San Francisco, CA—The increasing rate of infection with the human papillomavirus (HPV) in the United States has changed the field of head and neck cancer, or oral cancer, and HPV infection now causes a growing majority (70%-90%) of oropharyngeal squamous-cell carcinomas. As its incidence is rising, so is patients’ curiosity about what sets this cancer apart from other malignancies.
At the 2019 Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology annual meeting, Eleni Rettig, MD, Head and Neck Surgery Fellow, Mayo Clinic, Rochester, MN, provided answers to common patient questions about HPV-positive head and neck cancer.
“This rise in incidence of HPV-positive cancers has really changed our clinical practice, because there are some compelling demographic differences between HPV-positive and -negative patients,” said Dr Rettig.
Patients with HPV infection are less likely to be smokers (than nonsmokers) and more likely to be white and male (than black and female). People are usually younger (median age in the 50s rather than 60s), with higher socioeconomic status, and not surprisingly, they report more sexual partners than those without HPV infection.
“As an increasing proportion of our practice is comprised of these HPV-positive patients, it really has been uncharted territory, especially for head and neck surgeons who aren’t used to discussing these issues,” Dr Rettig said. “But these patients are subject to some unique psychosocial considerations that are related to an STI [sexually transmitted infection]-related cancer.”
Studies of patients with cervical cancer or head and neck cancer describe feelings of guilt and self-blame, as well as concern for HPV transmission between partners. Some studies show significant knowledge gaps regarding HPV transmission, prevalence, and the consequences of their cancer.1
In addition, most patients get their information from the Internet: one study showed that 80.9% of patients use the Internet as their source of medical information, whereas only 37.9% reported using a healthcare provider.1
“What this tells me is that patients have a lot of questions that they aren’t asking for one reason or another,” she said. “It’s incumbent on the care team to provide guidance about where to find accurate information.”
Answers to Common Patient Questions
Why does HPV matter?
It matters a lot, because HPV-positive patients with cancer have dramatically improved survival compared with HPV-negative patients with cancer.
“I tell patients that, whereas we used to be discussing 5-year survival of about 50%, now we’re talking about 85% to 90%,” Dr Rettig said.
Most HPV-positive tumors are now considered early- rather than late-stage, which also reflects these patients’ prognosis.
De-intensification of therapy is also being explored in this patient population, who respond so well to treatment.
How did I get HPV-positive oropharyngeal cancer?
HPV is a very common sexually transmitted infection of the anogenital tract and oral cavity/oropharynx. More than 80% of individuals in the United States have been exposed to the virus by age 45 years, and oral HPV infection is the presumed precursor to HPV-positive cancer.
Individuals generally acquire oral HPV infection through sexual exposure, and the incidence varies widely by population and depending on sexual norms, particularly variations in oral sex.
The annual incidence is estimated at approximately 4% to 12% among healthy individuals, and although the vast majority (approximately 90%) of these incident infections clear within 2 years, a subset does persist.
Of these persistent infections, a subset will have invasive cancer. “But we don’t really know much about who persists, and how it turns into cancer,” Dr Rettig explained. “It’s different from cervical cancer in that there’s no precursor lesion. So there’s definitely some significant differences, and a lot to learn.”
Are oral HPV infection and HPV-positive oropharyngeal cancer caused by oral sex?
According to Dr Rettig, oral sex is certainly a big risk factor. There is approximately a 3-fold higher risk for oropharyngeal cancer in patients who reported ≥6 oral sex partners, but there are other important factors to consider, including male sex, tobacco use, age, race, immune suppression, and marijuana use.
Men have a 3 to 5 times higher prevalence of oral HPV infection than women, likely because of immunologic differences and lower rates of viral clearance among men. In addition, performing oral sex on a woman is a higher risk than on a man. This is also evidenced in the fact that HPV-positive oropharyngeal cancer is >3 times more common in lesbian and bisexual women than in heterosexual women.
How many people with oral HPV infection get cancer?
At any given time, the prevalence of oncogenic HPV is approximately 400 per 10,000, whereas the lifetime risk for an HPV-positive cancer is 37 per 10,000. Even the highest-risk group (men aged 50-59 years) has an 8% oncogenic oral HPV prevalence rate at any given time, but only a 0.7% lifetime risk for cancer.
“So, it’s not that high of a risk, all things considered,” Dr Rettig noted.
Is my partner at risk for HPV-positive oropharyngeal cancer?
Partners of patients with HPV-positive cancer may be at a slightly increased risk (approximately 1%-3%) of HPV-related cancer, possibly because of a history of shared exposures. However, the prevalence of oral HPV infection among partners of patients with HPV-positive oropharyngeal cancer is the same as the general population. “But exposure to HPV is common, and progression to cancer is rare,” she said.
“For future partners, you may want to consider protection, because barrier use has been associated with decreased oral HPV infection,” she added. “But we don’t know what this means in terms of the risk for developing cancer down the line.” Overall, patients need not sacrifice intimacy over transmission concerns, Dr Rettig suggests.
Should I get the vaccine?
There is no evidence to support vaccination among HPV-positive patients, but all others should get vaccinated. The recommendations have been expanded to individuals aged 9 to 45 years, and some evidence suggests that vaccination is linked to lower rates of the vaccine-type oral HPV infection.
- Inglehjart RC, Taberna M, Pickard RK, et al. HPV knowledge gaps and information seeking by oral cancer patients. Oral Oncol. 2016;63:23-29.