Cancer screening: Theory and applications
The objective of screening is to reduce the public health burden from the target disease. For cancer, this means primarily prevention of cancer screening deaths. For some cancer types, a premalignant lesion can be detected by screening and treated, so that incidence of invasive cancer can be reduced. Before adopting a cancer screening program as a health-system wide policy, valid evidence of screening effectiveness in decreasing cancer mortality must be available from large population studies, ideally randomized screening trials.