Men who had 5 oral sex partners have highest cancer risk

Men who have performed oral sex on five or more partners have the highest risk of HPV-related head and neck cancer, a new study shows. 

While the current rate of diagnoses is low – affecting just 0.7 percent of the male population – researchers at Johns Hopkins warned men may not be aware that they have a far higher risk than women, especially if they smoke.

The study, released today, is the latest piece of evidence to show that boys do need the HPV vaccine as much as girls – and in some cases it is more pressing for males. 

When the vaccine was first rolled out, it was only provided to teenage girls to protect them from HPV-related cervical cancer.  

But data suggest the incidence of oropharyngeal cancer will overtake cervical cancer in the US by 2020 – and sexually active men have a high risk.

There are over 100 different kinds of HPV but only a few are known to cause cancer.

HPV strains 16 and 18 are already known to trigger most cervical cancer, and HPV16 also causes most oropharyngeal cancer. 

But the new paper, published in the leading cancer journal Annals of Oncology, says we now need to go a step further: we could better curb the rate of HPV-related cancers if we identify who is most at-risk and why.

‘For these reasons, it would be useful to be able to identify healthy people who are most at risk of developing oropharyngeal cancer in order to inform potential screening strategies, if effective screening tests could be developed,’ said lead author Dr Amber D’Souza, associate professor at the Johns Hopkins Bloomberg School of Public Health.

‘Most people perform oral sex in their lives, and we found that oral infection with cancer-causing HPV was rare among women regardless of how many oral sex partners they had. 

‘Among men who did not smoke, cancer-causing oral HPV was rare among everyone who had less than five oral sex partners, although the chances of having oral HPV infection did increase with number of oral sexual partners, and with smoking.’

The researchers analyzed data on 13,089 people between the ages of 20 and 69 who were part of the National Health and Nutrition Examination Survey (NHANES) and had been tested for oral HPV.

They then compared those data with federal figures on oropharyngeal cancer diagnoses and deaths to predict the risk of cancer from oral HPV.

They also specifically investigated the numbers of new cases of oropharyngeal squamous cell cancer (OSCC) – the commonest type of oropharyngeal cancer.

The researchers found that women had a low risk of oral HPV infection from oral sex in general – regardless of their number of sexual partners. 

Those who’d had one or no oral sex partners had the lowest rate of cancer-causing oral HPV – affecting 1.8 percent of smokers and 0.5 percent of non-smokers.

If women had had two or more oral sex partners in their lifetime, the rate of infection increased slightly to 1.5 percent.

Among men, the lowest risk group were non-smokers who had never had oral sex, with a rate of 1.5 percent.

Prevalence rose to 4 percent among male non-smokers with two to four oral sex partners. 

For men who smoked and had two to four oral sex partners, the rate was 7.1 percent. 

It was even higher among non-smoking men who had five or more oral sex partners (7.4 percent).

The prevalence of infection was highest (15 percent) among men who smoked and had five or more oral sex partners.

Dr Carole Fakhry, associate professor in the Department of Otolaryngology – head and neck surgery – who co-authored the study, said: ‘Currently there are no tests that could be used for screening people for oropharyngeal cancer. 

‘It is a rare cancer and for most healthy people the harms of screening for it would outweigh the benefits because of the problem of false positive test results and consequent anxiety. 

‘Our research shows that identifying those who have oral HPV infection does not predict their future risk of cancer well, and so screening based on detecting cancer-causing oral HPV infection would be challenging. 

‘However, we are carrying out further research of oral HPV infection in young healthy men to explore this further.

‘Other research is being done on different biological markers and it is possible some of them could be used for oropharyngeal cancer screening in the future in some people.

‘For example, they might be useful in men but not in women given their lower cancer risk. 

‘Some studies suggest people who have antibodies against cancer-causing types of HPV have an increased risk of HPV-related cancer, but these antibodies are very rare. 

‘Therefore, it is not yet clear whether they will be useful for screening. Presently, these tests are not commercially available, and are still in research labs only.’