Cervical cancer begins when abnormal cells in the lining of the cervix grow uncontrollably. Anyone with a cervix can get cervical cancer – women, transgender men and intersex people.
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)
- Glandular cells – column-shaped cells that cover the inner surface of the cervix (cervical canal or endocervix).
The area where the squamous cells and glandular cells meet is known as the transformation zone. This is where most cervical cancers start. The cancer 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.
About 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 and:
- 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.
How common is cervical cancer?
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.
Learn more about cervical cancer statistics and trends
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 and are 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.
Precancerous cervical cell changes usually have no symptoms. The only way to know if there are abnormal cells in the cervix that may develop into cancer is to have a cervical screening test. If symptoms occur, they usually include:
- vaginal bleeding between periods, after menopause, or during or after sexual intercourse
- pelvic pain
- pain during sexual intercourse
- a change to your usual vaginal discharge, e.g. there may be more discharge or it may have a strong or unusual smell or colour
- heavier periods or periods that last longer than usual.
Any of these symptoms can happen for other reasons, but it is best to rule out cervical cancer. See your doctor if you are worried or the symptoms are ongoing. This is important for anyone with a cervix, whether straight, lesbian, gay, bisexual, transgender or intersex, even if you are up to date with cervical screening tests.
What are precancerous cervical cell changes?
Sometimes the squamous cells and glandular cells in the cervix start to change. They no longer appear normal when they are viewed under a microscope. These early cervical cell changes may be precancerous. This means there is an area of abnormal tissue (a lesion) that is not cancer, but may lead to cancer.
Some women with precancerous changes of the cervix will develop cervical cancer, so it is important to investigate any changes. Finding and treating precancerous cervical cell changes will prevent them developing into cervical cancer.
How precancerous cell changes start
Precancerous cervical cell changes are caused by some types of the human papillomavirus (HPV). HPV and cervical cell changes don’t cause symptoms but can be found during a routine cervical screening test.
Types of cervical cell changes
Abnormal squamous cells – these are called squamous intraepithelial lesions (SIL). They can be classified as either low grade (LSIL) or high grade (HSIL). LSIL usually disappear without treatment, while HSIL are precancerous. High-grade abnormalities have the potential to develop into early cervical cancer over 10–15 years if they are not found and treated.
Abnormal glandular cells – these can be either low grade or high grade. High grade changes are called adenocarcinoma in situ (AIS or ACIS). They will need treatment to reduce the chance they develop into adenocarcinoma.
Human papillomavirus (HPV)
Almost all cases of cervical cancer are caused by a common infection called human papillomavirus (HPV), 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. The virus is mostly 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.
13 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. There is also a vaccine that protects people from some types of HPV.
What is the cervical screening test?
Screening is organised testing to find cancer in people before any symptoms appear. The cervical screening test finds cancer-causing types of HPV in a sample of cells taken from the cervix. This test replaced the Pap test in 2017.
The National Cervical Screening Program recommends that women start cervical screening at age 25 and then have a cervical screening test every five years up to the age of 74.
If you have a cervix you need to have regular cervical screening tests. If the results show:
- a higher risk – your GP will refer you for a colposcopy
- an intermediate risk – you will be monitored for changes by having a follow-up test for HPV in 12 months
- a low risk – you will be due for your next cervical screening test in five years.
- 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.
Your GP will arrange the first tests to assess your symptoms. If these tests do not rule out cancer, you will usually be referred to a specialist, such as a gynaecologist or gynaecological oncologist, who will arrange further tests.
If cervical cancer is diagnosed, the specialist will consider treatment options. Often these will be discussed with other health professionals who specialise in different aspects of your care, including an oncologist, dietician and physiotherapist, at what is known as a multidisciplinary team (MDT) meeting.
Understanding Cervical Cancer
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Expert content reviewers:
Dr Pearly Khaw, Lead Radiation Oncologist, Gynae-Tumour Stream, Peter MacCallum Cancer Centre, VIC; Dr Deborah Neesham, Gynaecological Oncologist, The Royal Women’s Hospital and Frances Perry House, VIC; Kate Barber, 13 11 20 Consultant, VIC; Dr Alison Davis, Medical Oncologist, Canberra Hospital, ACT; Krystle Drewitt, Consumer; Shannon Philp, Nurse Practitioner, Gynaecological Oncology, Chris O’Brien Lifehouse and The University of Sydney Susan Wakil School of Nursing and Midwifery, NSW; Dr Robyn Sayer, Gynaecological Oncologist Cancer Surgeon, Chris O’Brien Lifehouse, NSW; Megan Smith, Senior Research Fellow, Cancer Council NSW; Melissa Whalen, Consumer.
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The information on this webpage was adapted from Understanding Cervical Cancer - A guide for people with cancer, their families and friends (2021 edition). This webpage was last updated in October 2021.