Why is HPV a problem?
HPV is generally passed from person to person via sexual contact. The virus is extremely contagious and is the most common STI in the world. The virus lives in the skin and spreads via skin to skin contact, making it slightly different from STI’s like chlamydia and STD’s like HIV which are spread through bodily fluids. This means you can can contract HPV through things like vaginal and anal sex, oral sex, mutual masturbation - anything where infected skin touches skin (it is important to remember your skin is not just on the outside).
HPV is extremely common, and if you are over the the age of 27 then you are likely to have had HPV of some kind. Some researchers believe that HPV is so prevalent that sexual transmission cannot be the only way the virus is transferred from person to person. and that it may be transferred by non sexual contact.
The majority of people have no symptoms and their body gets rid of the virus naturally without any major health issues. HPV becomes a problem when you are infected by a “high risk” strain of the virus. These are types of HPV which can cause cells to mutate and become cancerous.
high risk and low risk strains of hpv
HPV has different strains which can affect the body in different ways and each strain is assigned a name for identification purposes. There are around 200 strains of HPV in total, and in the majority of cases, HPV will cause no lasting damage nor present any symptoms.
Some strains however will cause warts to grow, and others can lead to cancer. Scientists are able to identify which strains of HPV can cause cancer by testing the cancer cells of patients. While there are always going to be some exceptions, the HPV strains which cause the most problems are:
- HPV 6 and 11 which can cause genital warts in men and women. These are called low risk strains of HPV.
- HPV 16, 18 and 39 which can cause cervical, anal, penis and vagina cancers. These are called the high risk strains of HPV.
This doesn’t mean other strains cannot cause problems, but these particular strains are known to be the biggest trouble makers.
Why does HPV cause cancers?
Research has established the link between HPV and cervical cancer however, more and more scientists are seeing a link between HPV and cancers of the head and neck, anus, penis and vagina. The reasons for this are still being researched but what is clear is that HPV is a virus which affects the skin and the majority of cancers that are caused by HPV are Squamous Cell Carcinoma which is a type of skin cancer.
Humans have two kinds of skin on and in their body. They are the cutaneous and the mucosal. The cutaneous is the skin you can see - covering your body. The mucosal skin is the skin you generally do not see. This kind of skin lines the inside of the body and covers things like the throat, the anus and the vagina. HPV can cause changes to the skin and sometimes these changes lead to skin cells in the mucosal skin to mutate and become cancerous.
Recent statistics below show the number of HPV related cancer cases in the UK:
- 99% of cervical cancer
- 40 to 70% of vaginal and vulval cancers
- 40% of penile cancers
- 85% of anal cancers
- 25% of mouth cancers
- 35% of throat cancers
Researchers gather these statistics by testing the cancerous cells and checking if they carry a high viral load of HPV.
The type of throat cancer most associated with HPV is oropharyngeal cancer and we are starting to see more men in particular suffering at a younger age. Leading experts like Professor Margaret Stanley, Director of Research, Department of Pathology, University of Cambridge believe there is a direct link between this steep rise in cases and HPV.
In a presentation to the UK Parliament - Professor Stanley stated that:
"If recent incidence trends continue, the annual number of HPV-positive oropharyngeal cancers is expected to surpass the annual number of cervical cancers by the year 2020."
The Throat Cancer Foundation are campaigning for HPV vaccination to be offered to boys as well as girls which will reduce the cases of HPV-related cancer.