On this page: The cervix | Cervical cell changes | What is cervical cancer? | What types are there? | How common is it? | What are the symptoms? | What are the causes and risk factors? | What is a screening test? | The HPV vaccine
The cervix is part of the female reproductive system. The female reproductive system also includes the uterus (womb), ovaries, fallopian tubes, vagina and vulva (the external genitals).
Also called the neck of the uterus, the cervix connects the uterus to the vagina. It has an outer surface (lining) that opens into the vagina and an inner surface that faces into the uterus.
The functions of the cervix include:
- producing moisture to lubricate the vagina, which keeps the vagina clean
- producing mucus that helps sperm travel up to the fallopian tube to fertilise an egg that has been released from the ovary
- holding a developing baby in the uterus during pregnancy
- widening to enable a baby to be born via the vagina.
The cervix is covered by two kinds of cells:
Flat, thin cells that are found on the outer surface of the part of the cervix that opens into the vagina (ectocervix). Cancer of the squamous cells is called squamous cell carcinoma.
Glandular cells or columnar cells
Column-shaped cells that are found on the inner surface of the cervix (cervical canal or endocervix). Cancer of the glandular cells is called adenocarcinoma.
The area where the squamous cells and glandular cells meet is called the transformation zone. This is where most cervical cancers start.
Cervical cell changes
Sometimes the squamous cells and glandular cells in the cervix start to change and no longer appear normal when they are examined under a microscope. These changes are called precancerous lesions. This means there is a lesion (area of abnormal tissue) that is not cancer but may lead to cancer.
Cervical cell changes may be found during a routine screening test.
For some women, these precancerous lesions will disappear without treatment. Other lesions can be treated before they develop into cervical cancer. Treatment may include large loop excision of the transformation zone, laser surgery, a cone biopsy or dilation and curettage. Only some women with precancerous changes of the cervix will develop cervical cancer.
There are different types of precancerous changes:
The cervical cells have changed slightly. The cells may return to normal by themselves or the changes may worsen. If a cell shows signs of atypia, it does not necessarily mean you have cervical cancer or will get cancer. Atypia can be caused by an infection, such as HPV (see below), or irritation.
The squamous cells of the cervix are abnormal. This abnormality may be classified as low grade or high grade. Low-grade abnormalities usually disappear withouttreatment. High-grade abnormalities are precancerous. Although they do not usually cause symptoms, high-grade abnormalities in the cervix have the potential to progress to early cervical cancer over about 10–15 years if they are not detected and treated.
The glandular cells of the cervix are abnormal. These abnormalities always require further testing, as they may be either precancerous or cancerous.
If the results from a screening test show that your cervix has any of the abnormal changes described above, your doctor will recommend one of the following options depending on the grade of the changes:
- another screening test in 6–12 months to monitor the cells
- a biopsy to look at the cells in more detail using an instrument called a colposcope
- immediate treatment.
Squamous abnormalities and CIN
Squamous abnormalities are also called cervical intraepithelial neoplasia (CIN). They are graded according to how deep the abnormal cells are within the surface of the cervix. This is detected by taking a sample of tissue (biopsy) from the surface of the cervix. Early changes are graded as CIN 1, and they will usually disappear without treatment. Further abnormal changes are graded as CIN 2 or CIN 3 and will require treatment.
What is cervical cancer?
Cervical cancer is the growth of abnormal cells in the lining of the cervix.
Cancer most commonly begins in the area of the cervix called the transformation zone (see above), but it may spread to tissues around the cervix, such as the vagina, or to other parts of the body, such as the lungs or liver.
What types are there?
There are two main types of cervical cancer, which are named after the cells they start in:
Squamous cell carcinoma
The most common type, accounting for about 70% of cases.
A less common type, starting in the glandular cells of the cervix. Adenocarcinoma is more difficult to diagnose because it occurs higher up in the cervix and is harder to reach with the instruments a doctor uses during a screening test.
A small number of cervical cancers feature both squamous cells and glandular cells. These cancers are known as adenosquamous carcinomas or mixed carcinomas.
Other rarer types of cancer that can start in the cervix include small cell carcinoma and cervical sarcoma.
How common is it?
About 800 women in Australia are diagnosed with cervical cancer every year. Cervical cancer accounts for about 1.5% of all cancers diagnosed in women.
The incidence of cervical cancer in Australia has decreased significantly since a national screening program was introduced in the 1990s.
What are the symptoms?
In its early stages, cervical cancer usually has no symptoms. The only way to know if there are abnormal cells in the cervix, which may develop into cervical cancer, is to have a screening test.
If symptoms are present, they usually include:
- vaginal bleeding between periods, after menopause or after sexual intercourse
- pain during sexual intercourse
- an unusual vaginal discharge
- heavier periods or periods that last longer than usual
- excessive tiredness
- leg pain or swelling
- lower back pain.
