Causes of vulval cancer
The exact cause of vulval cancer is unknown. However, risk factors can increase the chance of developing it.
The exact cause of vulval cancer is unknown. However, certain risk factors can increase the chance of developing it.
Having one or more risk factors does not mean you will definitely get cancer. And if you do not have any risk factors, it does not mean you will not get vulval cancer.
The risk of developing vulval cancer increases with age. Most of the women who are diagnosed with vulval cancer are aged 65 or over. Vulval cancer in older women is usually linked to a skin condition called lichen sclerosus.
But younger women can also be affected. About 15 in every 100 vulval cancers (15%) develop in women aged under 50. Vulval cancer is becoming more common in younger women, where it is often linked to human papillomavirus infection (HPV) and smoking.
Some long-term (chronic) skin conditions of the vulva can increase a woman’s risk of developing vulval cancer.
Vulval lichen sclerosus (LS) and vulval lichen planus (LP)
Lichen sclerosus and lichen planus are fairly common, non-cancerous skin conditions. They can affect different parts of the body, but commonly affect the vulva. When they affect the skin of the vulva, they are known as vulval LS or vulval LP.
Less than 5 in every 100 women who have vulval LS or LP (less than 5%) develop vulval cancer. It is thought that, over a long period of time, the inflammation caused by these skin conditions increases the risk of cancer developing.
Paget's disease of the vulva
This condition causes abnormal changes in the cells that cover the skin of the vulva. It is rare and usually only affects women who have been through the menopause.
In a small number of women with Paget’s disease of the vulva, cancer is found underneath the area where the Paget’s disease is.
Human papilloma virus (HPV) is a very common infection. It is usually passed between people during sex.
There are more than 100 types of HPV, and each has a number. Some types (particularly 16, 18 and 33) are linked to vulval cancer and pre-cancerous changes called vulval intraepithelial neoplasia (VIN).
Most women with an HPV infection do not have any problems, as their immune system quickly gets rid of the virus. But in a few women, the virus stays and may cause abnormal changes in the skin of the vulva, and sometimes vulval cancer.
A vaccination against HPV is offered to girls aged 12 to 13 in the UK. This protects against HPV types 16 and 18.
It may take several years to see whether this vaccination reduces the number of vulval cancers. This is because vulval cancers can take a long time to develop.
The term VIN describes changes that can happen in the skin that covers the vulva. If the changes become more severe, there is a chance that cancer might develop after many years. VIN is called a pre-cancerous condition.
There are two types of VIN:
Smoking increases the risk of developing both VIN and vulval cancer. The longer a woman smokes for and the more cigarettes she smokes, the greater the risk. Smoking makes the immune system less effective and less able to get rid of HPV. This may be one reason why it increases the risk of vulval cancer.
We have more information about giving up smoking.
Women with pre-cancerous changes in the cells of the cervix (CIN), or those who have had cervical cancer, have an increased risk of developing cancer of the vulva. This may be related to shared risk factors, such as HPV infection and smoking.
The immune system is part of the body’s defence against infections. Having a lowered immunity because of illness or treatment can increase the risk of vulval cancer. This could be if:
- you have HIV
- you are taking medicines to suppress your immune system after an organ transplant.
If you are worried that you are at risk of developing vulval cancer because you have lowered immunity, talk to your GP or specialist nurse, if you have one. They will be able to give you further advice.