San Francisco, CA—The human papillomavirus (HPV) has changed the field of head and neck cancer, and HPV now causes a growing majority (70%-90%) of oropharyngeal squamous-cell carcinomas. As its incidence is rising in the United States, so is patient 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, discussed common patient questions about HPV-positive head and neck cancer, and armed providers with the knowledge to answer them.
“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.
HPV-positive patients are less likely to be smokers and are more likely to be white and male. They are younger on average (median, 50s vs 60s), with higher socioeconomic status, and they report more sexual partners than their HPV-negative counterparts.
“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,” she said. “But these patients are subject to some unique psychosocial considerations that are related to an STI [sexually transmitted infection]-related cancer.”
Cervical cancer literature, and now some head and neck cancer literature, describe feelings of guilt and self-blame, as well as concern for transmission between partners. Some studies of patients with HPV-positive oropharynx cancer also show significant knowledge gaps regarding transmission, prevalence, and health consequences of their cancer. Compounding this problem is the fact that most patients get their information from the Internet; one study showed that 81% of patients use the Internet as their source of information, whereas only 38% reported using a healthcare provider.
“What this tells me is that patients have a lot of questions that they aren’t asking for one reason or another,” she said. “So, I think for this reason it’s really incumbent on the care team to provide guidance about where to find accurate information.”
According to Dr Rettig, it matters a lot, as HPV-positive patients have dramatically improved survival compared with patients who are HPV-negative.
“I tell patients that, whereas we used to be discussing 5-year survival of about 50%, now we’re talking about 85%-90%,” she said.
There is also a different American Joint Committee on Cancer staging system for HPV-positive tumors. Now most tumors are considered early-stage as opposed to late-stage, which more accurately reflects these patients’ prognosis.
Deintensification (giving less treatment with fewer side effects) is also being explored in this patient population, since they do respond so well to treatment.
HPV is a very common STI 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 incidence varies widely by population and depending on sexual norms, particularly variations in oral sex.
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 go on to develop invasive cancer. “But we don’t really know much about who persists and how it turns into cancer,” she explained. “It’s different from cervical cancer in that there’s no precursor lesion. So, there’s definitely some significant differences there, and a lot to learn.”
According to Dr Rettig, oral sex is certainly a big risk factor. There is approximately a 3-fold higher risk for oropharynx cancer in patients who reported ≥6 oral sex partners, but there are also a number of 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, likely because of immunologic differences and lower rates of viral clearance among men, in addition to the fact that performing oral sex on a woman is higher risk than on a man. This is also evidenced in the fact that HPV-positive oropharyngeal cancer is more than 3 times more common in lesbian and bisexual women than in heterosexual women.
The prevalence at any given time of oncogenic HPV is approximately 400 per 10,000, whereas the lifetime risk of developing an HPV-positive cancer is only 37 per 10,000. Even the highest-risk group (men 50 to 59 years of age), has an 8% oncogenic oral HPV prevalence at any given time, but only a 0.7% lifetime risk of developing cancer.
“So, it’s not that high of a risk, all things considered,” Dr Rettig noted.
Partners of patients with HPV-positive cancer may be at a slightly increased risk (approximately 1%-3%) of developing an HPV-related cancer, likely caused by a history of shared exposures. However, the prevalence of oral HPV infection among partners of patients with HPV-positive oropharynx cancer is similar to the general population.
“But exposure to HPV is common and progression to cancer is rare,” she said.
According to Dr Rettig, there is no evidence to support patients changing their sexual practices with current partners, and there is no specific obligation to share HPV status with a sexual partner.
“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.”
Bottom line, patients needn’t sacrifice intimacy over transmission concerns.
There is no evidence to support vaccination among HPV-positive patients, but others should be encouraged to get vaccinated, she said. The recommendations have now been expanded to individuals aged 9 to 45 years, and there is some evidence that vaccination is associated with a lower rate of the vaccine-type oral HPV infection.
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