Screening for prevention and early diagnosis of cancer.

The poor outcomes for cancers diagnosed at an advanced stage have been the driver behind research into techniques to detect disease before symptoms are manifest. For cervical and colorectal cancer, detection and treatment of "precancers" can prevent the development of cancer, a form of primary prevention. For other cancers-breast, prostate, lung, and ovarian-screening is a form of secondary prevention, aiming to improve outcomes through earlier diagnosis. International and national expert organizations regularly assess the balance of benefits and harms of screening technologies, issuing clinical guidelines for population-wide implementation. Psychological research has made important contributions to this process, assessing the psychological costs and benefits of possible screening outcomes (e.g., the impact of false positive results) and public tolerance of overdiagnosis. Cervical, colorectal, and breast screening are currently recommended, and prostate, lung, and ovarian screening are under active review. Once technologies and guidelines are in place, delivery of screening is implemented according to the health care system of the country, with invitation systems and provider recommendations playing a key role. Behavioral scientists can then investigate how individuals make screening decisions, assessing the impact of knowledge, perceived cancer risk, worry, and normative beliefs about screening, and this information can be used to develop strategies to promote screening uptake. This article describes current cancer screening options, discusses behavioral research designed to reduce underscreening and minimize inequalities, and considers the issues that are being raised by informed decision making and the development of risk-stratified approaches to screening.