A risk factor is any factor that is associated with increasing someone’s chances of developing a certain condition, such as cancer. Some risk factors can be modified, such as lifestyle or environmental risk factors, and others cannot be modified, such as inherited factors or whether someone in the family has had cancer.

Having 1 or more risk factors does not mean that a person will develop cancer. Many people have at least 1 risk factor but will never develop cancer, while others with cancer may have had no known risk factors.

Even if a person with cancer has a risk factor, it is usually hard to know how much that risk factor contributed to the development of their disease.

Vulvar cancer risk factors

The main risk factors for vulvar cancer are:

• human papillomavirus (HPV) infection
• untreated precancerous skin conditions
• smoking
• human immunodeficiency virus (HIV) infection, the virus that can lead to AIDS
• other gynaecological cancers, such as cervical cancer
• melanoma or atypical moles, or a family history of melanoma.
• age – it is more common in women who are over 70 years old.

HPV infection

HPV is a common infection affecting the skin surface of any part of the body, including the vulva, the vagina and the cervix. More than 100 types of HPV have been identified, but about 12 are considered high risk because they can lead to cancer.

HPV is infectious – it spreads from person to person through genital skin contact. Around 8 out of 10 women will become infected with genital HPV at some time in their lives. It is so common that it could be considered a normal part of being sexually active.

However, vaginal cancer is not infectious.

HPV does not often cause symptoms, so many people are unaware they have the virus. For about 98% of women, the virus is cleared rapidly by the immune system.

HPV can cause precancerous cells that may be found during a routine cervical screening test.

Precancerous skin conditions

Women who have certain noncancerous skin conditions for a long time have an increased risk of developing vulvar cancer.

Vulvar intraepithelial neoplasia (VIN)

VIN risk factors are similar to the risk factors for vulvar cancer, and it is more common in women who:

• smoke
• have human papillomavirus (HPV) infection
• may have had genital herpes
• have a suppressed immune system
• have a skin condition called lichen sclerosis.

Lichen sclerosus and lichen planus

Lichen sclerosus and lichen planus affect the skin in the vulval area. It is sometimes called lichen sclerosus et atrophicus, or LSA.

In women with lichen sclerosus, the vulvar skin can become inflamed and itchy, and split and crack, causing pain. The vulva may become distorted, and change in shape and size.

About 6–7 out of 10 vulvar cancers occur in women who also have lichen sclerosus. But only a small number of (1–2 out of 100) women with lichen sclerosus will go on to develop vulvar cancer.