What are the risk factors for cervical cancer?

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A risk factor is any factor that is associated with increasing someone’s chances of developing a certain condition, such as cancer. Some risk factors are modifiable, such as lifestyle or environmental risk factors. Others cannot be modified, such as inherited factors or whether someone in the family has had cancer.

Having one or more risk factors does not mean that a person will develop cancer. Many people have at least one risk factor but will never develop cancer, while others with cancer may have had no known risk factors. Even if a person with cancer has a risk factor, it is usually hard to know how much that risk factor contributed to the development of their disease.

Cervical cancer risk factors

Cervical cancer is not infectious. It is not caused by an inherited faulty gene, so other members of the family are not likely to be at risk of developing it.

Risk factors for cervical cancer are:

HPV infection

Nearly all cervical cancers are caused by a human papillomavirus (HPV) infection. Genital HPV is a common virus that is spread by genital skin-to-skin contact during sexual activity. It is so common that many people have it at some point in their lives and never know it as there are usually no symptoms.

There are many types of HPV and the body’s immune system will naturally clear most types within one to two years.

If the body’s immune system does not clear an HPV infection, it can cause changes to cells in the cervix, which in rare cases can develop into cervical cancer. It usually takes 10 to 15 years for HPV to develop into cervical cancer.

More than 100 types of HPV have been identified, and about a dozen of these are considered high risk because they can lead to cervical cancer. The HPV vaccine (also known as the ‘cervical cancer vaccine’) can protect against several types of HPV, including types that cause cancer.

The Cervical Screening Test has replaced the two-yearly Pap test and is more accurate at detecting HPV. The Pap test used to look for cell changes in the cervix, whereas the new Cervical Screening Test looks for HPV which can lead to cell changes in the cervix. For more information about HPV and cervical cancer, see About the National Cervical Screening Program.

Sexual history[1]

The risk of cervical cancer can be increased based on sexual history of chances of being exposed to HPV.

The risk of cervical cancer may be higher in people who:

•       become sexually active at a young age, especially younger than 18 years old

•       have many sexual partners

•       have a sexual partner who is considered high risk (i.e. someone who has an HPV infection or has many sexual partners).

Weakened immune system[2]

The immune system helps clear HPV infection. This means that people with a weakened immune system have a higher risk of developing cervical cancer.

People with a weakened immune system need to have cervical screening tests more often. This includes people with the human immunodeficiency virus (HIV) and those who take medicines that lower their immunity.

Chlamydia infection[2]

Chlamydia is a common type of bacteria that is spread by sexual contact. It can infect the reproductive system, causing pelvic inflammation that may lead to infertility. It usually causes no symptoms.

People who have past or current chlamydia infection may have a higher risk of cervical cancer. This is because the chlamydia bacteria may help HPV grow and survive in the cervix.

Smoking and passive smoking

Chemicals in tobacco may damage the cells of the cervix and make cancer more likely to develop.

Lack of regular Cervical Screening Tests

Cervical cancer is more common among people who don’t have regular Cervical Screening Tests.

All people with a cervix who have ever had sex should have a Cervical Screening Test every 5 years between the ages of 25 and 74. The Cervical Screening Test detects HPV which can lead to cell changes in the cervix. This means that precancerous cells can be removed or treated as early as possible, which reduces the risk of developing invasive cervical cancer.

Regular Cervical Screening Tests are important, even if you have been vaccinated against HPV.

Age

Cervical cancer mainly occurs in people over 35 years old and is less common in people under 25. Around 70% of cervical cancers are diagnosed in people under 60 years old.

Taking contraceptive pills for a long time

Using oral contraceptive pills (also called birth control pills, or the ‘pill’) for 5 or more years may increase the risk of cervical cancer in people who also have HPV infection. This risk decreases quickly if you stop using the pill. However, the pill can also help protect against other types of cancer, including uterine and ovarian cancers. If you are concerned, talk to your doctor.[3]

Screening abnormality or previous cancer

People who have HPV detected on the Cervical Screening Test are at higher risk of cervical abnormalities. The recommended management will either be a repeat screening test in 12 months or referral to a specialist for further assessment by colposcopy, depending on the type of HPV present. If abnormal cells are found during colposcopy, further treatment may be required. For more information about the Cervical Screening test results and treatment for abnormal cells, see Understanding your Cervical Screening Test results.

People who have had an abnormality on a previous Cervical Screening Test or Pap test should discuss their ongoing management with their doctor.

People who have been diagnosed with cervical cancer in the past are also at higher risk of developing cervical cancer again. Your doctor will discuss how to manage this risk with you.

Having many children

Studies suggest that giving birth to 3 or more children may slightly increase the risk of cervical cancer for people who have HPV infection. The risk is also higher in those who were younger than 20 years old when they had their first full-term pregnancy.[4]

Diethylstilboestrol

DES is a synthetic form of the female hormone oestrogen. It was used to prevent miscarriage and other complications of pregnancy, and was given to some pregnant women from 1939 to 1971.[5] DES is no longer given to pregnant women.

DES may increase the risk of a rare form of cervical cancer (and some other cancers of the reproductive system) in daughters who were exposed to this drug before they were born (i.e. if your mother took DES while she was pregnant with you).

If you were exposed to DES before you were born, you should have Cervical Screening Tests and colposcopic examination of the cervix and vagina every year, and discuss your risk of cervical cancer with your doctor.

For more information, see Cancer Australia’s webpage on DES.

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