What is cancer screening?

Coronavirus and cancer

We know it’s a worrying time for people with cancer, we have information to help. If you have symptoms of cancer contact your doctor.

Read our information about coronavirus and cancer

  • Cancer screening is a test that looks for early signs of cancer in people without symptoms.
  • It can help spot cancers at an early stage, when treatment is more likely to be successful. Cervical screening can even prevent cancer from developing.
  • Cancer screening is for people with no symptoms at all. If you have symptoms, don’t wait for a screening invitation - tell your doctor as soon as possible.

What screening programmes are there in the UK?

There are 3 national screening programmes in the UK:

  • Bowel cancer screening is offered to people aged 60-74 in England, Wales and Northern Ireland. In Scotland people aged 50-74 are offered bowel cancer screening.
  • Breast cancer screening is offered to women, some transgender men and some non-binary people aged 50-70 in the UK.
  • Cervical screening is offered to women, some transgender men and some non-binary people aged 25-64 in the UK.

You will only be invited for screening if you are registered with a GP. If you aren’t registered, you can find a local GP on the NHS website. 

What are the pros and cons of cancer screening?

Cancer screening isn’t perfect. It has both possible benefits (pros) and risks (cons). That’s why it’s important to read the information that comes with your screening invitation.

The balance of pros and cons is different for each type of cancer screening. Understanding the possible benefits and risks of screening can help you decide whether you want to take part or not.

The main potential benefit of screening is saving lives from cancer:

  • Screening can detect cancer at an early stage. If cancer is picked up early, it means that treatment is more likely to work and more people survive.
  • Cervical screening can detect abnormal changes before they can turn into cancer. Treating these early changes can prevent cancer from developing in the first place.

There are 4 main risks to screening:

  • Screening can miss cancers (a ‘false negative’ result). That’s why it is still important to tell your doctor about any unusual changes, even if you have had screening recently.
  • Screening can also give people abnormal results when they don’t have cancer (a ‘false positive’ result). This can make people unnecessarily anxious or worried. It can mean people have follow-up tests that they don’t need, which may have side-effects.
  • Sometimes, screening can pick up cancers that wouldn’t cause a person any problems, even if they were never found (overdiagnosis). This is different from a false-positive result. People with these harmless cancers would never have any symptoms, so treatment is unnecessary.
  • Sometimes, the tests themselves can have risks or side effects. Although the side effects are uncommon, this might include pain, bleeding, or infections.

You can find out about how common the possible benefits and risks are in the information that comes with your screening invitation.

Should I be screened for cancer?

It is your choice whether or not to go for screening.

You will be sent information with your screening invitation about the possible benefits and risks of the test. You should read this information to help you make a decision, and ask your doctor if you have any questions.

We may all feel differently about the possible benefits and risks of screening. You should make the decision that is right for you.

Cancer screening is offered at ages when the benefits are biggest and the harms are smallest (read more about these in the pros and cons section above).

People who are younger than the screening age are usually at a lower risk of cancer. This means that for most of these people, the harms of screening would outweigh the benefits.

Normally, you can’t be screened for cancer before the age the programme starts. But if you have a family history of breast or bowel cancer, you might be at higher risk and be able to start screening earlier. Talk to your GP if you are worried about your family history of cancer.

If you are older than the age range for bowel screening in England and Scotland, or for breast screening anywhere in the UK, you can still be screened if you want. You won’t get an automatic invitation, but your GP surgery can tell you who to contact to ask for screening.

Whatever your age, it’s important to remember screening is for people without symptoms. If you notice anything unusual, tell your doctor right away.

If you aren’t due to be invited for screening, there are still lots of things you can do to reduce your risk of cancer. Find out what changes could make the biggest difference in your life. 

Screening programmes are only set up for a cancer type if they will save lives from the disease without too much risk. If there isn’t a good enough screening test, or screening would do more harm overall, then a screening programme isn’t introduced.

A screening programme needs to have a good enough test for it to work. This test must:

  • reliably find any cancers or abnormal changes that could lead to cancer
  • not cause too many false alarms
  • be acceptable, so that people will actually take the test
  • not be dangerous to health
  • be cost-effective.

If a test doesn’t do these things, it’s unlikely to work well in a screening programme for the whole population.

If a cancer is rare, screening everyone wouldn’t work, and it would be harder for the benefits to outweigh the harms across everyone taking part. If good screening tests are available for rarer cancers, doctors will often offer them to people who are at highest risk of the disease.

At the moment, there isn’t enough evidence to say that screening for any type of cancer other than breast, bowel, and cervical cancer would be a good idea.

Researchers are always looking for new screening tests and new ways to spot cancers early. There has been lots of research into prostate cancer screeninglung cancer screening and ovarian cancer screening. None of these cancer types have national screening programmes at the moment.

Public Health England. NHS Population Screening Explained. (2019) https://www.gov.uk/guidance/nhs-population-screening-explained

Public Health England. NHS Bowel Cancer Screening – Helping You Decide (2019)

Public Health England. NHS Breast Screening – Helping You Decide (2020)

Public Health England. NHS Cervical Screening – Helping You Decide (2020)

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