About cervical cancer

Cervical cancer begins when abnormal cells in the lining of the cervix grow uncontrollably.

Cancer most commonly starts in the area of the cervix called the transformation zone. It may then spread to tissues around the cervix, such as the vagina, or to other parts of the body, such as the lymph nodes, lungs or liver.

Learn more about:

• The cervix
• Types of cervical cancer
• Who gets cervical cancer?
• What causes cervical cancer?
• National HPV vaccination program
• What are the risk factors?

The cervix

The cervix is part of the female reproductive system, which also includes the ovaries, fallopian tubes, uterus (womb), vagina (birth canal) and vulva (external genitals).

The cervix connects the uterus to the vagina. The cervix:

• produces fluid to help keep the vagina healthy
• opens to let menstrual blood pass from the uterus into the vagina
• produces mucus that helps sperm travel up the uterus and fallopian tubes to fertilise an egg that has been released from the ovary
• holds a developing baby in the uterus during pregnancy by remaining closed, then widens to let a baby be born through the vagina.

Where cervical cancer starts

The cervix has an outer surface that opens into the vagina (ectocervix) and an inner surface that lines the cervical canal (endocervix). These surfaces are covered by two types of cells:

Squamous cells – flat, thin cells that cover the outer surface of the cervix (ectocervix). Cancer of the squamous cells is called squamous cell carcinoma.

Glandular cells – column-shaped cells that cover 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 known as the transformation zone. This is where most cervical cancers start.

The female reproductive system

Types of cervical cancer

There are two main types of cervical cancer, which are named after the cells they start in:

Squamous cell carcinoma (SCC) – the most common type (about 70% of cases), starts in the squamous cells of the cervix.

Adenocarcinoma – a less common type (about 25% of cases), starts in the glandular cells of the cervix. Adenocarcinoma is more difficult to diagnose because it occurs higher up in the cervix and the abnormal glandular cells are harder to find.

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, clear cell adenocarcinoma and cervical sarcoma.

Who gets cervical cancer?

Anyone with a cervix can get cervical cancer – women, transgender men and intersex people. Each year about 910 Australian women are diagnosed with cervical cancer. Cervical cancer is most commonly diagnosed in women over 30, but it can occur at any age.

Diagnoses of cervical cancer in Australia have reduced significantly since a national screening program was introduced in the 1990s. The introduction of a national HPV vaccination program in 2007 and improvements to the screening program in 2017 are expected to further reduce rates of cervical cancer.

What causes cervical cancer?

Almost all cases of cervical cancer are caused by an infection called human papillomavirus (HPV). Read more about other known risk factors.

Infection with HPV

HPV is the name for a group of viruses. It 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 over 40 types that affect the genitals. Genital HPV is usually spread during close contact with genital skin during sexual activity. This includes penetrative sex as well as oral sex. Using condoms or dental dams offers some protection against HPV.

About four out of five people will become infected with at least one type of genital HPV at some time in their lives. Some other types of HPV cause common warts on the hands and feet.

Most people will not know they have HPV as it doesn’t cause symptoms. In most people, the virus is cleared quickly by the immune system and no treatment is needed. If the infection doesn’t go away, there’s an increased risk of developing changes in the cervix. These changes usually develop slowly over many years.

Thirteen types of genital HPV are known to cause cervical cancer. Screening tests are used to detect most of these types of HPV or the precancerous cell changes caused by the virus. For more on this see screening. There is also a vaccine (see below) that protects people from some types of HPV.

What are the risk factors?

Smoking and passive smoking – Chemicals in tobacco can damage the cells of the cervix, making cancer more likely to develop in people with HPV.

Using oral contraceptives (the pill) for a long time – Research has shown that taking the pill for five years or more increases the risk of developing cervical cancer in people with HPV. The reason for this is not clear. However, the risk is small and the pill can also help protect against other types of cancer, such as uterine and ovarian cancers. Talk to your doctor if you are concerned.

Having a weakened immune system – The immune system helps rid the body of HPV. Women with a weakened immune system have an increased risk of developing cervical cancer and need to have more frequent cervical screening tests. This includes women with the human immunodeficiency virus (HIV) and women who take medicines that lower their immunity.

Exposure to diethylstilbestrol (DES) – This is a manufactured form of the hormone oestrogen. DES was prescribed to pregnant women from the 1940s to the early 1970s to prevent miscarriage. Studies have shown that women exposed to DES because their mother took DES when pregnant have a small but increased risk of developing clear cell adenocarcinoma, a rare type of cervical cancer.