In the past twenty years, throat cancer cases have surged in Western countries, reaching almost epidemic proportions.
The primary contributor to this increase is a particular form of throat cancer known as oropharyngeal cancer. This cancer affects the tonsils and throat back.
The leading cause of this cancer is the human papillomavirus (HPV), which is also responsible for most cervical cancer cases. Oropharyngeal cancer now surpasses cervical cancer in prevalence in the United States and the United Kingdom.
HPV is transmitted through sexual contact. The primary risk factor for oropharyngeal cancer is the number of lifetime sexual partners, particularly those involving oral sex.
Individuals with six or more lifetime oral-sex partners are 8.5 times more likely to develop oropharyngeal cancer than those who abstain from oral sex.
Research on behavioral trends reveals that oral sex is quite common in certain countries. In a study that I and my colleagues conducted on nearly 1,000 people who underwent tonsillectomy for non-cancerous reasons in the UK, 80% of adults reported engaging in oral sex at some point.
Only a small fraction of these individuals develop oropharyngeal cancer, and the reasons are unclear.
The dominant hypothesis suggests that most people contract HPV infections and can successfully eliminate them.
However, a small percentage of individuals may be unable to clear the infection, possibly due to a deficiency in a specific component of their immune system. In these cases, the virus continues to replicate, eventually integrating randomly into the host’s DNA, potentially causing cancerous host cells.
Many countries have implemented HPV vaccination programs for young girls to prevent cervical cancer. There is growing, though still indirect, evidence that these vaccines may also prevent oral HPV infections.
Additionally, some evidence suggests that boys in countries with high vaccination coverage among girls (over 85%) may benefit from “herd immunity.”
Collectively, these factors could potentially contribute to a decrease in oropharyngeal cancer cases in the coming decades.
While this is a positive development from a public health perspective, it relies on high vaccination coverage among girls – exceeding 85% – and individuals remaining within the protected “herd.”
However, this does not guarantee protection at an individual level, especially in international travel.
For instance, someone engaging in sexual activity with a partner from a country with low vaccination coverage could still be at risk. Furthermore, countries with low HPV vaccination rates among girls, such as the United States where only 54.3% of adolescents aged 13 to 15 years received two or three HPV vaccination doses in 2020, may not provide adequate protection against the virus.
Several countries, such as the United Kingdom, Australia, and the United States, have expanded their national HPV vaccination recommendations to include young boys. This is done by adopting a gender-neutral vaccination policy.
However, implementing a universal vaccination policy does not necessarily ensure widespread coverage.
Certain populations remain opposed to HPV vaccination due to safety concerns or concerns about promoting promiscuity.
Interestingly, some population studies have found that young adults may choose oral sex as an alternative to penetrative intercourse.
The COVID-19 pandemic has also presented its own challenges. For one, it temporarily halted efforts to reach young people at schools for vaccinations. Additionally, there has been a growing trend of vaccine hesitancy or “anti-vax” sentiment in many countries, which may further reduce vaccine uptake.