ABSTRACT
Screening diers from the treatment of cancer in fundamental ways. While screening for some types of cancer clearly causes more good than harm, at a reasonable cost, screening can also harm healthy individuals, people that would not have been aected by the disease in the absence of screening. A balanced, evidence-based view is required, which is complex, as screening data are subject to a range of inherent biases which may make interpretation of benets and harms dicult.
