As a sexually transmitted disease, discussions surrounding human papillomavirus (HPV) can understandably be uncomfortable and/or embarrassing. Interestingly, according to the Centers for Disease Control and Prevention (CDC), HPV is so common that nearly ALL sexually active men and women get the virus at some point in their lives. About 79 million Americans (~25% of the U.S. population) are currently infected with some type of HPV. About 14 million people in the United States become newly infected each year. Accordingly, I thought that a more detailed blog post on the subject was warranted.
HPV is a virus with the ability to infect skin and mucous membranes, or mucosa, that lines various cavities in the body and surrounds internal organs. It can cause normal cells in infected areas to turn abnormal. Most of the time, you cannot see or feel these cell changes. In the majority of cases, the body fights off the HPV infection naturally and infected cells then go back to normal.
There are approximately 179 distinct HPV genotypes, which can be divided into “low risk” and “high risk” groups based on their capacity to drive cancer transformation. Most people with HPV never develop symptoms or health problems; 9 out of 10 HPV infections go away by themselves within two years. Sometimes HPV infections will last longer and can cause certain cancers, warts, and other diseases. There is currently no test to find out a person’s “HPV status.”
The “high risk” HPV subtypes most clearly implicated in cancer are HPV16, 18, 31, 33, 35, 45, 51, 52, and 56, which are capable of causing cancers of the cervix, head and neck, anus, vagina, vulva, and penis. Every year in the United States, HPV causes 30,700 such cancers in men and women.
Most of the time, people get HPV from having vaginal and/or anal sex with an infected partner. In fact, “genital HPV” is the most common sexually transmitted infection (STI) in the U.S.
However, the same types of HPV that infect the genital areas can also infect the mouth and throat. HPV found in the mouth and throat is called “oral HPV.” Only a few studies have looked at how people get oral HPV, and some of these studies show conflicting results. Some studies suggest that oral HPV may be passed on during oral sex (from mouth-to-genital or mouth-to-anus contact) or simply open-mouthed (“French”) kissing, others have not. The likelihood of getting HPV from kissing or having oral sex with someone who has HPV is not known. According to the CDC, more research is needed to understand exactly how people get and give oral HPV infections.
Oral HPV is about three times more common in men than in women. Overall, HPV types 2, 4, 6, 11, 13 and 32 have been associated with benign oral lesions while HPV types 16 and 18 have been associated with malignant lesions, especially in cancers of the tonsils and elsewhere in the oropharynx. The most commonly implicated subtype in oropharyngeal cancer is HPV16, accounting for over 80% of HPV positive cases. Not surprisingly, my initial biopsy results showed that tumor cells were positive for HPV16.
Patients with oral HPV cancer present at a younger age and are less likely to partake in excess alcohol consumption or heavy tobacco use that are associated with corresponding HPV-negative cancers. Additionally, HPV-related tumors more frequently arise in the oropharynx – the part of the throat at the back of the mouth behind the oral cavity. It includes the back third of the tongue, the soft palate, the side and back walls of the throat, and the tonsils (where my cancer started). Smoking-related tumors arise more commonly in the oral cavity, larynx, or hypopharynx.
Oral HPV tumors are more likely to be smaller and poorly differentiated, with a higher incidence of advanced lymph node metastases in comparison to HPV negative tumors. Despite a more aggressive clinical presentation, HPV status is the best independent predictor of survival in these patients.
Signs and symptoms of oral HPV may include persistent sore throat, earaches, hoarseness, enlarged lymph nodes, pain when swallowing, and unexplained weight loss. In my case, the first sign of disease in November 2015 was an enlarged (3-4cm) lymph node on the right side of my neck where the cancer had spread from my right tonsil. Some people have no signs or symptoms.
While there is currently no cure for the virus, there are commercially available prophylactic vaccines against HPV available today: the bivalent (HPV16 and 18) Cervarix®, the tetravalent (HPV6, 11, 16 and 18) Gardasil®, and newer Gardasil 9 (HPV6, 11, 16, 18, 31, 33, 45, 52, 58). Since the HPV subtype 16 was included in each of these vaccines, and this subtype was found in my tumor cells, it is very likely that my cancer could have been prevented had such vaccines been available to me when I was younger.
The HPV vaccine was initially developed to prevent cervical and other less common genital cancers, which raised questions regarding the ability to also prevent oral cancers. In one of the first large studies to explore the possible impact of HPV vaccination on oral HPV infections, researchers found it may confer a high degree of protection. The study of young adults in the U.S. showed that the prevalence of high-risk HPV infection was 88% lower among those who reported getting at least one vaccine dose than among those who were not vaccinated. Researchers reported the results at the recent American Society of Clinical Oncology (ASCO) 2017 annual meeting.
To be an effective preventive strategy, HPV vaccination should start before “sexual puberty.” The CDC recommends routine HPV vaccination for girls and boys at age 11 or 12 (two doses six months apart, a 2016 revision of guidelines that previously recommended three doses). People who get vaccinated later (up to age 26 for young women and up to age 21 for young men) will need three.
The same research reported at ASCO 2017 found that from 2011 through 2014 fewer than 1 in 5 (18.3%) young adults in the U.S. reported receiving at least one dose of the HPV vaccine before age 26. The vaccination rate was much lower among men than women (6.9% vs. 29.2%) at this time.
“The HPV vaccine has the potential to be one of the most significant cancer prevention tools ever developed, and it’s already reducing the world’s burden of cervical cancers,” said ASCO President-Elect Bruce E. Johnson, MD, FASCO. “The hope is that vaccination will also curb rising rates of HPV-related oral and genital cancers, which are hard to treat. This study confirms that the HPV vaccine can prevent oral HPV infections, but we know it only works if it’s used.”
More research is needed to understand exactly how people get and give oral HPV infections that resulted in my oropharyngeal cancer. Recent studies confirm that the HPV vaccine can prevent such oral HPV infections, but only when they are used – and vaccination rates are extremely low. This is disappointing, as vaccination is widely considered one of the greatest medical achievements of modern civilization. Childhood diseases that were commonplace less than a generation ago are now increasingly rare because of vaccines (although the measles are making a comeback since elimination was first documented in the U.S. in 2000). In order to be effective at eliminating communicable diseases, vaccines must be administered to sufficient levels of persons in the community.
If you have a son or daughter, please talk to your doctor about the HPV vaccine. HPV has become a recognized driver of six cancers affecting more than 30,000 people each year, yet there are available vaccines to prevent the majority (about 28,000) of these cases from ever occurring.
American Cancer Society. Cancer Facts & Figures 2017. Atlanta: American Cancer Society; 2017.
From HPV-positive towards HPV-driven oropharyngeal squamous cell carcinomas. Cancer Treat Rev. 2015 Oct 31.
Centers for Disease Control and Prevention: Human Papillomavirus (HPV) Statistics
J Clin Oncol 35, 2017 (suppl; abstr 6003)