Link Between HPV and Head and Neck Cancer

HPV, or human papillomavirus, is a very common viral infection that can be acquired from childhood to adulthood. There are many different strains of the virus, and they all live in thin, flat cells called epithelial cells. These cells are found on the skin’s surface and the lining of the mouth and throat, as well as the surface of the vagina, anus, vulva, cervix, and head of the penis.

The strains of the virus typically acquired during childhood cause warts on the hands or feet (plantar warts), and usually come from contact with an infected person or by coming into direct contact with the virus in places such as locker rooms or around swimming pools. These warts and infections are typically self-resolving.

In adults, other strains of HPV may be acquired, which are considered a sexually transmitted infection (STI). According to the Centers for Disease Control and Prevention (CDC), HPV is the most common STI in the United States. It is so common, in fact, that nearly all sexually active men and women will contract at least one of the many types of HPV at some point in their lives. Studies estimate that in any given time, approximately 80 million people (or 1 in 4) in the U.S. have an active HPV infection. The virus is transmitted through direct, intimate contact with an infected person. HPV infection via sexual activity happens most commonly during the adolescent to young adult years, though it can happen at any time.

The only obvious symptom of infection is the development of benign genital warts, which does not happen in the majority of cases. However, sometimes tumors of the mucosal surfaces of the genitalia or oral cavity can develop later in life. In fact, the cancer-causing HPV strains (particularly types 16 and 18) cause almost all cases of cervical cancer and are one of the major culprits leading to 5 other types of cancer including penile, anal, vaginal, vulvar, and oropharyngeal (throat) cancers.

The risk of acquiring oral HPV infection–and thus HPV-related throat cancer–is strongly related to sexual practices, number of lifetime sexual partners, and gender. It was estimated from one large national study that about 3.5% of all adults ages 20-69 have a detectable high-risk (potentially cancer-causing) oral HPV infection. Infection rates are higher among both men and women who’ve had higher numbers of sexual partners and those who’ve reported having performed oral sex. Oral HPV infection tends to be more common in men than in women. It is thought that the higher rates of oral HPV in men may be related to a higher average number of sex partners, decreased clearance of the virus in the mouth, or that the female anatomy provides more places for the virus to dwell thus making transmission to their partners more likely.

HPV of any strain tends to be a “silent” infection. Most types, including high-risk, cancer-causing strains, typically do not cause any noticeable symptoms and can persist for months to years. Often, people are unaware they ever had an oral HPV infection until cancer has already developed many years after the initial infection. This is why vaccination is so important for preteens (before they are exposed to sexually-transmitted HPV) and why people should see their doctor immediately for any persistent sore throat, change in speech or swallowing, or neck mass that does not resolve within a couple of weeks. Like other cancers, the sooner it is caught, the easier it is to treat. And preventing it altogether through vaccination is even better.

The number of people affected by head and neck cancers overall has been declining in the United States, which is thought to coincide with a decline in tobacco use (a major risk factor for head and neck cancers). However, oropharyngeal (throat) cancer rates have been increasing substantially. It’s estimated that about 16,000 people per year will be diagnosed, of which almost 12,000 cases are thought to be caused by HPV. The reason for the uptick in HPV-related throat cancer is not entirely clear. It could be a combination of different factors, including current sexual practices, low regional vaccination rates, as well as the evolving behavior of the virus as it infects more people.

The known high-risk strains of HPV include types 16, 18, 31, 33, 45, 52, and 58, all of which are covered by the Gardasil 9 vaccine. If you are the parent of preteen or teenager, ask your pediatrician about getting your child vaccinated. Although cancer screening and treatment continues to improve, prevention will always be better. For more information about the link between HPV and oropharyngeal cancer, visit cdc.gov. For information about HPV vaccination, please visit cdc.gov/hpv or hpvroundtable.org.

References:

  1. The Centers for Disease Control and Prevention. (2017, July 17). HPV and Oropharyngeal Cancer. Retrieved from: https://www.cdc.gov/cancer/hpv/basic_info/hpv_oropharyngeal.htm
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