This information is about the human papilloma virus (HPV) and how it may increase the risk of cancer. HPV is known to increase the risk of cancer of the cervix. It may also increase the risk of cancers affecting other parts of the body, including the vagina, vulva, anus, mouth, and penis.
What is HPV?
HPV (the human papilloma virus) is a common group of viruses. Over 100 different types of HPV have been identified and each is known by a number. HPV affects the skin and the mucosa (the moist membranes that line parts of the body, such as the insides the mouth, throat and anus). Some types of HPV are known to increase the risk of developing particular types of cancer and are known as high-risk HPVs. The types most often associated with cancer are types 16 and 18. High-risk HPVs can lead to abnormal changes in the cells, which is sometimes called dysplasia. Although dysplasia is not cancer, it is sometimes described as being pre-cancerous.
Other types of HPV can cause warts and verrucas. These may appear on different parts of the body, but are more commonly seen on the hands and feet, in the genital area, and around the anus. The types of HPV that cause visible warts and verrucas are less clearly linked with cell changes that can increase the risk of cancer. They are known as low-risk HPVs.
This information is about the high-risk HPV types that increase the risk of developing cancer.
How HPV is spread
Over 10 different types of high-risk HPV can be passed from one person to another. HPV is spread through skin contact, often during sex. Exactly how a person gets the virus is often uncertain; and it is not always possible to find a sexual explanation. It is thought that there may be other ways of spreading the virus that have not yet been identified.
HPV can affect both men and women and because the virus is very common, most people who are sexually active will have HPV at some time during their life. Many people don't have any symptoms and are unaware that they have HPV. The virus may be inactive for weeks, months, and - for some people - possibly even years after infection. The body's immune system is usually able to get rid of an HPV infection and many infections come and go without causing any problems.
Although HPV can increase the risk of developing some types of cancer, most people who have HPV will not develop cancer.
Preventing HPV infection
If you are sexually active it may be difficult to avoid becoming infected with HPV. As most high-risk HPVs do not cause symptoms, it can be impossible to tell if your partner is infected. Condoms and other barrier methods of contraception can help to reduce the risk of becoming infected but they do not cover all of the skin and are therefore not completely effective.
You are more likely to become infected with HPV if you start having sex at a younger age and if you have a large number of sexual partners, especially if you are having sex without a barrier method of contraception.
HPV infection may be more likely if there are abrasions or small cuts and tears in the skin or mucosa. Abrasions and tears are more likely to occur during anal sex, or if the vagina is drier than normal (following the menopause, for example). In these situations it can help to use a lubricant during sex, such as KY Jelly®, Senselle® or Sylk®.
As HPV infection is common (and difficult to prevent), it is important for people to be alert to any changes in the parts of the body where we know HPV may cause cancer. Cancer diagnosed in the very early stages, before it has begun to spread, is much easier to treat and cure. It is very important that women have regular smear tests as these can pick up changes in the cervix at a very early stage.
There is some evidence to suggest that people who smoke and have HPV are more likely to develop cell changes that can lead to cancer than people who have HPV but do not smoke. So if you know you have HPV, or even if you don’t know, it can help to try to boost your immune system by stopping smoking.
How HPV is diagnosed
As there are usually no symptoms of high-risk HPV, the infection is often not diagnosed. There are no blood tests to detect HPV.
HPV infection of the cervix is mainly diagnosed in women as a result of the cervical screening programme. A woman may be told that she has HPV when she receives her cervical screening result. If an HPV infection is present, changes in the appearance of the cells can sometimes be seen when they are looked at under a microscope during the screening process. Some women who have an abnormal smear test result will attend a colposcopy clinic, where their cervix will be examined using an instrument like a microscope (a colposcope). During the examination, the nurse or doctor can apply a solution to the cervix that makes cells infected with HPV turn white.
An HPV DNA test is sometimes done using cells collected during a routine cervical screening test or colposcopy. The test looks at the genetic make-up (DNA) of the HPV within the cells and can detect which type of HPV is present. This can be useful as it may help to identify whether the HPV is a type that may cause pre-cancerous changes. HPV DNA tests are not widely available in the UK.
In men, high-risk HPVs do not cause symptoms and are often very difficult to diagnose.
Some people who are known to be at a high-risk of having anal HPV and of developing anal cancer may be offered an ‘anal smear’. Men who have receptive anal sex are more likely to have anal HPV and are at an increased risk of developing anal cancer.
Men and women with HIV are at an even greater risk of anal HPV regardless of their sexual orientation. The anal smear is very similar to a cervical smear and involves collecting cells from the anal area using a special wipe. However, anal smears are not widely available in the UK. If you are in a high risk group, and more likely to have anal HPV, you can discuss with your GP, or with a doctor at your local sexual health clinic, whether you should have regular anal smears.
