Causes of vulval cancer

Cancer of the vulva is rare; just over 1,000 women in the UK are diagnosed with it each year.

Doctors don’t know exactly what causes vulval cancer. But, like other cancers, it isn’t infectious and can’t be passed on to other people. Vulval cancer isn’t caused by an inherited faulty gene and so other members of your family are not likely to be at risk of developing it.

There are a number of risk factors known to increase the chances of vulval cancer developing:

Age The risk of developing vulval cancer increases with age. About 8 out of 10 women (80%) who are diagnosed with vulval cancer are over the age of 60. Vulval cancer in older women is usually associated with a skin condition called lichen sclerosus. But vulval cancer is becoming increasingly common among younger women, in whom it is often linked to HPV infection.

Vulval skin conditions Women who have non-cancerous skin conditions of the vulva, such as vulval lichen sclerosus and vulval lichen planus| , have a higher risk of developing cancer of the vulva. About 3 to 5 out of every 100 women (3-5%) who have lichen sclerosus go on to 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 in the skin of the vulva.

Human papilloma virus ( HPV |) Infection with this virus is a risk factor for vulval cancer. HPV is a very common infection and is usually passed between people during sex. There are many different types of HPV and each is identified by a number. Some types (particularly 16, 18 and 31) are linked to vulval cancer and pre-cancerous changes called VIN.

Most women with HPV infection don’t have any problems, as their immune system quickly gets rid of the virus. But in a few women, the virus remains and may go on to cause abnormal changes in the skin of the vulva and sometimes vulval cancer.

Vulval intraepithelial neoplasia (VIN| ) This is a pre-cancerous condition that can occur in the skin of the vulva. In some women VIN develops into vulval cancer.

There are two types of VIN:

• VIN usual type This is the type linked to HPV infection and mainly affects younger women below the age of 50.
• VIN differentiated This type of VIN is linked to lichen sclerosus and more commonly affects women over 50 years of age.

Smoking 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 our immune systems less effective, and less able to clear the HPV virus. This may be one reason why it increases the risk of vulval cancer.

Paget’s disease of the vulva This is a condition that causes abnormal changes in the cells that cover the skin of the vulva. It's rare and usually only affects women who've been through the menopause. In some women with Paget’s disease of the vulva (fewer than 20%) an invasive cancer of the vulva is found underneath the area affected by Paget's.