What is cancer screening?

Cancer screening involves testing large groups of healthy people for early signs of certain types of cancer. This can help doctors find any abnormal changes before you develop symptoms.

Screening tests can help to detect cancer early by picking up warning signs, but they aren't enough to diagnose the disease by themselves. If someone gets a positive result in a screening test, they are usually invited for further diagnostic tests to confirm if they have cancer.

There are three screening programmes in the UK:

Why screen for cancer?

• Screening can detect cancer at an early stage. For most cancers, early detection means that treatments are easier and have a higher chance of success.
• Some, but not all screening programmes can prevent cancer.
• The cervical and bowel cancer screening programmes can detect abnormal changes before they become a cancer. Treating early changes can prevent cancer from developing

Why don’t we screen for every cancer?

Screening programmes can only be set up for a particular cancer if we have a reliable enough test for it. For a test to be of value, it must:

• reliably detect any cancers or abnormal changes that could lead to cancer
• not cause too many false alarms, by saying that someone has cancer when they haven’t
• be acceptable, so that the people who would benefit will actually come and take the test
• not be dangerous to health
• be cost-effective