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Chapter 078. Prevention and Early Detection of Cancer (Part 6)

Cancer Screening Screening is a means of detecting disease early in asymptomatic individuals, with the goal of decreasing morbidity and mortality. While screening can potentially save lives and has been shown to do so in cervical, colon, and probably breast cancer, it is also subject to a number of biases that can suggest a benefit when actually there is none. Biases can even mask net harm. Early detection does not in itself confer benefit. To be of value, screening must detect disease earlier, and treatment of earlier disease must yield a better outcome than treatment at the onset of. | Chapter 078. Prevention and Early Detection of Cancer Part 6 Cancer Screening Screening is a means of detecting disease early in asymptomatic individuals with the goal of decreasing morbidity and mortality. While screening can potentially save lives and has been shown to do so in cervical colon and probably breast cancer it is also subject to a number of biases that can suggest a benefit when actually there is none. Biases can even mask net harm. Early detection does not in itself confer benefit. To be of value screening must detect disease earlier and treatment of earlier disease must yield a better outcome than treatment at the onset of symptoms. Cause-specific mortality rather than survival after diagnosis is the preferred endpoint see below . Because screening is done on asymptomatic healthy persons it should offer substantial likelihood of benefit that outweighs harm. Screening tests and their appropriate use should be carefully evaluated before their use is widely encouraged in screening programs as a matter of public policy. Screening examinations tests or procedures are usually not diagnostic of cancer but instead indicate that a cancer may be present. The diagnosis is then made following a workup that includes a biopsy and pathologic confirmation. A number of genes have been identified that predispose for a disease and many more will be identified in the near future. Testing for these genes can define a high-risk population. The ability to predict the development of a particular cancer may some day present therapeutic options as well as ethical dilemmas. It may eventually allow for early intervention to prevent a cancer or limit its severity. People at high risk may be ideal candidates for chemoprevention and screening however efficacy of these interventions in the high-risk population should be investigated. Currently persons at high risk for a particular cancer can engage in intensive screening. While this course is clinically prudent it is not known if