Over the past 2 decades there has been a rapid increase in throat cancer in the West, to the point that some have called it an epidemic. This has been due to a large increase in a specific type of throat cancer called oropharyngeal cancer.
This type of cancer affects the area around the tonsils and the back of the throat. Its main cause is the human papillomavirus (HPV), which is also behind many cases of cervical cancer.
Oropharyngeal cancer is now more common than cervical cancer in the United States and the United Kingdom. In Spain, oropharyngeal cancer is among the 10 most diagnosed, with some 8,000 new cases per year. And in Central and South America it is an increasingly serious problem, to the point that an increase of 17.2% in oral cancer mortality is expected by 2030.
HPV is transmitted sexually
In the case of oropharyngeal cancer, the main risk factor is the number of sexual partners throughout life, especially through the practice of oral sex. People with 6 or more oral sex partners in their lifetime are 8.5 times more likely to develop oropharyngeal cancer than those who do not engage in oral sex.
Around 80% of adults practice oral sex
Studies on behavioral trends show that oral sex is widespread in some countries. In a study my colleagues and I conducted of around 1,000 people who underwent tonsillectomy for non-cancer reasons in the UK, 80% of adults reported having performed oral sex at some point in their lives. Fortunately, however, only a small number of those people develop oropharyngeal cancer.
Although it’s still not entirely clear what it depends on, the prevailing theory is that most of us get HPV infections and are able to clear them completely. However, a small number of people are not able to get rid of the infection, perhaps due to a defect in a particular aspect of their immune system. In such patients, the virus is capable of continuous replication and, over time, integrates into random positions in the host’s DNA, some of which can cause the host’s cells to become cancerous.
HPV vaccination
HPV vaccination of young women has been introduced in many countries to prevent cervical cancer. There is now increasing evidence, although still indirect evidence, that it may also be effective in preventing HPV infection in the mouth.
There is also evidence to suggest that boys are protected by “herd immunity” in countries where vaccine coverage in girls is high (over 85%). It is expected that in a few decades the increase in protection will lead to a reduction in oropharyngeal cancer.
That is all very well from a public health standpoint, but only if coverage among girls is high, above 85%, and only if one remains within the protected “herd”. However, this does not guarantee protection at the individual level -and especially in these times of international travel- if, for example, someone has sexual relations with people from countries with low coverage.
And it certainly offers no protection in countries where vaccination coverage for girls is low, for example the US, where only 54.3% of adolescent girls aged 13-15 had received 2-3 doses of HPV vaccination in 2020.
Boys should also get vaccinated
This has prompted several countries, including the UK, Australia and the US, to expand their national HPV vaccination recommendations to include young men, following a gender-neutral vaccination policy. But having a universal vaccination policy does not guarantee coverage; regarding this, there is significant proportion of some populations that oppose HPV vaccination.
This is due to safety concerns, necessity or, in some less common cases, the encouragement of promiscuity. Paradoxically, there is some evidence from population studies that, possibly in an effort to abstain from penetrative sex, young adults may engage in oral sex instead, at least initially, without being fully aware that it also poses a risk.