These symptoms can also be caused by other conditions. See your general practitioner (GP) if you are worried or the symptoms are ongoing.
What are the causes and risk-factors?
Most cases of cervical cancer are caused by an infection called human papillomavirus (HPV). There are also other known risk factors (see below).
Human papillomavirus is the name for a group of viruses. HPV is a common infection that affects the surface of different areas of the body, such as the cervix, vagina and skin.
There are more than 100 different types of HPV, including more than 40 types of genital HPV. Some types of HPV cause common warts on the hands and feet.
Genital HPV is usually spread via the skin during sexual contact. About four out of five people will become infected with genital HPV at some time in their lives. Most people will not be aware they have HPV as it is usually harmless and doesn’t cause symptoms.
In most women, the virus is cleared quickly by the immune system and no treatment is needed.
Only a few types of genital HPV cause cervical cancer. Screening tests are used to detect these types of HPV or the precancerous cell changes caused by the virus. See more information on screening tests below. There is also a vaccination against HPV.
Smoking and passive smoking
Chemicals in tobacco can damage the cells of the cervix, making cancer more likely to develop in women with HPV.
Weakened immune system
The immune system helps the body get rid of HPV. Women with a weakened immune system are at increased risk of cervical cancer. This includes women with HIV (the virus that causes AIDS) and women who take medicines that lower their immunity. Ask your doctor if this applies to you.
Taking an oral contraceptive (the pill)
Research has shown that women who have taken the pill for five years or more are at increased risk of developing cervical cancer. The reason for this is not clear. However, the risk is small and the pill can help protect against other types of cancer, such as uterine and ovarian cancers. Talk to your doctor if you are concerned.
Diethylstilbestrol (DES) exposure
DES is a synthetic (artificial) form of the female hormone oestrogen. DES was prescribed to pregnant women from the 1940s to the early 1970s to prevent miscarriage.
Studies have shown that the daughters of women who took DES have a small but increased risk of developing a rare type of cervical adenocarcinoma.
What is a screening test?
Screening tests help to detect cancer in people who don’t have any symptoms. The Pap test (also called a Pap smear) has been used as a screening test for cervical cancer in Australia for several decades.
However, scientific evidence has found that screening women for HPV – the virus that causes cervical cancer – is a more effective way of preventing cervical cancer. For this reason, in 2017, an HPV test will replace the Pap test as part of the National Cervical Screening Program.
The current program recommends two-yearly Pap tests for women aged 18–70 who are or have ever been sexually active. Under the new program, women aged 25–74 will be tested for HPV every five years.
During both the Pap test and HPV test, the doctor gently inserts an instrument called a speculum into the vagina to get a clear view of the cervix. The doctor uses a brush or spatula to remove some cells from the surface of the cervix. This can feel slightly uncomfortable, but it usually takes only a minute or two. The sample is placed onto a glass slide or put into a fluid and then sent to a laboratory for examination by a pathologist.
The results of the screening test are used to predict your level of risk for precancerous cell changes or cervical cancer. If the results show a higher risk, your GP may refer you to a specialist (gynaecologist) to discuss:
- whether you need further tests or treatment
- how you will be regularly monitored, including whether you will have another screening test immediately or more frequent screening tests in the future.
For more information about screening tests, call Cancer Council 13 11 20 or visit cervicalscreen.health.gov.au.
It is very important to continue having regular Pap tests every two years until the new HPV test is introduced in 2017.
The HPV vaccine
The HPV vaccine provides protection against two strains of HPV that are known to cause 70–80% of cervical cancers. The vaccine also offers some protection against other less common cancers in women, including vaginal, vulvar and anal cancers.
As part of the National HPV Vaccination Program, the vaccine is free for girls and boys aged 12–13 (the vaccine helps to protect males against penile and anal cancers).
Some older people who are already sexually active may still benefit from the HPV vaccine. Ask your GP for information.
The HPV vaccine cannot be given to treat precancerous changes or cervical cancer. It does not provide protection against all types of HPV, so it is important to continue having screening tests even if you’ve been vaccinated.
For more information, visit hpvvaccine.org.au.
Reviewed by: Dr Archana Rao, Gynaecological Oncologist, Royal Hospital for Women, NSW; Danielle Carpenter, Gynaecological Cancer Nurse Consultant, Gynaecology Unit, The Royal Women’s Hospital, VIC; Carmen Heathcote, 13 11 20 Consultant, Cancer Council Queensland, QLD; A/Prof Michael Jackson, Director, Radiation Oncology, Prince of Wales Hospital, NSW; Haley McNamara, Social Worker, Cancer Care Services, Metro North Hospital and Health Service, QLD; Isabelle Rousseau, Consumer.