Find out what a risk factor is, and the possible causes of vulval cancer.
What a risk factor is
Anything that can increase your risk of getting a disease is called a risk factor.
Different cancers have different risk factors. Having one or more of these risk factors doesn't mean you will definitely get that cancer.
Vulval cancer is more common in older women. On average each year more than 40 out of 100 (more than 40%) of new cases are in women aged 75 and over.
Vulval cancers can occur in young women and have been seen in women in their 20's. But it is extremely rare to get vulval cancer at such a young age.
Human papilloma virus (HPV) infection
The human papilloma virus (HPV) is a type of virus that can infect the skin in different parts of the body, including the vulva. HPV is an important factor in the development of some vulval cancers.
HPV can pass from one person to another by skin to skin contact, and during sexual contact. Around 80 out of 100 people (80%) in the UK will have the HPV virus at some time during their lifetime. So it is a very common infection.
Reviewers think that around half (50%) of vulval cancers are caused by the human papilloma virus (HPV). HPV related vulval cancers tend to occur in younger women between the ages of 35 and 55.
It is important to know that most women infected with HPV do not go on to develop vulval cancer. For many people, the virus causes no harm and goes away without treatment.
There are many different types of HPV and some are more likely to lead to vulval cancer than others. HPV types 6 and 11 can infect the female and male genital organs and the anal area, causing visible genital warts. These types of the virus are called low risk types and are rarely linked to cancer.
Research shows that HPV type 16 is the most common type of HPV found in vulval cancer. Followed by HPV types 33 and 18. Infection with these types of HPV does not usually produce any warts or other visible signs until pre cancerous changes or cancer develop.
There is now a vaccine that can protect against HPV infection. In the future, we should see a fall in vulval cancer rates. This will take some years to show up because vulval cancer can take such a long time to develop.
Chronic skin conditions and inflammation
Some long term vulval skin conditions are associated with vulval cancer.
- lichen sclerosus
- lichen planus
The most common of these is lichen sclerosus. This causes itching and sometimes pain in the vulva area. This usually affects women over the age of 60. Women with lichen sclerosus may develop a condition called differentiated vulval intraepithelial neoplasia (dVIN).
Although differentiated VIN can progress to invasive cancer, fewer than 5 in 100 women (5%) with lichen sclerosus or lichen planus develop vulval cancer.
Lichen sclerosus and lichen planus cause long term (chronic) irritation of the skin of the vulva. This may be a possible cause of the increased cancer risk.
Vulval intraepithelial neoplasia (VIN)
Vulval intraepithelial neoplasia (VIN) means there are pre cancerous changes in the top layer of the skin (epithelium) covering the vulva. VIN is not cancer, but there is a risk that it may go on to develop into vulval cancer. This usually takes many years.
There are different types of VIN, these include:
High grade squamous intraepithelial lesion (HSIL)
This type tends to occur in younger women aged 45 to 50 years. It is associated with long term human papilloma virus (HPV) infections.
Differentiated Vin (dVIN)
This type is rare and usually seen in older women and is associated with a skin condition called lichen sclerosus. Although most cases of VIN will not develop into cancer, it is not possible to tell which will and which won’t. Everyone with this condition should have treatment or close monitoring by a doctor.
Cervix cell changes (CIN) or cervical cancer
Some studies show that women with a previous cervical cancer, or pre cancerous changes in the cells of the cervix (CIN), have an increased risk of vulval cancer.
This link is probably due to both cancers sharing risk factors such as HPV.
Weakened immune system
The risk of vulval cancer is also increased after organ transplant. People who have had organ transplants have to take drugs to suppress their immune system. This is to stop the body rejecting the transplanted organ.
HIV (human immunodeficiency virus) is the virus that causes AIDS (acquired immune deficiency syndrome). HIV can increase the risk of vulval cancer because it weakens your immune system. So if you have HIV, you are more likely to pick up other infections, such as HPV. This can increase your risk of getting pre cancerous cells in the vulva (vulval intraepithelial neoplasia).
Radiotherapy for womb cancer
Women who have had radiotherapy treatment for a womb cancer have an increased risk of vulval cancer some years later.
Other medical conditions
Systemic lupus erythematosus (SLE or lupus) is a chronic auto immune disease. The immune system attacks the body’s own connective tissue cells and tissues, causing inflammation and damage. People with SLE have an increased risk of vulval cancer.