Cancer begins with a change in the structure of DNA. DNA provides our cells with a basic set of instructions, such as when to grow and reproduce.
A change in DNA structure is known as a mutation, and it can alter the instructions that control cell growth. This means that the cells continue to grow instead of stopping when they should. This causes the cells to reproduce in an uncontrollable manner, producing a lump of tissue called a tumour.
How does vulval cancer spread?
There are three ways that vulval cancer can spread.
The first is directly, spreading out of the tissue of the vulva and into surrounding parts of the body such as into the inside of the vagina or urethra.
The second is via the lymphatic system. The lymphatic system is a series of nodes (or glands) and channels that are spread throughout your body, much like your blood circulation system.
One way of thinking about it is as a kind of underground railway where the channels are the train tracks and the lymph nodes the underground stations.
You may sometimes notice swollen nodes in your neck or under your armpit when you have an infection.
The lymph nodes produce many of the specialised cells that are needed by your immune system.
The first group of lymph nodes that can become affected by the cancerous cells are located in your groin.
The final way is via the bloodstream into distant organs such as the lungs, brain, liver and bones.
This generally only occurs in advanced vulval cancer after the cancer cells have spread to multiple lymph nodes.
Cancer that has spread to other parts of the body is known as metastatic cancer.
Known risk factors
Exactly what causes the cells of the vulva to become cancerous is unclear though a number of risk factors have been identified. These are:
- age
- human papilloma virus (HPV)
- vulval intraepithelial neoplasia (VIN)
- skin conditions that can affect the vulva, such as lichen sclerosus (see below)
- smoking
Age
Two out of three cases of vulval cancer develop in women aged 65 or over, with just under half of the cases occurring in older women aged 75 or above.
Age is also a significant risk for a whole range of other cancers, such as lung cancer, prostate cancer and breast cancer. The older you get the more chance there is that certain cells in your body could be damaged, triggering the onset of cancer.
Human papilloma virus (HPV)
Human papilloma virus (HPV) is the name given to a family of viruses that affect the skin and the moist membranes that line the body, such as those in the cervix, anus, mouth and throat.
HPV is known to cause changes in the cells of the cervix, which can lead to cervical cancer. It is thought that the virus could have a similar effect on the cells of the vulva. One expert has estimated that around 30% of vulval cancer cases are associated with an HPV infection.
The HPV virus is spread during sexual intercourse, including anal and oral sex.
Vulval intra-epithelial neoplasia (VIN)
Vulval intra-epithelial neoplasia is what's known as a pre-cancerous condition.
A pre-cancerous condition is where there are some changes to the biological make-up of certain cells.
The changes are not the same as with new cancers but potentially these changes could lead to the formation of a new cancer at a later date.
Symptoms of VIN are similar to that of vulval cancer and include:
- persistent itchiness in the vulva
- a burning sensation when passing urine
- the development of raised patches of skin that can be red or white in appearance
There are two types of VIN:
- usual VIN or undifferentiated VIN – this usually affects women aged 35 to 55 and is thought to be caused by an HPV infection
- differentiated VIN or dVIN – this is a rarer type, usually affecting older women aged 55 to 85 and is associated with skin conditions that can affect the vulva (see below)
VIN can be treated by removing affected areas of skin or in some cases using a cream called Imiquimod that is designed to help kill abnormal cells. There is also ongoing research seeing whether another type of cream called cidofovir may be an effective treatment for VIN – Cancer Research UK has more information on the current state of research into vulval cancer.
For more information of VIN, visit the British Society for the Study of Vulval Disease (BBSVD) website’s article on VIN.
Skin conditions
There are several skin conditions that can affect the vulva, with two being lichen sclerosus and lichen planus.
Both conditions cause similar symptoms in that they cause affected areas of skin to become very itchy and sore and lead to the development of a red raised rash.
The causes of both conditions are unknown.
It is estimated that around 1 in 50 women who develop one of these conditions will go on to develop vulval cancer.
For more information, see Lichen planus and Lichen sclerosus.
Smoking
Smoking increases your risk of developing vulval cancer as well as a range of other serious diseases such as heart disease, stroke and lung cancer.
One study found that women who smoked were twice as likely to develop vulval cancer than non-smokers.
The chemicals in tobacco smoke are known to cause damage to the cells of the body. Smoking can also weaken your immunity (defence against infection), making you more vulnerable to the harmful effects of a HPV infection.
