What is vulvar cancer?

The vulva is the outer part of the female genitals. The vulva includes the opening of the vagina (sometimes called the vestibule), the labia majora (outer lips), the labia minora (inner lips), and the clitoris.

 Around the opening of the vagina, there are 2 sets of skin folds. The inner set, called the labia minora, are small and hairless. The outer set, the labia majora, are larger, with hair on the outer surface. These inner and outer labia (Latin for lips) meet, protecting the vaginal opening and, just above it, the opening of the urethra (the short tube that carries urine from the bladder). The Bartholin glands are found just inside the opening of the vagina -- one on each side. These glands produce a mucus-like fluid that acts as a lubricant during sex.

At the front of the vagina, the labia minora meet to form a fold or small hood of skin called the prepuce. The clitoris is beneath the prepuce. The clitoris is an approximately ¾-inch structure of highly sensitive tissue that becomes swollen with blood during sexual stimulation. The labia minora also meet at a place just beneath the vaginal opening, at the fourchette. Beyond the fourchette is the anus, the opening to the rectum. The space between the vagina and the anus is called the perineum.

Cancer of the vulva (also known as vulvar cancer) most often affects the inner edges of the labia majora or the labia minora. Cancer occurs on the clitoris or in the Bartholin glands less often.  

What are the risk factors?

A risk factor is anything that changes a person's chance of getting a disease such as cancer. Different cancers have different risk factors. For example, exposing skin to strong sunlight is a risk factor for skin cancer. Smoking is a risk factor for many cancers. But risk factors don't tell us everything. Cancers often occur in patients without risk factors. Also, having a risk factor, or even several, doesn't mean that you will get the disease.

Although several risk factors increase the odds of developing vulvar cancer, most women with these risks do not develop it. And some women without any apparent risk factors develop vulvar cancer. When a woman develops vulvar cancer, it is usually not possible to say with certainty that a particular risk factor was the cause.

• Age
• Human papilloma virus
• Smoking
• Human immunodeficiency virus
• Vulvar intraepithelial neoplasia
• Lichen sclerosus
• Other genital cancers
• Melanoma or atypical moles

Do we know what causes vulva cancer?

Several risk factors for cancer of the vulva have been identified, and we are beginning to understand how these factors can cause cells in the vulva to become cancerous.

Researchers have made a lot of progress in understanding how certain changes in DNA can cause normal cells to become cancerous. DNA is the chemical that carries the instructions for nearly everything our cells do. We usually look like our parents because they are the source of our DNA. However, DNA affects more than our outward appearance. Some genes (parts of our DNA) contain instructions for controlling when our cells grow and divide.

Certain genes that promote cell division are called oncogenes. Others that slow down cell division or cause cells to die at the right time are called tumor suppressor genes. Cancers can be caused by DNA mutations (defects) that turn on oncogenes or turn off tumor suppressor genes. Usually DNA mutations related to cancers of the vulva occur during life rather than having been inherited before birth. Acquired mutations may result from cancer-causing chemicals in tobacco smoke. Sometimes they occur for no apparent reason.

Studies suggest that squamous cell cancer of the vulva (the most common type) can develop in at least 2 ways. In up to half of cases, human papilloma virus (HPV) infection appears to have an important role. Vulvar cancers associated with HPV infection seem to have certain distinctive features. They are often found along with several other areas of vulvar intraepithelial neoplasia (VIN). The women who have these cancers tend to be younger and are often smokers.

The second process by which vulvar cancers develop does not involve HPV infection. Vulvar cancers not linked to HPV infection usually are diagnosed in older women (over age 55). These women often have lichen sclerosis but rarely have VIN. DNA tests from vulvar cancers in older women rarely show HPV infection, but often show mutations of the p53 tumor suppressor gene. The p53 gene is important in preventing cells from becoming cancerous. When this gene has undergone mutation, it is easier for cancer to develop. Younger vulvar cancer patients with HPV infection rarely have p53 mutations.

These discoveries have not yet affected treatment. But, they may help in finding ways to prevent cancer of the vulva and at some point may lead to changes in treatment.

Because vulvar melanomas and adenocarcinomas are so rare, much less is known about how they develop.

Detecting pre-cancerous conditions

Pre-cancerous vulvar conditions that are not causing any symptoms can be found through regular gynecologic checkups. It is also important to see your health care provider if any problems come up between checkups. Symptoms such as vulvar itching, rashes, moles, or lumps that don't go away could be caused by vulvar pre-cancer and should be checked out. If VIN is found, treating it may help prevent invasive squamous cell vulvar cancer. Also, some vulvar melanomas can be prevented by removing atypical moles.

Examination of the vulva is done at the same time a woman has a Pap test and pelvic examination. The Pap test is not used to screen for vulvar cancer. The purpose of the Pap test is to find cervical cancers and pre-cancers early. The American Cancer Society recommends these guidelines for the early detection of cervical cancer:

• All women should begin cervical cancer screening about 3 years after they start having sex (vaginal intercourse). A woman who waits until she is over 18 to have sex should start screening no later than age 21. Screening should be done every year with the regular Pap test. If the liquid-based Pap test is used, testing can be done every 2 years.
• Beginning at age 30, women who have had 3 normal Pap test results in a row may be screened less often -- every 2 to 3 years. Testing can be with either the conventional (regular) or liquid-based Pap test. Some women -- such as those exposed to diethylstilbestrol (DES) before birth, and those with a weakened immune system (from HIV infection, an organ transplant, chemotherapy, or chronic steroid use) -- should continue getting tested yearly.
• Another reasonable option for women over 30 is to get screened every 3 years (but not more frequently) with either the conventional or liquid-based Pap test, plus the HPV DNA test.
• Women 70 years of age or older who have had 3 or more normal Pap tests in a row and no abnormal Pap test results in the last 10 years may choose to stop having cervical cancer screening. Women with a history of cervical cancer, DES exposure before birth, HIV infection, or a weakened immune system should continue to have screening as long as they are in good health.
• Women who have had a total hysterectomy (removal of the uterus and cervix) may also choose to stop having cervical cancer screening, unless the surgery was done as a treatment for cervical cancer or pre-cancer. Women who have had a hysterectomy without removal of the cervix need to continue cervical cancer screening, and should continue to follow the guidelines above.

Self-examination of the vulva is also a way to find vulvar cancer early. You can become aware of any changes in the skin of your vulva by examining yourself monthly using a mirror. Look for any areas that are white, darkly pigmented, or red and irritated. You should also note any new growths, nodules, bumps, or ulcers (open sores). Report any of these to a doctor, since they could indicate vulvar cancers or pre-cancerous conditions.

Can vulvar cancer be found early?

Having pelvic exams and knowing any signs and symptoms of vulvar cancer greatly improve the chances of early detection and successful treatment. If you have any of the problems discussed in the next section, you should see a doctor. If the doctor finds anything abnormal during a pelvic examination, you may need more tests to figure out what is wrong. This may mean referral to a gynecologist (specialist in problems of the female genital system).

There is no standard screening for this disease other than routine physical examinations.