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Screening evidence

Reading screening research

A signal is the beginning of the question.

Three steps that often get collapsed into a single headline.

01

Detect a signal

Can the test find a biological signal associated with cancer?

Test performance
02

Confirm a diagnosis

What do scans, biopsies and other follow-up investigations find?

Diagnostic workup
03

Improve outcomes

Do fewer people die of cancer, with acceptable harms?

Long-term comparison
False positives can lead to extra investigations.Negative results can miss cancer.Earlier detection alone does not prove longer survival.
Conceptual diagram · PATHFINDER primary study NHS-Galleri trial results