.S. are HPV-associated.

Historically, oropharyngeal cancers have been associated with tobacco and alcohol use, but now researchers have found a link between HPV and a dramatic rise in throat cancer in patients who have neither classic risk factor.

The oropharynx is the middle part of the throat behind the mouth, and includes the base of the tongue, the side and back walls of the throat and the tonsils. Nearly 10,000 new cases of oropharyngeal cancer are diagnosed a year, according to the Centers for Disease Control and Prevention (CDC).

Between 1984 and 1989, roughly 16 percent of cancers involving the base of the tongue and the back of the throat and tonsils were HPV related. Today, the virus is detected in 70 percent of those cancers, which mostly are diagnosed in men, according to a recent study appearing in the Journal of Clinical Oncology. Researchers believe the rise in HPV-related throat cancer can be attributed to sexual transmission because at least 90 percent of HPV-positive throat cancers are the HPV16 strain, which is the same high-risk genotype most frequently observed in cervical cancer. But doctors have not determined if the virus also can be spread through casual saliva contact, such as kissing. Most people with HPV do not develop symptoms or health problems from it. In 90 percent of cases, the body's immune system clears HPV naturally within two years. When the virus persists, it can develop into cancer.

The HPV strains that can cause genital warts are not the same ones that can cause cancers. There is no way to know which people who get HPV will go on to develop cancer or other health problems.

The U.S. Food and Drug Administration has approved an HPV test that can identify 13 of the high-risk types of HPVs associated with the development of cervical cancer. There is no test to determine if a man has HPV.

Men who have had more than four oral sex partners (or intercourse with six or more partners) are at the highest risk for HPV-related oral cancers.

How do people get HPV?

HPV is passed on through genital contact, most often during vaginal and anal sex. HPV may also be passed on during oral sex and genital-to-genital contact. HPV can be passed even when the infected partner has no signs or symptoms.

Signs of HPV-related throat cancer

Persistent sore throat

Ear Pain

Painless white or red patch or a sore on the tongue

Pain or difficulty with chewing or swallowing

Swelling of the jaw

Hoarseness or other change in the voice

Pain in the ear

Source: Centers for Disease Control and Prevention, American Cancer Society