The cervix is at the lower part of the uterus (womb), which extends into the vagina. The cervix is sometimes called the neck of the womb. There is a small opening in the cervix, the cervical canal, which leads through the cervix into the main part of the uterus.
The cervix has several important functions. It produces some of the moistness that helps lubricate the vagina. It also produces the mucus that helps sperm travel up to the fallopian tubes to fertilise an egg from the ovary. The cervix holds the baby in the uterus during a pregnancy. During labour the cervix opens to allow the baby to be born.
Pap tests and dysplasia
Cervical cancer develops in stages. Pap tests are useful because they can detect abnormal cell changes that may one day become cancerous. Early detection means they can be treated before cancer happens. These changes are known as dysplasia. Pap tests are not designed to pick up cancer, although they sometimes do.
A Pap test checks for abnormal cell changes in the cervix at the top of the vagina. It is a screening test to find early warning signs that cancer might develop in the future. If abnormal cell changes are found, your doctor may advise further tests to see if treatment is needed.
The Pap test is quick and simple. The doctor or nurse gently inserts an instrument called a speculum into the vagina. This allows the cervix to be clearly seen. A small sample of cells are taken from the cervix and placed on to a glass slide. The slide is then sent to laboratory, where it is examined under a microscope.
The result usually comes back to your doctor or nurse within two weeks. Ask when you should contact your doctor to find out your result.
You may bleed a little after a Pap test.
Regular Pap tests can find most cell changes that could become cancerous if not detected and treated. It is advised that women have a Pap test once every two years. Women who have had abnormal cell changes may need to have more frequent Pap tests for a period of time. Visit PapScreen Victoria for more information about Pap tests.
Dysplasia means abnormal changes in the cells of the cervix. Abnormal cell changes are grouped as:
- Low-grade squamous intraepithelial lesions (LSIL). These are minor changes that normally go away within 12 months.
- High-grade squamous intraepithelial lesions (HSIL). These are more serious changes that require further tests and sometimes treatment.
Doctors may call abnormal cell changes ‘cervical intraepithelial neoplasia (CIN)'. CIN is graded into CIN I, CIN II and CIN III: that is, mild, moderate and severe cervical cell changes. These are not cancer but could develop into cancer if not treated.
Sometimes the term ‘carcinoma in situ' is used to describe abnormal cell changes in the cervix. These changes are high-grade (serious) and need further tests.
There are two main types of cervical cancer, named after the type of cell they start in. Squamous cell carcinoma, the most common type of cervical cancer, starts in the squamous or skin-like cells that cover the outer surface of the cervix at the top of the vagina. Adenocarcinoma is a less common type of cervical cancer. It starts in the glandular cells, in the cervical canal.
In addition, cervical cancer may be microinvasive or invasive.
Microinvasive cervical cancer
This is when cancer cells have just broken through the bottom layer of the skin of the cervix. At this stage, the cells have not spread more than 5mm into the tissues of the cervix.
Invasive cervical cancer
This is when cancer cells have spread from the surface skin of the cervix into the deeper tissues of the cervix. The cancer may also have spread to part of the vagina or to the lymph nodes and other tissues around the cervix, within the pelvis, or beyond the genital and pelvic areas into nearby organs.
How common is cervical cancer?
In Victoria about 150 women are diagnosed with cervical cancer each year.
Cervical cancer takes a long time to develop. This is one reason why it is more common in women over the age of 40. However, cervical sometimes develops very quickly and is sometimes diagnosed in younger women.
Causes of cervical cancer
Some factors seem to put some women at a higher risk of cervical cancer. These risk factors include:
- Human papilloma virus (HPV): almost everyone is infected with HPV at some stage in their life. Most cases of HPV resolve without treatment and have no ill effects. Most women who have HPV don't ever show signs of abnormal cell changes. However, in some women it can cause cell changes that lead to dysplasia. If untreated, these changes may become cancer. HPV is the cause of almost all cases of cervical cancer. There is a vaccine that prevents the types of HPV most commonly linked to cervical cancer. The vaccine is most effective if given to young girls before they are exposed to HPV, that is, before they start having sex. Through the government-funded National Immunisation Program, most girls will receive the vaccine at around the age of 12.
- Being the daughter of a woman who used the drug diethylstilboestrol (DES) during pregnancy. DES was used to prevent a miscarriage. Its use has declined since the 1940s and 1950s. DES has been linked to a rare type of cervical cancer in a small number of daughters of women who took DES while pregnant.
- Smoking, which increases the risk of cervical cancer, especially in women who have had a persistent infection with a high-risk HPV type.
For information or cancer support call 13 11 20.
For more information, see the Cancer Council of Victoria Website (see the link below).