Friday, 27 July 2018

Human Papillomavirus and Cancer

Human Papillomavirus (HPV)

The human papillomavirus, or HPV, is a type of virus that infects the skin and the cells lining body cavities. For most people, the infection will get better on its own and they will never know they had it. 

There are different types of HPV:

Some infect the skin, usually on the fingers and hands. These can cause minor problems, such as common skin warts and verrucas.

Others infect the genitals, mouth and throat. These can cause genital warts, or more rarely, cancer.
From this point onwards, the discussion is on genital and oral HPV, as these types are the ones which can cause cancer.

HPV is a very common infection. Around 8 out of 10 people will be infected with the virus at some point in their lives. It usually doesn’t cause any symptoms and most people will never know they had it. HPV spreads through close skin-to-skin contact, usually during sexual activity including oral sex. Having a high number of sexual partners does increase the chances of infection. 

HPV infection usually causes no problems at all. But in some people the infection will stay around for a long time and become persistent. Around 13 types of HPV can cause cancer. These are called ‘high-risk’ types. People with persistent infections with ‘high-risk’ HPV types are those who are most likely to go on to develop cancer.

HPV & Cancer

The main type of cancer linked to HPV infection is cervical cancer. Virtually all cases of cervical cancer are caused by HPV. About 3,100 cases of cervical cancer are diagnosed in the UK each year.
HPV can also cause cancer in other genital areas, like the vagina, vulva, penis, and anus. It can also cause some types of cancer of the mouth and throat.

The majority of vaginal, vulval, penile and anal cancers are caused by HPV. But they 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, particularly in people in their 40s, 50s and 60s.30–34 And the evidence suggests that the proportion of cases linked to HPV is rising.

How HPV leads to Cancer

HPV can cause cells to divide more than usual. Fast cell 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 persistent ‘high-risk’ HPV infections, the virus can damage DNA and cause cells to start dividing and growing out of control. This can lead to cancer.

HPV Vaccine

HPV can cause changes to the DNA in our cells that make them more likely to turn cancerous. So by protecting against HPV infection, we can help prevent those changes and reduce the risk of cervical cancer.

HPV Vaccination for Women

Since 2008, girls aged 11-13 have been offered a vaccination against the two most common ‘high-risk’ types of HPV, HPV 16 and 18. Together, these two types cause about 7 out of 10 cervical cancers. Girls up to the age of 18 can request vaccination through the NHS if they weren’t vaccinated routinely. The HPV vaccine has been proven to be safe and effective.
The HPV vaccine currently used in the UK (Gardisil) also protects against HPV 6 and 11, which are the HPV types that cause most genital warts.
The HPV vaccine doesn’t protect against all types of HPV, so screening is still important, even if you have been vaccinated.

HPV Vaccination for Men

As HPV is linked to cancers in men as well as women, offering HPV vaccination to men would help reduce the risk of disease. Men who have sex with men have a higher risk of anal cancer than men who don’t.

From April 2018, the vaccine is being rolled out men who have sex with men in all sexual health and HIV clinics across the UK.

The Joint Committee for Vaccination and Immunisation are also currently considering whether to offer HPV vaccination to all teenage boys as well as girls.

Cervical Screening for HPV

Cervical screening aims to pick up early cell changes that are caused by HPV and remove these cells before they have a chance to become cancerous. This is done by taking a sample of cells and sending them to a lab where they are tested to see if they are normal (cytology). If the cells look abnormal, they will be tested for HPV to see if they are more likely to become cancerous. If they test positive for HPV, the cells will be removed.

Call for abstracts: https://std-hiv-aids.cmesociety.com/call-for-abstracts
Abstract submission: https://std-hiv-aids.cmesociety.com/abstract-submission
Registration: https://std-hiv-aids.cmesociety.com/registration

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