Cancer screening

Cancer screening aims to detect cancer before symptoms appear. This may involve blood tests, urine tests, other tests, or medical imaging. The benefits of screening in terms of cancer prevention, early detection and subsequent treatment must be weighed against any harms.

Universal screening, mass screening or population screening involves screening everyone, usually within a specific age group.Selective screening identifies people who are known to be at higher risk of developing cancer, such as people with a family history of cancer.

Screening can lead to false positive results and subsequent invasive procedures. Screening can also lead to false negative results, where an existing cancer is missed. Controversy arises when it is not clear if the benefits of screening outweigh the risks of the screening procedure itself, and any follow-up diagnostic tests and treatments.

Screening tests must be effective, safe, well-tolerated with acceptably low rates of false positive and false negative results. If signs of cancer are detected, more definitive and invasive follow-up tests are performed to reach a diagnosis. Screening for cancer can lead to cancer prevention and earlier diagnosis. Early diagnosis may lead to higher rates of successful treatment and extended life. However, it may also falsely appear to increase the time to death through lead time bias or length time bias.

The goal of cancer screening is to provide useful health information which can guide medical treatment. A good cancer screening is one which would detect when a person has cancer so that the person could seek treatment to protect their health. Good cancer screening would not be more likely to cause harm than to provide useful information. In general, cancer screening has risks and should not be done except with a medical indication.

Different kinds of cancer screening procedures have different risks, but good tests share some characteristics. If a test detects cancer, then that test result should also lead to options for treatment. Good tests come with a patient explanation of why that person has high enough risk of cancer to justify the test. Part of the testing experience is for the health care provider to explain how common false positive results are so that the patient can understand the context of their results. If multiple tests are available, then any test should be presented along with other options.

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Wikipedia