HPV and cancer

HPV image HPV, or human papillomavirus, is a virus that infects the skin and the lining of body cavities. It is spread through close skin-to-skin contact. It is a very common infection which usually causes no symptoms at all.

Up to 8 out of 10 people in the UK will be infected with the virus at some point in their lives. HPV infections are usually on the fingers, hands, mouth and genitals. For most people, the infection will get better on its own and they will never know they had it. But in some people the infection will stay around for a long time and become persistent.

There are hundreds of different types of HPV. Most are harmless. But around 30 types of HPV can cause cancer. These are called ‘high-risk’ strains. People with persistent infections with ‘high-risk’ HPV types are those who are most likely to go on to develop cancer.

How can HPV cause cancer?
Cervical cancer and HPV
Other HPV related cancers

HPV vaccination
Reducing the risk

Normally, HPV infections start in the deepest layers of the skin. During an infection, HPV causes skin cells to grow faster than usual so that the virus can reach the surface of the skin and infect new people.

This fast skin growth can cause warts to develop, but often it doesn’t cause any symptoms at all. The types of HPV that cause warts are not the same types that cause cancer.

In some people with persistent ‘high-risk’ HPV infections, the virus damages the skin cells and causes them to start dividing and growing out of control. This can lead to cancer.

About 2,800 cases of cervical cancer are diagnosed in the UK each year. All are related to HPV.

HPV is spread to the cervix through sexual contact - not only penetrative sex. Using a condom reduces the chance of passing the infection on but it isn’t completely effective.

Most infections, even high-risk ones, are symptomless, so it is not always obvious if you or a partner carry HPV.

Taking up your cervical screening invitations is a great way of reducing the risk of cervical cancer. Screening aims to pick up early cell changes that are caused by HPV, and remove them before they have a chance to become cancerous.

By doing this, screening can prevent cervical cancer from developing in the first place. It already prevents many cervical cancers, preventing around 5000 deaths from cervical cancer a year in the UK.

In January 2011, the Government announced that HPV testing will now be included in the cervical screening programme for women who have borderline or mild changes in their first test . If they are found to have a high-risk HPV infection, they will be referred for further examinations. If they don’t have an infection, they will continue to be screened normally.

This should mean fewer women need to be called for further investigations.

HPV can cause cancers in other genital areas, like the vagina, vulva, penis and anus, as well as some types of cancer in the head and neck. As with cervical HPV infections, using a condom can reduce the risk of spreading HPV.

Vaginal, vulval, penile and anal cancers are less common than cervical cancer. Men who have sex with men may be at increased risk of anal cancer.

HPV infection also increases the risk of some types of mouth and throat cancers. Rates of mouth cancer, especially tongue and tonsil cancers, are on the increase, especially in people in their 40s, 50s and 60s. Estimates of how many of these cases are down to HPV have varied, but it seems that the proportion of cases linked to HPV is rising.

People who have a persistent high-risk HPV infection in the mouth are at higher risk of developing mouth cancer. In one study, people who had more than 26 sexual partners or more than 6 oral sex partners had a higher risk of mouth cancer than those who had fewer partners. But there is still much more to learn about how HPV behaves in the mouth and how people can reduce the risk.

Mouth cancers linked to HPV have a better prognosis than cases which aren’t linked to the infection.

Since 2008, girls aged 12-13 have been offered a vaccination against the two most common ‘high-risk’ strains of HPV, HPV 16 and 18. There is also currently a catch-up programme for girls up to the age of 18.

This vaccine is very effective at preventing cervical cell changes and cancers associated with HPV 16 or 18 infection. Together, these two strains cause up to 8 out of 10 cervical cancers in the UK.

HPV vaccination has great potential to reduce the number of women who develop cervical cancer. But it is still important to take up screening invitations even if you have been vaccinated.

It is likely that the cervical screening programme will have to change when most women have been vaccinated against HPV 16 and 18. More research will be needed before it is clear what is the most effective way to screen women who have been vaccinated against HPV.

HPV infections are mostly spread through direct skin-to-skin contact, usually during sexual activity. Practising safer sex by using a barrier method like a condom reduces the risk of passing on genital HPV infections.

The risk of HPV infection is higher for people who have had more sexual partners or who started having sex at an earlier age.

For cervical cancer, attending screening is a very important way of reducing the risk of developing the disease.