Author: Laurie Wertich
For many years the most significant risk factors for head and neck cancers have been alcohol and tobacco use. More recently, infection with a virus called the human papillomavirus (HPV) has been identified as a risk factor for a new subset of head and neck cancer.
HPV-related head and neck cancer is on the rise, and some experts are predicting an epidemic in the next decade. This type of head and neck cancer defies all stereotypes—it develops in a younger population, regardless of alcohol or tobacco use. But there is a shred of good news: it often comes with a higher cure rate.
There are more than 120 strains of the HPV virus, and 30 to 40 of these strains are transmitted through sexual contact, including anal, genital and oral contact. Some sexually transmitted HPV types can cause genital warts and some—like HPV types 16 and 18—are considered high risk and are associated with an increased risk of developing cancer, including cervical cancer and head and neck cancer.
“HPV is the most common sexually transmitted infection in the world,” explains Lanceford Chong, MD, MPH, Medical Director of Radiation Oncology at Cancer Treatment Centers of America (CTCA) in Goodyear, Arizona.
In fact, the virus is so common that nearly all sexually active men and women get it at some point in their lives, according to the Centers for Disease Control and Prevention.1 The risk of developing HPV is higher among those who begin sexual activity early and have a higher number of sexual partners, but even people with only one lifetime sex partner can develop the virus.
There is no treatment for HPV, but some vaccines are designed to prevent high-risk strains of the virus. Most HPV infections go away by themselves within two years, as the body’s immune system clears the virus; however, some people don’t clear the virus, perhaps as a result of genetic factors. In these cases, HPV can be associated with other health problems, including head and neck cancer.
The same types of HPV that infect the genital areas can infect the mouth and throat. HPV found in the mouth and throat is referred to as oral HPV. Oral HPV is associated in particular with a type of head and neck cancer known as oropharyngeal cancer. Oral HPV is about three times more common in men than in women. Interestingly, oropharyngeal cancers are also about three times more common in men than women.2
Oral HPV can be transmitted during oral sex or open-mouthed kissing, although the likelihood of contracting oral HPV from these behaviors is unknown.
HPV and head and neck cancer
Helen Yoo Bowne, MD, an Otolaryngologist at CTCA in Philadelphia, Pennsylvania, explains that not all patients get infected with HPV when exposed, and not all patients who are infected with HPV get cancer. P16-positive cancers are caused by HPV, so we routinely test for HPV in oropharyngeal tumor specimens, and, if positive, we know there is direct causal relationship,” she says.
In fact, HPV16 has become a major factor in head and neck cancer—specifically in oropharyngeal cancers of the tonsils and the base of the tongue. According to the results of a study published in the Journal of Clinical Oncology, HPV was associated with about 16 percent of oropharyngeal cancers diagnosed during the 1980s and more than 70 percent of those diagnosed during the 2000s.3
“This is something that is of major public health importance,” explains Dr. Chong. “It is shooting head and neck cancer concerns way into the stratosphere, and we are predicting an epidemic within the next 10 to 15 years.”
Characteristics of HPV-related head and neck cancer
There are some key differences between HPV-related head and neck cancer and tobacco/alcohol–related head and neck cancer. For one, not all types of head and neck cancers are associated with HPV. In fact, HPV-related cancer is typically associated with one type of head and neck cancer: oropharyngeal cancers of the tonsils and the base of the tongue.
What’s more, HPV-related head and neck cancer is typically diagnosed at a younger age—usually when patients are in their fifties, compared with heavy smokers or drinkers, who are more often diagnosed in their sixties. It is also more common in men than in women.
But there is another key difference: better prognosis. “Patients who have HPV-related oropharyngeal cancer have an improved survival compared with those who have alcohol or smoking–related cancer,” Dr. Yoo Bowne says.
“If someone has HPV-related cancer and has never smoked, the cure rate is 80 to 90 percent; but if you look at the patients who are heavy smokers or drinkers and don’t have HPV, the cure rates are 30 to 40 percent,” Dr. Chong explains.
Individuals who are smokers and have HPV-associated cancer have an intermediate prognosis with a 50 to 60 percent cure rate.
The treatment for oropharyngeal cancer is the same, regardless of HPV status. Typically, these patients are treated with combined chemotherapy and intensity-modulated radiation therapy. More limited surgery, including robotic techniques, is in use at select medical centers.
“HPV-associated tumors tend to respond significantly better to chemotherapy and radiation,” Dr. Chong says.
Indeed, the median survival is nearly 11 years in HPV-related tumors compared with 1.6 years in tumors that don’t carry the virus.3
Of course, that begs the question of whether treatment can be scaled back in this group. Because these patients are diagnosed at a younger age, that means some may face decades of long-term side effects such as dry mouth or difficulty swallowing. Scaling back treatment could help reduce the impact of those side effects.
“Right now, if we are going to recommend chemoradiation as a concurrent approach for oropharyngeal cancer, we will not change the dose or treatment. We will use the same course of treatment that we do for the heavy drinker/smoker group,” explains Dr. Chong. “Research is looking at whether we can drop doses in HPV-related cancer precisely because it responds so well—but we’re not quite there yet.”
Public health concern
As the rate of HPV-related head and neck cancer continues to climb, doctors and researchers are predicting an epidemic. Dr. Chong stresses that this is a public health dilemma. “It’s important to make the diagnosis early and get proper treatment,” he says. “It’s also important to administer proper vaccination when appropriate.”
For now the problem does not seem to be going away—but researchers hope that as more and more parents comply with vaccination recommendations, they will see a decline in HPV-related cancers in the future.
1. Genital HPV Infection: Fact Sheet. Centers for Disease Control and Prevention. Available at: http://www.cdc.gov/std/HPV/STDFact-HPV.htm.
2. Human Papillomavirus (HPV) and Oropharyngeal Cancer: Fact Sheet. Centers for Disease Control and Prevention. Available at: http://www.cdc.gov/std/HPV/ STDFact-HPVandOralCancer.htm.
3. Chaturvedi, A.K., Engels, E.A., Pfeiffer, R.M. et al. "Human papillomavirus and rising oropharyngeal cancer incidence in the United States." Journal of Clinical Oncology. 2011;29(32):4294-301. doi: 10.1200/JCO.2011.36.4596. 4. Recommendations on the Use of Quadrivalent Human Papillomavirus Vaccine in Males: Advisory Committee on Immunization Practices (ACIP), 2011. Centers for Disease Control and Prevention. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6050a3.htm.