Oral sex, tobacco and alcohol are the causes of throat cancer

BarcelonaThe incidence of pharyngeal cancer is increasing year after year and it is estimated that by 2030 it will reach one million new cases annually. It is a type of head and neck cancer, which represents the sixth most common tumor worldwide. Now, for the first time, a team of Catalan researchers has evaluated at an international level the prevalence of oral infection by human papillomavirus (HPV) and the associated risk factors, since together with tobacco and alcohol they are the main causes behind this disease. The magazineeClinicalMedicine publishes the results of the study which determines that in northern European countries and the United States, eight out of ten cases of this type of cancer are caused by oral HPV infection, which is directly related to risky sexual behaviour.

Specifically, it is the persistence of the human papillomavirus in the pharynx which can end up causing the appearance of a tumour, as it happens in the cervix, vulva, anus and penis. The probability of this occurring is greater in the case of high-risk HPV compared to low-risk HPV. "7% of the population analysed had oral HPV and did not know it because they had no symptoms and there are no routine screening programmes to detect the infection," warns the researcher from the Bellvitge Biomedical Research Institute (Idibell) and the Catalan Institute of Oncology (ICO) who has led the ICO in a conversation with ARA.

Researchers have carried out oral HPV screening tests on 7,674 participants from around the world in collaboration with research centres in the United States, Germany, France and the United Kingdom and the pharmaceutical company Merck. In all the countries analysed, the prevalence of high-risk HPV is two to four times higher in men than in women and Alemany explains that cases of head and neck cancer are also more frequent in men than in women. The authors highlight that more cases of oral HPV have been detected in France, where "more bisexual practices, smoking and gingivitis are also reported", and in the United Kingdom, where participants have "a greater number of sexual partners and cases of periodontitis", Idibell reports in a statement.

Researchers have found other factors associated with oral HPV infection, such as smoking marijuana, and the authors suggest that one possible cause is because this substance deteriorates the immune system. As seen in previous studies, the number of female sexual partners with whom oral sex is practiced is also a risk factor for the transmission of high-risk HPV, but only in men, not in women. Age is also a key factor in HPV infection: the frequency increases in older age groups, specifically from the age of forty, "probably because as time goes by, exposure to the virus and the persistence of the infection increases, therefore, latent infections can be reactivated and the activity of the immune system decreases."

Condom use is key

The main way to stop this cancer is through primary prevention of HPV infection through vaccination and reduction of alcohol and tobacco consumption. Since 2023, the Department of Health has included boys aged eleven to twelve in the HPV vaccination plan, a free coverage that until then was only offered to girls of this age and to some people with risky health conditions, such as homosexual men up to 26 years old and women who have overcome cancer. Thus, two doses are offered to them in sixth grade, in the year from which adolescents are considered to begin having sexual relations, with a six-month gap between injections.

Alemán also insists on the use of condoms for all sexual practices, not only when there is penetration. For the researcher, "it is key" to also use it when practicing oral sex, since this reduces the risk of infection. The expert also argues that it is necessary to prepare programs and policies to prevent this infection in the long term.