HPV and mouth cancer

Mouth cancer kills nearly 2000 people in the UK each year. The Human Papilloma Virus (HPV) of which there are over 100 different types, is more commonly associated with cervical cancer and genital warts, but it can also cause oral cancer, particularly of the back of the tongue and tonsils. The virus incorporates itself into the cell’s DNA and causes the cell to multiply out of control, leading to cancer.

In Britain, the number of mouth and throat cancers have increased by 40 per cent in just a decade, to 6,200 cases a year. According to Cancer Research UK, the HPV virus, which is transmitted to the mouth region from the genitals during oral sex, may be key to the ‘rapid rise’. Statistics also show that the more sexual partners you have the greater your chance of acquiring mouth cancer.

“There is now scientific evidence that a proportion of mouth and throat cancers are linked to HPV infection,” says Hazel Nunn, head of health information at Cancer Research UK. “We know that HPV is found in the mouth but we do not yet know how it gets there – whether through oral sex or otherwise. HPV virus has been found on the fingers and elsewhere on the body. It is possible that oral sex is having an impact but more research needs to be done into the kinds of behaviour that leads to this infection.”

“HPV has been causing mouth cancer for decades but  the link is only now becoming clear.  HPV is a hardy virus that likes sitting in lymphoid tissue wherever it is in the body,” explains Professor Mark McGurk, a senior consultant ENT surgeon based at London Bridge Hospital in London. That means it thrives in the lymphoid tissue in the mouth, including that of the tonsils and at the base of the tongue. For the same reason, it settles in the cervix, the vulva and around the anus.

For many people, HPV won’t cause any problems at all. “In fact, we know that 80 per cent of women and men will have the HPV infection at some time in their lives and clear it themselves without any symptoms,” explains Mr Mike Bowen, a consultant  obstetrician and gynaecologist based at St John and St Elizabeth Hospital in London.  “But for a few it can cause cellular changes that lead to cancer.”

Professor McGurk says that over the last 30 years, he has seen a rise in oropharyngeal cancer, which typically affects sexually active men in their 50s and 60s. “They may have been infected with the virus for some time and ,” he explains. The cancer reveals itself as growths on the tonsils and back of the tongue.

Many patients are only diagnosed at the late stage of their disease. Michael Douglas, the actor, already had stage 4 cancer when his cancer was recognised. Fortunately, oral cancer caused by HPV is very treatable, even when it is very advanced, using radiotherapy. “We used to do surgery on these cases, but we don’t need to anymore. In many cases, the cancer simply melts away with radiotherapy,” explains Professor McGurk. Patients with stage 1 and 2 Oral cancer caused by HPV have an 85 per cent chance of surviving for 5 years after treatment, and patients with stage 4 disease have a 60 per cent chance of surviving five years – impressive compared to the survival rates for other types of oral cancer where overall survival is 50 per cent over 5 years. [Cancer Research UK]

Cancer research UK is pushing for all mouth tumours to be tested to see if they are HPV positive, to assist with effective treatment of patients. “At the moment, it varies massively depending on what hospital you are in. We think it should be standard,” says Hazel Nunn.

Professor McGurk believes there is a simple explanation why men are more likely to have HPV in their mouths than women. “Women harbour the virus in their genitalia which provides a hospitable environment while the male penile area is a relatively hostile area for the virus to settle.”

One way to try and turn the tide would be to introduce a HPV vaccination for boys and girls before they become sexually active. Girls from the age of 12 in the UK have been offered vaccinations since 2008 against the two most common strains of HPV -16 and 18- which are linked to cervical cancer.

Boys are not offered the vaccine, but this should change, according to Professor Margaret Stanley, a virologist based at Cambridge University who believes that boys must be given the vaccine for HPV too from the age of 12 or 13.

‘Obviously cervical cancer is the big one but the other cancers – cancers of the anus and increasingly the tonsil and tongue – there is no screening for them and no way of detecting them until they are proper cancers and they are more common in men than in women.’

Hazel Nunn of Cancer Research UK points out that there is no evidence that vaccinating boys will help protect them from oral cancer. “It is theoretically possible but there have been no trials that had this as an end point. There is a danger that we get too far ahead of ourselves without evidence-based medicine.”

She insists that although HPV is a worrying factor, by far the most significant risks associated with mouth and throat cancers of all types are smoking and alcohol. “