Human papillomavirus (HPV) related throat and mouth cancers could soon be among the most common forms of the disease in adults between the ages of 45 and 65.
Experts in the United States are becoming increasingly concerned about the rapidly rising rates of middle throat cancer, known medically as oropharyngeal cancer.
If the trend continues they suggest it may grow to be one of the top three cancers in middle-aged men in the US by 2045 – and the most common form among elderly males within the next decade.
According to Dr Matthew Old, a head and neck surgeon at The Ohio State University Comprehensive Cancer Center – Arthur G James Cancer Hospital and Richard J Solove Research Institute (OSUCCC – James), the rise of middle throat cancers in this age group is a direct impact of HPV infection before modern vaccines were introduced in the mid-Noughties.
HPV is a large group of viruses passed on through skin-to-skin and oral contact that occurs during sexual activity.
The virus spreads easily, and an estimated 98% of the population has been exposed to it.
HPV can remain dormant for decades. High-risk strains of the virus have long been linked to an increased risk of cervical cancer. However, data from the past decade shows high-risk HPV is also strongly linked to cancers of the mouth, base of the tongue and the throat.
Gardasil, developed by Merck & Co, was widely introduced as an HPV vaccine in 2006, and is now recommended for use in both males and females from the age of nine to protect against the high-risk strains of the virus linked to cancer, including cervical, vulvar, throat, mouth, penis and anal. It is also administered for non-cancerous conditions, such as genital warts.
Although it has been available for nearly two decades, lack of awareness about it as a means of cancer prevention in later life has slowed progress in preventing these cancers.
The Centers for Disease Control and Prevention (CDC) in the US estimates that timely HPV vaccination could prevent 90% of cervical cancers alone. The National Cancer Institute believes that as of 2020 just 54.5% of young people in the US aged between 13 and 15 were vaccinated.
Dr Matthew Old
Dr Old said: “We have a long way to go in educating the public about the importance of HPV vaccination in youth, and of the risk factors and warning signs of HPV-related cancers for adults who did not have an opportunity to get vaccinated in childhood.
“I strongly encourage all parents with children of vaccination age to consider the HPV vaccine. Data increasingly show this is a powerful tool to prevent cancers later in life, and HPV is a risk factor that all genders should be aware of.”
Cervical cancer is the only type caused by HPV that has a recommended screening test to detect it at an early stage. Currently, there are not recommended screening tests for cancers of the back of the throat, anus, vulva, penis and vagina caused by HPV, so they may not be detected until they cause serious health problems.
In the US alone, it is estimated there are 14,800 new HPV-related cancers of the back of the throat diagnosed every year, 6,900 of the anus, 2,900 of the vulva, 900 of the penis and 700 of the vagina. There are just over 11,000 new cervical cancer cases each year in the US – the most common HPV-related form of the disease in women.
Back of the throat is most common in men, accounting for 12,500 new cases annually, compared to 2,300 in women.
Electra Paskett, a cancer epidemiologist and co-leader of the OSUCCC – James Cancer Control Program, believes the conversation about the benefits of HPV vaccines among parents and health care providers needs to change.
“We need to shift the focus on HPV vaccination from preventing a sexually transmitted disease to preventing future cancers in order to stem the sharp increase in HPV-related cancers.
“The vaccine has historically been billed as a way to prevent infection risk related to sexual activity. It’s given in childhood not to encourage sexual activity at an early age, but because it is most effective at preventing HPV infection before the time of exposure and prevents cancer,” she said.
HPV vaccination is typically given in two doses between the ages of 9 and 14 and three doses in those aged 15 through to 26.
While HPV vaccination in adulthood is thought to provide less benefit because most people have already been exposed to the virus, it is now also available for individuals from ages 27 to 45 with a shared decision-making discussion with a health care provider.
According to data from the CDC, there is significant progress in one area. HPV infections and cervical precancers (abnormal cells in the cervix) have dropped since 2006, when the vaccines were first used in the United States.
Among teen girls, HPV types that cause most HPV cancers and genital warts have dropped 88%. Infections among young adult women have dropped 81%. Among vaccinated women overall, the percentage of HPV-related precancers have also dropped by 40%.
“We monitor women for HPV, but this should be a concern for people of all genders because partners expose partners,” Dr Old said.