HPV and cervical cancer
High-risk HPV can cause changes to the cells that cover the cervix. The changes are known as cervical intra-epithelial neoplasia, or CIN. Not all women with these types of HPV develop CIN. For many women, HPV infection is temporary and any cell changes will go back to normal.
CIN is not a cancer, but in some women, if left untreated, it can develop into cancer over a number of years.
Treatment for CIN is very effective, and the risk of it coming back after treatment is low. Treatment will usually depend upon how severe the abnormal changes are. The changes are often graded as being CIN 1, 2 and 3. CIN 1 may not need any treatment, but will be closely monitored by your doctor. CIN 2 and 3 will usually be treated by removing the abnormal area using surgery, laser therapy, loop diathermy, cryotherapy (freezing the area), or cold coagulation (heating the area). CIN does not usually cause symptoms.
Symptoms of cervical cancer include:
- abnormal vaginal bleeding
- discomfort during sex
- abnormal vaginal discharge.
These symptoms can also be caused by many other things, but it is important to get any symptoms you may have checked by your GP.
HPV vaccines and cervical cancer
HPV types 16 and 18 are present in about 7 in 10 (70%) of cervical cancers. Because of this, two vaccines to prevent HPV infection have recently been developed. Large research trials using the vaccines Gardasil® and Cervarix®, have shown that they can prevent HPV infection in nearly all women who are given the vaccine before they become infected with HPV. However, as cervical cancer can take many years to develop after HPV infection, it is too early to tell whether the HPV vaccines will help to prevent cervical cancer in the long-term.
The vaccines need to be given three times, over a period of six months, and apart from mild soreness at the injection site there are very few side effects. When women are vaccinated they will still need to be screened for cervical changes, as the HPV vaccination will not completely prevent all cervical cancers.
From September 2008, all 12-13 year-old girls in the UK will routinely be offered an HPV vaccination. Starting in the autumn of 2009, there will also be a 'catch-up' programme to vaccinate girls under 18. It is also possible to obtain the vaccines privately.
Although it is known that the vaccines help to prevent HPV types 16 and 18, it is not known what the best age is to give the vaccines, or whether women will need a booster to keep them immune. As HPV is mainly spread by sexual contact, it is also not known if boys should also be vaccinated. The current vaccines are only helpful at preventing HPV infection. However research studies are looking at vaccines that could in the future be used as treatment for women who already have HPV.
HPV and vulval cancer
High-risk HPV infection can cause cell changes in the vulval area (a woman’s external genitalia). The changes are known as vulval intra-epithelial neoplasia, or VIN. Not everyone who has HPV will develop VIN.
VIN is not cancer, but in some women it can develop into vulval cancer over many years. Not all VIN will develop into a cancer, although it is thought that high-risk HPV infection causes nearly half of all vulval cancers. Cancer of the vulva is rare and only about 1000 women are diagnosed with this cancer each year in the UK.
Treatment of VIN will depend upon how severe the cell changes are. Mild changes (VIN 1) will usually only need to be closely monitored with regular outpatient appointments. More severe changes (VIN 2 or 3) may need treatment, which usually involves removing the abnormal area using surgery, laser therapy or diathermy (which uses an electrical current to cut away the affected area).
Symptoms of vulval cancer include:
- pain, discomfort and itching of the vulva
- small lumps or swellings in the vulva
- abnormal vaginal bleeding or discharge
- a sore or ulcerated area on the vulva.
These can also be symptoms of other, non-cancerous, conditions, but it is important to get any symptoms checked by your GP.
The vaccines that are currently being researched to prevent HPV infection and cervical intra-epithelial neoplasia (CIN) may also help to prevent VIN. Trials using these vaccines are currently underway. Other vaccines, to be given to women who already have HPV, are being developed. They aim to boost the immune system to get rid of the HPV.
HPV and vaginal cancer
High-risk HPV can cause cell changes to the cells that cover the vagina. The changes are known as vaginal intra-epithelial neoplasia, or VAIN. Not everyone who has HPV will develop VAIN.
VAIN is not cancer but in a few women it may develop into a vaginal cancer over many years. Not all VAIN will develop into a cancer. Cancer of the vagina is rare and fewer than 300 women are diagnosed with this type of cancer in the UK each year.
Treatment of VAIN will depend upon how severe the cell changes are. Mild changes (VAIN 1) will usually only need to be closely monitored with regular out-patient appointments. More severe changes (VAIN 2 or 3) may need treatment, which usually involves either surgery to remove the abnormal cells, diathermy, laser therapy, and chemotherapy creams. Sometimes radiotherapy is used.
