Understanding cancer screening
What is screening?
Cancer screening is meant for healthy people with no symptoms at all. If you have symptoms, you should tell your doctor.
Screening looks for early signs that could mean cancer is developing. It can help spot cancers at an early stage, when treatment is more likely to be successful and the chances of survival are much better. In some cases, it can even prevent cancers from developing at all, by picking up early changes that can then be treated to stop them turning into cancer. This is how cervical screening prevents cervical cancer.
Screening has harms as well as benefits so make sure you read the leaflet that comes with your invitation to help you decide.
Find out some key signs and symptoms of cancer
What screening programmes are available?
In the UK there are national screening programmes - for breast, cervical and bowel cancer.
Breast screening is offered to women aged 50-70 in all UK nations. In England there is a trial in some areas to see the effect of inviting women aged 47-73.
Cervical screening is offered to women aged 25-64 in the UK. It is offered every three years for women aged 25-49, and every five years for women 50-64.
Bowel screening is offered to men and women aged 60-74 in England, Wales and Northern Ireland. In Scotland, men and women aged 50-74 are offered screening. In England, another type of bowel screening called Bowel Scope is also starting to be offered to people at age 55.
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 NHS Choices.
What about people with a high family risk of cancer?
Some people may have a higher risk of certain cancers, perhaps because of a strong family history or certain medical conditions. Their doctor may recommend they have tests that are different to screening for the general population or have them more often.
What if I’m not eligible for screening?
If you are older than the age range for breast screening, or for bowel screening in England and Scotland, you can still be screened if you want. But you won’t get an automatic invitation. You can make your own breast screening appointment, or request a bowel screening kit. How to do this depends on your local area, but your GP surgery can tell you who to contact.
There are also lots of things you can do to reduce your risk of developing cancer in the first place.
Should I be screened?
Whether or not to go for screening is your choice. You will be sent information with your screening invitation about the benefits and harms of the test. You should read this information to help you make a decision, you can also ask your doctor if you have any questions.
Benefits of screening
Cancer screening saves thousands of lives each year.
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.
Some screening programmes can also prevent cancer. The cervical screening programme, as well as the new Bowel Scope test, can detect abnormal changes before they can turn into cancer. Treating these early changes can prevent cancer from developing in the first place.
Harms of screening
Screening is not perfect, and it can miss cancers. How often this happens varies for different types of screening test. That’s why it is still important to know your body and see your doctor about any unusual changes, even if you have had screening.
Screening can also mean people have to come back for more tests and then find out they don’t have cancer. This can make people anxious or worried unnecessarily.
Sometimes, screening can pick up cancers that grow so slowly that if they went undetected they wouldn’t cause a person any problems. People with these harmless cancers won’t have any symptoms, and they won’t die from the disease. When these slow-growing cancers are found they’re said to be overdiagnosed. Unfortunately, there’s currently no way of telling apart the cancers that need to be found and treated and the ones that could have been left alone. This means that some patients will receive an unnecessary diagnosis, unnecessary treatment, and the emotional and physical side effects they come with.
Sometimes, the tests themselves can have risks or side effects, like bleeding, pain, or infections.
Know your body
Screening programmes can save lives from cancer. But not all cancers can be screened for, and screening tests are not perfect.
Knowing your body and what’s normal for you can help you to notice any unusual changes that could be signs of cancer. Even if you have been screened or are going for screening soon, if you notice any unusual or persistent changes in your body, it’s is important that you go and see your doctor.
Why isn't screening available for all cancers?
Screening programmes can only be set up for a particular cancer type if it will save lives without harming too many people. For the current UK bowel, breast and cervical screening programmes there is evidence that benefits outweigh the harms.
There is no screening programme for prostate cancer because the PSA test is not reliable enough, but men over 50 can talk to their doctor about the test.