WHY ? CANCER SCREENING- Checking for cancer in people who have no symptoms is cancer screening .Can help doctors find and treat several type of cancers early, before they cause symptoms. Early detection is important because when abnormal tissue or cancer is found early, it may be easier to treat .By the time symptoms appear, cancer may have begun to spread and be harder to treat.
In Whom? - In Diseases where following principles can be followed like Disease should be important health problem in terms of frequency .Natural history of disease presents window of opportunity for early detection. Effective treatment should be available that favorably alters natural history of disease. Treatment should be more effective if initiated earlier than during the symptomatic stage .Suitable screening test - Cheap/Easily Available/Reproducible/Socially Acceptable
Caution!! Easier Said than Done due to False positive results - anxiety /unwanted additional tests False negative results - false reassurance, leading to delays in diagnosis
Over-diagnosis - cancer detected was slow growing and would not have harmed that person in his or her lifetime
Some screening tests may cause bleeding or other health problems – Sigmoidoscopy/Colonoscopy Cost burden on healthcare/ Radiation Exposure of some tests / Incidental Lesions
When? & How? - In cancers like Breast,Prostate,Colon and Cervix