Symptoms of vaginal cancer include:
- blood-stained vaginal discharge
- pain and discomfort in the vaginal area
- bleeding after sex
- difficulty or pain when passing urine.
These can also be caused by non-cancerous conditions, but it is important to get any symptoms checked by your GP.
HPV and anal cancer
Not much is known about HPV and anal cancer, but high-risk HPV can cause cell changes around the anus. The changes are known as anal intra-epithelial neoplasia, or AIN. Not everyone who has HPV will develop AIN. AIN occurs more often in men who have anal sex or in HIV-positive men or women.
AIN is not cancer but in some people it can develop into anal cancer over many years. Anal cancer is rare in the UK and fewer than 500 people are diagnosed with it each year. Treatment of AIN may involve surgery, which can be painful and can affect the normal function of the anus. Usually, people who have AIN will have regular appointments to detect early signs of an anal cancer, when it is easier to treat and more likely to be cured.
Symptoms of anal cancer include:
- bleeding from the rectum
- pain, discomfort and itching around the anus
- small lumps around the anus
- faecal incontinence.
These can also be caused by non-cancerous conditions, such as piles (haemorrhoids). It is important to get any symptoms checked by your GP.
The vaccines that are currently being researched to prevent HPV infection and cervical intra-epithelial neoplasia (CIN) may also help to prevent AIN. Trials using these vaccines are currently underway.
HPV and head and neck cancers
The high-risk HPVs, especially type 16, have been linked to cancers affecting the tonsils, tongue and pharynx (the area at the back of the throat). The HPV is most commonly transmitted during oral sex.
Head and neck cancers are more common in people who smoke, and especially if they also drink alcohol. However, about a quarter of head and neck cancers are diagnosed in people who have never smoked. It is thought that HPV may play a part in the development of some of these cancers. Like HPV affecting other areas of the body, the infection can lay dormant for many months, or even years before causing cell changes that, in some people, may develop into cancer.
Most people who have HPV in their mouths will never develop any symptoms and won't develop cancer. At the moment there is no way of detecting HPV in the head and neck area before a cancer is diagnosed. However, research trials using the HPV vaccines may help to prevent HPV infection which could reduce the number of people who develop head and neck cancer. Further research looking into the link between HPV and head and neck cancers is also being done.
Symptoms of a head and neck cancer include:
- an ulcer or sore that doesn't heal
- difficult or painful swallowing
- pain when chewing
- a constant sore throat or hoarse voice
- a swelling or lump in the mouth
- a numb feeling in the mouth or lips.
Any symptoms that you are unsure about, or that have persisted for a couple of weeks, should always be checked by your GP.
HPV and cancer of the penis
Some research studies suggest that high-risk HPV, especially type 16, is a possible cause of cancer of the penis, although its exact role in the development of this type of cancer is not clear. There is no established HPV test for men, and many men will never know that they have HPV infection of the penis. Because of this, it is important that men are aware of the early signs of penile cancer.
Cancer of the penis is rare and approximately 600 men are diagnosed with it each year in the UK. It can often be treated very successfully if it is diagnosed early. Many of the symptoms of penile cancer can also be symptoms of other conditions, but should always be checked by your GP or a sexual health doctor.
Symptoms of cancer of the penis include:
- a change in colour of the skin of the penis
- thickening of the skin of the penis
- a growth or sore, especially under the foreskin
- discharge and bleeding.
Many people feel concerned when they are first told that they have HPV, and worry that they may develop cancer. You may find the treatments embarrassing, and may feel tense, tearful, or withdrawn. At times, these feelings can be overwhelming and hard to control.
Everyone has their own way of coping with difficult situations. Some people find it helpful to talk to friends or family, while others prefer to seek help from people outside their situation. Others may prefer to keep their feelings to themselves. There is no right or wrong way to cope, but help is available if you need it. Our cancer support service can give you details of how to find counsellors in your local area or see our list of counselling organisations.
This information has been compiled using information from a number of reliable sources, including:
- Souhami and Tobias. Cancer and Its Management (5th edition). 2005. Blackwell Scientific Publications. Oxford.
- Hoskins et al. Principles & Practice of Gynaecologic Oncology (3rd edition). 2000. Lippincott Williams and Wilkins.
- CancerHelp UK website. www.cancerhelp.org.uk (February 2006).
- Patient’s Guide to Human Papilloma Virus. Restorative Dentistry Oncology Clinic. February 2006.
- E Bernard. Anal pap smears: Is screening for anal cancer ready for prime time? Aids Treatment Update. November 2005.
For further references please see general bibliography.